arm: add early_ioremap support

PATCH New Leif Lindholm 7 participants 16 messages Jul 9, 2014 – Jul 25, 2014 Arm (32-bit)

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Leif Lindholm

author

2014-07-09 09:39 UTC #0 lore raw

cover arm: add early_ioremap support

early_ioremap()/early_memremap() create temporary virtual mappings in the fixmap region during boot time. Part of the support now exists in core code, but depends on the generic fixmap support.

This set converts arm to use the generic fixmap support, and adds the architecture-specific part of early_ioremap support.

The fixmap/kmap changes in 3.15 complicated things slightly compared to previous iterations of these patches - this version works around that by introducing local macros in arm/mm/highmem.c.

Tested on TC2 and software models, with/without LPAE.

Mark Salter (2):
arm: use generic fixmap.h
arm: add early_ioremap support

 arch/arm/Kconfig              |   11 ++++++
 arch/arm/include/asm/Kbuild   |    1 +
 arch/arm/include/asm/fixmap.h |   45 +++++++++++++--------
 arch/arm/include/asm/io.h     |    1 +
 arch/arm/kernel/setup.c       |    3 ++
 arch/arm/mm/Makefile          |    1 +
 arch/arm/mm/early_ioremap.c   |   86 +++++++++++++++++++++++++++++++++++++++++
 arch/arm/mm/highmem.c         |   13 ++++---
 arch/arm/mm/init.c            |    2 +-
 arch/arm/mm/mmu.c             |    2 +
 10 files changed, 143 insertions(+), 22 deletions(-)
 create mode 100644 arch/arm/mm/early_ioremap.c

Signature · 1 line

1.7.10.4

Leif Lindholm

author

2014-07-09 09:39 UTC #1 lore raw

PATCH 1/2 arm: use generic fixmap.h

From: Mark Salter <[email protected]>

ARM is different from other architectures in that fixmap pages are indexed with a positive offset from FIXADDR_START. Other architectures index with a negative offset from FIXADDR_TOP. In order to use the generic fixmap.h definitions, this patch redefines FIXADDR_TOP to be inclusive of the useable range. That is, FIXADDR_TOP is the virtual address of the topmost fixed page. The newly defined FIXADDR_END is the first virtual address past the fixed mappings.

The patch also introduces local helper macros in highmem.c to reverse the iteration order of fixmap pages.

Signed-off-by Mark Salter <[email protected]>

[Rebased to 3.16-rc4, reverse kmap fixmap traversal]

Signed-off-by Leif Lindholm <[email protected]>

---
 arch/arm/include/asm/fixmap.h |   45 ++++++++++++++++++++++++++---------------
 arch/arm/mm/highmem.c         |   13 +++++++-----
 arch/arm/mm/init.c            |    2 +-
 3 files changed, 38 insertions(+), 22 deletions(-)

arch/arm/include/asm/fixmap.h +29 ~~-16~~

index 74124b0..8992431 100644
@@ -1,28 +1,41 @@
 #ifndef _ASM_FIXMAP_H
 #define _ASM_FIXMAP_H
 
+#include <asm/pgtable.h>
+
 #define FIXADDR_START		0xffc00000UL
-#define FIXADDR_TOP		0xffe00000UL
-#define FIXADDR_SIZE		(FIXADDR_TOP - FIXADDR_START)
+#define FIXADDR_END		0xffe00000UL
+#define FIXADDR_SIZE		(FIXADDR_END - FIXADDR_START)
+#define FIXADDR_TOP		(FIXADDR_END - PAGE_SIZE)
 
 #define FIX_KMAP_NR_PTES	(FIXADDR_SIZE >> PAGE_SHIFT)
 
-#define __fix_to_virt(x)	(FIXADDR_START + ((x) << PAGE_SHIFT))
-#define __virt_to_fix(x)	(((x) - FIXADDR_START) >> PAGE_SHIFT)
+enum fixed_addresses {
+	FIX_KMAP_BEGIN,
+	FIX_KMAP_END = FIX_KMAP_NR_PTES - 1,
+	__end_of_fixed_addresses
+};
+
+/*
+ * Temporary boot-time mappings, used by early_ioremap(),
+ * before ioremap() is functional.
+ *
+ * (P)re-using the last pmd of the FIXADDR region, which is used for
+ * highmem later on, and statically aligned to 1MB.
+ * Growing down from FIXADDR_TOP
+ */
+#define NR_FIX_BTMAPS		32
+#define FIX_BTMAPS_SLOTS	(PTRS_PER_PTE / NR_FIX_BTMAPS)
+#define TOTAL_FIX_BTMAPS	(NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
+#define FIX_BTMAP_END		FIX_KMAP_BEGIN
+#define FIX_BTMAP_BEGIN		(FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1)
 
-extern void __this_fixmap_does_not_exist(void);
+#define FIXMAP_PAGE_NORMAL (L_PTE_MT_WRITEBACK | L_PTE_YOUNG | L_PTE_PRESENT)
+#define FIXMAP_PAGE_IO (L_PTE_MT_DEV_NONSHARED | L_PTE_YOUNG | L_PTE_PRESENT)
 
-static inline unsigned long fix_to_virt(const unsigned int idx)
-{
-	if (idx >= FIX_KMAP_NR_PTES)
-		__this_fixmap_does_not_exist();
-	return __fix_to_virt(idx);
-}
+extern void __early_set_fixmap(enum fixed_addresses idx,
+			       phys_addr_t phys, pgprot_t flags);
 
-static inline unsigned int virt_to_fix(const unsigned long vaddr)
-{
-	BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
-	return __virt_to_fix(vaddr);
-}
+#include <asm-generic/fixmap.h>
 
 #endif

arch/arm/mm/highmem.c +8 -5

index 45aeaac..3c59cdf 100644
@@ -20,16 +20,19 @@
 
 pte_t *fixmap_page_table;
 
+#define __kmap_fix_to_virt(x)	(__fix_to_virt(FIX_KMAP_NR_PTES - 1 - (x)))
+#define __kmap_virt_to_fix(x)	(FIX_KMAP_NR_PTES - 1 - __fix_to_virt(x))
+
 static inline void set_fixmap_pte(int idx, pte_t pte)
 {
-	unsigned long vaddr = __fix_to_virt(idx);
+	unsigned long vaddr = __kmap_fix_to_virt(idx);
 	set_pte_ext(fixmap_page_table + idx, pte, 0);
 	local_flush_tlb_kernel_page(vaddr);
 }
 
 static inline pte_t get_fixmap_pte(unsigned long vaddr)
 {
-	unsigned long idx = __virt_to_fix(vaddr);
+	unsigned long idx = __kmap_virt_to_fix(vaddr);
 	return *(fixmap_page_table + idx);
 }

@@ -78,7 +81,7 @@ void *kmap_atomic(struct page *page)
 	type = kmap_atomic_idx_push();
 
 	idx = type + KM_TYPE_NR * smp_processor_id();
-	vaddr = __fix_to_virt(idx);
+	vaddr = __kmap_fix_to_virt(idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
 	/*
 	 * With debugging enabled, kunmap_atomic forces that entry to 0.

@@ -109,7 +112,7 @@ void __kunmap_atomic(void *kvaddr)
 		if (cache_is_vivt())
 			__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
 #ifdef CONFIG_DEBUG_HIGHMEM
-		BUG_ON(vaddr != __fix_to_virt(idx));
+		BUG_ON(vaddr != __kmap_fix_to_virt(idx));
 		set_fixmap_pte(idx, __pte(0));
 #else
 		(void) idx;  /* to kill a warning */

@@ -132,7 +135,7 @@ void *kmap_atomic_pfn(unsigned long pfn)
 
 	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR * smp_processor_id();
-	vaddr = __fix_to_virt(idx);
+	vaddr = __kmap_fix_to_virt(idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
 	BUG_ON(!pte_none(*(fixmap_page_table + idx)));
 #endif

arch/arm/mm/init.c +1 -1

index 659c75d..ad82c05 100644
@@ -570,7 +570,7 @@ void __init mem_init(void)
 			MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
 			MLK(ITCM_OFFSET, (unsigned long) itcm_end),
 #endif
-			MLK(FIXADDR_START, FIXADDR_TOP),
+			MLK(FIXADDR_START, FIXADDR_END),
 			MLM(VMALLOC_START, VMALLOC_END),
 			MLM(PAGE_OFFSET, (unsigned long)high_memory),
 #ifdef CONFIG_HIGHMEM

Signature · 1 line

1.7.10.4

Mark Salter

2014-07-09 20:49 UTC #2 lore raw

PATCH 1/2 arm: use generic fixmap.h

Quoted 89 lines · Leif Lindholm

From: Mark Salter <[email protected]>

The patch also introduces local helper macros in highmem.c to reverse the iteration order of fixmap pages.

Signed-off-by Mark Salter <[email protected]>

[Rebased to 3.16-rc4, reverse kmap fixmap traversal]

Signed-off-by Leif Lindholm <[email protected]>

---
 arch/arm/include/asm/fixmap.h |   45 ++++++++++++++++++++++++++---------------
 arch/arm/mm/highmem.c         |   13 +++++++-----
 arch/arm/mm/init.c            |    2 +-
 3 files changed, 38 insertions(+), 22 deletions(-)

arch/arm/include/asm/fixmap.h +29 ~~-16~~

index 74124b0..8992431 100644
@@ -1,28 +1,41 @@
 #ifndef _ASM_FIXMAP_H
 #define _ASM_FIXMAP_H
 
+#include <asm/pgtable.h>
+
 #define FIXADDR_START		0xffc00000UL
-#define FIXADDR_TOP		0xffe00000UL
-#define FIXADDR_SIZE		(FIXADDR_TOP - FIXADDR_START)
+#define FIXADDR_END		0xffe00000UL
+#define FIXADDR_SIZE		(FIXADDR_END - FIXADDR_START)
+#define FIXADDR_TOP		(FIXADDR_END - PAGE_SIZE)
 
 #define FIX_KMAP_NR_PTES	(FIXADDR_SIZE >> PAGE_SHIFT)
 
-#define __fix_to_virt(x)	(FIXADDR_START + ((x) << PAGE_SHIFT))
-#define __virt_to_fix(x)	(((x) - FIXADDR_START) >> PAGE_SHIFT)
+enum fixed_addresses {
+	FIX_KMAP_BEGIN,
+	FIX_KMAP_END = FIX_KMAP_NR_PTES - 1,
+	__end_of_fixed_addresses
+};
+
+/*
+ * Temporary boot-time mappings, used by early_ioremap(),
+ * before ioremap() is functional.
+ *
+ * (P)re-using the last pmd of the FIXADDR region, which is used for
+ * highmem later on, and statically aligned to 1MB.
+ * Growing down from FIXADDR_TOP
+ */
+#define NR_FIX_BTMAPS		32
+#define FIX_BTMAPS_SLOTS	(PTRS_PER_PTE / NR_FIX_BTMAPS)
+#define TOTAL_FIX_BTMAPS	(NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
+#define FIX_BTMAP_END		FIX_KMAP_BEGIN
+#define FIX_BTMAP_BEGIN		(FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1)
 
-extern void __this_fixmap_does_not_exist(void);
+#define FIXMAP_PAGE_NORMAL (L_PTE_MT_WRITEBACK | L_PTE_YOUNG | L_PTE_PRESENT)
+#define FIXMAP_PAGE_IO (L_PTE_MT_DEV_NONSHARED | L_PTE_YOUNG | L_PTE_PRESENT)
 
-static inline unsigned long fix_to_virt(const unsigned int idx)
-{
-	if (idx >= FIX_KMAP_NR_PTES)
-		__this_fixmap_does_not_exist();
-	return __fix_to_virt(idx);
-}
+extern void __early_set_fixmap(enum fixed_addresses idx,
+			       phys_addr_t phys, pgprot_t flags);
 
-static inline unsigned int virt_to_fix(const unsigned long vaddr)
-{
-	BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
-	return __virt_to_fix(vaddr);
-}
+#include <asm-generic/fixmap.h>
 
 #endif

arch/arm/mm/highmem.c +0 -0

index 45aeaac..3c59cdf 100644

arch/arm/mm/highmem.c line 23

Quoted 4 lines

arch/arm/mm/highmem.c +1 -0

@@ -20,16 +20,19 @@
 
 pte_t *fixmap_page_table;
 
+#define __kmap_fix_to_virt(x)	(__fix_to_virt(FIX_KMAP_NR_PTES - 1 - (x)))

FIX_KMAP_END - (x) ?

arch/arm/mm/highmem.c line 24

Quoted 1 line

arch/arm/mm/highmem.c +1 -0

+#define __kmap_virt_to_fix(x)	(FIX_KMAP_NR_PTES - 1 - __fix_to_virt(x))

shouldn't this use __virt_to_fix(x)?

Quoted 56 lines

arch/arm/mm/highmem.c +6 -5

+
 static inline void set_fixmap_pte(int idx, pte_t pte)
 {
-	unsigned long vaddr = __fix_to_virt(idx);
+	unsigned long vaddr = __kmap_fix_to_virt(idx);
 	set_pte_ext(fixmap_page_table + idx, pte, 0);
 	local_flush_tlb_kernel_page(vaddr);
 }
 
 static inline pte_t get_fixmap_pte(unsigned long vaddr)
 {
-	unsigned long idx = __virt_to_fix(vaddr);
+	unsigned long idx = __kmap_virt_to_fix(vaddr);
 	return *(fixmap_page_table + idx);
 }

@@ -78,7 +81,7 @@ void *kmap_atomic(struct page *page)
 	type = kmap_atomic_idx_push();
 
 	idx = type + KM_TYPE_NR * smp_processor_id();
-	vaddr = __fix_to_virt(idx);
+	vaddr = __kmap_fix_to_virt(idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
 	/*
 	 * With debugging enabled, kunmap_atomic forces that entry to 0.

@@ -109,7 +112,7 @@ void __kunmap_atomic(void *kvaddr)
 		if (cache_is_vivt())
 			__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
 #ifdef CONFIG_DEBUG_HIGHMEM
-		BUG_ON(vaddr != __fix_to_virt(idx));
+		BUG_ON(vaddr != __kmap_fix_to_virt(idx));
 		set_fixmap_pte(idx, __pte(0));
 #else
 		(void) idx;  /* to kill a warning */

@@ -132,7 +135,7 @@ void *kmap_atomic_pfn(unsigned long pfn)
 
 	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR * smp_processor_id();
-	vaddr = __fix_to_virt(idx);
+	vaddr = __kmap_fix_to_virt(idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
 	BUG_ON(!pte_none(*(fixmap_page_table + idx)));
 #endif

arch/arm/mm/init.c +1 -1

index 659c75d..ad82c05 100644
@@ -570,7 +570,7 @@ void __init mem_init(void)
 			MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
 			MLK(ITCM_OFFSET, (unsigned long) itcm_end),
 #endif
-			MLK(FIXADDR_START, FIXADDR_TOP),
+			MLK(FIXADDR_START, FIXADDR_END),
 			MLM(VMALLOC_START, VMALLOC_END),
 			MLM(PAGE_OFFSET, (unsigned long)high_memory),
 #ifdef CONFIG_HIGHMEM

Leif Lindholm

author

2014-07-18 14:33 UTC #3 lore raw

PATCH 1/2 arm: use generic fixmap.h

Quoted 9 lines · Mark Salter

Quoted 8 lines · Leif Lindholm
arch/arm/mm/highmem.c +0 -0
index 45aeaac..3c59cdf 100644
@@ -20,16 +20,19 @@
 
 pte_t *fixmap_page_table;
 

Quoted 7 lines

arch/arm/mm/highmem.c line 23
Quoted 1 line
arch/arm/mm/highmem.c +1 -0
+#define __kmap_fix_to_virt(x)	(__fix_to_virt(FIX_KMAP_NR_PTES - 1 - (x)))
FIX_KMAP_END - (x) ?
arch/arm/mm/highmem.c line 24
Quoted 1 line
arch/arm/mm/highmem.c +1 -0
+#define __kmap_virt_to_fix(x)	(FIX_KMAP_NR_PTES - 1 - __fix_to_virt(x))
shouldn't this use __virt_to_fix(x)?

Err, clearly.
Good thing I managed to mess up the end of the interface that actually isn't used anywhere in the kernel(!).

Fixed in the below.

/
Leif

Quoted 1 line

From d0a82cd19000139d32232f415bcf46f476c16561 Mon Sep 17 00:00:00 2001

From: Mark Salter <[email protected]>
Date: Thu, 14 Nov 2013 11:37:32 -0500
Subject: [PATCH 1/2] arm: use generic fixmap.h

The patch also introduces local helper macros in highmem.c to reverse the iteration order of fixmap pages.

Signed-off-by Mark Salter <[email protected]>

[Rebased to 3.16-rc4, reverse kmap fixmap traversal]

Signed-off-by Leif Lindholm <[email protected]>

---
 arch/arm/include/asm/fixmap.h |   45 ++++++++++++++++++++++++++---------------
 arch/arm/mm/highmem.c         |   13 +++++++-----
 arch/arm/mm/init.c            |    2 +-
 3 files changed, 38 insertions(+), 22 deletions(-)

arch/arm/include/asm/fixmap.h +29 ~~-16~~

index 74124b0..8992431 100644
@@ -1,28 +1,41 @@
 #ifndef _ASM_FIXMAP_H
 #define _ASM_FIXMAP_H
 
+#include <asm/pgtable.h>
+
 #define FIXADDR_START		0xffc00000UL
-#define FIXADDR_TOP		0xffe00000UL
-#define FIXADDR_SIZE		(FIXADDR_TOP - FIXADDR_START)
+#define FIXADDR_END		0xffe00000UL
+#define FIXADDR_SIZE		(FIXADDR_END - FIXADDR_START)
+#define FIXADDR_TOP		(FIXADDR_END - PAGE_SIZE)
 
 #define FIX_KMAP_NR_PTES	(FIXADDR_SIZE >> PAGE_SHIFT)
 
-#define __fix_to_virt(x)	(FIXADDR_START + ((x) << PAGE_SHIFT))
-#define __virt_to_fix(x)	(((x) - FIXADDR_START) >> PAGE_SHIFT)
+enum fixed_addresses {
+	FIX_KMAP_BEGIN,
+	FIX_KMAP_END = FIX_KMAP_NR_PTES - 1,
+	__end_of_fixed_addresses
+};
+
+/*
+ * Temporary boot-time mappings, used by early_ioremap(),
+ * before ioremap() is functional.
+ *
+ * (P)re-using the last pmd of the FIXADDR region, which is used for
+ * highmem later on, and statically aligned to 1MB.
+ * Growing down from FIXADDR_TOP
+ */
+#define NR_FIX_BTMAPS		32
+#define FIX_BTMAPS_SLOTS	(PTRS_PER_PTE / NR_FIX_BTMAPS)
+#define TOTAL_FIX_BTMAPS	(NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
+#define FIX_BTMAP_END		FIX_KMAP_BEGIN
+#define FIX_BTMAP_BEGIN		(FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1)
 
-extern void __this_fixmap_does_not_exist(void);
+#define FIXMAP_PAGE_NORMAL (L_PTE_MT_WRITEBACK | L_PTE_YOUNG | L_PTE_PRESENT)
+#define FIXMAP_PAGE_IO (L_PTE_MT_DEV_NONSHARED | L_PTE_YOUNG | L_PTE_PRESENT)
 
-static inline unsigned long fix_to_virt(const unsigned int idx)
-{
-	if (idx >= FIX_KMAP_NR_PTES)
-		__this_fixmap_does_not_exist();
-	return __fix_to_virt(idx);
-}
+extern void __early_set_fixmap(enum fixed_addresses idx,
+			       phys_addr_t phys, pgprot_t flags);
 
-static inline unsigned int virt_to_fix(const unsigned long vaddr)
-{
-	BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
-	return __virt_to_fix(vaddr);
-}
+#include <asm-generic/fixmap.h>
 
 #endif

arch/arm/mm/highmem.c +8 -5

index 45aeaac..2e5b773 100644
@@ -20,16 +20,19 @@
 
 pte_t *fixmap_page_table;
 
+#define __kmap_fix_to_virt(x)	(__fix_to_virt(FIX_KMAP_NR_PTES - 1 - (x)))
+#define __kmap_virt_to_fix(x)	(FIX_KMAP_NR_PTES - 1 - __virt_to_fix(x))
+
 static inline void set_fixmap_pte(int idx, pte_t pte)
 {
-	unsigned long vaddr = __fix_to_virt(idx);
+	unsigned long vaddr = __kmap_fix_to_virt(idx);
 	set_pte_ext(fixmap_page_table + idx, pte, 0);
 	local_flush_tlb_kernel_page(vaddr);
 }
 
 static inline pte_t get_fixmap_pte(unsigned long vaddr)
 {
-	unsigned long idx = __virt_to_fix(vaddr);
+	unsigned long idx = __kmap_virt_to_fix(vaddr);
 	return *(fixmap_page_table + idx);
 }

@@ -78,7 +81,7 @@ void *kmap_atomic(struct page *page)
 	type = kmap_atomic_idx_push();
 
 	idx = type + KM_TYPE_NR * smp_processor_id();
-	vaddr = __fix_to_virt(idx);
+	vaddr = __kmap_fix_to_virt(idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
 	/*
 	 * With debugging enabled, kunmap_atomic forces that entry to 0.

@@ -109,7 +112,7 @@ void __kunmap_atomic(void *kvaddr)
 		if (cache_is_vivt())
 			__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
 #ifdef CONFIG_DEBUG_HIGHMEM
-		BUG_ON(vaddr != __fix_to_virt(idx));
+		BUG_ON(vaddr != __kmap_fix_to_virt(idx));
 		set_fixmap_pte(idx, __pte(0));
 #else
 		(void) idx;  /* to kill a warning */

@@ -132,7 +135,7 @@ void *kmap_atomic_pfn(unsigned long pfn)
 
 	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR * smp_processor_id();
-	vaddr = __fix_to_virt(idx);
+	vaddr = __kmap_fix_to_virt(idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
 	BUG_ON(!pte_none(*(fixmap_page_table + idx)));
 #endif

arch/arm/mm/init.c +1 -1

index 659c75d..ad82c05 100644
@@ -570,7 +570,7 @@ void __init mem_init(void)
 			MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
 			MLK(ITCM_OFFSET, (unsigned long) itcm_end),
 #endif
-			MLK(FIXADDR_START, FIXADDR_TOP),
+			MLK(FIXADDR_START, FIXADDR_END),
 			MLM(VMALLOC_START, VMALLOC_END),
 			MLM(PAGE_OFFSET, (unsigned long)high_memory),
 #ifdef CONFIG_HIGHMEM

Signature · 1 line

1.7.10.4

Kees Cook

2014-07-25 19:56 UTC #4 lore raw

PATCH 1/2 arm: use generic fixmap.h

Quoted 184 lines · Leif Lindholm

Quoted 9 lines · Mark Salter

Quoted 8 lines · Leif Lindholm
arch/arm/mm/highmem.c +0 -0
index 45aeaac..3c59cdf 100644
@@ -20,16 +20,19 @@
 
 pte_t *fixmap_page_table;
 

Quoted 7 lines

arch/arm/mm/highmem.c line 23
Quoted 1 line
arch/arm/mm/highmem.c +1 -0
+#define __kmap_fix_to_virt(x)      (__fix_to_virt(FIX_KMAP_NR_PTES - 1 - (x)))
FIX_KMAP_END - (x) ?
arch/arm/mm/highmem.c line 24
Quoted 1 line
arch/arm/mm/highmem.c +1 -0
+#define __kmap_virt_to_fix(x)      (FIX_KMAP_NR_PTES - 1 - __fix_to_virt(x))
shouldn't this use __virt_to_fix(x)?

Err, clearly.
Good thing I managed to mess up the end of the interface that actually isn't used anywhere in the kernel(!).

Fixed in the below.

/
Leif

From d0a82cd19000139d32232f415bcf46f476c16561 Mon Sep 17 00:00:00 2001
From: Mark Salter <[email protected]>
Date: Thu, 14 Nov 2013 11:37:32 -0500
Subject: [PATCH 1/2] arm: use generic fixmap.h

The patch also introduces local helper macros in highmem.c to reverse the iteration order of fixmap pages.

Signed-off-by Mark Salter <[email protected]>

[Rebased to 3.16-rc4, reverse kmap fixmap traversal]

Signed-off-by Leif Lindholm <[email protected]>

---
 arch/arm/include/asm/fixmap.h |   45 ++++++++++++++++++++++++++---------------
 arch/arm/mm/highmem.c         |   13 +++++++-----
 arch/arm/mm/init.c            |    2 +-
 3 files changed, 38 insertions(+), 22 deletions(-)

arch/arm/include/asm/fixmap.h +29 ~~-16~~

index 74124b0..8992431 100644
@@ -1,28 +1,41 @@
 #ifndef _ASM_FIXMAP_H
 #define _ASM_FIXMAP_H
 
+#include <asm/pgtable.h>
+
 #define FIXADDR_START          0xffc00000UL
-#define FIXADDR_TOP            0xffe00000UL
-#define FIXADDR_SIZE           (FIXADDR_TOP - FIXADDR_START)
+#define FIXADDR_END            0xffe00000UL
+#define FIXADDR_SIZE           (FIXADDR_END - FIXADDR_START)
+#define FIXADDR_TOP            (FIXADDR_END - PAGE_SIZE)
 
 #define FIX_KMAP_NR_PTES       (FIXADDR_SIZE >> PAGE_SHIFT)
 
-#define __fix_to_virt(x)       (FIXADDR_START + ((x) << PAGE_SHIFT))
-#define __virt_to_fix(x)       (((x) - FIXADDR_START) >> PAGE_SHIFT)
+enum fixed_addresses {
+       FIX_KMAP_BEGIN,
+       FIX_KMAP_END = FIX_KMAP_NR_PTES - 1,
+       __end_of_fixed_addresses
+};
+
+/*
+ * Temporary boot-time mappings, used by early_ioremap(),
+ * before ioremap() is functional.
+ *
+ * (P)re-using the last pmd of the FIXADDR region, which is used for
+ * highmem later on, and statically aligned to 1MB.
+ * Growing down from FIXADDR_TOP
+ */
+#define NR_FIX_BTMAPS          32
+#define FIX_BTMAPS_SLOTS       (PTRS_PER_PTE / NR_FIX_BTMAPS)
+#define TOTAL_FIX_BTMAPS       (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
+#define FIX_BTMAP_END          FIX_KMAP_BEGIN
+#define FIX_BTMAP_BEGIN                (FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1)
 
-extern void __this_fixmap_does_not_exist(void);
+#define FIXMAP_PAGE_NORMAL (L_PTE_MT_WRITEBACK | L_PTE_YOUNG | L_PTE_PRESENT)
+#define FIXMAP_PAGE_IO (L_PTE_MT_DEV_NONSHARED | L_PTE_YOUNG | L_PTE_PRESENT)
 
-static inline unsigned long fix_to_virt(const unsigned int idx)
-{
-       if (idx >= FIX_KMAP_NR_PTES)
-               __this_fixmap_does_not_exist();
-       return __fix_to_virt(idx);
-}
+extern void __early_set_fixmap(enum fixed_addresses idx,
+                              phys_addr_t phys, pgprot_t flags);
 
-static inline unsigned int virt_to_fix(const unsigned long vaddr)
-{
-       BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
-       return __virt_to_fix(vaddr);
-}
+#include <asm-generic/fixmap.h>
 
 #endif

arch/arm/mm/highmem.c +8 -5

index 45aeaac..2e5b773 100644
@@ -20,16 +20,19 @@
 
 pte_t *fixmap_page_table;
 
+#define __kmap_fix_to_virt(x)  (__fix_to_virt(FIX_KMAP_NR_PTES - 1 - (x)))
+#define __kmap_virt_to_fix(x)  (FIX_KMAP_NR_PTES - 1 - __virt_to_fix(x))
+
 static inline void set_fixmap_pte(int idx, pte_t pte)
 {
-       unsigned long vaddr = __fix_to_virt(idx);
+       unsigned long vaddr = __kmap_fix_to_virt(idx);
        set_pte_ext(fixmap_page_table + idx, pte, 0);
        local_flush_tlb_kernel_page(vaddr);
 }
 
 static inline pte_t get_fixmap_pte(unsigned long vaddr)
 {
-       unsigned long idx = __virt_to_fix(vaddr);
+       unsigned long idx = __kmap_virt_to_fix(vaddr);
        return *(fixmap_page_table + idx);
 }

@@ -78,7 +81,7 @@ void *kmap_atomic(struct page *page)
        type = kmap_atomic_idx_push();
 
        idx = type + KM_TYPE_NR * smp_processor_id();
-       vaddr = __fix_to_virt(idx);
+       vaddr = __kmap_fix_to_virt(idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
        /*
         * With debugging enabled, kunmap_atomic forces that entry to 0.

@@ -109,7 +112,7 @@ void __kunmap_atomic(void *kvaddr)
                if (cache_is_vivt())
                        __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
 #ifdef CONFIG_DEBUG_HIGHMEM
-               BUG_ON(vaddr != __fix_to_virt(idx));
+               BUG_ON(vaddr != __kmap_fix_to_virt(idx));
                set_fixmap_pte(idx, __pte(0));
 #else
                (void) idx;  /* to kill a warning */

@@ -132,7 +135,7 @@ void *kmap_atomic_pfn(unsigned long pfn)
 
        type = kmap_atomic_idx_push();
        idx = type + KM_TYPE_NR * smp_processor_id();
-       vaddr = __fix_to_virt(idx);
+       vaddr = __kmap_fix_to_virt(idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
        BUG_ON(!pte_none(*(fixmap_page_table + idx)));
 #endif

arch/arm/mm/init.c +1 -2

index 659c75d..ad82c05 100644
@@ -570,7 +570,7 @@ void __init mem_init(void)
                        MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
                        MLK(ITCM_OFFSET, (unsigned long) itcm_end),
 #endif
-                       MLK(FIXADDR_START, FIXADDR_TOP),
+                       MLK(FIXADDR_START, FIXADDR_END),
                        MLM(VMALLOC_START, VMALLOC_END),
                        MLM(PAGE_OFFSET, (unsigned long)high_memory),
 #ifdef CONFIG_HIGHMEM
--

1.7.10.4

Quoted 4 lines

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel at lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

I'd like to use this for kernel RO text handling too (kprobes and kgdb). Is this patch alone in good enough shape for landing in -next? I would want this added as well:
https://patchwork.kernel.org/patch/3941001/

Thoughts?

-Kees

Signature · 2 lines

Kees Cook
Chrome OS Security

Tomasz Figa

2014-07-22 16:39 UTC #5 lore raw

PATCH 1/2 arm: use generic fixmap.h

In reply to Leif Lindholm

Hi Leif,

Quoted 13 lines · Leif Lindholm

From: Mark Salter <[email protected]>
ARM is different from other architectures in that fixmap pages are indexed with a positive offset from FIXADDR_START. Other architectures index with a negative offset from FIXADDR_TOP. In order to use the generic fixmap.h definitions, this patch redefines FIXADDR_TOP to be inclusive of the useable range. That is, FIXADDR_TOP is the virtual address of the topmost fixed page. The newly defined FIXADDR_END is the first virtual address past the fixed mappings.
The patch also introduces local helper macros in highmem.c to reverse the iteration order of fixmap pages.

Quoted 9 lines

Signed-off-by Mark Salter <[email protected]>
[Rebased to 3.16-rc4, reverse kmap fixmap traversal]
Signed-off-by Leif Lindholm <[email protected]>
---
 arch/arm/include/asm/fixmap.h |   45 ++++++++++++++++++++++++++---------------
 arch/arm/mm/highmem.c         |   13 +++++++-----
 arch/arm/mm/init.c            |    2 +-
 3 files changed, 38 insertions(+), 22 deletions(-)

I've tried to use this series to enable earlycon without hardcoded static mappings, but apparently something is not right yet. Please see below.

[snip]

arch/arm/include/asm/fixmap.h line 34

Quoted 3 lines

arch/arm/include/asm/fixmap.h +2 -1

-extern void __this_fixmap_does_not_exist(void);
+#define FIXMAP_PAGE_NORMAL (L_PTE_MT_WRITEBACK | L_PTE_YOUNG | L_PTE_PRESENT)
+#define FIXMAP_PAGE_IO (L_PTE_MT_DEV_NONSHARED | L_PTE_YOUNG | L_PTE_PRESENT)

This set of flags gives a read-only mapping on the machine I'm testing on (Exynos4412, Cortex A9MPcore). If I use the same set of flags as used in arch/arm/mm/mmu.c for MT_DEVICE_NONSHARED then the mapping works fine.

Best regards,
Tomasz

Leif Lindholm

author

2014-07-09 09:39 UTC #6 lore raw

PATCH 2/2 arm: add early_ioremap support

In reply to Leif Lindholm

From: Mark Salter <[email protected]>

This patch uses the generic early_ioremap code to implement early_ioremap for ARM. The ARM-specific bits come mostly from an earlier patch from Leif Lindholm <[email protected]> here:

https://lkml.org/lkml/2013/10/3/279

Signed-off-by Mark Salter <[email protected]>

Signed-off-by Leif Lindholm <[email protected]>

Tested-by Leif Lindholm <[email protected]>

Acked-by Catalin Marinas <[email protected]>

CC linux-arm-kernel at lists.infradead.org

CC Russell King <[email protected]>

CC Catalin Marinas <[email protected]>

CC Will Deacon <[email protected]>

CC Arnd Bergmann <[email protected]>

---
 arch/arm/Kconfig            |   11 ++++++
 arch/arm/include/asm/Kbuild |    1 +
 arch/arm/include/asm/io.h   |    1 +
 arch/arm/kernel/setup.c     |    3 ++
 arch/arm/mm/Makefile        |    1 +
 arch/arm/mm/early_ioremap.c |   86 +++++++++++++++++++++++++++++++++++++++++++
 arch/arm/mm/mmu.c           |    2 +
 7 files changed, 105 insertions(+)
 create mode 100644 arch/arm/mm/early_ioremap.c

arch/arm/Kconfig +11 -0

index 245058b..04b8f8a 100644
@@ -1800,6 +1800,17 @@ config UACCESS_WITH_MEMCPY
 	  However, if the CPU data cache is using a write-allocate mode,
 	  this option is unlikely to provide any performance gain.
 
+config EARLY_IOREMAP
+	depends on MMU
+	bool "Provide early_ioremap() support for kernel initialization."
+	select GENERIC_EARLY_IOREMAP
+	help
+	  Provide a mechanism for kernel initialisation code to temporarily
+	  map, in a highmem-agnostic way, memory pages in before ioremap()
+	  and friends are available (before paging_init() has run). It uses
+	  the same virtual memory range as kmap so all early mappings must
+	  be unmapped before paging_init() is called.
+
 config SECCOMP
 	bool
 	prompt "Enable seccomp to safely compute untrusted bytecode"

arch/arm/include/asm/Kbuild +1 -0

index f5a3576..0bc5a02 100644
@@ -4,6 +4,7 @@ generic-y += auxvec.h
 generic-y += bitsperlong.h
 generic-y += cputime.h
 generic-y += current.h
+generic-y += early_ioremap.h
 generic-y += emergency-restart.h
 generic-y += errno.h
 generic-y += exec.h

arch/arm/include/asm/io.h +1 -0

index 3d23418..7b8a981 100644
@@ -28,6 +28,7 @@
 #include <asm/byteorder.h>
 #include <asm/memory.h>
 #include <asm-generic/pci_iomap.h>
+#include <asm/early_ioremap.h>
 #include <xen/xen.h>
 
 /*

arch/arm/kernel/setup.c +3 -0

index 8a16ee5..aa2621a 100644
@@ -36,6 +36,7 @@
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/elf.h>
+#include <asm/io.h>
 #include <asm/procinfo.h>
 #include <asm/psci.h>
 #include <asm/sections.h>

@@ -894,6 +895,8 @@ void __init setup_arch(char **cmdline_p)
 
 	parse_early_param();
 
+	early_ioremap_init();
+
 	early_paging_init(mdesc, lookup_processor_type(read_cpuid_id()));
 	setup_dma_zone(mdesc);
 	sanity_check_meminfo();

arch/arm/mm/Makefile +1 -0

index 91da64d..1c8ce752 100644
@@ -16,6 +16,7 @@ obj-$(CONFIG_ARM_PTDUMP)	+= dump.o
 obj-$(CONFIG_MODULES)		+= proc-syms.o
 
 obj-$(CONFIG_ALIGNMENT_TRAP)	+= alignment.o
+obj-$(CONFIG_EARLY_IOREMAP)	+= early_ioremap.o
 obj-$(CONFIG_HIGHMEM)		+= highmem.o
 obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o

arch/arm/mm/early_ioremap.c new file +86 -0

86 lines not on this page · raw message

arch/arm/mm/mmu.c +2 -0

index ab14b79..608dc36 100644
@@ -36,6 +36,7 @@
 #include <asm/mach/map.h>
 #include <asm/mach/pci.h>
 #include <asm/fixmap.h>
+#include <asm/early_ioremap.h>
 
 #include "mm.h"
 #include "tcm.h"

@@ -1474,6 +1475,7 @@ void __init paging_init(const struct machine_desc *mdesc)
 {
 	void *zero_page;
 
+	early_ioremap_reset();
 	build_mem_type_table();
 	prepare_page_table();
 	map_lowmem();

Signature · 1 line

1.7.10.4

Russell King - ARM Linux

2014-07-09 09:49 UTC #7 lore raw

PATCH 2/2 arm: add early_ioremap support

arch/arm/Kconfig config UACCESS_WITH_MEMCPY · line 1806

Quoted 4 lines · Leif Lindholm

arch/arm/Kconfig +4 -0

+config EARLY_IOREMAP
+	depends on MMU
+	bool "Provide early_ioremap() support for kernel initialization."
+	select GENERIC_EARLY_IOREMAP

Nit: please order as bool, then depends, then select.

arch/arm/kernel/setup.c line 39

Quoted 9 lines

arch/arm/kernel/setup.c +1 -0

index 8a16ee5..aa2621a 100644
@@ -36,6 +36,7 @@
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/elf.h>
+#include <asm/io.h>

Please always use linux/io.h in preference to asm/io.h.

arch/arm/kernel/setup.c

Quoted 4 lines

arch/arm/kernel/setup.c +4 -0

+static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
+{
+	unsigned int index = pgd_index(addr);
+	pgd_t *pgd = cpu_get_pgd() + index;

What is the reasoning for using cpu_get_pgd() ? Is there some specific reason you want to read from the hardware register rather than using the pgd_offset_k() macro here?

arch/arm/kernel/setup.c

Quoted 2 lines

arch/arm/kernel/setup.c +2 -0
+void __init
+early_ioremap_shutdown(void)

Nit: should be a single line.

The rest of the patch looks fine, thanks.

Signature · 2 lines

FTTC broadband for 0.8mile line: now at 9.7Mbps down 460kbps up... slowly
improving, and getting towards what was expected from it.

Leif Lindholm

author

2014-07-09 11:48 UTC #8 lore raw

PATCH 2/2 arm: add early_ioremap support

Hi Russell,

Quoted 7 lines · Russell King - ARM Linux

Review
Quoted 4 lines · Leif Lindholm
(quoted diff) +4 -0
+config EARLY_IOREMAP
+	depends on MMU
+	bool "Provide early_ioremap() support for kernel initialization."
+	select GENERIC_EARLY_IOREMAP
Nit: please order as bool, then depends, then select.

Fixed in attached.

Quoted 11 lines

arch/arm/kernel/setup.c line 39
Quoted 9 lines
arch/arm/kernel/setup.c +1 -0
index 8a16ee5..aa2621a 100644
@@ -36,6 +36,7 @@
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/elf.h>
+#include <asm/io.h>
Please always use linux/io.h in preference to asm/io.h.

Fixed in attached.

Quoted 8 lines

arch/arm/kernel/setup.c
Quoted 4 lines
arch/arm/kernel/setup.c +4 -0
+static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
+{
+	unsigned int index = pgd_index(addr);
+	pgd_t *pgd = cpu_get_pgd() + index;
What is the reasoning for using cpu_get_pgd() ? Is there some specific reason you want to read from the hardware register rather than using the pgd_offset_k() macro here?

No, merely picked the wrong interface, and it seemed to work. Fixed in attached.

Quoted 4 lines

arch/arm/kernel/setup.c
Quoted 2 lines
arch/arm/kernel/setup.c +2 -0
+void __init
+early_ioremap_shutdown(void)
Nit: should be a single line.

Fixed in attached.

Quoted 1 line

The rest of the patch looks fine, thanks.

Thank you for your comments.

/
Leif

Quoted 1 line

From 6937e88fc0bc62e125d891889334b6659f2efd28 Mon Sep 17 00:00:00 2001

From: Mark Salter <[email protected]>
Date: Wed, 27 Nov 2013 10:21:11 -0500
Subject: [PATCH 2/2] arm: add early_ioremap support

This patch uses the generic early_ioremap code to implement early_ioremap for ARM. The ARM-specific bits come mostly from an earlier patch from Leif Lindholm <[email protected]> here:

https://lkml.org/lkml/2013/10/3/279

Signed-off-by Mark Salter <[email protected]>

Signed-off-by Leif Lindholm <[email protected]>

Tested-by Leif Lindholm <[email protected]>

Acked-by Catalin Marinas <[email protected]>

CC linux-arm-kernel at lists.infradead.org

CC Russell King <[email protected]>

CC Catalin Marinas <[email protected]>

CC Will Deacon <[email protected]>

CC Arnd Bergmann <[email protected]>

---
 arch/arm/Kconfig            |   11 ++++++
 arch/arm/include/asm/Kbuild |    1 +
 arch/arm/include/asm/io.h   |    1 +
 arch/arm/kernel/setup.c     |    3 ++
 arch/arm/mm/Makefile        |    1 +
 arch/arm/mm/early_ioremap.c |   84 +++++++++++++++++++++++++++++++++++++++++++
 arch/arm/mm/mmu.c           |    2 ++
 7 files changed, 103 insertions(+)
 create mode 100644 arch/arm/mm/early_ioremap.c

arch/arm/Kconfig +11 -0

index 245058b..5ddafaf 100644
@@ -1800,6 +1800,17 @@ config UACCESS_WITH_MEMCPY
 	  However, if the CPU data cache is using a write-allocate mode,
 	  this option is unlikely to provide any performance gain.
 
+config EARLY_IOREMAP
+	bool "Provide early_ioremap() support for kernel initialization."
+	depends on MMU
+	select GENERIC_EARLY_IOREMAP
+	help
+	  Provide a mechanism for kernel initialisation code to temporarily
+	  map, in a highmem-agnostic way, memory pages in before ioremap()
+	  and friends are available (before paging_init() has run). It uses
+	  the same virtual memory range as kmap so all early mappings must
+	  be unmapped before paging_init() is called.
+
 config SECCOMP
 	bool
 	prompt "Enable seccomp to safely compute untrusted bytecode"

arch/arm/include/asm/Kbuild +1 -0

index f5a3576..0bc5a02 100644
@@ -4,6 +4,7 @@ generic-y += auxvec.h
 generic-y += bitsperlong.h
 generic-y += cputime.h
 generic-y += current.h
+generic-y += early_ioremap.h
 generic-y += emergency-restart.h
 generic-y += errno.h
 generic-y += exec.h

arch/arm/include/asm/io.h +1 -0

index 3d23418..7b8a981 100644
@@ -28,6 +28,7 @@
 #include <asm/byteorder.h>
 #include <asm/memory.h>
 #include <asm-generic/pci_iomap.h>
+#include <asm/early_ioremap.h>
 #include <xen/xen.h>
 
 /*

arch/arm/kernel/setup.c +3 -0

index 8a16ee5..b1f397c 100644
@@ -30,6 +30,7 @@
 #include <linux/bug.h>
 #include <linux/compiler.h>
 #include <linux/sort.h>
+#include <linux/io.h>
 
 #include <asm/unified.h>
 #include <asm/cp15.h>

@@ -894,6 +895,8 @@ void __init setup_arch(char **cmdline_p)
 
 	parse_early_param();
 
+	early_ioremap_init();
+
 	early_paging_init(mdesc, lookup_processor_type(read_cpuid_id()));
 	setup_dma_zone(mdesc);
 	sanity_check_meminfo();

arch/arm/mm/Makefile +1 -0

index 91da64d..1c8ce752 100644
@@ -16,6 +16,7 @@ obj-$(CONFIG_ARM_PTDUMP)	+= dump.o
 obj-$(CONFIG_MODULES)		+= proc-syms.o
 
 obj-$(CONFIG_ALIGNMENT_TRAP)	+= alignment.o
+obj-$(CONFIG_EARLY_IOREMAP)	+= early_ioremap.o
 obj-$(CONFIG_HIGHMEM)		+= highmem.o
 obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o

arch/arm/mm/early_ioremap.c new file +84 -0

84 lines not on this page · raw message

arch/arm/mm/mmu.c +2 -0

index ab14b79..608dc36 100644
@@ -36,6 +36,7 @@
 #include <asm/mach/map.h>
 #include <asm/mach/pci.h>
 #include <asm/fixmap.h>
+#include <asm/early_ioremap.h>
 
 #include "mm.h"
 #include "tcm.h"

@@ -1474,6 +1475,7 @@ void __init paging_init(const struct machine_desc *mdesc)
 {
 	void *zero_page;
 
+	early_ioremap_reset();
 	build_mem_type_table();
 	prepare_page_table();
 	map_lowmem();

Signature · 1 line

1.7.10.4

Tomasz Figa

2014-07-22 16:48 UTC #9 lore raw

PATCH 2/2 arm: add early_ioremap support

In reply to Leif Lindholm

Hi Leif,

Quoted 8 lines · Leif Lindholm

From: Mark Salter <[email protected]>
This patch uses the generic early_ioremap code to implement early_ioremap for ARM. The ARM-specific bits come mostly from an earlier patch from Leif Lindholm <[email protected]> here:
https://lkml.org/lkml/2013/10/3/279

[snip]

arch/arm/mm/early_ioremap.c line 6

Quoted 12 lines

arch/arm/mm/early_ioremap.c new file +6 -0

new file mode 100644
index 0000000..1013109
@@ -0,0 +1,86 @@
+/*
+ * early_ioremap() support for ARM
+ *
+ * Based on existing support in arch/x86/mm/ioremap.c
+ *
+ * Restrictions: currently only functional before paging_init()

Uhm, that's bad... This would explain why my earlycon code generates a fault as soon as something prints after paging_init(). I'd say this feature would be much more useful if mappings were carried over paging_init(), so that mapped devices are available later as well.

I'll see if I can code this on top of your patch, but unfortunately it might end up with -ENOTIME.

Best regards,
Tomasz

Rob Herring

2014-07-22 17:11 UTC #10 lore raw

PATCH 2/2 arm: add early_ioremap support

Quoted 32 lines · Tomasz Figa

Hi Leif,
Quoted 8 lines · Leif Lindholm
From: Mark Salter <[email protected]>
This patch uses the generic early_ioremap code to implement early_ioremap for ARM. The ARM-specific bits come mostly from an earlier patch from Leif Lindholm <[email protected]> here:
https://lkml.org/lkml/2013/10/3/279
[snip]
arch/arm/mm/early_ioremap.c line 6
Quoted 12 lines
arch/arm/mm/early_ioremap.c new file +6 -0
new file mode 100644
index 0000000..1013109
@@ -0,0 +1,86 @@
+/*
+ * early_ioremap() support for ARM
+ *
+ * Based on existing support in arch/x86/mm/ioremap.c
+ *
+ * Restrictions: currently only functional before paging_init()
Uhm, that's bad... This would explain why my earlycon code generates a fault as soon as something prints after paging_init(). I'd say this feature would be much more useful if mappings were carried over paging_init(), so that mapped devices are available later as well.

Quoted 2 lines

I'll see if I can code this on top of your patch, but unfortunately it might end up with -ENOTIME.

I have fixmap support that's needed for earlycon. Here is the branch:

git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git fixmap

It is based on an earlier version of patchset and not on the latest version from Leif. Unfortunately, I don't have more time to spend on it ATM.

Rob

Tomasz Figa

2014-07-22 17:27 UTC #11 lore raw

PATCH 2/2 arm: add early_ioremap support

Quoted 36 lines · Rob Herring

Quoted 32 lines · Tomasz Figa
Hi Leif,
Quoted 8 lines · Leif Lindholm
From: Mark Salter <[email protected]>
This patch uses the generic early_ioremap code to implement early_ioremap for ARM. The ARM-specific bits come mostly from an earlier patch from Leif Lindholm <[email protected]> here:
https://lkml.org/lkml/2013/10/3/279
[snip]
arch/arm/mm/early_ioremap.c line 6
Quoted 12 lines
arch/arm/mm/early_ioremap.c new file +6 -0
new file mode 100644
index 0000000..1013109
@@ -0,0 +1,86 @@
+/*
+ * early_ioremap() support for ARM
+ *
+ * Based on existing support in arch/x86/mm/ioremap.c
+ *
+ * Restrictions: currently only functional before paging_init()
Uhm, that's bad... This would explain why my earlycon code generates a fault as soon as something prints after paging_init(). I'd say this feature would be much more useful if mappings were carried over paging_init(), so that mapped devices are available later as well.
Quoted 2 lines
I'll see if I can code this on top of your patch, but unfortunately it might end up with -ENOTIME.

Quoted 7 lines

I have fixmap support that's needed for earlycon. Here is the branch:
git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git fixmap
It is based on an earlier version of patchset and not on the latest version from Leif. Unfortunately, I don't have more time to spend on it ATM.

Thanks Rob. I'll give it a try.

Best regards,
Tomasz

Russell King - ARM Linux

2014-07-09 09:42 UTC #12 lore raw

cover arm: add early_ioremap support

In reply to Leif Lindholm

Quoted 3 lines · Leif Lindholm

early_ioremap()/early_memremap() create temporary virtual mappings in the fixmap region during boot time. Part of the support now exists in core code, but depends on the generic fixmap support.

Does this mean that the changes upon which this patch depends are already merged in mainline, or are they queued in some other tree?

Thanks.

Signature · 2 lines

FTTC broadband for 0.8mile line: now at 9.7Mbps down 460kbps up... slowly
improving, and getting towards what was expected from it.

Leif Lindholm

author

2014-07-09 09:58 UTC #13 lore raw

cover arm: add early_ioremap support

Quoted 7 lines · Russell King - ARM Linux

Quoted 3 lines · Leif Lindholm
early_ioremap()/early_memremap() create temporary virtual mappings in the fixmap region during boot time. Part of the support now exists in core code, but depends on the generic fixmap support.
Does this mean that the changes upon which this patch depends are already merged in mainline, or are they queued in some other tree?

Yes, they went into 3.15.

/
Leif

Will Deacon

2014-07-09 09:47 UTC #14 lore raw

cover arm: add early_ioremap support

In reply to Leif Lindholm

Quoted 11 lines · Leif Lindholm

early_ioremap()/early_memremap() create temporary virtual mappings in the fixmap region during boot time. Part of the support now exists in core code, but depends on the generic fixmap support.
This set converts arm to use the generic fixmap support, and adds the architecture-specific part of early_ioremap support.
The fixmap/kmap changes in 3.15 complicated things slightly compared to previous iterations of these patches - this version works around that by introducing local macros in arm/mm/highmem.c.

Quoted 5 lines

Tested on TC2 and software models, with/without LPAE.
Mark Salter (2):
arm: use generic fixmap.h
arm: add early_ioremap support

Curious: why are you sending these patches instead of Mark?

Will

Leif Lindholm

author

2014-07-09 10:02 UTC #15 lore raw

cover arm: add early_ioremap support

Quoted 12 lines · Will Deacon

Quoted 11 lines · Leif Lindholm
early_ioremap()/early_memremap() create temporary virtual mappings in the fixmap region during boot time. Part of the support now exists in core code, but depends on the generic fixmap support.
This set converts arm to use the generic fixmap support, and adds the architecture-specific part of early_ioremap support.
The fixmap/kmap changes in 3.15 complicated things slightly compared to previous iterations of these patches - this version works around that by introducing local macros in arm/mm/highmem.c.

Quoted 7 lines

Quoted 5 lines
Tested on TC2 and software models, with/without LPAE.
Mark Salter (2):
arm: use generic fixmap.h
arm: add early_ioremap support
Curious: why are you sending these patches instead of Mark?

Well, it used to form part of the larger UEFI patchset, which I'm still marshalling the 32-bit parts of (and which will follow later, but I will treat them separately from here on).
Also, I did the hacky rework to Mark's original patches for the kmap changes.

/
Leif