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Reimplement huge pages without hugepd on powerpc (8xx, e500, book3s/64)

PATCH Superseded Christophe Leroy 4 participants 28 messages Jun 24, 2024 – Jul 2, 2024

Subsystems (22)

v6 of 7 Superseded Latest is v7 →

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v6 cover Reimplement huge pages without hugepd on powerpc (8xx, e500, book3s/64)

This series should have reached maturity for linux-next.

Also see https://github.com/linuxppc/issues/issues/483

Unlike most architectures, powerpc 8xx HW requires a two-level pagetable topology for all page sizes. So a leaf PMD-contig approach is not feasible as such.

Possible sizes on 8xx are 4k, 16k, 512k and 8M.

First level (PGD/PMD) covers 4M per entry. For 8M pages, two PMD entries must point to a single entry level-2 page table. Until now that was done using hugepd. This series changes it to use standard page tables where the entry is replicated 1024 times on each of the two pagetables refered by the two associated PMD entries for that 8M page.

For e500 and book3s/64 there are less constraints because it is not tied to the HW assisted tablewalk like on 8xx, so it is easier to use leaf PMDs (and PUDs).

On e500 the supported page sizes are 4M, 16M, 64M, 256M and 1G. All at PMD level on e500/32 (mpc85xx) and mix of PMD and PUD for e500/64. We encode page size with 4 available bits in PTE entries. On e300/32 PGD entries size is increases to 64 bits in order to allow leaf-PMD entries because PTE are 64 bits on e500.

On book3s/64 only the hash-4k mode is concerned. It supports 16M pages as cont-PMD and 16G pages as cont-PUD. In other modes (radix-4k, radix-6k and hash-64k) the sizes match with PMD and PUD sizes so that's just leaf entries. The hash processing make things a bit more complex. To ease things, __hash_page_huge() is modified to bail out when DIRTY or ACCESSED bits are missing, leaving it to mm core to fix it.

Global changes in v6:
- Unsquashed preliminary series from Michael so that everything gets merged together through mm
- In patch 3, removed the modification of pte-40x.h, because 40x is going away completely in another series. This has no impact.
- Added a WARN_ON_ONCE() in patch 21 as commented by Oscar.

Global changes in v5:
- Now use PAGE SIZE field in e500's PTE to store TSIZE instead of using U0-U3
- On e500/64, use highest bit to discriminate leaf entries because PUD entries are not garantied to be 4k aligned so PAGE SIZE field is not garantied to be 0 on a non-leaf entry.

Global changes in v4:
- Fixed a few issues reported privately by robots
- Rebased on top of v6.10-rc1

Global changes in v3:
- Removed patches 1 and 2
- Squashed patch 11 into patch 5
- Replaced patches 12 and 13 with a series from Michael
- Reordered patches a bit to have more general patches up front

For more details on changes, see in each patch.

Christophe Leroy (17):
mm: Define __pte_leaf_size() to also take a PMD entry
mm: Provide mm_struct and address to huge_ptep_get() powerpc/mm: Remove _PAGE_PSIZE
powerpc/mm: Fix __find_linux_pte() on 32 bits with PMD leaf entries powerpc/mm: Allow hugepages without hugepd
powerpc/8xx: Fix size given to set_huge_pte_at() powerpc/8xx: Rework support for 8M pages using contiguous PTE entries powerpc/8xx: Simplify struct mmu_psize_def
powerpc/e500: Remove enc and ind fields from struct mmu_psize_def powerpc/e500: Switch to 64 bits PGD on 85xx (32 bits) powerpc/e500: Encode hugepage size in PTE bits powerpc/e500: Don't pre-check write access on data TLB error powerpc/e500: Free r10 for FIND_PTE
powerpc/e500: Use contiguous PMD instead of hugepd powerpc/64s: Use contiguous PMD/PUD instead of HUGEPD powerpc/mm: Remove hugepd leftovers
mm: Remove CONFIG_ARCH_HAS_HUGEPD

Michael Ellerman (6):
powerpc/64e: Remove unused IBM HTW code powerpc/64e: Split out nohash Book3E 64-bit code powerpc/64e: Drop E500 ifdefs in 64-bit code powerpc/64e: Drop MMU_FTR_TYPE_FSL_E checks in 64-bit code powerpc/64e: Consolidate TLB miss handler patching powerpc/64e: Drop unused TLB miss handlers

 arch/arm/include/asm/hugetlb-3level.h         |   4 +-
 arch/arm64/include/asm/hugetlb.h              |   2 +-
 arch/arm64/mm/hugetlbpage.c                   |   2 +-
 arch/powerpc/Kconfig                          |   1 -
 arch/powerpc/include/asm/book3s/32/pgalloc.h  |   2 -
 arch/powerpc/include/asm/book3s/64/hash-4k.h  |  15 -
 arch/powerpc/include/asm/book3s/64/hash.h     |  40 +-
 arch/powerpc/include/asm/book3s/64/hugetlb.h  |  38 --
 .../include/asm/book3s/64/pgtable-4k.h        |  47 --
 .../include/asm/book3s/64/pgtable-64k.h       |  20 -
 arch/powerpc/include/asm/book3s/64/pgtable.h  |  22 +-
 arch/powerpc/include/asm/hugetlb.h            |  15 +-
 .../include/asm/nohash/32/hugetlb-8xx.h       |  38 +-
 arch/powerpc/include/asm/nohash/32/mmu-8xx.h  |   9 +-
 arch/powerpc/include/asm/nohash/32/pte-44x.h  |   3 -
 arch/powerpc/include/asm/nohash/32/pte-85xx.h |   3 -
 arch/powerpc/include/asm/nohash/32/pte-8xx.h  |  58 ++-
 .../powerpc/include/asm/nohash/hugetlb-e500.h |  39 +-
 arch/powerpc/include/asm/nohash/mmu-e500.h    |   6 +-
 arch/powerpc/include/asm/nohash/pgalloc.h     |   2 -
 arch/powerpc/include/asm/nohash/pgtable.h     |  46 +-
 arch/powerpc/include/asm/nohash/pte-e500.h    |  63 ++-
 arch/powerpc/include/asm/page.h               |  32 --
 arch/powerpc/include/asm/pgtable-be-types.h   |  10 -
 arch/powerpc/include/asm/pgtable-types.h      |  13 +-
 arch/powerpc/include/asm/pgtable.h            |   3 +
 arch/powerpc/kernel/exceptions-64e.S          |   4 +-
 arch/powerpc/kernel/head_85xx.S               |  70 +--
 arch/powerpc/kernel/head_8xx.S                |  10 +-
 arch/powerpc/kernel/setup_64.c                |   6 +-
 arch/powerpc/mm/book3s64/hash_utils.c         |  11 +-
 arch/powerpc/mm/book3s64/hugetlbpage.c        |  10 +
 arch/powerpc/mm/book3s64/pgtable.c            |  12 -
 arch/powerpc/mm/hugetlbpage.c                 | 455 +-----------------
 arch/powerpc/mm/init-common.c                 |   8 +-
 arch/powerpc/mm/kasan/8xx.c                   |  21 +-
 arch/powerpc/mm/nohash/8xx.c                  |  43 +-
 arch/powerpc/mm/nohash/Makefile               |   2 +-
 arch/powerpc/mm/nohash/book3e_pgtable.c       |   4 +-
 arch/powerpc/mm/nohash/tlb.c                  | 407 +---------------
 arch/powerpc/mm/nohash/tlb_64e.c              | 314 ++++++++++++
 arch/powerpc/mm/nohash/tlb_low_64e.S          | 428 +---------------
 arch/powerpc/mm/pgtable.c                     |  94 ++--
 arch/powerpc/mm/pgtable_32.c                  |   2 +-
 arch/riscv/include/asm/hugetlb.h              |   2 +-
 arch/riscv/mm/hugetlbpage.c                   |   2 +-
 arch/s390/include/asm/hugetlb.h               |   4 +-
 arch/s390/mm/hugetlbpage.c                    |   4 +-
 fs/hugetlbfs/inode.c                          |   2 +-
 fs/proc/task_mmu.c                            |  10 +-
 fs/userfaultfd.c                              |   2 +-
 include/asm-generic/hugetlb.h                 |   2 +-
 include/linux/hugetlb.h                       |   6 -
 include/linux/pgtable.h                       |   3 +
 include/linux/swapops.h                       |   4 +-
 kernel/events/core.c                          |   2 +-
 mm/Kconfig                                    |  10 -
 mm/damon/vaddr.c                              |   6 +-
 mm/gup.c                                      | 183 +------
 mm/hmm.c                                      |   2 +-
 mm/hugetlb.c                                  |  44 +-
 mm/memory-failure.c                           |   2 +-
 mm/mempolicy.c                                |   2 +-
 mm/migrate.c                                  |   4 +-
 mm/mincore.c                                  |   2 +-
 mm/pagewalk.c                                 |  57 +--
 mm/userfaultfd.c                              |   2 +-
 67 files changed, 751 insertions(+), 2040 deletions(-)
 delete mode 100644 arch/powerpc/include/asm/book3s/64/pgtable-4k.h
 create mode 100644 arch/powerpc/mm/nohash/tlb_64e.c
Signature · 1 line
2.44.0
#1 lore raw

PATCH v6 1/23 powerpc/64e: Remove unused IBM HTW code

From: Michael Ellerman <[email protected]>

The nohash HTW_IBM (Hardware Table Walk) code is unused since support for A2 was removed in commit fb5a515704d7 ("powerpc: Remove platforms/ wsp and associated pieces") (2014).

The remaining supported CPUs use either no HTW (data_tlb_miss_bolted), or the e6500 HTW (data_tlb_miss_e6500).

---
 arch/powerpc/include/asm/nohash/mmu-e500.h |   3 +-
 arch/powerpc/mm/nohash/tlb.c               |  57 +-----
 arch/powerpc/mm/nohash/tlb_low_64e.S       | 195 ---------------------
 3 files changed, 2 insertions(+), 253 deletions(-)
arch/powerpc/include/asm/nohash/mmu-e500.h +1 -2
index 6ddced0415cb..7dc24b8632d7 100644
@@ -303,8 +303,7 @@ extern unsigned long linear_map_top;
 extern int book3e_htw_mode;
 
 #define PPC_HTW_NONE	0
-#define PPC_HTW_IBM	1
-#define PPC_HTW_E6500	2
+#define PPC_HTW_E6500	1
 
 /*
  * 64-bit booke platforms don't load the tlb in the tlb miss handler code.
arch/powerpc/mm/nohash/tlb.c +1 -56

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arch/powerpc/mm/nohash/tlb_low_64e.S +0 -195

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Signature · 1 line
2.44.0
#2 lore raw

PATCH v6 2/23 powerpc/64e: Split out nohash Book3E 64-bit code

In reply to Christophe Leroy

From: Michael Ellerman <[email protected]>

A reasonable chunk of nohash/tlb.c is 64-bit only code, split it out into a separate file.

---
 arch/powerpc/mm/nohash/Makefile             |   2 +-
 arch/powerpc/mm/nohash/tlb.c                | 343 +-------------------
 arch/powerpc/mm/nohash/{tlb.c => tlb_64e.c} | 328 -------------------
 3 files changed, 2 insertions(+), 671 deletions(-)
 copy arch/powerpc/mm/nohash/{tlb.c => tlb_64e.c} (56%)
arch/powerpc/mm/nohash/Makefile +1 -1
index b3f0498dd42f..90e846f0c46c 100644
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-y				+= mmu_context.o tlb.o tlb_low.o kup.o
-obj-$(CONFIG_PPC_BOOK3E_64)  	+= tlb_low_64e.o book3e_pgtable.o
+obj-$(CONFIG_PPC_BOOK3E_64)  	+= tlb_64e.o tlb_low_64e.o book3e_pgtable.o
 obj-$(CONFIG_40x)		+= 40x.o
 obj-$(CONFIG_44x)		+= 44x.o
 obj-$(CONFIG_PPC_8xx)		+= 8xx.o
arch/powerpc/mm/nohash/tlb.c +1 -342

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arch/powerpc/mm/nohash/tlb_64e.c renamed from arch/powerpc/mm/nohash/tlb.c +0 -328

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Signature · 1 line
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#3 lore raw

PATCH v6 3/23 powerpc/64e: Drop E500 ifdefs in 64-bit code

In reply to Christophe Leroy

From: Michael Ellerman <[email protected]>

All 64-bit Book3E have E500=y, so drop the unneeded ifdefs.

---
 arch/powerpc/mm/nohash/tlb_64e.c | 12 ------------
 1 file changed, 12 deletions(-)
arch/powerpc/mm/nohash/tlb_64e.c +0 -12
index 7d5506d23eab..9db85ee9ba5b 100644
@@ -85,7 +85,6 @@ static void __init setup_page_sizes(void)
 	unsigned int eptcfg;
 	int psize;
 
-#ifdef CONFIG_PPC_E500
 	unsigned int mmucfg = mfspr(SPRN_MMUCFG);
 	int fsl_mmu = mmu_has_feature(MMU_FTR_TYPE_FSL_E);
 
@@ -151,7 +150,6 @@ static void __init setup_page_sizes(void)
 
 		goto out;
 	}
-#endif
 out:
 	/* Cleanup array and print summary */
 	pr_info("MMU: Supported page sizes\n");
@@ -180,13 +178,11 @@ static void __init setup_mmu_htw(void)
 	 */
 
 	switch (book3e_htw_mode) {
-#ifdef CONFIG_PPC_E500
 	case PPC_HTW_E6500:
 		extlb_level_exc = EX_TLB_SIZE;
 		patch_exception(0x1c0, exc_data_tlb_miss_e6500_book3e);
 		patch_exception(0x1e0, exc_instruction_tlb_miss_e6500_book3e);
 		break;
-#endif
 	}
 	pr_info("MMU: Book3E HW tablewalk %s\n",
 		book3e_htw_mode != PPC_HTW_NONE ? "enabled" : "not supported");
@@ -217,7 +213,6 @@ static void early_init_this_mmu(void)
 	}
 	mtspr(SPRN_MAS4, mas4);
 
-#ifdef CONFIG_PPC_E500
 	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {
 		unsigned int num_cams;
 		bool map = true;
@@ -238,7 +233,6 @@ static void early_init_this_mmu(void)
 			linear_map_top = map_mem_in_cams(linear_map_top,
 							 num_cams, false, true);
 	}
-#endif
 
 	/* A sync won't hurt us after mucking around with
 	 * the MMU configuration
@@ -270,7 +264,6 @@ static void __init early_init_mmu_global(void)
 	/* Look for HW tablewalk support */
 	setup_mmu_htw();
 
-#ifdef CONFIG_PPC_E500
 	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {
 		if (book3e_htw_mode == PPC_HTW_NONE) {
 			extlb_level_exc = EX_TLB_SIZE;
@@ -279,7 +272,6 @@ static void __init early_init_mmu_global(void)
 				exc_instruction_tlb_miss_bolted_book3e);
 		}
 	}
-#endif
 
 	/* Set the global containing the top of the linear mapping
 	 * for use by the TLB miss code
@@ -291,7 +283,6 @@ static void __init early_init_mmu_global(void)
 
 static void __init early_mmu_set_memory_limit(void)
 {
-#ifdef CONFIG_PPC_E500
 	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {
 		/*
 		 * Limit memory so we dont have linear faults.
@@ -302,7 +293,6 @@ static void __init early_mmu_set_memory_limit(void)
 		 */
 		memblock_enforce_memory_limit(linear_map_top);
 	}
-#endif
 
 	memblock_set_current_limit(linear_map_top);
 }
@@ -340,7 +330,6 @@ void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 	 * We crop it to the size of the first MEMBLOCK to
 	 * avoid going over total available memory just in case...
 	 */
-#ifdef CONFIG_PPC_E500
 	if (early_mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {
 		unsigned long linear_sz;
 		unsigned int num_cams;
@@ -353,7 +342,6 @@ void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 
 		ppc64_rma_size = min_t(u64, linear_sz, 0x40000000);
 	} else
-#endif
 		ppc64_rma_size = min_t(u64, first_memblock_size, 0x40000000);
 
 	/* Finally limit subsequent allocations */
Signature · 1 line
2.44.0
#4 lore raw

PATCH v6 4/23 powerpc/64e: Drop MMU_FTR_TYPE_FSL_E checks in 64-bit code

In reply to Christophe Leroy

From: Michael Ellerman <[email protected]>

All 64-bit Book3E have MMU_FTR_TYPE_FSL_E, since A2 was removed, so remove checks for it in 64-bit only code.

---
 arch/powerpc/kernel/setup_64.c   |  6 +-
 arch/powerpc/mm/nohash/tlb_64e.c | 97 ++++++++++++--------------------
 2 files changed, 38 insertions(+), 65 deletions(-)
arch/powerpc/kernel/setup_64.c +1 -5
index ae36a129789f..22f83fbbc762 100644
@@ -696,11 +696,7 @@ __init u64 ppc64_bolted_size(void)
 {
 #ifdef CONFIG_PPC_BOOK3E_64
 	/* Freescale BookE bolts the entire linear mapping */
-	/* XXX: BookE ppc64_rma_limit setup seems to disagree? */
-	if (early_mmu_has_feature(MMU_FTR_TYPE_FSL_E))
-		return linear_map_top;
-	/* Other BookE, we assume the first GB is bolted */
-	return 1ul << 30;
+	return linear_map_top;
 #else
 	/* BookS radix, does not take faults on linear mapping */
 	if (early_radix_enabled())
arch/powerpc/mm/nohash/tlb_64e.c +37 -60

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Signature · 1 line
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#5 lore raw

PATCH v6 5/23 powerpc/64e: Consolidate TLB miss handler patching

In reply to Christophe Leroy

From: Michael Ellerman <[email protected]>

The 64e TLB miss handler patching is done in setup_mmu_htw(), and then again immediately afterward in early_init_mmu_global(). Consolidate it into a single location.

---
 arch/powerpc/mm/nohash/tlb_64e.c | 38 +++++++++++++-------------------
 1 file changed, 15 insertions(+), 23 deletions(-)
arch/powerpc/mm/nohash/tlb_64e.c +15 -23
index 21c4b2442fcf..d83ecf466929 100644
@@ -169,24 +169,6 @@ static void __init setup_page_sizes(void)
 	}
 }
 
-static void __init setup_mmu_htw(void)
-{
-	/*
-	 * If we want to use HW tablewalk, enable it by patching the TLB miss
-	 * handlers to branch to the one dedicated to it.
-	 */
-
-	switch (book3e_htw_mode) {
-	case PPC_HTW_E6500:
-		extlb_level_exc = EX_TLB_SIZE;
-		patch_exception(0x1c0, exc_data_tlb_miss_e6500_book3e);
-		patch_exception(0x1e0, exc_instruction_tlb_miss_e6500_book3e);
-		break;
-	}
-	pr_info("MMU: Book3E HW tablewalk %s\n",
-		book3e_htw_mode != PPC_HTW_NONE ? "enabled" : "not supported");
-}
-
 /*
  * Early initialization of the MMU TLB code
  */
@@ -252,15 +234,25 @@ static void __init early_init_mmu_global(void)
 	/* Look for supported page sizes */
 	setup_page_sizes();
 
-	/* Look for HW tablewalk support */
-	setup_mmu_htw();
-
-	if (book3e_htw_mode == PPC_HTW_NONE) {
-		extlb_level_exc = EX_TLB_SIZE;
+	/*
+	 * If we want to use HW tablewalk, enable it by patching the TLB miss
+	 * handlers to branch to the one dedicated to it.
+	 */
+	extlb_level_exc = EX_TLB_SIZE;
+	switch (book3e_htw_mode) {
+	case PPC_HTW_E6500:
+		patch_exception(0x1c0, exc_data_tlb_miss_e6500_book3e);
+		patch_exception(0x1e0, exc_instruction_tlb_miss_e6500_book3e);
+		break;
+	case PPC_HTW_NONE:
 		patch_exception(0x1c0, exc_data_tlb_miss_bolted_book3e);
 		patch_exception(0x1e0, exc_instruction_tlb_miss_bolted_book3e);
+		break;
 	}
 
+	pr_info("MMU: Book3E HW tablewalk %s\n",
+		book3e_htw_mode != PPC_HTW_NONE ? "enabled" : "not supported");
+
 	/* Set the global containing the top of the linear mapping
 	 * for use by the TLB miss code
 	 */
Signature · 1 line
2.44.0
#6 lore raw

PATCH v6 6/23 powerpc/64e: Drop unused TLB miss handlers

In reply to Christophe Leroy

From: Michael Ellerman <[email protected]>

There are two possibilities for book3e_htw_mode, PPC_HTW_E6500 or PPC_HTW_NONE.

The TLB miss handlers are patched to use, respectively:
- exc_[data|indstruction]_tlb_miss_e6500_book3e
- exc_[data|indstruction]_tlb_miss_bolted_book3e

Which means the default handlers are never used. Remove those, and use the bolted handlers (PPC_HTW_NONE) by default.

---
 arch/powerpc/kernel/exceptions-64e.S |   4 +-
 arch/powerpc/mm/nohash/tlb_64e.c     |   4 -
 arch/powerpc/mm/nohash/tlb_low_64e.S | 226 ---------------------------
 3 files changed, 2 insertions(+), 232 deletions(-)
arch/powerpc/kernel/exceptions-64e.S +2 -2
index dcf0591ad3c2..63f6b9f513a4 100644
@@ -485,8 +485,8 @@ interrupt_base_book3e:					/* fake trap */
 	EXCEPTION_STUB(0x160, decrementer)		/* 0x0900 */
 	EXCEPTION_STUB(0x180, fixed_interval)		/* 0x0980 */
 	EXCEPTION_STUB(0x1a0, watchdog)			/* 0x09f0 */
-	EXCEPTION_STUB(0x1c0, data_tlb_miss)
-	EXCEPTION_STUB(0x1e0, instruction_tlb_miss)
+	EXCEPTION_STUB(0x1c0, data_tlb_miss_bolted)
+	EXCEPTION_STUB(0x1e0, instruction_tlb_miss_bolted)
 	EXCEPTION_STUB(0x200, altivec_unavailable)
 	EXCEPTION_STUB(0x220, altivec_assist)
 	EXCEPTION_STUB(0x260, perfmon)
arch/powerpc/mm/nohash/tlb_64e.c +0 -4
index d83ecf466929..053128a5636c 100644
@@ -244,10 +244,6 @@ static void __init early_init_mmu_global(void)
 		patch_exception(0x1c0, exc_data_tlb_miss_e6500_book3e);
 		patch_exception(0x1e0, exc_instruction_tlb_miss_e6500_book3e);
 		break;
-	case PPC_HTW_NONE:
-		patch_exception(0x1c0, exc_data_tlb_miss_bolted_book3e);
-		patch_exception(0x1e0, exc_instruction_tlb_miss_bolted_book3e);
-		break;
 	}
 
 	pr_info("MMU: Book3E HW tablewalk %s\n",
arch/powerpc/mm/nohash/tlb_low_64e.S +0 -226

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Signature · 1 line
2.44.0
#7 lore raw

PATCH v6 7/23 mm: Define __pte_leaf_size() to also take a PMD entry

In reply to Christophe Leroy

On powerpc 8xx, when a page is 8M size, the information is in the PMD entry. So allow architectures to provide __pte_leaf_size() instead of pte_leaf_size() and provide the PMD entry to that function.

When __pte_leaf_size() is not defined, define it as a pte_leaf_size() so that architectures not interested in the PMD arguments are not impacted.

Only define a default pte_leaf_size() when __pte_leaf_size() is not defined to make sure nobody adds new calls to pte_leaf_size() in the core.

---
v3: Don't change pte_leaf_size() to not impact other architectures

---
 include/linux/pgtable.h | 3 +++
 kernel/events/core.c    | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)
include/linux/pgtable.h +3 -0
index 18019f037bae..3080e7cde3de 100644
@@ -1888,9 +1888,12 @@ typedef unsigned int pgtbl_mod_mask;
 #ifndef pmd_leaf_size
 #define pmd_leaf_size(x) PMD_SIZE
 #endif
+#ifndef __pte_leaf_size
 #ifndef pte_leaf_size
 #define pte_leaf_size(x) PAGE_SIZE
 #endif
+#define __pte_leaf_size(x,y) pte_leaf_size(y)
+#endif
 
 /*
  * We always define pmd_pfn for all archs as it's used in lots of generic
kernel/events/core.c +1 -1
index 8f908f077935..b2ca11bdc11e 100644
@@ -7609,7 +7609,7 @@ static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
 
 	pte = ptep_get_lockless(ptep);
 	if (pte_present(pte))
-		size = pte_leaf_size(pte);
+		size = __pte_leaf_size(pmd, pte);
 	pte_unmap(ptep);
 #endif /* CONFIG_HAVE_GUP_FAST */
 
Signature · 1 line
2.44.0
#8 lore raw

PATCH v6 8/23 mm: Provide mm_struct and address to huge_ptep_get()

In reply to Christophe Leroy

On powerpc 8xx huge_ptep_get() will need to know whether the given ptep is a PTE entry or a PMD entry. This cannot be known with the PMD entry itself because there is no easy way to know it from the content of the entry.

So huge_ptep_get() will need to know either the size of the page or get the pmd.

In order to be consistent with huge_ptep_get_and_clear(), give mm and address to huge_ptep_get().

---
v2: Add missing changes in arch implementations
v3: Fixed a comment in ARM and missing changes in S390
v4: Fix missing or bad changes in mm/hugetlb.c and rebased on v6.10-rc1
v5: Fix vma->mm to vma->vm_mm

---
 arch/arm/include/asm/hugetlb-3level.h |  4 +--
 arch/arm64/include/asm/hugetlb.h      |  2 +-
 arch/arm64/mm/hugetlbpage.c           |  2 +-
 arch/riscv/include/asm/hugetlb.h      |  2 +-
 arch/riscv/mm/hugetlbpage.c           |  2 +-
 arch/s390/include/asm/hugetlb.h       |  4 +--
 arch/s390/mm/hugetlbpage.c            |  4 +--
 fs/hugetlbfs/inode.c                  |  2 +-
 fs/proc/task_mmu.c                    | 10 +++---
 fs/userfaultfd.c                      |  2 +-
 include/asm-generic/hugetlb.h         |  2 +-
 include/linux/swapops.h               |  4 +--
 mm/damon/vaddr.c                      |  6 ++--
 mm/gup.c                              |  2 +-
 mm/hmm.c                              |  2 +-
 mm/hugetlb.c                          | 44 +++++++++++++--------------
 mm/memory-failure.c                   |  2 +-
 mm/mempolicy.c                        |  2 +-
 mm/migrate.c                          |  4 +--
 mm/mincore.c                          |  2 +-
 mm/userfaultfd.c                      |  2 +-
 21 files changed, 53 insertions(+), 53 deletions(-)
arch/arm/include/asm/hugetlb-3level.h +2 -2
index a30be5505793..87d48e2d90ad 100644
@@ -13,12 +13,12 @@
 
 /*
  * If our huge pte is non-zero then mark the valid bit.
- * This allows pte_present(huge_ptep_get(ptep)) to return true for non-zero
+ * This allows pte_present(huge_ptep_get(mm,addr,ptep)) to return true for non-zero
  * ptes.
  * (The valid bit is automatically cleared by set_pte_at for PROT_NONE ptes).
  */
 #define __HAVE_ARCH_HUGE_PTEP_GET
-static inline pte_t huge_ptep_get(pte_t *ptep)
+static inline pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
 	pte_t retval = *ptep;
 	if (pte_val(retval))
arch/arm64/include/asm/hugetlb.h +1 -1
index 3954cbd2ff56..293f880865e8 100644
@@ -46,7 +46,7 @@ extern pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
 extern void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
 			   pte_t *ptep, unsigned long sz);
 #define __HAVE_ARCH_HUGE_PTEP_GET
-extern pte_t huge_ptep_get(pte_t *ptep);
+extern pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep);
 
 void __init arm64_hugetlb_cma_reserve(void);
 
arch/arm64/mm/hugetlbpage.c +1 -1
index 3f09ac73cce3..5f1e2103888b 100644
@@ -127,7 +127,7 @@ static inline int num_contig_ptes(unsigned long size, size_t *pgsize)
 	return contig_ptes;
 }
 
-pte_t huge_ptep_get(pte_t *ptep)
+pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
 	int ncontig, i;
 	size_t pgsize;
arch/riscv/include/asm/hugetlb.h +1 -1
index b1ce97a9dbfc..faf3624d8057 100644
@@ -44,7 +44,7 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 			       pte_t pte, int dirty);
 
 #define __HAVE_ARCH_HUGE_PTEP_GET
-pte_t huge_ptep_get(pte_t *ptep);
+pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep);
 
 pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags);
 #define arch_make_huge_pte arch_make_huge_pte
arch/riscv/mm/hugetlbpage.c +1 -1
index 0ebd968b33c9..42314f093922 100644
@@ -3,7 +3,7 @@
 #include <linux/err.h>
 
 #ifdef CONFIG_RISCV_ISA_SVNAPOT
-pte_t huge_ptep_get(pte_t *ptep)
+pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
 	unsigned long pte_num;
 	int i;
arch/s390/include/asm/hugetlb.h +2 -2
index ce5f4fe8be4d..cf1b5d6fb1a6 100644
@@ -19,7 +19,7 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 		     pte_t *ptep, pte_t pte, unsigned long sz);
 void __set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 		     pte_t *ptep, pte_t pte);
-pte_t huge_ptep_get(pte_t *ptep);
+pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep);
 pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 			      unsigned long addr, pte_t *ptep);
 
@@ -64,7 +64,7 @@ static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 					     unsigned long addr, pte_t *ptep,
 					     pte_t pte, int dirty)
 {
-	int changed = !pte_same(huge_ptep_get(ptep), pte);
+	int changed = !pte_same(huge_ptep_get(vma->vm_mm, addr, ptep), pte);
 	if (changed) {
 		huge_ptep_get_and_clear(vma->vm_mm, addr, ptep);
 		__set_huge_pte_at(vma->vm_mm, addr, ptep, pte);
arch/s390/mm/hugetlbpage.c +2 -2
index 2675aab4acc7..1be481672f4a 100644
@@ -169,7 +169,7 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 	__set_huge_pte_at(mm, addr, ptep, pte);
 }
 
-pte_t huge_ptep_get(pte_t *ptep)
+pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
 	return __rste_to_pte(pte_val(*ptep));
 }
@@ -177,7 +177,7 @@ pte_t huge_ptep_get(pte_t *ptep)
 pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 			      unsigned long addr, pte_t *ptep)
 {
-	pte_t pte = huge_ptep_get(ptep);
+	pte_t pte = huge_ptep_get(mm, addr, ptep);
 	pmd_t *pmdp = (pmd_t *) ptep;
 	pud_t *pudp = (pud_t *) ptep;
 
fs/hugetlbfs/inode.c +1 -1
index 412f295acebe..970c7e6fb144 100644
@@ -422,7 +422,7 @@ static bool hugetlb_vma_maps_page(struct vm_area_struct *vma,
 	if (!ptep)
 		return false;
 
-	pte = huge_ptep_get(ptep);
+	pte = huge_ptep_get(vma->vm_mm, addr, ptep);
 	if (huge_pte_none(pte) || !pte_present(pte))
 		return false;
 
fs/proc/task_mmu.c +5 -5
index f8d35f993fe5..a74c1e42da0c 100644
@@ -730,7 +730,7 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
 {
 	struct mem_size_stats *mss = walk->private;
 	struct vm_area_struct *vma = walk->vma;
-	pte_t ptent = huge_ptep_get(pte);
+	pte_t ptent = huge_ptep_get(walk->mm, addr, pte);
 	struct folio *folio = NULL;
 
 	if (pte_present(ptent)) {
@@ -1582,7 +1582,7 @@ static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
 	if (vma->vm_flags & VM_SOFTDIRTY)
 		flags |= PM_SOFT_DIRTY;
 
-	pte = huge_ptep_get(ptep);
+	pte = huge_ptep_get(walk->mm, addr, ptep);
 	if (pte_present(pte)) {
 		struct folio *folio = page_folio(pte_page(pte));
 
@@ -2271,7 +2271,7 @@ static int pagemap_scan_hugetlb_entry(pte_t *ptep, unsigned long hmask,
 	if (~p->arg.flags & PM_SCAN_WP_MATCHING) {
 		/* Go the short route when not write-protecting pages. */
 
-		pte = huge_ptep_get(ptep);
+		pte = huge_ptep_get(walk->mm, start, ptep);
 		categories = p->cur_vma_category | pagemap_hugetlb_category(pte);
 
 		if (!pagemap_scan_is_interesting_page(categories, p))
@@ -2283,7 +2283,7 @@ static int pagemap_scan_hugetlb_entry(pte_t *ptep, unsigned long hmask,
 	i_mmap_lock_write(vma->vm_file->f_mapping);
 	ptl = huge_pte_lock(hstate_vma(vma), vma->vm_mm, ptep);
 
-	pte = huge_ptep_get(ptep);
+	pte = huge_ptep_get(walk->mm, start, ptep);
 	categories = p->cur_vma_category | pagemap_hugetlb_category(pte);
 
 	if (!pagemap_scan_is_interesting_page(categories, p))
@@ -2679,7 +2679,7 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
 		unsigned long addr, unsigned long end, struct mm_walk *walk)
 {
-	pte_t huge_pte = huge_ptep_get(pte);
+	pte_t huge_pte = huge_ptep_get(walk->mm, addr, pte);
 	struct numa_maps *md;
 	struct page *page;
 
fs/userfaultfd.c +1 -1
index eee7320ab0b0..bafce25fd676 100644
@@ -257,7 +257,7 @@ static inline bool userfaultfd_huge_must_wait(struct userfaultfd_ctx *ctx,
 		goto out;
 
 	ret = false;
-	pte = huge_ptep_get(ptep);
+	pte = huge_ptep_get(vma->vm_mm, vmf->address, ptep);
 
 	/*
 	 * Lockless access: we're in a wait_event so it's ok if it
include/asm-generic/hugetlb.h +1 -1
index 6dcf4d576970..594d5905f615 100644
@@ -144,7 +144,7 @@ static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 #endif
 
 #ifndef __HAVE_ARCH_HUGE_PTEP_GET
-static inline pte_t huge_ptep_get(pte_t *ptep)
+static inline pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
 	return ptep_get(ptep);
 }
include/linux/swapops.h +2 -2
index a5c560a2f8c2..cb468e418ea1 100644
@@ -334,7 +334,7 @@ static inline bool is_migration_entry_dirty(swp_entry_t entry)
 
 extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
 					unsigned long address);
-extern void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte);
+extern void migration_entry_wait_huge(struct vm_area_struct *vma, unsigned long addr, pte_t *pte);
 #else  /* CONFIG_MIGRATION */
 static inline swp_entry_t make_readable_migration_entry(pgoff_t offset)
 {
@@ -359,7 +359,7 @@ static inline int is_migration_entry(swp_entry_t swp)
 static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
 					unsigned long address) { }
 static inline void migration_entry_wait_huge(struct vm_area_struct *vma,
-					pte_t *pte) { }
+					     unsigned long addr, pte_t *pte) { }
 static inline int is_writable_migration_entry(swp_entry_t entry)
 {
 	return 0;
mm/damon/vaddr.c +3 -3
index 381559e4a1fa..58829baf8b5d 100644
@@ -339,7 +339,7 @@ static void damon_hugetlb_mkold(pte_t *pte, struct mm_struct *mm,
 				struct vm_area_struct *vma, unsigned long addr)
 {
 	bool referenced = false;
-	pte_t entry = huge_ptep_get(pte);
+	pte_t entry = huge_ptep_get(mm, addr, pte);
 	struct folio *folio = pfn_folio(pte_pfn(entry));
 	unsigned long psize = huge_page_size(hstate_vma(vma));
 
@@ -373,7 +373,7 @@ static int damon_mkold_hugetlb_entry(pte_t *pte, unsigned long hmask,
 	pte_t entry;
 
 	ptl = huge_pte_lock(h, walk->mm, pte);
-	entry = huge_ptep_get(pte);
+	entry = huge_ptep_get(walk->mm, addr, pte);
 	if (!pte_present(entry))
 		goto out;
 
@@ -509,7 +509,7 @@ static int damon_young_hugetlb_entry(pte_t *pte, unsigned long hmask,
 	pte_t entry;
 
 	ptl = huge_pte_lock(h, walk->mm, pte);
-	entry = huge_ptep_get(pte);
+	entry = huge_ptep_get(walk->mm, addr, pte);
 	if (!pte_present(entry))
 		goto out;
 
mm/gup.c +1 -1
index ca0f5cedce9b..43491246f39d 100644
@@ -547,7 +547,7 @@ static int gup_hugepte(struct vm_area_struct *vma, pte_t *ptep, unsigned long sz
 	if (pte_end < end)
 		end = pte_end;
 
-	pte = huge_ptep_get(ptep);
+	pte = huge_ptep_get(vma->vm_mm, addr, ptep);
 
 	if (!pte_access_permitted(pte, flags & FOLL_WRITE))
 		return 0;
mm/hmm.c +1 -1
index 93aebd9cc130..7e0229ae4a5a 100644
@@ -480,7 +480,7 @@ static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask,
 	pte_t entry;
 
 	ptl = huge_pte_lock(hstate_vma(vma), walk->mm, pte);
-	entry = huge_ptep_get(pte);
+	entry = huge_ptep_get(walk->mm, addr, pte);
 
 	i = (start - range->start) >> PAGE_SHIFT;
 	pfn_req_flags = range->hmm_pfns[i];
mm/hugetlb.c +22 -22

173 lines not on this page · raw message

mm/memory-failure.c +1 -1
index d3c830e817e3..b8216b769784 100644
@@ -834,7 +834,7 @@ static int hwpoison_hugetlb_range(pte_t *ptep, unsigned long hmask,
 			    struct mm_walk *walk)
 {
 	struct hwpoison_walk *hwp = walk->private;
-	pte_t pte = huge_ptep_get(ptep);
+	pte_t pte = huge_ptep_get(walk->mm, addr, ptep);
 	struct hstate *h = hstate_vma(walk->vma);
 
 	return check_hwpoisoned_entry(pte, addr, huge_page_shift(h),
mm/mempolicy.c +1 -1
index aec756ae5637..b01bb1ebfee7 100644
@@ -624,7 +624,7 @@ static int queue_folios_hugetlb(pte_t *pte, unsigned long hmask,
 	pte_t entry;
 
 	ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte);
-	entry = huge_ptep_get(pte);
+	entry = huge_ptep_get(walk->mm, addr, pte);
 	if (!pte_present(entry)) {
 		if (unlikely(is_hugetlb_entry_migration(entry)))
 			qp->nr_failed++;
mm/migrate.c +2 -2
index 2cc5a68f6843..9e9ee1f2f813 100644
@@ -338,14 +338,14 @@ void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
  *
  * This function will release the vma lock before returning.
  */
-void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *ptep)
+void migration_entry_wait_huge(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
 {
 	spinlock_t *ptl = huge_pte_lockptr(hstate_vma(vma), vma->vm_mm, ptep);
 	pte_t pte;
 
 	hugetlb_vma_assert_locked(vma);
 	spin_lock(ptl);
-	pte = huge_ptep_get(ptep);
+	pte = huge_ptep_get(vma->vm_mm, addr, ptep);
 
 	if (unlikely(!is_hugetlb_entry_migration(pte))) {
 		spin_unlock(ptl);
mm/mincore.c +1 -1
index dad3622cc963..b5735a4aaa7d 100644
@@ -33,7 +33,7 @@ static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr,
 	 * Hugepages under user process are always in RAM and never
 	 * swapped out, but theoretically it needs to be checked.
 	 */
-	present = pte && !huge_pte_none_mostly(huge_ptep_get(pte));
+	present = pte && !huge_pte_none_mostly(huge_ptep_get(walk->mm, addr, pte));
 	for (; addr != end; vec++, addr += PAGE_SIZE)
 		*vec = present;
 	walk->private = vec;
mm/userfaultfd.c +1 -1
index defa5109cc62..8f1fd5af5909 100644
@@ -587,7 +587,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb(
 		}
 
 		if (!uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE) &&
-		    !huge_pte_none_mostly(huge_ptep_get(dst_pte))) {
+		    !huge_pte_none_mostly(huge_ptep_get(dst_mm, dst_addr, dst_pte))) {
 			err = -EEXIST;
 			hugetlb_vma_unlock_read(dst_vma);
 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
Signature · 1 line
2.44.0
#9 lore raw

PATCH v6 9/23 powerpc/mm: Remove _PAGE_PSIZE

In reply to Christophe Leroy

_PAGE_PSIZE macro is never used outside the place it is defined and is used only on 8xx and e500.

Remove indirection, remove it and use its content directly.

---
v6: Removed the change to pte-40x.h to avoid conflict with the removal of 40x

---
 arch/powerpc/include/asm/nohash/32/pte-44x.h  | 3 ---
 arch/powerpc/include/asm/nohash/32/pte-85xx.h | 3 ---
 arch/powerpc/include/asm/nohash/32/pte-8xx.h  | 5 ++---
 arch/powerpc/include/asm/nohash/pte-e500.h    | 4 +---
 4 files changed, 3 insertions(+), 12 deletions(-)
arch/powerpc/include/asm/nohash/32/pte-44x.h +0 -3
index 851813725237..da0469928273 100644
@@ -75,9 +75,6 @@
 #define _PAGE_NO_CACHE	0x00000400		/* H: I bit */
 #define _PAGE_WRITETHRU	0x00000800		/* H: W bit */
 
-/* No page size encoding in the linux PTE */
-#define _PAGE_PSIZE		0
-
 /* TODO: Add large page lowmem mapping support */
 #define _PMD_PRESENT	0
 #define _PMD_PRESENT_MASK (PAGE_MASK)
arch/powerpc/include/asm/nohash/32/pte-85xx.h +0 -3
index 653a342d3b25..14d64b4f3f14 100644
@@ -31,9 +31,6 @@
 #define _PAGE_WRITETHRU	0x00400	/* H: W bit */
 #define _PAGE_SPECIAL	0x00800 /* S: Special page */
 
-/* No page size encoding in the linux PTE */
-#define _PAGE_PSIZE		0
-
 #define _PMD_PRESENT	0
 #define _PMD_PRESENT_MASK (PAGE_MASK)
 #define _PMD_BAD	(~PAGE_MASK)
arch/powerpc/include/asm/nohash/32/pte-8xx.h +2 -3
index 137dc3c84e45..625c31d6ce5c 100644
@@ -74,12 +74,11 @@
 #define _PTE_NONE_MASK	0
 
 #ifdef CONFIG_PPC_16K_PAGES
-#define _PAGE_PSIZE	_PAGE_SPS
+#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_SPS)
 #else
-#define _PAGE_PSIZE		0
+#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED)
 #endif
 
-#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_PSIZE)
 #define _PAGE_BASE	(_PAGE_BASE_NC)
 
 #include <asm/pgtable-masks.h>
arch/powerpc/include/asm/nohash/pte-e500.h +1 -3
index f516f0b5b7a8..975facc7e38e 100644
@@ -65,8 +65,6 @@
 
 #define _PAGE_SPECIAL	_PAGE_SW0
 
-/* Base page size */
-#define _PAGE_PSIZE	_PAGE_PSIZE_4K
 #define	PTE_RPN_SHIFT	(24)
 
 #define PTE_WIMGE_SHIFT (19)
@@ -89,7 +87,7 @@
  * pages. We always set _PAGE_COHERENT when SMP is enabled or
  * the processor might need it for DMA coherency.
  */
-#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_PSIZE)
+#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_PSIZE_4K)
 #if defined(CONFIG_SMP)
 #define _PAGE_BASE	(_PAGE_BASE_NC | _PAGE_COHERENT)
 #else
Signature · 1 line
2.44.0
#10 lore raw

PATCH v6 10/23 powerpc/mm: Fix __find_linux_pte() on 32 bits with PMD leaf entries

In reply to Christophe Leroy

Building on 32 bits with pmd_leaf() not returning always false leads to the following error:

CC arch/powerpc/mm/pgtable.o
arch/powerpc/mm/pgtable.c: In function '__find_linux_pte':
arch/powerpc/mm/pgtable.c:506:1: error: function may return address of local variable [-Werror=return-local-addr]
506 | }

      | ^

arch/powerpc/mm/pgtable.c:394:15: note: declared here
394 | pud_t pud, *pudp;
| ^~~
arch/powerpc/mm/pgtable.c:394:15: note: declared here

This is due to pmd_offset() being a no-op in that case.

So rework it for powerpc/32 so that pXd_offset() are used on real pointers and not on on-stack copies.

Behind fixing the problem, it also has the advantage of simplifying __find_linux_pte() including the removal of stack frame:

After this patch:

	00000018 <__find_linux_pte>:
	  18:	2c 06 00 00 	cmpwi   r6,0
	  1c:	41 82 00 0c 	beq     28 <__find_linux_pte+0x10>
	  20:	39 20 00 00 	li      r9,0
	  24:	91 26 00 00 	stw     r9,0(r6)
	  28:	2f 85 00 00 	cmpwi   cr7,r5,0
	  2c:	41 9e 00 0c 	beq     cr7,38 <__find_linux_pte+0x20>
	  30:	39 20 00 00 	li      r9,0
	  34:	99 25 00 00 	stb     r9,0(r5)
	  38:	54 89 65 3a 	rlwinm  r9,r4,12,20,29
	  3c:	7c 63 48 2e 	lwzx    r3,r3,r9
	  40:	2f 83 00 00 	cmpwi   cr7,r3,0
	  44:	41 9e 00 30 	beq     cr7,74 <__find_linux_pte+0x5c>
	  48:	54 69 07 3a 	rlwinm  r9,r3,0,28,29
	  4c:	2f 89 00 0c 	cmpwi   cr7,r9,12
	  50:	54 63 00 26 	clrrwi  r3,r3,12
	  54:	54 84 b5 36 	rlwinm  r4,r4,22,20,27
	  58:	3c 63 c0 00 	addis   r3,r3,-16384
	  5c:	7c 63 22 14 	add     r3,r3,r4
	  60:	4c be 00 20 	bnelr+  cr7
	  64:	4d 82 00 20 	beqlr
	  68:	39 20 00 17 	li      r9,23
	  6c:	91 26 00 00 	stw     r9,0(r6)
	  70:	4e 80 00 20 	blr
	  74:	38 60 00 00 	li      r3,0
	  78:	4e 80 00 20 	blr

Before this patch:

	00000018 <__find_linux_pte>:
	  18:	2c 06 00 00 	cmpwi   r6,0
	  1c:	94 21 ff e0 	stwu    r1,-32(r1)
	  20:	41 82 00 0c 	beq     2c <__find_linux_pte+0x14>
	  24:	39 20 00 00 	li      r9,0
	  28:	91 26 00 00 	stw     r9,0(r6)
	  2c:	2f 85 00 00 	cmpwi   cr7,r5,0
	  30:	41 9e 00 0c 	beq     cr7,3c <__find_linux_pte+0x24>
	  34:	39 20 00 00 	li      r9,0
	  38:	99 25 00 00 	stb     r9,0(r5)
	  3c:	54 89 65 3a 	rlwinm  r9,r4,12,20,29
	  40:	7c 63 48 2e 	lwzx    r3,r3,r9
	  44:	54 69 07 3a 	rlwinm  r9,r3,0,28,29
	  48:	2f 89 00 0c 	cmpwi   cr7,r9,12
	  4c:	90 61 00 0c 	stw     r3,12(r1)
	  50:	41 9e 00 4c 	beq     cr7,9c <__find_linux_pte+0x84>
	  54:	80 61 00 0c 	lwz     r3,12(r1)
	  58:	54 69 07 3a 	rlwinm  r9,r3,0,28,29
	  5c:	2f 89 00 0c 	cmpwi   cr7,r9,12
	  60:	90 61 00 08 	stw     r3,8(r1)
	  64:	41 9e 00 38 	beq     cr7,9c <__find_linux_pte+0x84>
	  68:	80 61 00 08 	lwz     r3,8(r1)
	  6c:	2f 83 00 00 	cmpwi   cr7,r3,0
	  70:	41 9e 00 54 	beq     cr7,c4 <__find_linux_pte+0xac>
	  74:	54 69 07 3a 	rlwinm  r9,r3,0,28,29
	  78:	2f 89 00 0c 	cmpwi   cr7,r9,12
	  7c:	54 69 00 26 	clrrwi  r9,r3,12
	  80:	54 8a b5 36 	rlwinm  r10,r4,22,20,27
	  84:	3c 69 c0 00 	addis   r3,r9,-16384
	  88:	7c 63 52 14 	add     r3,r3,r10
	  8c:	54 84 93 be 	srwi    r4,r4,14
	  90:	41 9e 00 14 	beq     cr7,a4 <__find_linux_pte+0x8c>
	  94:	38 21 00 20 	addi    r1,r1,32
	  98:	4e 80 00 20 	blr
	  9c:	54 69 00 26 	clrrwi  r9,r3,12
	  a0:	54 84 93 be 	srwi    r4,r4,14
	  a4:	3c 69 c0 00 	addis   r3,r9,-16384
	  a8:	54 84 25 36 	rlwinm  r4,r4,4,20,27
	  ac:	7c 63 22 14 	add     r3,r3,r4
	  b0:	41 a2 ff e4 	beq     94 <__find_linux_pte+0x7c>
	  b4:	39 20 00 17 	li      r9,23
	  b8:	91 26 00 00 	stw     r9,0(r6)
	  bc:	38 21 00 20 	addi    r1,r1,32
	  c0:	4e 80 00 20 	blr
	  c4:	38 60 00 00 	li      r3,0
	  c8:	38 21 00 20 	addi    r1,r1,32
	  cc:	4e 80 00 20 	blr

---
v3: Removed p4dp and pudp locals for PPC32 and add a comment.
v4: Properly set pdshift on PPC32 case
v5: Enhanced commit message

---
 arch/powerpc/mm/pgtable.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)
arch/powerpc/mm/pgtable.c +10 -1
index 9e7ba9c3851f..bce8a8619589 100644
@@ -382,8 +382,10 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
 			bool *is_thp, unsigned *hpage_shift)
 {
 	pgd_t *pgdp;
+#ifdef CONFIG_PPC64
 	p4d_t p4d, *p4dp;
 	pud_t pud, *pudp;
+#endif
 	pmd_t pmd, *pmdp;
 	pte_t *ret_pte;
 	hugepd_t *hpdp = NULL;
@@ -401,8 +403,12 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
 	 * page fault or a page unmap. The return pte_t * is still not
 	 * stable. So should be checked there for above conditions.
 	 * Top level is an exception because it is folded into p4d.
+	 *
+	 * On PPC32, P4D/PUD/PMD are folded into PGD so go straight to
+	 * PMD level.
 	 */
 	pgdp = pgdir + pgd_index(ea);
+#ifdef CONFIG_PPC64
 	p4dp = p4d_offset(pgdp, ea);
 	p4d  = READ_ONCE(*p4dp);
 	pdshift = P4D_SHIFT;
@@ -442,8 +448,11 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
 		goto out_huge;
 	}
 
-	pdshift = PMD_SHIFT;
 	pmdp = pmd_offset(&pud, ea);
+#else
+	pmdp = pmd_offset(pud_offset(p4d_offset(pgdp, ea), ea), ea);
+#endif
+	pdshift = PMD_SHIFT;
 	pmd  = READ_ONCE(*pmdp);
 
 	/*
Signature · 1 line
2.44.0
#11 lore raw

PATCH v6 11/23 powerpc/mm: Allow hugepages without hugepd

In reply to Christophe Leroy

In preparation of implementing huge pages on powerpc 8xx without hugepd, enclose hugepd related code inside an ifdef CONFIG_ARCH_HAS_HUGEPD

This also allows removing some stubs.

---
v3:
- Prepare huge_pte_alloc() for full standard topology, not only for 2-level
- Reordered last part of huge_pte_alloc()

v4:
- Rebased of v6.10-rc1

v5:
- Moved the Kconfig split in this patch.

---
 arch/powerpc/Kconfig                         |  1 -
 arch/powerpc/include/asm/book3s/32/pgalloc.h |  2 --
 arch/powerpc/include/asm/hugetlb.h           | 10 ++----
 arch/powerpc/include/asm/nohash/pgtable.h    |  2 +-
 arch/powerpc/mm/hugetlbpage.c                | 33 ++++++++++++++++++++
 arch/powerpc/mm/pgtable.c                    |  2 ++
 arch/powerpc/platforms/Kconfig.cputype       |  3 ++
 7 files changed, 41 insertions(+), 12 deletions(-)
arch/powerpc/Kconfig +0 -1
index c88c6d46a5bc..b60b6e991227 100644
@@ -135,7 +135,6 @@ config PPC
 	select ARCH_HAS_DMA_MAP_DIRECT 		if PPC_PSERIES
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL
-	select ARCH_HAS_HUGEPD			if HUGETLB_PAGE
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_KERNEL_FPU_SUPPORT	if PPC64 && PPC_FPU
 	select ARCH_HAS_MEMBARRIER_CALLBACKS
arch/powerpc/include/asm/book3s/32/pgalloc.h +0 -2
index dc5c039eb28e..dd4eb3063175 100644
@@ -47,8 +47,6 @@ static inline void pgtable_free(void *table, unsigned index_size)
 	}
 }
 
-#define get_hugepd_cache_index(x)  (x)
-
 static inline void pgtable_free_tlb(struct mmu_gather *tlb,
 				    void *table, int shift)
 {
arch/powerpc/include/asm/hugetlb.h +2 -8
index ea71f7245a63..79176a499763 100644
@@ -30,10 +30,12 @@ static inline int is_hugepage_only_range(struct mm_struct *mm,
 }
 #define is_hugepage_only_range is_hugepage_only_range
 
+#ifdef CONFIG_ARCH_HAS_HUGEPD
 #define __HAVE_ARCH_HUGETLB_FREE_PGD_RANGE
 void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
 			    unsigned long end, unsigned long floor,
 			    unsigned long ceiling);
+#endif
 
 #define __HAVE_ARCH_HUGE_PTEP_GET_AND_CLEAR
 static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
@@ -67,14 +69,6 @@ static inline void flush_hugetlb_page(struct vm_area_struct *vma,
 {
 }
 
-#define hugepd_shift(x) 0
-static inline pte_t *hugepte_offset(hugepd_t hpd, unsigned long addr,
-				    unsigned pdshift)
-{
-	return NULL;
-}
-
-
 static inline void __init gigantic_hugetlb_cma_reserve(void)
 {
 }
arch/powerpc/include/asm/nohash/pgtable.h +1 -1
index f5f39d4f03c8..e7fc1314c23e 100644
@@ -340,7 +340,7 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
 
 #define pgprot_writecombine pgprot_noncached_wc
 
-#ifdef CONFIG_HUGETLB_PAGE
+#ifdef CONFIG_ARCH_HAS_HUGEPD
 static inline int hugepd_ok(hugepd_t hpd)
 {
 #ifdef CONFIG_PPC_8xx
arch/powerpc/mm/hugetlbpage.c +33 -0
index 594a4b7b2ca2..20fad59ff9f5 100644
@@ -42,6 +42,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long s
 	return __find_linux_pte(mm->pgd, addr, NULL, NULL);
 }
 
+#ifdef CONFIG_ARCH_HAS_HUGEPD
 static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
 			   unsigned long address, unsigned int pdshift,
 			   unsigned int pshift, spinlock_t *ptl)
@@ -193,6 +194,36 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
 
 	return hugepte_offset(*hpdp, addr, pdshift);
 }
+#else
+pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
+		      unsigned long addr, unsigned long sz)
+{
+	p4d_t *p4d;
+	pud_t *pud;
+	pmd_t *pmd;
+
+	addr &= ~(sz - 1);
+
+	p4d = p4d_offset(pgd_offset(mm, addr), addr);
+	if (!mm_pud_folded(mm) && sz >= P4D_SIZE)
+		return (pte_t *)p4d;
+
+	pud = pud_alloc(mm, p4d, addr);
+	if (!pud)
+		return NULL;
+	if (!mm_pmd_folded(mm) && sz >= PUD_SIZE)
+		return (pte_t *)pud;
+
+	pmd = pmd_alloc(mm, pud, addr);
+	if (!pmd)
+		return NULL;
+
+	if (sz >= PMD_SIZE)
+		return (pte_t *)pmd;
+
+	return pte_alloc_huge(mm, pmd, addr);
+}
+#endif
 
 #ifdef CONFIG_PPC_BOOK3S_64
 /*
@@ -248,6 +279,7 @@ int __init alloc_bootmem_huge_page(struct hstate *h, int nid)
 	return __alloc_bootmem_huge_page(h, nid);
 }
 
+#ifdef CONFIG_ARCH_HAS_HUGEPD
 #ifndef CONFIG_PPC_BOOK3S_64
 #define HUGEPD_FREELIST_SIZE \
 	((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t))
@@ -505,6 +537,7 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 		}
 	} while (addr = next, addr != end);
 }
+#endif
 
 bool __init arch_hugetlb_valid_size(unsigned long size)
 {
arch/powerpc/mm/pgtable.c +2 -0
index bce8a8619589..9010973f036c 100644
@@ -496,8 +496,10 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
 	if (!hpdp)
 		return NULL;
 
+#ifdef CONFIG_ARCH_HAS_HUGEPD
 	ret_pte = hugepte_offset(*hpdp, ea, pdshift);
 	pdshift = hugepd_shift(*hpdp);
+#endif
 out:
 	if (hpage_shift)
 		*hpage_shift = pdshift;
arch/powerpc/platforms/Kconfig.cputype +3 -0
index b2d8c0da2ad9..0c3c69ebf19f 100644
@@ -37,6 +37,7 @@ config PPC_85xx
 
 config PPC_8xx
 	bool "Freescale 8xx"
+	select ARCH_HAS_HUGEPD if HUGETLB_PAGE
 	select ARCH_SUPPORTS_HUGETLBFS
 	select FSL_SOC
 	select PPC_KUEP
@@ -98,6 +99,7 @@ config PPC_BOOK3S_64
 	select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
 	select ARCH_ENABLE_SPLIT_PMD_PTLOCK
 	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
+	select ARCH_HAS_HUGEPD if HUGETLB_PAGE
 	select ARCH_SUPPORTS_HUGETLBFS
 	select ARCH_SUPPORTS_NUMA_BALANCING
 	select HAVE_MOVE_PMD
@@ -290,6 +292,7 @@ config PPC_BOOK3S
 config PPC_E500
 	select FSL_EMB_PERFMON
 	bool
+	select ARCH_HAS_HUGEPD if HUGETLB_PAGE
 	select ARCH_SUPPORTS_HUGETLBFS if PHYS_64BIT || PPC64
 	select PPC_SMP_MUXED_IPI
 	select PPC_DOORBELL
Signature · 1 line
2.44.0
#12 lore raw

PATCH v6 12/23 powerpc/8xx: Fix size given to set_huge_pte_at()

In reply to Christophe Leroy

set_huge_pte_at() expects the size of the hugepage as an int, not the psize which is the index of the page definition in table mmu_psize_defs[]

Fixes 935d4f0c6dc8 ("mm: hugetlb: add huge page size param to set_huge_pte_at()")
---
 arch/powerpc/mm/nohash/8xx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
arch/powerpc/mm/nohash/8xx.c +2 -1
index 43d4842bb1c7..d93433e26ded 100644
@@ -94,7 +94,8 @@ static int __ref __early_map_kernel_hugepage(unsigned long va, phys_addr_t pa,
 		return -EINVAL;
 
 	set_huge_pte_at(&init_mm, va, ptep,
-			pte_mkhuge(pfn_pte(pa >> PAGE_SHIFT, prot)), psize);
+			pte_mkhuge(pfn_pte(pa >> PAGE_SHIFT, prot)),
+			1UL << mmu_psize_to_shift(psize));
 
 	return 0;
 }
Signature · 1 line
2.44.0
#13 lore raw

PATCH v6 13/23 powerpc/8xx: Rework support for 8M pages using contiguous PTE entries

In reply to Christophe Leroy

In order to fit better with standard Linux page tables layout, add support for 8M pages using contiguous PTE entries in a standard page table. Page tables will then be populated with 1024 similar entries and two PMD entries will point to that page table.

The PMD entries also get a flag to tell it is addressing an 8M page, this is required for the HW tablewalk assistance.

---
v3:
- Move huge_ptep_get() for a more readable commit diff
- Flag PMD as 8Mbytes in set_huge_pte_at()
- Define __pte_leaf_size()
- Change pte_update() instead of all huge callers of pte_update()
- Added ptep_is_8m_pmdp() helper
- Fixed kasan early memory 8M allocation

v5:
- In huge_ptep_get(), change pte_offset_kernel((pmd_t *)ptep, 0) to pte_offset_kernel((pmd_t *)ptep, ALIGN_DOWN(addr, SZ_8M)) which is more correct allthough not different.

---
 .../include/asm/nohash/32/hugetlb-8xx.h       | 38 +++----------
 arch/powerpc/include/asm/nohash/32/pte-8xx.h  | 53 ++++++++++++-------
 arch/powerpc/include/asm/nohash/pgtable.h     |  4 --
 arch/powerpc/include/asm/page.h               |  5 --
 arch/powerpc/include/asm/pgtable.h            |  3 ++
 arch/powerpc/kernel/head_8xx.S                | 10 +---
 arch/powerpc/mm/hugetlbpage.c                 | 21 +++++---
 arch/powerpc/mm/kasan/8xx.c                   | 21 +++++---
 arch/powerpc/mm/nohash/8xx.c                  | 40 +++++++-------
 arch/powerpc/mm/pgtable.c                     | 27 +++++++---
 arch/powerpc/mm/pgtable_32.c                  |  2 +-
 arch/powerpc/platforms/Kconfig.cputype        |  1 -
 12 files changed, 111 insertions(+), 114 deletions(-)
arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h +8 -30
index 92df40c6cc6b..014799557f60 100644
@@ -4,42 +4,12 @@
 
 #define PAGE_SHIFT_8M		23
 
-static inline pte_t *hugepd_page(hugepd_t hpd)
-{
-	BUG_ON(!hugepd_ok(hpd));
-
-	return (pte_t *)__va(hpd_val(hpd) & ~HUGEPD_SHIFT_MASK);
-}
-
-static inline unsigned int hugepd_shift(hugepd_t hpd)
-{
-	return PAGE_SHIFT_8M;
-}
-
-static inline pte_t *hugepte_offset(hugepd_t hpd, unsigned long addr,
-				    unsigned int pdshift)
-{
-	unsigned long idx = (addr & (SZ_4M - 1)) >> PAGE_SHIFT;
-
-	return hugepd_page(hpd) + idx;
-}
-
 static inline void flush_hugetlb_page(struct vm_area_struct *vma,
 				      unsigned long vmaddr)
 {
 	flush_tlb_page(vma, vmaddr);
 }
 
-static inline void hugepd_populate(hugepd_t *hpdp, pte_t *new, unsigned int pshift)
-{
-	*hpdp = __hugepd(__pa(new) | _PMD_USER | _PMD_PRESENT | _PMD_PAGE_8M);
-}
-
-static inline void hugepd_populate_kernel(hugepd_t *hpdp, pte_t *new, unsigned int pshift)
-{
-	*hpdp = __hugepd(__pa(new) | _PMD_PRESENT | _PMD_PAGE_8M);
-}
-
 static inline int check_and_get_huge_psize(int shift)
 {
 	return shift_to_mmu_psize(shift);
@@ -49,6 +19,14 @@ static inline int check_and_get_huge_psize(int shift)
 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
 		     pte_t pte, unsigned long sz);
 
+#define __HAVE_ARCH_HUGE_PTEP_GET
+static inline pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+	if (ptep_is_8m_pmdp(mm, addr, ptep))
+		ptep = pte_offset_kernel((pmd_t *)ptep, ALIGN_DOWN(addr, SZ_8M));
+	return ptep_get(ptep);
+}
+
 #define __HAVE_ARCH_HUGE_PTE_CLEAR
 static inline void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
 				  pte_t *ptep, unsigned long sz)
arch/powerpc/include/asm/nohash/32/pte-8xx.h +34 -19

104 lines not on this page · raw message

arch/powerpc/include/asm/nohash/pgtable.h +0 -4
index e7fc1314c23e..90d6a0943b35 100644
@@ -343,12 +343,8 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
 #ifdef CONFIG_ARCH_HAS_HUGEPD
 static inline int hugepd_ok(hugepd_t hpd)
 {
-#ifdef CONFIG_PPC_8xx
-	return ((hpd_val(hpd) & _PMD_PAGE_MASK) == _PMD_PAGE_8M);
-#else
 	/* We clear the top bit to indicate hugepd */
 	return (hpd_val(hpd) && (hpd_val(hpd) & PD_HUGE) == 0);
-#endif
 }
 
 #define is_hugepd(hpd)		(hugepd_ok(hpd))
arch/powerpc/include/asm/page.h +0 -5
index e411e5a70ea3..018c3d55232c 100644
@@ -293,13 +293,8 @@ static inline const void *pfn_to_kaddr(unsigned long pfn)
 /*
  * Some number of bits at the level of the page table that points to
  * a hugepte are used to encode the size.  This masks those bits.
- * On 8xx, HW assistance requires 4k alignment for the hugepte.
  */
-#ifdef CONFIG_PPC_8xx
-#define HUGEPD_SHIFT_MASK     0xfff
-#else
 #define HUGEPD_SHIFT_MASK     0x3f
-#endif
 
 #ifndef __ASSEMBLY__
 
arch/powerpc/include/asm/pgtable.h +3 -0
index 239709a2f68e..264a6c09517a 100644
@@ -106,6 +106,9 @@ unsigned long vmalloc_to_phys(void *vmalloc_addr);
 
 void pgtable_cache_add(unsigned int shift);
 
+#ifdef CONFIG_PPC32
+void __init *early_alloc_pgtable(unsigned long size);
+#endif
 pte_t *early_pte_alloc_kernel(pmd_t *pmdp, unsigned long va);
 
 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_PPC32)
arch/powerpc/kernel/head_8xx.S +2 -8
index edc479a7c2bc..ac74321b1192 100644
@@ -415,14 +415,13 @@ FixupDAR:/* Entry point for dcbx workaround. */
 	oris	r11, r11, (swapper_pg_dir - PAGE_OFFSET)@ha
 3:
 	lwz	r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11)	/* Get the level 1 entry */
+	rlwinm	r11, r11, 0, ~_PMD_PAGE_8M
 	mtspr	SPRN_MD_TWC, r11
-	mtcrf	0x01, r11
 	mfspr	r11, SPRN_MD_TWC
 	lwz	r11, 0(r11)	/* Get the pte */
-	bt	28,200f		/* bit 28 = Large page (8M) */
 	/* concat physical page address(r11) and page offset(r10) */
 	rlwimi	r11, r10, 0, 32 - PAGE_SHIFT, 31
-201:	lwz	r11,0(r11)
+	lwz	r11,0(r11)
 /* Check if it really is a dcbx instruction. */
 /* dcbt and dcbtst does not generate DTLB Misses/Errors,
  * no need to include them here */
@@ -441,11 +440,6 @@ FixupDAR:/* Entry point for dcbx workaround. */
 141:	mfspr	r10,SPRN_M_TW
 	b	DARFixed	/* Nope, go back to normal TLB processing */
 
-200:
-	/* concat physical page address(r11) and page offset(r10) */
-	rlwimi	r11, r10, 0, 32 - PAGE_SHIFT_8M, 31
-	b	201b
-
 144:	mfspr	r10, SPRN_DSISR
 	rlwinm	r10, r10,0,7,5	/* Clear store bit for buggy dcbst insn */
 	mtspr	SPRN_DSISR, r10
arch/powerpc/mm/hugetlbpage.c +13 -8
index 20fad59ff9f5..394846197974 100644
@@ -183,9 +183,6 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (!hpdp)
 		return NULL;
 
-	if (IS_ENABLED(CONFIG_PPC_8xx) && pshift < PMD_SHIFT)
-		return pte_alloc_huge(mm, (pmd_t *)hpdp, addr);
-
 	BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
 
 	if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr,
@@ -218,8 +215,18 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (!pmd)
 		return NULL;
 
-	if (sz >= PMD_SIZE)
+	if (sz >= PMD_SIZE) {
+		/* On 8xx, all hugepages are handled as contiguous PTEs */
+		if (IS_ENABLED(CONFIG_PPC_8xx)) {
+			int i;
+
+			for (i = 0; i < sz / PMD_SIZE; i++) {
+				if (!pte_alloc_huge(mm, pmd + i, addr))
+					return NULL;
+			}
+		}
 		return (pte_t *)pmd;
+	}
 
 	return pte_alloc_huge(mm, pmd, addr);
 }
@@ -617,10 +624,8 @@ static int __init hugetlbpage_init(void)
 		 * use pgt cache for hugepd.
 		 */
 		if (pdshift > shift) {
-			if (!IS_ENABLED(CONFIG_PPC_8xx))
-				pgtable_cache_add(pdshift - shift);
-		} else if (IS_ENABLED(CONFIG_PPC_E500) ||
-			   IS_ENABLED(CONFIG_PPC_8xx)) {
+			pgtable_cache_add(pdshift - shift);
+		} else if (IS_ENABLED(CONFIG_PPC_E500)) {
 			pgtable_cache_add(PTE_T_ORDER);
 		}
 
arch/powerpc/mm/kasan/8xx.c +13 -8
index 2784224054f8..989d6cdf4141 100644
@@ -6,28 +6,33 @@
 #include <linux/memblock.h>
 #include <linux/hugetlb.h>
 
+#include <asm/pgalloc.h>
+
 static int __init
 kasan_init_shadow_8M(unsigned long k_start, unsigned long k_end, void *block)
 {
 	pmd_t *pmd = pmd_off_k(k_start);
 	unsigned long k_cur, k_next;
 
-	for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd += 2, block += SZ_8M) {
-		pte_basic_t *new;
+	for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd++, block += SZ_4M) {
+		pte_t *ptep;
+		int i;
 
 		k_next = pgd_addr_end(k_cur, k_end);
-		k_next = pgd_addr_end(k_next, k_end);
 		if ((void *)pmd_page_vaddr(*pmd) != kasan_early_shadow_pte)
 			continue;
 
-		new = memblock_alloc(sizeof(pte_basic_t), SZ_4K);
-		if (!new)
+		ptep = memblock_alloc(PTE_FRAG_SIZE, PTE_FRAG_SIZE);
+		if (!ptep)
 			return -ENOMEM;
 
-		*new = pte_val(pte_mkhuge(pfn_pte(PHYS_PFN(__pa(block)), PAGE_KERNEL)));
+		for (i = 0; i < PTRS_PER_PTE; i++) {
+			pte_t pte = pte_mkhuge(pfn_pte(PHYS_PFN(__pa(block + i * PAGE_SIZE)), PAGE_KERNEL));
 
-		hugepd_populate_kernel((hugepd_t *)pmd, (pte_t *)new, PAGE_SHIFT_8M);
-		hugepd_populate_kernel((hugepd_t *)pmd + 1, (pte_t *)new, PAGE_SHIFT_8M);
+			__set_pte_at(&init_mm, k_cur, ptep + i, pte, 1);
+		}
+		pmd_populate_kernel(&init_mm, pmd, ptep);
+		*pmd = __pmd(pmd_val(*pmd) | _PMD_PAGE_8M);
 	}
 	return 0;
 }
arch/powerpc/mm/nohash/8xx.c +18 -22
index d93433e26ded..388bba0ab3e7 100644
@@ -11,6 +11,7 @@
 #include <linux/hugetlb.h>
 
 #include <asm/fixmap.h>
+#include <asm/pgalloc.h>
 
 #include <mm/mmu_decl.h>
 
@@ -48,20 +49,6 @@ unsigned long p_block_mapped(phys_addr_t pa)
 	return 0;
 }
 
-static pte_t __init *early_hugepd_alloc_kernel(hugepd_t *pmdp, unsigned long va)
-{
-	if (hpd_val(*pmdp) == 0) {
-		pte_t *ptep = memblock_alloc(sizeof(pte_basic_t), SZ_4K);
-
-		if (!ptep)
-			return NULL;
-
-		hugepd_populate_kernel((hugepd_t *)pmdp, ptep, PAGE_SHIFT_8M);
-		hugepd_populate_kernel((hugepd_t *)pmdp + 1, ptep, PAGE_SHIFT_8M);
-	}
-	return hugepte_offset(*(hugepd_t *)pmdp, va, PGDIR_SHIFT);
-}
-
 static int __ref __early_map_kernel_hugepage(unsigned long va, phys_addr_t pa,
 					     pgprot_t prot, int psize, bool new)
 {
@@ -75,24 +62,33 @@ static int __ref __early_map_kernel_hugepage(unsigned long va, phys_addr_t pa,
 		if (WARN_ON(slab_is_available()))
 			return -EINVAL;
 
-		if (psize == MMU_PAGE_512K)
+		if (psize == MMU_PAGE_512K) {
 			ptep = early_pte_alloc_kernel(pmdp, va);
-		else
-			ptep = early_hugepd_alloc_kernel((hugepd_t *)pmdp, va);
+			/* The PTE should never be already present */
+			if (WARN_ON(pte_present(*ptep) && pgprot_val(prot)))
+				return -EINVAL;
+		} else {
+			if (WARN_ON(!pmd_none(*pmdp) || !pmd_none(*(pmdp + 1))))
+				return -EINVAL;
+
+			ptep = early_alloc_pgtable(PTE_FRAG_SIZE);
+			pmd_populate_kernel(&init_mm, pmdp, ptep);
+
+			ptep = early_alloc_pgtable(PTE_FRAG_SIZE);
+			pmd_populate_kernel(&init_mm, pmdp + 1, ptep);
+
+			ptep = (pte_t *)pmdp;
+		}
 	} else {
 		if (psize == MMU_PAGE_512K)
 			ptep = pte_offset_kernel(pmdp, va);
 		else
-			ptep = hugepte_offset(*(hugepd_t *)pmdp, va, PGDIR_SHIFT);
+			ptep = (pte_t *)pmdp;
 	}
 
 	if (WARN_ON(!ptep))
 		return -ENOMEM;
 
-	/* The PTE should never be already present */
-	if (new && WARN_ON(pte_present(*ptep) && pgprot_val(prot)))
-		return -EINVAL;
-
 	set_huge_pte_at(&init_mm, va, ptep,
 			pte_mkhuge(pfn_pte(pa >> PAGE_SHIFT, prot)),
 			1UL << mmu_psize_to_shift(psize));
arch/powerpc/mm/pgtable.c +19 -8
index 9010973f036c..294775c793ab 100644
@@ -297,11 +297,8 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 }
 
 #if defined(CONFIG_PPC_8xx)
-void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
-		     pte_t pte, unsigned long sz)
+static void __set_huge_pte_at(pmd_t *pmd, pte_t *ptep, pte_basic_t val)
 {
-	pmd_t *pmd = pmd_off(mm, addr);
-	pte_basic_t val;
 	pte_basic_t *entry = (pte_basic_t *)ptep;
 	int num, i;
 
@@ -311,15 +308,29 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
 	 */
 	VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep));
 
-	pte = set_pte_filter(pte, addr);
-
-	val = pte_val(pte);
-
 	num = number_of_cells_per_pte(pmd, val, 1);
 
 	for (i = 0; i < num; i++, entry++, val += SZ_4K)
 		*entry = val;
 }
+
+void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
+		     pte_t pte, unsigned long sz)
+{
+	pmd_t *pmdp = pmd_off(mm, addr);
+
+	pte = set_pte_filter(pte, addr);
+
+	if (sz == SZ_8M) { /* Flag both PMD entries as 8M and fill both page tables */
+		*pmdp = __pmd(pmd_val(*pmdp) | _PMD_PAGE_8M);
+		*(pmdp + 1) = __pmd(pmd_val(*(pmdp + 1)) | _PMD_PAGE_8M);
+
+		__set_huge_pte_at(pmdp, pte_offset_kernel(pmdp, 0), pte_val(pte));
+		__set_huge_pte_at(pmdp, pte_offset_kernel(pmdp + 1, 0), pte_val(pte) + SZ_4M);
+	} else {
+		__set_huge_pte_at(pmdp, ptep, pte_val(pte));
+	}
+}
 #endif
 #endif /* CONFIG_HUGETLB_PAGE */
 
arch/powerpc/mm/pgtable_32.c +1 -1
index cfd622ebf774..787b22206386 100644
@@ -48,7 +48,7 @@ notrace void __init early_ioremap_init(void)
 	early_ioremap_setup();
 }
 
-static void __init *early_alloc_pgtable(unsigned long size)
+void __init *early_alloc_pgtable(unsigned long size)
 {
 	void *ptr = memblock_alloc(size, size);
 
arch/powerpc/platforms/Kconfig.cputype +0 -1
index 0c3c69ebf19f..fa4bb096b3ae 100644
@@ -37,7 +37,6 @@ config PPC_85xx
 
 config PPC_8xx
 	bool "Freescale 8xx"
-	select ARCH_HAS_HUGEPD if HUGETLB_PAGE
 	select ARCH_SUPPORTS_HUGETLBFS
 	select FSL_SOC
 	select PPC_KUEP
Signature · 1 line
2.44.0
#14 lore raw

PATCH v6 14/23 powerpc/8xx: Simplify struct mmu_psize_def

In reply to Christophe Leroy

On 8xx, only the shift field is used in struct mmu_psize_def

Remove other fields and related macros.

---
 arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)
arch/powerpc/include/asm/nohash/32/mmu-8xx.h +2 -7
index 141d82e249a8..a756a1e59c54 100644
@@ -189,19 +189,14 @@ typedef struct {
 
 #define PHYS_IMMR_BASE (mfspr(SPRN_IMMR) & 0xfff80000)
 
-/* Page size definitions, common between 32 and 64-bit
+/*
+ * Page size definitions for 8xx
  *
  *    shift : is the "PAGE_SHIFT" value for that page size
- *    penc  : is the pte encoding mask
  *
  */
 struct mmu_psize_def {
 	unsigned int	shift;	/* number of bits */
-	unsigned int	enc;	/* PTE encoding */
-	unsigned int    ind;    /* Corresponding indirect page size shift */
-	unsigned int	flags;
-#define MMU_PAGE_SIZE_DIRECT	0x1	/* Supported as a direct size */
-#define MMU_PAGE_SIZE_INDIRECT	0x2	/* Supported as an indirect size */
 };
 
 extern struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT];
Signature · 1 line
2.44.0
#15 lore raw

PATCH v6 15/23 powerpc/e500: Remove enc and ind fields from struct mmu_psize_def

In reply to Christophe Leroy

enc field is hidden behind BOOK3E_PAGESZ_XX macros, and when you look closer you realise that this field is nothing else than the value of shift minus ten.

So remove enc field and calculate tsize from shift field.

Also remove inc field which is unused.

---
 arch/powerpc/include/asm/nohash/mmu-e500.h | 3 ---
 arch/powerpc/mm/nohash/book3e_pgtable.c    | 4 ++--
 arch/powerpc/mm/nohash/tlb.c               | 9 +--------
 arch/powerpc/mm/nohash/tlb_64e.c           | 2 +-
 4 files changed, 4 insertions(+), 14 deletions(-)
arch/powerpc/include/asm/nohash/mmu-e500.h +0 -3
index 7dc24b8632d7..b281d9eeaf1e 100644
@@ -244,14 +244,11 @@ typedef struct {
 /* Page size definitions, common between 32 and 64-bit
  *
  *    shift : is the "PAGE_SHIFT" value for that page size
- *    penc  : is the pte encoding mask
  *
  */
 struct mmu_psize_def
 {
 	unsigned int	shift;	/* number of bits */
-	unsigned int	enc;	/* PTE encoding */
-	unsigned int    ind;    /* Corresponding indirect page size shift */
 	unsigned int	flags;
 #define MMU_PAGE_SIZE_DIRECT	0x1	/* Supported as a direct size */
 #define MMU_PAGE_SIZE_INDIRECT	0x2	/* Supported as an indirect size */
arch/powerpc/mm/nohash/book3e_pgtable.c +2 -2
index 1c5e4ecbebeb..ad2a7c26f2a0 100644
@@ -29,10 +29,10 @@ int __meminit vmemmap_create_mapping(unsigned long start,
 		_PAGE_KERNEL_RW;
 
 	/* PTEs only contain page size encodings up to 32M */
-	BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].enc > 0xf);
+	BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].shift - 10 > 0xf);
 
 	/* Encode the size in the PTE */
-	flags |= mmu_psize_defs[mmu_vmemmap_psize].enc << 8;
+	flags |= (mmu_psize_defs[mmu_vmemmap_psize].shift - 10) << 8;
 
 	/* For each PTE for that area, map things. Note that we don't
 	 * increment phys because all PTEs are of the large size and
arch/powerpc/mm/nohash/tlb.c +1 -8
index f57dc721d063..b653a7be4cb1 100644
@@ -53,37 +53,30 @@
 struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT] = {
 	[MMU_PAGE_4K] = {
 		.shift	= 12,
-		.enc	= BOOK3E_PAGESZ_4K,
 	},
 	[MMU_PAGE_2M] = {
 		.shift	= 21,
-		.enc	= BOOK3E_PAGESZ_2M,
 	},
 	[MMU_PAGE_4M] = {
 		.shift	= 22,
-		.enc	= BOOK3E_PAGESZ_4M,
 	},
 	[MMU_PAGE_16M] = {
 		.shift	= 24,
-		.enc	= BOOK3E_PAGESZ_16M,
 	},
 	[MMU_PAGE_64M] = {
 		.shift	= 26,
-		.enc	= BOOK3E_PAGESZ_64M,
 	},
 	[MMU_PAGE_256M] = {
 		.shift	= 28,
-		.enc	= BOOK3E_PAGESZ_256M,
 	},
 	[MMU_PAGE_1G] = {
 		.shift	= 30,
-		.enc	= BOOK3E_PAGESZ_1GB,
 	},
 };
 
 static inline int mmu_get_tsize(int psize)
 {
-	return mmu_psize_defs[psize].enc;
+	return mmu_psize_defs[psize].shift - 10;
 }
 #else
 static inline int mmu_get_tsize(int psize)
arch/powerpc/mm/nohash/tlb_64e.c +1 -1
index 053128a5636c..7988238496d7 100644
@@ -53,7 +53,7 @@ int extlb_level_exc;
  */
 void tlb_flush_pgtable(struct mmu_gather *tlb, unsigned long address)
 {
-	int tsize = mmu_psize_defs[mmu_pte_psize].enc;
+	int tsize = mmu_psize_defs[mmu_pte_psize].shift - 10;
 
 	if (book3e_htw_mode != PPC_HTW_NONE) {
 		unsigned long start = address & PMD_MASK;
Signature · 1 line
2.44.0
#16 lore raw

PATCH v6 16/23 powerpc/e500: Switch to 64 bits PGD on 85xx (32 bits)

In reply to Christophe Leroy

At the time being when CONFIG_PTE_64BIT is selected, PTE entries are 64 bits but PGD entries are still 32 bits.

In order to allow leaf PMD entries, switch the PGD to 64 bits entries.

---
 arch/powerpc/include/asm/pgtable-types.h |  4 ++++
 arch/powerpc/kernel/head_85xx.S          | 10 ++++++----
 2 files changed, 10 insertions(+), 4 deletions(-)
arch/powerpc/include/asm/pgtable-types.h +4 -0
index 082c85cc09b1..db965d98e0ae 100644
@@ -49,7 +49,11 @@ static inline unsigned long pud_val(pud_t x)
 #endif /* CONFIG_PPC64 */
 
 /* PGD level */
+#if defined(CONFIG_PPC_E500) && defined(CONFIG_PTE_64BIT)
+typedef struct { unsigned long long pgd; } pgd_t;
+#else
 typedef struct { unsigned long pgd; } pgd_t;
+#endif
 #define __pgd(x)	((pgd_t) { (x) })
 static inline unsigned long pgd_val(pgd_t x)
 {
arch/powerpc/kernel/head_85xx.S +6 -4
index 39724ff5ae1f..a305244afc9f 100644
@@ -307,8 +307,9 @@ set_ivor:
 #ifdef CONFIG_PTE_64BIT
 #ifdef CONFIG_HUGETLB_PAGE
 #define FIND_PTE	\
-	rlwinm	r12, r10, 13, 19, 29;	/* Compute pgdir/pmd offset */	\
-	lwzx	r11, r12, r11;		/* Get pgd/pmd entry */		\
+	rlwinm	r12, r10, 14, 18, 28;	/* Compute pgdir/pmd offset */	\
+	add	r12, r11, r12;						\
+	lwz	r11, 4(r12);		/* Get pgd/pmd entry */		\
 	rlwinm.	r12, r11, 0, 0, 20;	/* Extract pt base address */	\
 	blt	1000f;			/* Normal non-huge page */	\
 	beq	2f;			/* Bail if no table */		\
@@ -321,8 +322,9 @@ set_ivor:
 1001:	lwz	r11, 4(r12);		/* Get pte entry */
 #else
 #define FIND_PTE	\
-	rlwinm	r12, r10, 13, 19, 29;	/* Compute pgdir/pmd offset */	\
-	lwzx	r11, r12, r11;		/* Get pgd/pmd entry */		\
+	rlwinm	r12, r10, 14, 18, 28;	/* Compute pgdir/pmd offset */	\
+	add	r12, r11, r12;						\
+	lwz	r11, 4(r12);		/* Get pgd/pmd entry */		\
 	rlwinm.	r12, r11, 0, 0, 20;	/* Extract pt base address */	\
 	beq	2f;			/* Bail if no table */		\
 	rlwimi	r12, r10, 23, 20, 28;	/* Compute pte address */	\
Signature · 1 line
2.44.0
#17 lore raw

PATCH v6 17/23 powerpc/e500: Encode hugepage size in PTE bits

In reply to Christophe Leroy

Use PTE page size bits to encode hugepage size with the following format corresponding to the values expected in bits 52-55 in MAS1 register. Those bits are called TSIZE:

	0001 	4 Kbyte
	0010 	16 Kbyte
	0011 	64 Kbyte
	0100 	256 Kbyte
	0101 	1 Mbyte
	0110 	4 Mbyte
	0111 	16 Mbyte
	1000 	64 Mbyte
	1001 	256 Mbyte
	1010 	1 Gbyte
	1011 	4 Gbyte
	1100 	16 Gbyte
	1101	64 Gbyte
	1110	256 Gbyte
	1111	1 Tbyte

It corresponds to shift value minus 10 with lowest bit removed.

It is not the value expected in the PTE in that field, but only e6500 performs HW based TLB loading and the e6500 reference manual explicitely says that this field is ignored.

Also add pte_huge_size() which will be used later.

---
v5: Use PAGE SIZE field instead of U0-U3 because on some HW U2-U3 are used for something else.

---
 .../powerpc/include/asm/nohash/hugetlb-e500.h |  9 ++++++
 arch/powerpc/include/asm/nohash/pte-e500.h    | 28 +++++++++----------
 2 files changed, 22 insertions(+), 15 deletions(-)
arch/powerpc/include/asm/nohash/hugetlb-e500.h +9 -0
index 8f04ad20e040..c6a0938e86fd 100644
@@ -42,4 +42,13 @@ static inline int check_and_get_huge_psize(int shift)
 	return shift_to_mmu_psize(shift);
 }
 
+static inline pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
+{
+	unsigned int tsize = shift - _PAGE_PSIZE_SHIFT_OFFSET;
+	pte_basic_t val = (tsize << _PAGE_PSIZE_SHIFT) & _PAGE_PSIZE_MSK;
+
+	return __pte((pte_val(entry) & ~(pte_basic_t)_PAGE_PSIZE_MSK) | val);
+}
+#define arch_make_huge_pte arch_make_huge_pte
+
 #endif /* _ASM_POWERPC_NOHASH_HUGETLB_E500_H */
arch/powerpc/include/asm/nohash/pte-e500.h +13 -15
index 975facc7e38e..6dac1c0a6937 100644
@@ -19,20 +19,7 @@
 #define _PAGE_BAP_SX	0x000040
 #define _PAGE_BAP_UX	0x000080
 #define _PAGE_PSIZE_MSK	0x000f00
-#define _PAGE_PSIZE_4K	0x000200
-#define _PAGE_PSIZE_8K	0x000300
-#define _PAGE_PSIZE_16K	0x000400
-#define _PAGE_PSIZE_32K	0x000500
-#define _PAGE_PSIZE_64K	0x000600
-#define _PAGE_PSIZE_128K	0x000700
-#define _PAGE_PSIZE_256K	0x000800
-#define _PAGE_PSIZE_512K	0x000900
-#define _PAGE_PSIZE_1M	0x000a00
-#define _PAGE_PSIZE_2M	0x000b00
-#define _PAGE_PSIZE_4M	0x000c00
-#define _PAGE_PSIZE_8M	0x000d00
-#define _PAGE_PSIZE_16M	0x000e00
-#define _PAGE_PSIZE_32M	0x000f00
+#define _PAGE_TSIZE_4K	0x000100
 #define _PAGE_DIRTY	0x001000 /* C: page changed */
 #define _PAGE_SW0	0x002000
 #define _PAGE_U3	0x004000
@@ -46,6 +33,9 @@
 #define _PAGE_NO_CACHE	0x400000 /* I: cache inhibit */
 #define _PAGE_WRITETHRU	0x800000 /* W: cache write-through */
 
+#define _PAGE_PSIZE_SHIFT		7
+#define _PAGE_PSIZE_SHIFT_OFFSET	10
+
 /* "Higher level" linux bit combinations */
 #define _PAGE_EXEC		(_PAGE_BAP_SX | _PAGE_BAP_UX) /* .. and was cache cleaned */
 #define _PAGE_READ		(_PAGE_BAP_SR | _PAGE_BAP_UR) /* User read permission */
@@ -87,7 +77,7 @@
  * pages. We always set _PAGE_COHERENT when SMP is enabled or
  * the processor might need it for DMA coherency.
  */
-#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_PSIZE_4K)
+#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_TSIZE_4K)
 #if defined(CONFIG_SMP)
 #define _PAGE_BASE	(_PAGE_BASE_NC | _PAGE_COHERENT)
 #else
@@ -103,6 +93,14 @@ static inline pte_t pte_mkexec(pte_t pte)
 }
 #define pte_mkexec pte_mkexec
 
+static inline unsigned long pte_huge_size(pte_t pte)
+{
+	pte_basic_t val = pte_val(pte);
+
+	return 1UL << (((val & _PAGE_PSIZE_MSK) >> _PAGE_PSIZE_SHIFT) + _PAGE_PSIZE_SHIFT_OFFSET);
+}
+#define pte_huge_size pte_huge_size
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __KERNEL__ */
Signature · 1 line
2.44.0
#18 lore raw

PATCH v6 18/23 powerpc/e500: Don't pre-check write access on data TLB error

In reply to Christophe Leroy

Don't pre-check write access on read-only pages on data TLB error.

Load the TLB anyway and take a DSI exception when it happens. This avoids reading SPRN_ESR at every data TLB error exception.

---
v5: New

---
 arch/powerpc/kernel/head_85xx.S | 15 ---------------
 1 file changed, 15 deletions(-)
arch/powerpc/kernel/head_85xx.S +0 -15
index a305244afc9f..282e49c51deb 100644
@@ -472,27 +472,12 @@ END_BTB_FLUSH_SECTION
 #endif
 
 4:
-	/* Mask of required permission bits. Note that while we
-	 * do copy ESR:ST to _PAGE_WRITE position as trying to write
-	 * to an RO page is pretty common, we don't do it with
-	 * _PAGE_DIRTY. We could do it, but it's a fairly rare
-	 * event so I'd rather take the overhead when it happens
-	 * rather than adding an instruction here. We should measure
-	 * whether the whole thing is worth it in the first place
-	 * as we could avoid loading SPRN_ESR completely in the first
-	 * place...
-	 *
-	 * TODO: Is it worth doing that mfspr & rlwimi in the first
-	 *       place or can we save a couple of instructions here ?
-	 */
-	mfspr	r12,SPRN_ESR
 #ifdef CONFIG_PTE_64BIT
 	li	r13,_PAGE_PRESENT|_PAGE_BAP_SR
 	oris	r13,r13,_PAGE_ACCESSED@h
 #else
 	li	r13,_PAGE_PRESENT|_PAGE_READ|_PAGE_ACCESSED
 #endif
-	rlwimi	r13,r12,11,29,29
 
 	FIND_PTE
 	andc.	r13,r13,r11		/* Check permission */
Signature · 1 line
2.44.0
#19 lore raw

PATCH v6 19/23 powerpc/e500: Free r10 for FIND_PTE

In reply to Christophe Leroy

Move r13 load after the call to FIND_PTE, and use r13 instead of r10 for storing fault address. This will allow using r10 freely in FIND_PTE in following patch to handle hugepage size.

---
v5: New

---
 arch/powerpc/kernel/head_85xx.S | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)
arch/powerpc/kernel/head_85xx.S +16 -14
index 282e49c51deb..226f88e77d6d 100644
@@ -294,9 +294,10 @@ set_ivor:
 /* Macros to hide the PTE size differences
  *
  * FIND_PTE -- walks the page tables given EA & pgdir pointer
- *   r10 -- EA of fault
+ *   r10 -- free
  *   r11 -- PGDIR pointer
  *   r12 -- free
+ *   r13 -- EA of fault
  *   label 2: is the bailout case
  *
  * if we find the pte (fall through):
@@ -307,7 +308,7 @@ set_ivor:
 #ifdef CONFIG_PTE_64BIT
 #ifdef CONFIG_HUGETLB_PAGE
 #define FIND_PTE	\
-	rlwinm	r12, r10, 14, 18, 28;	/* Compute pgdir/pmd offset */	\
+	rlwinm	r12, r13, 14, 18, 28;	/* Compute pgdir/pmd offset */	\
 	add	r12, r11, r12;						\
 	lwz	r11, 4(r12);		/* Get pgd/pmd entry */		\
 	rlwinm.	r12, r11, 0, 0, 20;	/* Extract pt base address */	\
@@ -317,26 +318,26 @@ set_ivor:
 	andi.	r10, r11, HUGEPD_SHIFT_MASK@l; /* extract size field */	\
 	xor	r12, r10, r11;		/* drop size bits from pointer */ \
 	b	1001f;							\
-1000:	rlwimi	r12, r10, 23, 20, 28;	/* Compute pte address */	\
+1000:	rlwimi	r12, r13, 23, 20, 28;	/* Compute pte address */	\
 	li	r10, 0;			/* clear r10 */			\
 1001:	lwz	r11, 4(r12);		/* Get pte entry */
 #else
 #define FIND_PTE	\
-	rlwinm	r12, r10, 14, 18, 28;	/* Compute pgdir/pmd offset */	\
+	rlwinm	r12, r13, 14, 18, 28;	/* Compute pgdir/pmd offset */	\
 	add	r12, r11, r12;						\
 	lwz	r11, 4(r12);		/* Get pgd/pmd entry */		\
 	rlwinm.	r12, r11, 0, 0, 20;	/* Extract pt base address */	\
 	beq	2f;			/* Bail if no table */		\
-	rlwimi	r12, r10, 23, 20, 28;	/* Compute pte address */	\
+	rlwimi	r12, r13, 23, 20, 28;	/* Compute pte address */	\
 	lwz	r11, 4(r12);		/* Get pte entry */
 #endif /* HUGEPAGE */
 #else /* !PTE_64BIT */
 #define FIND_PTE	\
-	rlwimi	r11, r10, 12, 20, 29;	/* Create L1 (pgdir/pmd) address */	\
+	rlwimi	r11, r13, 12, 20, 29;	/* Create L1 (pgdir/pmd) address */	\
 	lwz	r11, 0(r11);		/* Get L1 entry */			\
 	rlwinm.	r12, r11, 0, 0, 19;	/* Extract L2 (pte) base address */	\
 	beq	2f;			/* Bail if no table */			\
-	rlwimi	r12, r10, 22, 20, 29;	/* Compute PTE address */		\
+	rlwimi	r12, r13, 22, 20, 29;	/* Compute PTE address */		\
 	lwz	r11, 0(r12);		/* Get Linux PTE */
 #endif
 
@@ -443,13 +444,13 @@ START_BTB_FLUSH_SECTION
 	BTB_FLUSH(r10)
 1:
 END_BTB_FLUSH_SECTION
-	mfspr	r10, SPRN_DEAR		/* Get faulting address */
+	mfspr	r13, SPRN_DEAR		/* Get faulting address */
 
 	/* If we are faulting a kernel address, we have to use the
 	 * kernel page tables.
 	 */
 	lis	r11, PAGE_OFFSET@h
-	cmplw	5, r10, r11
+	cmplw	5, r13, r11
 	blt	5, 3f
 	lis	r11, swapper_pg_dir@h
 	ori	r11, r11, swapper_pg_dir@l
@@ -472,14 +473,14 @@ END_BTB_FLUSH_SECTION
 #endif
 
 4:
+	FIND_PTE
+
 #ifdef CONFIG_PTE_64BIT
 	li	r13,_PAGE_PRESENT|_PAGE_BAP_SR
 	oris	r13,r13,_PAGE_ACCESSED@h
 #else
 	li	r13,_PAGE_PRESENT|_PAGE_READ|_PAGE_ACCESSED
 #endif
-
-	FIND_PTE
 	andc.	r13,r13,r11		/* Check permission */
 
 #ifdef CONFIG_PTE_64BIT
@@ -536,13 +537,13 @@ START_BTB_FLUSH_SECTION
 1:
 END_BTB_FLUSH_SECTION
 
-	mfspr	r10, SPRN_SRR0		/* Get faulting address */
+	mfspr	r13, SPRN_SRR0		/* Get faulting address */
 
 	/* If we are faulting a kernel address, we have to use the
 	 * kernel page tables.
 	 */
 	lis	r11, PAGE_OFFSET@h
-	cmplw	5, r10, r11
+	cmplw	5, r13, r11
 	blt	5, 3f
 	lis	r11, swapper_pg_dir@h
 	ori	r11, r11, swapper_pg_dir@l
@@ -551,6 +552,7 @@ END_BTB_FLUSH_SECTION
 	rlwinm	r12,r12,0,16,1
 	mtspr	SPRN_MAS1,r12
 
+	FIND_PTE
 	/* Make up the required permissions for kernel code */
 #ifdef CONFIG_PTE_64BIT
 	li	r13,_PAGE_PRESENT | _PAGE_BAP_SX
@@ -571,6 +573,7 @@ END_BTB_FLUSH_SECTION
 	beq	2f			/* KUAP fault */
 #endif
 
+	FIND_PTE
 	/* Make up the required permissions for user code */
 #ifdef CONFIG_PTE_64BIT
 	li	r13,_PAGE_PRESENT | _PAGE_BAP_UX
@@ -580,7 +583,6 @@ END_BTB_FLUSH_SECTION
 #endif
 
 4:
-	FIND_PTE
 	andc.	r13,r13,r11		/* Check permission */
 
 #ifdef CONFIG_PTE_64BIT
Signature · 1 line
2.44.0
#20 lore raw

PATCH v6 20/23 powerpc/e500: Use contiguous PMD instead of hugepd

In reply to Christophe Leroy

e500 supports many page sizes among which the following size are implemented in the kernel at the time being: 4M, 16M, 64M, 256M, 1G.

On e500, TLB miss for hugepages is exclusively handled by SW even on e6500 which has HW assistance for 4k pages, so there are no constraints like on the 8xx.

On e500/32, all are at PGD/PMD level and can be handled as cont-PMD.

On e500/64, smaller ones are on PMD while bigger ones are on PUD. Again, they can easily be handled as cont-PMD and cont-PUD instead of hugepd.

On e500/32, use the pagesize bits in PTE to know if it is a PMD or a leaf entry. This works because the pagesize bits are in the last 12 bits and page tables are 4k aligned.

On e500/64, use highest bit which is always 1 on PxD (Because PxD contains virtual address of a kernel memory) and always 0 on PTEs because not all bits of RPN are used/possible.

---
v3: Add missing pmd_leaf_size() and pud_leaf_size()
v4: Rebased of v6.10-rc1 : pmd_huge() and pud_huge() are gone
v5:
- Define pte_huge_size() to reduce redundant and handle the case of mpc85xx with 32 bits PTE.
- Replace hard-coded page shift offset (10) with new macro _PAGE_PSIZE_SHIFT_OFFSET
- Use TSIZE encoding in SIZE field in PTE
- On 64 bits, use highest bit to know if it is a PUD/PMD or leaf entry. Avoids problem with page table alignment.

---
 .../powerpc/include/asm/nohash/hugetlb-e500.h | 32 ++------------
 arch/powerpc/include/asm/nohash/pgalloc.h     |  2 -
 arch/powerpc/include/asm/nohash/pgtable.h     | 42 ++++++++++++++-----
 arch/powerpc/include/asm/nohash/pte-e500.h    | 33 +++++++++++++++
 arch/powerpc/include/asm/page.h               | 15 +------
 arch/powerpc/kernel/head_85xx.S               | 21 ++++------
 arch/powerpc/mm/hugetlbpage.c                 |  2 -
 arch/powerpc/mm/nohash/tlb_low_64e.S          |  7 +---
 arch/powerpc/mm/pgtable.c                     | 31 ++++++++++++++
 arch/powerpc/platforms/Kconfig.cputype        |  1 -
 10 files changed, 107 insertions(+), 79 deletions(-)
arch/powerpc/include/asm/nohash/hugetlb-e500.h +3 -29
index c6a0938e86fd..812c71fc5eb1 100644
@@ -2,38 +2,12 @@
 #ifndef _ASM_POWERPC_NOHASH_HUGETLB_E500_H
 #define _ASM_POWERPC_NOHASH_HUGETLB_E500_H
 
-static inline pte_t *hugepd_page(hugepd_t hpd)
-{
-	if (WARN_ON(!hugepd_ok(hpd)))
-		return NULL;
-
-	return (pte_t *)((hpd_val(hpd) & ~HUGEPD_SHIFT_MASK) | PD_HUGE);
-}
-
-static inline unsigned int hugepd_shift(hugepd_t hpd)
-{
-	return hpd_val(hpd) & HUGEPD_SHIFT_MASK;
-}
-
-static inline pte_t *hugepte_offset(hugepd_t hpd, unsigned long addr,
-				    unsigned int pdshift)
-{
-	/*
-	 * On FSL BookE, we have multiple higher-level table entries that
-	 * point to the same hugepte.  Just use the first one since they're all
-	 * identical.  So for that case, idx=0.
-	 */
-	return hugepd_page(hpd);
-}
+#define __HAVE_ARCH_HUGE_SET_HUGE_PTE_AT
+void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
+		     pte_t pte, unsigned long sz);
 
 void flush_hugetlb_page(struct vm_area_struct *vma, unsigned long vmaddr);
 
-static inline void hugepd_populate(hugepd_t *hpdp, pte_t *new, unsigned int pshift)
-{
-	/* We use the old format for PPC_E500 */
-	*hpdp = __hugepd(((unsigned long)new & ~PD_HUGE) | pshift);
-}
-
 static inline int check_and_get_huge_psize(int shift)
 {
 	if (shift & 1)	/* Not a power of 4 */
arch/powerpc/include/asm/nohash/pgalloc.h +0 -2
index 4b62376318e1..d06efac6d7aa 100644
@@ -44,8 +44,6 @@ static inline void pgtable_free(void *table, int shift)
 	}
 }
 
-#define get_hugepd_cache_index(x)	(x)
-
 static inline void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift)
 {
 	unsigned long pgf = (unsigned long)table;
arch/powerpc/include/asm/nohash/pgtable.h +31 -11

64 lines not on this page · raw message

arch/powerpc/include/asm/nohash/pte-e500.h +33 -0
index 6dac1c0a6937..cb78392494da 100644
@@ -101,6 +101,39 @@ static inline unsigned long pte_huge_size(pte_t pte)
 }
 #define pte_huge_size pte_huge_size
 
+static inline int pmd_leaf(pmd_t pmd)
+{
+	if (IS_ENABLED(CONFIG_PPC64))
+		return (long)pmd_val(pmd) > 0;
+	else
+		return pmd_val(pmd) & _PAGE_PSIZE_MSK;
+}
+#define pmd_leaf pmd_leaf
+
+static inline unsigned long pmd_leaf_size(pmd_t pmd)
+{
+	return pte_huge_size(__pte(pmd_val(pmd)));
+}
+#define pmd_leaf_size pmd_leaf_size
+
+#ifdef CONFIG_PPC64
+static inline int pud_leaf(pud_t pud)
+{
+	if (IS_ENABLED(CONFIG_PPC64))
+		return (long)pud_val(pud) > 0;
+	else
+		return pud_val(pud) & _PAGE_PSIZE_MSK;
+}
+#define pud_leaf pud_leaf
+
+static inline unsigned long pud_leaf_size(pud_t pud)
+{
+	return pte_huge_size(__pte(pud_val(pud)));
+}
+#define pud_leaf_size pud_leaf_size
+
+#endif
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __KERNEL__ */
arch/powerpc/include/asm/page.h +1 -14
index 018c3d55232c..7d3c3bc40e6a 100644
@@ -269,20 +269,7 @@ static inline const void *pfn_to_kaddr(unsigned long pfn)
 #define is_kernel_addr(x)	((x) >= TASK_SIZE)
 #endif
 
-#ifndef CONFIG_PPC_BOOK3S_64
-/*
- * Use the top bit of the higher-level page table entries to indicate whether
- * the entries we point to contain hugepages.  This works because we know that
- * the page tables live in kernel space.  If we ever decide to support having
- * page tables at arbitrary addresses, this breaks and will have to change.
- */
-#ifdef CONFIG_PPC64
-#define PD_HUGE 0x8000000000000000UL
-#else
-#define PD_HUGE 0x80000000
-#endif
-
-#else	/* CONFIG_PPC_BOOK3S_64 */
+#ifdef CONFIG_PPC_BOOK3S_64
 /*
  * Book3S 64 stores real addresses in the hugepd entries to
  * avoid overlaps with _PAGE_PRESENT and _PAGE_PTE.
arch/powerpc/kernel/head_85xx.S +7 -14
index 226f88e77d6d..f9a73fae6464 100644
@@ -311,16 +311,14 @@ set_ivor:
 	rlwinm	r12, r13, 14, 18, 28;	/* Compute pgdir/pmd offset */	\
 	add	r12, r11, r12;						\
 	lwz	r11, 4(r12);		/* Get pgd/pmd entry */		\
+	rlwinm.	r10, r11, 32 - _PAGE_PSIZE_SHIFT, 0x1e; /* get tsize*/	\
+	bne	1000f;			/* Huge page (leaf entry) */	\
 	rlwinm.	r12, r11, 0, 0, 20;	/* Extract pt base address */	\
-	blt	1000f;			/* Normal non-huge page */	\
 	beq	2f;			/* Bail if no table */		\
-	oris	r11, r11, PD_HUGE@h;	/* Put back address bit */	\
-	andi.	r10, r11, HUGEPD_SHIFT_MASK@l; /* extract size field */	\
-	xor	r12, r10, r11;		/* drop size bits from pointer */ \
-	b	1001f;							\
-1000:	rlwimi	r12, r13, 23, 20, 28;	/* Compute pte address */	\
+	rlwimi	r12, r13, 23, 20, 28;	/* Compute pte address */	\
 	li	r10, 0;			/* clear r10 */			\
-1001:	lwz	r11, 4(r12);		/* Get pte entry */
+	lwz	r11, 4(r12);		/* Get pte entry */		\
+1000:
 #else
 #define FIND_PTE	\
 	rlwinm	r12, r13, 14, 18, 28;	/* Compute pgdir/pmd offset */	\
@@ -735,17 +733,12 @@ finish_tlb_load:
 	lwz	r15, 0(r14)
 100:	stw	r15, 0(r17)
 
-	/*
-	 * Calc MAS1_TSIZE from r10 (which has pshift encoded)
-	 * tlb_enc = (pshift - 10).
-	 */
-	subi	r15, r10, 10
 	mfspr	r16, SPRN_MAS1
-	rlwimi	r16, r15, 7, 20, 24
+	rlwimi	r16, r10, MAS1_TSIZE_SHIFT, MAS1_TSIZE_MASK
 	mtspr	SPRN_MAS1, r16
 
 	/* copy the pshift for use later */
-	mr	r14, r10
+	addi	r14, r10, _PAGE_PSIZE_SHIFT_OFFSET
 
 	/* fall through */
 
arch/powerpc/mm/hugetlbpage.c +0 -2
index 394846197974..9e692d96f9e1 100644
@@ -625,8 +625,6 @@ static int __init hugetlbpage_init(void)
 		 */
 		if (pdshift > shift) {
 			pgtable_cache_add(pdshift - shift);
-		} else if (IS_ENABLED(CONFIG_PPC_E500)) {
-			pgtable_cache_add(PTE_T_ORDER);
 		}
 
 		configured = true;
arch/powerpc/mm/nohash/tlb_low_64e.S +1 -6
index a54e7d6c3d0b..de568297d5c5 100644
@@ -450,11 +450,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_SMT)
 
 tlb_miss_huge_e6500:
 	beq	tlb_miss_fault_e6500
-	li	r10,1
-	andi.	r15,r14,HUGEPD_SHIFT_MASK@l /* r15 = psize */
-	rldimi	r14,r10,63,0		/* Set PD_HUGE */
-	xor	r14,r14,r15		/* Clear size bits */
-	ldx	r14,0,r14
+	rlwinm	r15,r14,32-_PAGE_PSIZE_SHIFT,0x1e
 
 	/*
 	 * Now we build the MAS for a huge page.
@@ -465,7 +461,6 @@ tlb_miss_huge_e6500:
 	 * MAS 2,3+7:	Needs to be redone similar to non-tablewalk handler
 	 */
 
-	subi	r15,r15,10		/* Convert psize to tsize */
 	mfspr	r10,SPRN_MAS1
 	rlwinm	r10,r10,0,~MAS1_IND
 	rlwimi	r10,r15,MAS1_TSIZE_SHIFT,MAS1_TSIZE_MASK
arch/powerpc/mm/pgtable.c +31 -0
index 294775c793ab..6498454959f3 100644
@@ -331,6 +331,37 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
 		__set_huge_pte_at(pmdp, ptep, pte_val(pte));
 	}
 }
+#elif defined(CONFIG_PPC_E500)
+void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
+		     pte_t pte, unsigned long sz)
+{
+	unsigned long pdsize;
+	int i;
+
+	pte = set_pte_filter(pte, addr);
+
+	/*
+	 * Make sure hardware valid bit is not set. We don't do
+	 * tlb flush for this update.
+	 */
+	VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep));
+
+	if (sz < PMD_SIZE)
+		pdsize = PAGE_SIZE;
+	else if (sz < PUD_SIZE)
+		pdsize = PMD_SIZE;
+	else if (sz < P4D_SIZE)
+		pdsize = PUD_SIZE;
+	else if (sz < PGDIR_SIZE)
+		pdsize = P4D_SIZE;
+	else
+		pdsize = PGDIR_SIZE;
+
+	for (i = 0; i < sz / pdsize; i++, ptep++, addr += pdsize) {
+		__set_pte_at(mm, addr, ptep, pte, 0);
+		pte = __pte(pte_val(pte) + ((unsigned long long)pdsize / PAGE_SIZE << PFN_PTE_SHIFT));
+	}
+}
 #endif
 #endif /* CONFIG_HUGETLB_PAGE */
 
arch/powerpc/platforms/Kconfig.cputype +0 -1
index fa4bb096b3ae..30a78e99663e 100644
@@ -291,7 +291,6 @@ config PPC_BOOK3S
 config PPC_E500
 	select FSL_EMB_PERFMON
 	bool
-	select ARCH_HAS_HUGEPD if HUGETLB_PAGE
 	select ARCH_SUPPORTS_HUGETLBFS if PHYS_64BIT || PPC64
 	select PPC_SMP_MUXED_IPI
 	select PPC_DOORBELL
Signature · 1 line
2.44.0
#21 lore raw

PATCH v6 21/23 powerpc/64s: Use contiguous PMD/PUD instead of HUGEPD

In reply to Christophe Leroy

On book3s/64, the only user of hugepd is hash in 4k mode.

All other setups (hash-64, radix-4, radix-64) use leaf PMD/PUD.

Rework hash-4k to use contiguous PMD and PUD instead.

In that setup there are only two huge page sizes: 16M and 16G.

16M sits at PMD level and 16G at PUD level.

pte_update doesn't know page size, lets use the same trick as hpte_need_flush() to get page size from segment properties. That's not the most efficient way but let's do that until callers of pte_update() provide page size instead of just a huge flag.

---
v3:
- Add missing pmd_leaf_size() and pud_leaf_size()
- More cleanup in hugetlbpage_init()
- Take a page fault when DIRTY or ACCESSED is missing on hash-4 hugepage

v4: Rebased on v6.10-rc1

v6: Added a WARN_ON_ONCE() in hash__pte_update() in case the pagesize is unexpected.

---
 arch/powerpc/include/asm/book3s/64/hash-4k.h  | 15 ------
 arch/powerpc/include/asm/book3s/64/hash.h     | 40 +++++++++++++---
 arch/powerpc/include/asm/book3s/64/hugetlb.h  | 38 ---------------
 .../include/asm/book3s/64/pgtable-4k.h        | 47 -------------------
 .../include/asm/book3s/64/pgtable-64k.h       | 20 --------
 arch/powerpc/include/asm/book3s/64/pgtable.h  | 22 +++++++--
 arch/powerpc/include/asm/hugetlb.h            |  4 ++
 .../powerpc/include/asm/nohash/hugetlb-e500.h |  4 --
 arch/powerpc/include/asm/page.h               |  8 ----
 arch/powerpc/mm/book3s64/hash_utils.c         | 11 +++--
 arch/powerpc/mm/book3s64/hugetlbpage.c        | 10 ++++
 arch/powerpc/mm/book3s64/pgtable.c            | 12 -----
 arch/powerpc/mm/hugetlbpage.c                 | 26 ----------
 arch/powerpc/mm/pgtable.c                     |  2 +-
 arch/powerpc/platforms/Kconfig.cputype        |  1 -
 15 files changed, 74 insertions(+), 186 deletions(-)
 delete mode 100644 arch/powerpc/include/asm/book3s/64/pgtable-4k.h
arch/powerpc/include/asm/book3s/64/hash-4k.h +0 -15
index 6472b08fa1b0..c654c376ef8b 100644
@@ -74,21 +74,6 @@
 #define remap_4k_pfn(vma, addr, pfn, prot)	\
 	remap_pfn_range((vma), (addr), (pfn), PAGE_SIZE, (prot))
 
-#ifdef CONFIG_HUGETLB_PAGE
-static inline int hash__hugepd_ok(hugepd_t hpd)
-{
-	unsigned long hpdval = hpd_val(hpd);
-	/*
-	 * if it is not a pte and have hugepd shift mask
-	 * set, then it is a hugepd directory pointer
-	 */
-	if (!(hpdval & _PAGE_PTE) && (hpdval & _PAGE_PRESENT) &&
-	    ((hpdval & HUGEPD_SHIFT_MASK) != 0))
-		return true;
-	return false;
-}
-#endif
-
 /*
  * 4K PTE format is different from 64K PTE format. Saving the hash_slot is just
  * a matter of returning the PTE bits that need to be modified. On 64K PTE,
arch/powerpc/include/asm/book3s/64/hash.h +33 -7
index faf3e3b4e4b2..0755f2567021 100644
@@ -4,6 +4,7 @@
 #ifdef __KERNEL__
 
 #include <asm/asm-const.h>
+#include <asm/book3s/64/slice.h>
 
 /*
  * Common bits between 4K and 64K pages in a linux-style PTE.
@@ -161,14 +162,10 @@ extern void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
 			    pte_t *ptep, unsigned long pte, int huge);
 unsigned long htab_convert_pte_flags(unsigned long pteflags, unsigned long flags);
 /* Atomic PTE updates */
-static inline unsigned long hash__pte_update(struct mm_struct *mm,
-					 unsigned long addr,
-					 pte_t *ptep, unsigned long clr,
-					 unsigned long set,
-					 int huge)
+static inline unsigned long hash__pte_update_one(pte_t *ptep, unsigned long clr,
+						 unsigned long set)
 {
 	__be64 old_be, tmp_be;
-	unsigned long old;
 
 	__asm__ __volatile__(
 	"1:	ldarx	%0,0,%3		# pte_update\n\
@@ -182,11 +179,40 @@ static inline unsigned long hash__pte_update(struct mm_struct *mm,
 	: "r" (ptep), "r" (cpu_to_be64(clr)), "m" (*ptep),
 	  "r" (cpu_to_be64(H_PAGE_BUSY)), "r" (cpu_to_be64(set))
 	: "cc" );
+
+	return be64_to_cpu(old_be);
+}
+
+static inline unsigned long hash__pte_update(struct mm_struct *mm,
+					 unsigned long addr,
+					 pte_t *ptep, unsigned long clr,
+					 unsigned long set,
+					 int huge)
+{
+	unsigned long old;
+
+	old = hash__pte_update_one(ptep, clr, set);
+
+	if (IS_ENABLED(CONFIG_PPC_4K_PAGES) && huge) {
+		unsigned int psize = get_slice_psize(mm, addr);
+		int nb, i;
+
+		if (psize == MMU_PAGE_16M)
+			nb = SZ_16M / PMD_SIZE;
+		else if (psize == MMU_PAGE_16G)
+			nb = SZ_16G / PUD_SIZE;
+		else
+			nb = 1;
+
+		WARN_ON_ONCE(nb == 1);	/* Should never happen */
+
+		for (i = 1; i < nb; i++)
+			hash__pte_update_one(ptep + i, clr, set);
+	}
 	/* huge pages use the old page table lock */
 	if (!huge)
 		assert_pte_locked(mm, addr);
 
-	old = be64_to_cpu(old_be);
 	if (old & H_PAGE_HASHPTE)
 		hpte_need_flush(mm, addr, ptep, old, huge);
 
arch/powerpc/include/asm/book3s/64/hugetlb.h +0 -38
index aa1c67c8bfc8..f0bba9c5f9c3 100644
@@ -49,9 +49,6 @@ static inline bool gigantic_page_runtime_supported(void)
 	return true;
 }
 
-/* hugepd entry valid bit */
-#define HUGEPD_VAL_BITS		(0x8000000000000000UL)
-
 #define huge_ptep_modify_prot_start huge_ptep_modify_prot_start
 extern pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma,
 					 unsigned long addr, pte_t *ptep);
@@ -60,29 +57,7 @@ extern pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma,
 extern void huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
 					 unsigned long addr, pte_t *ptep,
 					 pte_t old_pte, pte_t new_pte);
-/*
- * This should work for other subarchs too. But right now we use the
- * new format only for 64bit book3s
- */
-static inline pte_t *hugepd_page(hugepd_t hpd)
-{
-	BUG_ON(!hugepd_ok(hpd));
-	/*
-	 * We have only four bits to encode, MMU page size
-	 */
-	BUILD_BUG_ON((MMU_PAGE_COUNT - 1) > 0xf);
-	return __va(hpd_val(hpd) & HUGEPD_ADDR_MASK);
-}
-
-static inline unsigned int hugepd_mmu_psize(hugepd_t hpd)
-{
-	return (hpd_val(hpd) & HUGEPD_SHIFT_MASK) >> 2;
-}
 
-static inline unsigned int hugepd_shift(hugepd_t hpd)
-{
-	return mmu_psize_to_shift(hugepd_mmu_psize(hpd));
-}
 static inline void flush_hugetlb_page(struct vm_area_struct *vma,
 				      unsigned long vmaddr)
 {
@@ -90,19 +65,6 @@ static inline void flush_hugetlb_page(struct vm_area_struct *vma,
 		return radix__flush_hugetlb_page(vma, vmaddr);
 }
 
-static inline pte_t *hugepte_offset(hugepd_t hpd, unsigned long addr,
-				    unsigned int pdshift)
-{
-	unsigned long idx = (addr & ((1UL << pdshift) - 1)) >> hugepd_shift(hpd);
-
-	return hugepd_page(hpd) + idx;
-}
-
-static inline void hugepd_populate(hugepd_t *hpdp, pte_t *new, unsigned int pshift)
-{
-	*hpdp = __hugepd(__pa(new) | HUGEPD_VAL_BITS | (shift_to_mmu_psize(pshift) << 2));
-}
-
 void flush_hugetlb_page(struct vm_area_struct *vma, unsigned long vmaddr);
 
 static inline int check_and_get_huge_psize(int shift)
arch/powerpc/include/asm/book3s/64/pgtable-4k.h deleted +0 -47

47 lines not on this page · raw message

arch/powerpc/include/asm/book3s/64/pgtable-64k.h +0 -20
index 6ac73da7b80e..4d8d7b4ea16b 100644
@@ -5,26 +5,6 @@
 #ifndef __ASSEMBLY__
 #ifdef CONFIG_HUGETLB_PAGE
 
-/*
- * With 64k page size, we have hugepage ptes in the pgd and pmd entries. We don't
- * need to setup hugepage directory for them. Our pte and page directory format
- * enable us to have this enabled.
- */
-static inline int hugepd_ok(hugepd_t hpd)
-{
-	return 0;
-}
-
-#define is_hugepd(pdep)			0
-
-/*
- * This should never get called
- */
-static __always_inline int get_hugepd_cache_index(int index)
-{
-	BUILD_BUG();
-}
-
 #endif /* CONFIG_HUGETLB_PAGE */
 
 static inline int remap_4k_pfn(struct vm_area_struct *vma, unsigned long addr,
arch/powerpc/include/asm/book3s/64/pgtable.h +19 -3
index 8f9432e3855a..519b1743a0f4 100644
@@ -274,6 +274,24 @@ static inline bool pud_leaf(pud_t pud)
 {
 	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
 }
+
+#define pmd_leaf_size pmd_leaf_size
+static inline unsigned long pmd_leaf_size(pmd_t pmd)
+{
+	if (IS_ENABLED(CONFIG_PPC_4K_PAGES) && !radix_enabled())
+		return SZ_16M;
+	else
+		return PMD_SIZE;
+}
+
+#define pud_leaf_size pud_leaf_size
+static inline unsigned long pud_leaf_size(pud_t pud)
+{
+	if (IS_ENABLED(CONFIG_PPC_4K_PAGES) && !radix_enabled())
+		return SZ_16G;
+	else
+		return PUD_SIZE;
+}
 #endif /* __ASSEMBLY__ */
 
 #include <asm/book3s/64/hash.h>
@@ -285,11 +303,9 @@ static inline bool pud_leaf(pud_t pud)
 #define  MAX_PHYSMEM_BITS	R_MAX_PHYSMEM_BITS
 #endif
 
-
+/* hash 4k can't share hugetlb and also doesn't support THP */
 #ifdef CONFIG_PPC_64K_PAGES
 #include <asm/book3s/64/pgtable-64k.h>
-#else
-#include <asm/book3s/64/pgtable-4k.h>
 #endif
 
 #include <asm/barrier.h>
arch/powerpc/include/asm/hugetlb.h +4 -0
index 79176a499763..e959c26c0b52 100644
@@ -37,6 +37,10 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
 			    unsigned long ceiling);
 #endif
 
+#define __HAVE_ARCH_HUGE_SET_HUGE_PTE_AT
+void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
+		     pte_t pte, unsigned long sz);
+
 #define __HAVE_ARCH_HUGE_PTEP_GET_AND_CLEAR
 static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 					    unsigned long addr, pte_t *ptep)
arch/powerpc/include/asm/nohash/hugetlb-e500.h +0 -4
index 812c71fc5eb1..cab0e1f1eea0 100644
@@ -2,10 +2,6 @@
 #ifndef _ASM_POWERPC_NOHASH_HUGETLB_E500_H
 #define _ASM_POWERPC_NOHASH_HUGETLB_E500_H
 
-#define __HAVE_ARCH_HUGE_SET_HUGE_PTE_AT
-void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
-		     pte_t pte, unsigned long sz);
-
 void flush_hugetlb_page(struct vm_area_struct *vma, unsigned long vmaddr);
 
 static inline int check_and_get_huge_psize(int shift)
arch/powerpc/include/asm/page.h +0 -8
index 7d3c3bc40e6a..c0af246a64ff 100644
@@ -269,14 +269,6 @@ static inline const void *pfn_to_kaddr(unsigned long pfn)
 #define is_kernel_addr(x)	((x) >= TASK_SIZE)
 #endif
 
-#ifdef CONFIG_PPC_BOOK3S_64
-/*
- * Book3S 64 stores real addresses in the hugepd entries to
- * avoid overlaps with _PAGE_PRESENT and _PAGE_PTE.
- */
-#define HUGEPD_ADDR_MASK	(0x0ffffffffffffffful & ~HUGEPD_SHIFT_MASK)
-#endif /* CONFIG_PPC_BOOK3S_64 */
-
 /*
  * Some number of bits at the level of the page table that points to
  * a hugepte are used to encode the size.  This masks those bits.
arch/powerpc/mm/book3s64/hash_utils.c +7 -4
index 01c3b4b65241..6727a15ab94f 100644
@@ -1233,10 +1233,6 @@ void __init hash__early_init_mmu(void)
 	__pmd_table_size = H_PMD_TABLE_SIZE;
 	__pud_table_size = H_PUD_TABLE_SIZE;
 	__pgd_table_size = H_PGD_TABLE_SIZE;
-	/*
-	 * 4k use hugepd format, so for hash set then to
-	 * zero
-	 */
 	__pmd_val_bits = HASH_PMD_VAL_BITS;
 	__pud_val_bits = HASH_PUD_VAL_BITS;
 	__pgd_val_bits = HASH_PGD_VAL_BITS;
@@ -1546,6 +1542,13 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea,
 		goto bail;
 	}
 
+	if (IS_ENABLED(CONFIG_PPC_4K_PAGES) && !radix_enabled()) {
+		if (hugeshift == PMD_SHIFT && psize == MMU_PAGE_16M)
+			hugeshift = mmu_psize_defs[MMU_PAGE_16M].shift;
+		if (hugeshift == PUD_SHIFT && psize == MMU_PAGE_16G)
+			hugeshift = mmu_psize_defs[MMU_PAGE_16G].shift;
+	}
+
 	/*
 	 * Add _PAGE_PRESENT to the required access perm. If there are parallel
 	 * updates to the pte that can possibly clear _PAGE_PTE, catch that too.
arch/powerpc/mm/book3s64/hugetlbpage.c +10 -0
index 5a2e512e96db..83c3361b358b 100644
@@ -53,6 +53,16 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
 		/* If PTE permissions don't match, take page fault */
 		if (unlikely(!check_pte_access(access, old_pte)))
 			return 1;
+		/*
+		 * If hash-4k, hugepages use seeral contiguous PxD entries
+		 * so bail out and let mm make the page young or dirty
+		 */
+		if (IS_ENABLED(CONFIG_PPC_4K_PAGES)) {
+			if (!(old_pte & _PAGE_ACCESSED))
+				return 1;
+			if ((access & _PAGE_WRITE) && !(old_pte & _PAGE_DIRTY))
+				return 1;
+		}
 
 		/*
 		 * Try to lock the PTE, add ACCESSED and DIRTY if it was
arch/powerpc/mm/book3s64/pgtable.c +0 -12
index 2975ea0841ba..f4d8d3c40e5c 100644
@@ -461,18 +461,6 @@ static inline void pgtable_free(void *table, int index)
 	case PUD_INDEX:
 		__pud_free(table);
 		break;
-#if defined(CONFIG_PPC_4K_PAGES) && defined(CONFIG_HUGETLB_PAGE)
-		/* 16M hugepd directory at pud level */
-	case HTLB_16M_INDEX:
-		BUILD_BUG_ON(H_16M_CACHE_INDEX <= 0);
-		kmem_cache_free(PGT_CACHE(H_16M_CACHE_INDEX), table);
-		break;
-		/* 16G hugepd directory at the pgd level */
-	case HTLB_16G_INDEX:
-		BUILD_BUG_ON(H_16G_CACHE_INDEX <= 0);
-		kmem_cache_free(PGT_CACHE(H_16G_CACHE_INDEX), table);
-		break;
-#endif
 		/* We don't free pgd table via RCU callback */
 	default:
 		BUG();
arch/powerpc/mm/hugetlbpage.c +0 -26
index 9e692d96f9e1..1fe2843f5b12 100644
@@ -592,40 +592,14 @@ static int __init hugetlbpage_init(void)
 
 	for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
 		unsigned shift;
-		unsigned pdshift;
 
 		if (!mmu_psize_defs[psize].shift)
 			continue;
 
 		shift = mmu_psize_to_shift(psize);
 
-#ifdef CONFIG_PPC_BOOK3S_64
-		if (shift > PGDIR_SHIFT)
-			continue;
-		else if (shift > PUD_SHIFT)
-			pdshift = PGDIR_SHIFT;
-		else if (shift > PMD_SHIFT)
-			pdshift = PUD_SHIFT;
-		else
-			pdshift = PMD_SHIFT;
-#else
-		if (shift < PUD_SHIFT)
-			pdshift = PMD_SHIFT;
-		else if (shift < PGDIR_SHIFT)
-			pdshift = PUD_SHIFT;
-		else
-			pdshift = PGDIR_SHIFT;
-#endif
-
 		if (add_huge_page_size(1ULL << shift) < 0)
 			continue;
-		/*
-		 * if we have pdshift and shift value same, we don't
-		 * use pgt cache for hugepd.
-		 */
-		if (pdshift > shift) {
-			pgtable_cache_add(pdshift - shift);
-		}
 
 		configured = true;
 	}
arch/powerpc/mm/pgtable.c +1 -1
index 6498454959f3..218792cb2c47 100644
@@ -331,7 +331,7 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
 		__set_huge_pte_at(pmdp, ptep, pte_val(pte));
 	}
 }
-#elif defined(CONFIG_PPC_E500)
+#else
 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
 		     pte_t pte, unsigned long sz)
 {
arch/powerpc/platforms/Kconfig.cputype +0 -1
index 30a78e99663e..b2d8c0da2ad9 100644
@@ -98,7 +98,6 @@ config PPC_BOOK3S_64
 	select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
 	select ARCH_ENABLE_SPLIT_PMD_PTLOCK
 	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
-	select ARCH_HAS_HUGEPD if HUGETLB_PAGE
 	select ARCH_SUPPORTS_HUGETLBFS
 	select ARCH_SUPPORTS_NUMA_BALANCING
 	select HAVE_MOVE_PMD
Signature · 1 line
2.44.0
#22 lore raw

Re: [PATCH v6 21/23] powerpc/64s: Use contiguous PMD/PUD instead of HUGEPD

Quoted 16 lines · Christophe Leroy

On book3s/64, the only user of hugepd is hash in 4k mode.

All other setups (hash-64, radix-4, radix-64) use leaf PMD/PUD.

Rework hash-4k to use contiguous PMD and PUD instead.

In that setup there are only two huge page sizes: 16M and 16G.

16M sits at PMD level and 16G at PUD level.

pte_update doesn't know page size, lets use the same trick as hpte_need_flush() to get page size from segment properties. That's not the most efficient way but let's do that until callers of pte_update() provide page size instead of just a huge flag.

[snip]

Quoted 24 lines
arch/powerpc/include/asm/book3s/64/hash.h +23 -0
+static inline unsigned long hash__pte_update(struct mm_struct *mm,
+					 unsigned long addr,
+					 pte_t *ptep, unsigned long clr,
+					 unsigned long set,
+					 int huge)
+{
+	unsigned long old;
+
+	old = hash__pte_update_one(ptep, clr, set);
+
+	if (IS_ENABLED(CONFIG_PPC_4K_PAGES) && huge) {
+		unsigned int psize = get_slice_psize(mm, addr);
+		int nb, i;
+
+		if (psize == MMU_PAGE_16M)
+			nb = SZ_16M / PMD_SIZE;
+		else if (psize == MMU_PAGE_16G)
+			nb = SZ_16G / PUD_SIZE;
+		else
+			nb = 1;
+
+		WARN_ON_ONCE(nb == 1);	/* Should never happen */
+

arch/powerpc/include/asm/book3s/64/hash.h static inline unsigned long hash__pte_update(struct mm_struct *mm, · line 217

Quoted 10 lines
arch/powerpc/include/asm/book3s/64/hash.h +3 -1
+		for (i = 1; i < nb; i++)
+			hash__pte_update_one(ptep + i, clr, set);
+	}
 	/* huge pages use the old page table lock */
 	if (!huge)
 		assert_pte_locked(mm, addr);
 
-	old = be64_to_cpu(old_be);
 	if (old & H_PAGE_HASHPTE)
 		hpte_need_flush(mm, addr, ptep, old, huge);

We definitely need a bit more comment and changelog about the atomicity issues here. I think the plan should be all hash-side access just operates on PTE[0], which should avoid that whole race. There could be some cases that don't follow that. Adding some warnings to catch such things could be good too.

I'd been meaning to do more on this sooner, sorry. I've started tinkering with adding a bit of debug code. I'll see if I can help with adding a bit of comments.

[snip]

Quoted 11 lines
arch/powerpc/mm/book3s64/hugetlbpage.c +3 -0
index 5a2e512e96db..83c3361b358b 100644
@@ -53,6 +53,16 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
 		/* If PTE permissions don't match, take page fault */
 		if (unlikely(!check_pte_access(access, old_pte)))
 			return 1;
+		/*
+		 * If hash-4k, hugepages use seeral contiguous PxD entries
+		 * so bail out and let mm make the page young or dirty

arch/powerpc/mm/book3s64/hugetlbpage.c int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, · line 68

Quoted 10 lines
arch/powerpc/mm/book3s64/hugetlbpage.c +7 -0
+		 */
+		if (IS_ENABLED(CONFIG_PPC_4K_PAGES)) {
+			if (!(old_pte & _PAGE_ACCESSED))
+				return 1;
+			if ((access & _PAGE_WRITE) && !(old_pte & _PAGE_DIRTY))
+				return 1;
+		}
 
 		/*
 		 * Try to lock the PTE, add ACCESSED and DIRTY if it was

I'm hoping we wouldn't have to do this, if we follow the PTE[0] rule.

I think is minor enough that should not prevent testing in -mm.

Thanks,
Nick

#23 lore raw

Re: [PATCH v6 21/23] powerpc/64s: Use contiguous PMD/PUD instead of HUGEPD

Le 25/06/2024 à 06:49, Nicholas Piggin a écrit :

Quoted 50 lines · Christophe Leroy
Quoted 16 lines

On book3s/64, the only user of hugepd is hash in 4k mode.

All other setups (hash-64, radix-4, radix-64) use leaf PMD/PUD.

Rework hash-4k to use contiguous PMD and PUD instead.

In that setup there are only two huge page sizes: 16M and 16G.

16M sits at PMD level and 16G at PUD level.

pte_update doesn't know page size, lets use the same trick as hpte_need_flush() to get page size from segment properties. That's not the most efficient way but let's do that until callers of pte_update() provide page size instead of just a huge flag.

[snip]

Quoted 30 lines
arch/powerpc/include/asm/book3s/64/hash.h +26 -0
+static inline unsigned long hash__pte_update(struct mm_struct *mm,
+					 unsigned long addr,
+					 pte_t *ptep, unsigned long clr,
+					 unsigned long set,
+					 int huge)
+{
+	unsigned long old;
+
+	old = hash__pte_update_one(ptep, clr, set);
+
+	if (IS_ENABLED(CONFIG_PPC_4K_PAGES) && huge) {
+		unsigned int psize = get_slice_psize(mm, addr);
+		int nb, i;
+
+		if (psize == MMU_PAGE_16M)
+			nb = SZ_16M / PMD_SIZE;
+		else if (psize == MMU_PAGE_16G)
+			nb = SZ_16G / PUD_SIZE;
+		else
+			nb = 1;
+
+		WARN_ON_ONCE(nb == 1);	/* Should never happen */
+
+		for (i = 1; i < nb; i++)
+			hash__pte_update_one(ptep + i, clr, set);
+	}
  	/* huge pages use the old page table lock */
  	if (!huge)
  		assert_pte_locked(mm, addr);
Quoted 10 lines

arch/powerpc/include/asm/book3s/64/hash.h static inline unsigned long hash__pte_update(struct mm_struct *mm, · line 217

Quoted 4 lines
arch/powerpc/include/asm/book3s/64/hash.h +0 -1
-	old = be64_to_cpu(old_be);
  	if (old & H_PAGE_HASHPTE)
  		hpte_need_flush(mm, addr, ptep, old, huge);

We definitely need a bit more comment and changelog about the atomicity issues here. I think the plan should be all hash-side access just operates on PTE[0], which should avoid that whole race. There could be some cases that don't follow that. Adding some warnings to catch such things could be good too.

That seems to be the case indeed, as we have the following in hash_page_mm():

#ifndef CONFIG_PPC_64K_PAGES
	/*
	 * If we use 4K pages and our psize is not 4K, then we might
	 * be hitting a special driver mapping, and need to align the
	 * address before we fetch the PTE.
	 *
	 * It could also be a hugepage mapping, in which case this is
	 * not necessary, but it's not harmful, either.
	 */
	if (psize != MMU_PAGE_4K)
		ea &= ~((1ul << mmu_psize_defs[psize].shift) - 1);

#endif /* CONFIG_PPC_64K_PAGES */

Quoted 4 lines

I'd been meaning to do more on this sooner, sorry. I've started tinkering with adding a bit of debug code. I'll see if I can help with adding a bit of comments.

Yes would we very welcome, I guess you'll send it as followup/fixup patch to the series ?

Quoted 22 lines

[snip]

Quoted 19 lines
arch/powerpc/mm/book3s64/hugetlbpage.c +10 -0
index 5a2e512e96db..83c3361b358b 100644
@@ -53,6 +53,16 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
  		/* If PTE permissions don't match, take page fault */
  		if (unlikely(!check_pte_access(access, old_pte)))
  			return 1;
+		/*
+		 * If hash-4k, hugepages use seeral contiguous PxD entries
+		 * so bail out and let mm make the page young or dirty
+		 */
+		if (IS_ENABLED(CONFIG_PPC_4K_PAGES)) {
+			if (!(old_pte & _PAGE_ACCESSED))
+				return 1;
+			if ((access & _PAGE_WRITE) && !(old_pte & _PAGE_DIRTY))
+				return 1;
+		}
 
Quoted 4 lines

arch/powerpc/mm/book3s64/hugetlbpage.c int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, · line 68

Quoted 2 lines
arch/powerpc/mm/book3s64/hugetlbpage.c +0 -0
  		/*
  		 * Try to lock the PTE, add ACCESSED and DIRTY if it was

I'm hoping we wouldn't have to do this, if we follow the PTE[0] rule.

But we still need all entries to be updated so that page walker which don't know they must use PTE[0] get the right information ?

Quoted 2 lines

I think is minor enough that should not prevent testing in -mm.

Thanks.

Quoted 3 lines

Thanks,
Nick

Christophe

#24 lore raw

Re: [PATCH v6 21/23] powerpc/64s: Use contiguous PMD/PUD instead of HUGEPD

Quoted 78 lines · LEROY Christophe

Le 25/06/2024 à 06:49, Nicholas Piggin a écrit :

Quoted 50 lines · Christophe Leroy
Quoted 16 lines

On book3s/64, the only user of hugepd is hash in 4k mode.

All other setups (hash-64, radix-4, radix-64) use leaf PMD/PUD.

Rework hash-4k to use contiguous PMD and PUD instead.

In that setup there are only two huge page sizes: 16M and 16G.

16M sits at PMD level and 16G at PUD level.

pte_update doesn't know page size, lets use the same trick as hpte_need_flush() to get page size from segment properties. That's not the most efficient way but let's do that until callers of pte_update() provide page size instead of just a huge flag.

[snip]

Quoted 30 lines
arch/powerpc/include/asm/book3s/64/hash.h +26 -0
+static inline unsigned long hash__pte_update(struct mm_struct *mm,
+					 unsigned long addr,
+					 pte_t *ptep, unsigned long clr,
+					 unsigned long set,
+					 int huge)
+{
+	unsigned long old;
+
+	old = hash__pte_update_one(ptep, clr, set);
+
+	if (IS_ENABLED(CONFIG_PPC_4K_PAGES) && huge) {
+		unsigned int psize = get_slice_psize(mm, addr);
+		int nb, i;
+
+		if (psize == MMU_PAGE_16M)
+			nb = SZ_16M / PMD_SIZE;
+		else if (psize == MMU_PAGE_16G)
+			nb = SZ_16G / PUD_SIZE;
+		else
+			nb = 1;
+
+		WARN_ON_ONCE(nb == 1);	/* Should never happen */
+
+		for (i = 1; i < nb; i++)
+			hash__pte_update_one(ptep + i, clr, set);
+	}
  	/* huge pages use the old page table lock */
  	if (!huge)
  		assert_pte_locked(mm, addr);
Quoted 10 lines

arch/powerpc/include/asm/book3s/64/hash.h static inline unsigned long hash__pte_update(struct mm_struct *mm, · line 217

Quoted 4 lines
arch/powerpc/include/asm/book3s/64/hash.h +0 -1
-	old = be64_to_cpu(old_be);
  	if (old & H_PAGE_HASHPTE)
  		hpte_need_flush(mm, addr, ptep, old, huge);

We definitely need a bit more comment and changelog about the atomicity issues here. I think the plan should be all hash-side access just operates on PTE[0], which should avoid that whole race. There could be some cases that don't follow that. Adding some warnings to catch such things could be good too.

That seems to be the case indeed, as we have the following in hash_page_mm():

#ifndef CONFIG_PPC_64K_PAGES
	/*
	 * If we use 4K pages and our psize is not 4K, then we might
	 * be hitting a special driver mapping, and need to align the
	 * address before we fetch the PTE.
	 *
	 * It could also be a hugepage mapping, in which case this is
	 * not necessary, but it's not harmful, either.
	 */
	if (psize != MMU_PAGE_4K)
		ea &= ~((1ul << mmu_psize_defs[psize].shift) - 1);
Quoted 1 line

#endif /* CONFIG_PPC_64K_PAGES */

Yeah, for that one it works (comment needs updating to say that it *is* necessary). I think that's the main thing but there's other possible places where it might not hold -- KVM too, not just the hash refill.

Quoted 7 lines
Quoted 4 lines

I'd been meaning to do more on this sooner, sorry. I've started tinkering with adding a bit of debug code. I'll see if I can help with adding a bit of comments.

Yes would we very welcome, I guess you'll send it as followup/fixup patch to the series ?

Yeah, the basic approach I think is good, so it wouldn't be a big rework.

Quoted 23 lines
Quoted 23 lines

[snip]

Quoted 19 lines
arch/powerpc/mm/book3s64/hugetlbpage.c +10 -0
index 5a2e512e96db..83c3361b358b 100644
@@ -53,6 +53,16 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
  		/* If PTE permissions don't match, take page fault */
  		if (unlikely(!check_pte_access(access, old_pte)))
  			return 1;
+		/*
+		 * If hash-4k, hugepages use seeral contiguous PxD entries
+		 * so bail out and let mm make the page young or dirty
+		 */
+		if (IS_ENABLED(CONFIG_PPC_4K_PAGES)) {
+			if (!(old_pte & _PAGE_ACCESSED))
+				return 1;
+			if ((access & _PAGE_WRITE) && !(old_pte & _PAGE_DIRTY))
+				return 1;
+		}
 
Quoted 7 lines
Quoted 4 lines

arch/powerpc/mm/book3s64/hugetlbpage.c int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, · line 68

Quoted 2 lines
arch/powerpc/mm/book3s64/hugetlbpage.c +0 -0
  		/*
  		 * Try to lock the PTE, add ACCESSED and DIRTY if it was

I'm hoping we wouldn't have to do this, if we follow the PTE[0] rule.

But we still need all entries to be updated so that page walker which don't know they must use PTE[0] get the right information ?

Ah yeah. Maybe for ACCESSED|DIRTY we can slightly adjust that rule and apply it to all PTEs. If we can do that then it takes care of a few other cases too.

Bug what is the consequence of two pte_update racing? Let's say page_vma_mkclean_one vs setting dirty. Can you end up with some PTEs dirty and some not?

Thanks,
Nick

reviewer Acked-by on v6 21/23
#25 lore raw

Re: [PATCH v6 21/23] powerpc/64s: Use contiguous PMD/PUD instead of HUGEPD

In reply to Christophe Leroy
Quoted 35 lines · Christophe Leroy

On book3s/64, the only user of hugepd is hash in 4k mode.

All other setups (hash-64, radix-4, radix-64) use leaf PMD/PUD.

Rework hash-4k to use contiguous PMD and PUD instead.

In that setup there are only two huge page sizes: 16M and 16G.

16M sits at PMD level and 16G at PUD level.

pte_update doesn't know page size, lets use the same trick as hpte_need_flush() to get page size from segment properties. That's not the most efficient way but let's do that until callers of pte_update() provide page size instead of just a huge flag.

---
v3:
- Add missing pmd_leaf_size() and pud_leaf_size()
- More cleanup in hugetlbpage_init()
- Take a page fault when DIRTY or ACCESSED is missing on hash-4 hugepage

v4: Rebased on v6.10-rc1

v6: Added a WARN_ON_ONCE() in hash__pte_update() in case the pagesize is unexpected.

---
 arch/powerpc/include/asm/book3s/64/hash-4k.h  | 15 ------
 arch/powerpc/include/asm/book3s/64/hash.h     | 40 +++++++++++++---
 arch/powerpc/include/asm/book3s/64/hugetlb.h  | 38 ---------------
 .../include/asm/book3s/64/pgtable-4k.h        | 47 -------------------
 .../include/asm/book3s/64/pgtable-64k.h       | 20 --------
 arch/powerpc/include/asm/book3s/64/pgtable.h  | 22 +++++++--
 arch/powerpc/include/asm/hugetlb.h            |  4 ++
 .../powerpc/include/asm/nohash/hugetlb-e500.h |  4 --
 arch/powerpc/include/asm/page.h               |  8 ----
Quoted 8 lines
 arch/powerpc/mm/book3s64/hash_utils.c         | 11 +++--
 arch/powerpc/mm/book3s64/hugetlbpage.c        | 10 ++++
 arch/powerpc/mm/book3s64/pgtable.c            | 12 -----
 arch/powerpc/mm/hugetlbpage.c                 | 26 ----------
 arch/powerpc/mm/pgtable.c                     |  2 +-
 arch/powerpc/platforms/Kconfig.cputype        |  1 -
 15 files changed, 74 insertions(+), 186 deletions(-)
 delete mode 100644 arch/powerpc/include/asm/book3s/64/pgtable-4k.h

This looks good to me. I've run a few tests on it and haven't seen any issues.

I also dumped the page tables of a test program and checked they looked sensible. And I checked that the hash insert path is actually inserting a huge page entry (of course it is, but just to be sure).

On mainline using a hugepd page hits the first warning in try_grab_folio() (via gup_hugepd()) and hangs the process. I haven't seen that reported (it goes back to v6.5), so my impression is hugepd on hash-4k is essentially unused these days.

This series is an improvement on that, so let's get it into mm-unstable for some wider testing.

cheers

#26 lore raw

PATCH v6 22/23 powerpc/mm: Remove hugepd leftovers

In reply to Christophe Leroy

All targets have now opted out of CONFIG_ARCH_HAS_HUGEPD so remove left over code.

---
v5: Fix a forgotten #endif which ended up in following patch

---
 arch/powerpc/include/asm/hugetlb.h          |   7 -
 arch/powerpc/include/asm/page.h             |   6 -
 arch/powerpc/include/asm/pgtable-be-types.h |  10 -
 arch/powerpc/include/asm/pgtable-types.h    |   9 -
 arch/powerpc/mm/hugetlbpage.c               | 413 --------------------
 arch/powerpc/mm/init-common.c               |   8 +-
 arch/powerpc/mm/pgtable.c                   |  27 +-
 7 files changed, 3 insertions(+), 477 deletions(-)
arch/powerpc/include/asm/hugetlb.h +0 -7
index e959c26c0b52..18a3028ac3b6 100644
@@ -30,13 +30,6 @@ static inline int is_hugepage_only_range(struct mm_struct *mm,
 }
 #define is_hugepage_only_range is_hugepage_only_range
 
-#ifdef CONFIG_ARCH_HAS_HUGEPD
-#define __HAVE_ARCH_HUGETLB_FREE_PGD_RANGE
-void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
-			    unsigned long end, unsigned long floor,
-			    unsigned long ceiling);
-#endif
-
 #define __HAVE_ARCH_HUGE_SET_HUGE_PTE_AT
 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
 		     pte_t pte, unsigned long sz);
arch/powerpc/include/asm/page.h +0 -6
index c0af246a64ff..83d0a4fc5f75 100644
@@ -269,12 +269,6 @@ static inline const void *pfn_to_kaddr(unsigned long pfn)
 #define is_kernel_addr(x)	((x) >= TASK_SIZE)
 #endif
 
-/*
- * Some number of bits at the level of the page table that points to
- * a hugepte are used to encode the size.  This masks those bits.
- */
-#define HUGEPD_SHIFT_MASK     0x3f
-
 #ifndef __ASSEMBLY__
 
 #ifdef CONFIG_PPC_BOOK3S_64
arch/powerpc/include/asm/pgtable-be-types.h +0 -10
index 82633200b500..6bd8f89b25dc 100644
@@ -101,14 +101,4 @@ static inline bool pmd_xchg(pmd_t *pmdp, pmd_t old, pmd_t new)
 	return pmd_raw(old) == prev;
 }
 
-#ifdef CONFIG_ARCH_HAS_HUGEPD
-typedef struct { __be64 pdbe; } hugepd_t;
-#define __hugepd(x) ((hugepd_t) { cpu_to_be64(x) })
-
-static inline unsigned long hpd_val(hugepd_t x)
-{
-	return be64_to_cpu(x.pdbe);
-}
-#endif
-
 #endif /* _ASM_POWERPC_PGTABLE_BE_TYPES_H */
arch/powerpc/include/asm/pgtable-types.h +0 -9
index db965d98e0ae..7b3d4c592a10 100644
@@ -87,13 +87,4 @@ static inline bool pte_xchg(pte_t *ptep, pte_t old, pte_t new)
 }
 #endif
 
-#ifdef CONFIG_ARCH_HAS_HUGEPD
-typedef struct { unsigned long pd; } hugepd_t;
-#define __hugepd(x) ((hugepd_t) { (x) })
-static inline unsigned long hpd_val(hugepd_t x)
-{
-	return x.pd;
-}
-#endif
-
 #endif /* _ASM_POWERPC_PGTABLE_TYPES_H */
arch/powerpc/mm/hugetlbpage.c +0 -413

437 lines not on this page · raw message

arch/powerpc/mm/init-common.c +2 -6
index d3a7726ecf51..024e95c62a2d 100644
@@ -120,12 +120,8 @@ void pgtable_cache_add(unsigned int shift)
 	/* When batching pgtable pointers for RCU freeing, we store
 	 * the index size in the low bits.  Table alignment must be
 	 * big enough to fit it.
-	 *
-	 * Likewise, hugeapge pagetable pointers contain a (different)
-	 * shift value in the low bits.  All tables must be aligned so
-	 * as to leave enough 0 bits in the address to contain it. */
-	unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1,
-				     HUGEPD_SHIFT_MASK + 1);
+	 */
+	unsigned long minalign = MAX_PGTABLE_INDEX_SIZE + 1;
 	struct kmem_cache *new = NULL;
 
 	/* It would be nice if this was a BUILD_BUG_ON(), but at the
arch/powerpc/mm/pgtable.c +1 -26
index 218792cb2c47..ab0656115424 100644
@@ -409,11 +409,10 @@ unsigned long vmalloc_to_phys(void *va)
 EXPORT_SYMBOL_GPL(vmalloc_to_phys);
 
 /*
- * We have 4 cases for pgds and pmds:
+ * We have 3 cases for pgds and pmds:
  * (1) invalid (all zeroes)
  * (2) pointer to next table, as normal; bottom 6 bits == 0
  * (3) leaf pte for huge page _PAGE_PTE set
- * (4) hugepd pointer, _PAGE_PTE = 0 and bits [2..6] indicate size of table
  *
  * So long as we atomically load page table pointers we are safe against teardown,
  * we can follow the address down to the page and take a ref on it.
@@ -430,7 +429,6 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
 #endif
 	pmd_t pmd, *pmdp;
 	pte_t *ret_pte;
-	hugepd_t *hpdp = NULL;
 	unsigned pdshift;
 
 	if (hpage_shift)
@@ -463,11 +461,6 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
 		goto out;
 	}
 
-	if (is_hugepd(__hugepd(p4d_val(p4d)))) {
-		hpdp = (hugepd_t *)&p4d;
-		goto out_huge;
-	}
-
 	/*
 	 * Even if we end up with an unmap, the pgtable will not
 	 * be freed, because we do an rcu free and here we are
@@ -485,11 +478,6 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
 		goto out;
 	}
 
-	if (is_hugepd(__hugepd(pud_val(pud)))) {
-		hpdp = (hugepd_t *)&pud;
-		goto out_huge;
-	}
-
 	pmdp = pmd_offset(&pud, ea);
 #else
 	pmdp = pmd_offset(pud_offset(p4d_offset(pgdp, ea), ea), ea);
@@ -527,21 +515,8 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
 		goto out;
 	}
 
-	if (is_hugepd(__hugepd(pmd_val(pmd)))) {
-		hpdp = (hugepd_t *)&pmd;
-		goto out_huge;
-	}
-
 	return pte_offset_kernel(&pmd, ea);
 
-out_huge:
-	if (!hpdp)
-		return NULL;
-
-#ifdef CONFIG_ARCH_HAS_HUGEPD
-	ret_pte = hugepte_offset(*hpdp, ea, pdshift);
-	pdshift = hugepd_shift(*hpdp);
-#endif
 out:
 	if (hpage_shift)
 		*hpage_shift = pdshift;
Signature · 1 line
2.44.0
#27 lore raw

PATCH v6 23/23 mm: Remove CONFIG_ARCH_HAS_HUGEPD

In reply to Christophe Leroy

powerpc was the only user of CONFIG_ARCH_HAS_HUGEPD and doesn't use it anymore, so remove all related code.

---
v4: Rebased on v6.10-rc1

---
 include/linux/hugetlb.h |   6 --
 mm/Kconfig              |  10 ---
 mm/gup.c                | 183 ++--------------------------------------
 mm/pagewalk.c           |  57 +------------
 4 files changed, 9 insertions(+), 247 deletions(-)
include/linux/hugetlb.h +0 -6
index 2b3c3a404769..58daf7d14bf4 100644
@@ -20,12 +20,6 @@ struct user_struct;
 struct mmu_gather;
 struct node;
 
-#ifndef CONFIG_ARCH_HAS_HUGEPD
-typedef struct { unsigned long pd; } hugepd_t;
-#define is_hugepd(hugepd) (0)
-#define __hugepd(x) ((hugepd_t) { (x) })
-#endif
-
 void free_huge_folio(struct folio *folio);
 
 #ifdef CONFIG_HUGETLB_PAGE
mm/Kconfig +0 -10
index b4cb45255a54..049d29ec6e20 100644
@@ -1119,16 +1119,6 @@ config DMAPOOL_TEST
 config ARCH_HAS_PTE_SPECIAL
 	bool
 
-#
-# Some architectures require a special hugepage directory format that is
-# required to support multiple hugepage sizes. For example a4fe3ce76
-# "powerpc/mm: Allow more flexible layouts for hugepage pagetables"
-# introduced it on powerpc.  This allows for a more flexible hugepage
-# pagetable layouts.
-#
-config ARCH_HAS_HUGEPD
-	bool
-
 config MAPPING_DIRTY_HELPERS
         bool
 
mm/gup.c +5 -178

243 lines not on this page · raw message

mm/pagewalk.c +4 -53

87 lines not on this page · raw message

Signature · 1 line
2.44.0