generic early_ioremap support

PATCH Superseded Mark Salter 4 participants 12 messages Jan 7, 2014 – Jan 9, 2014

Subsystems (9)

Memory management Documentation Arm (32-bit) x86 +5 more subsystems

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Mark Salter

author

2014-01-07 02:35 UTC #0 lore raw

v2 cover generic early_ioremap support

This patch series takes the common bits from the x86 early ioremap implementation and creates a generic implementation which may be used by other architectures. The early ioremap interfaces are intended for situations where boot code needs to make temporary virtual mappings before the normal ioremap interfaces are available. Typically, this means before paging_init() has run.

These patches are layered on top of generic fixmap patches which were discussed here (and are in the akpm tree):

http://lkml.org/lkml/2013/11/25/474

This is version 2 of the patch series. These patches (and underlying fixmap patches) may be found at:

git://github.com/mosalter/linux.git (early-ioremap-v2 branch)

Changes from version 1:

* Moved the generic code into linux/mm instead of linux/lib

* Have early_memremap() return normal pointer instead of __iomem This is in response to sparse warning cleanups being made in an unrelated patch series:

https://lkml.org/lkml/2013/12/22/69

* Added arm64 patch to call init_mem_pgprot() earlier so that the pgprot macros are valid in time for early_ioremap use

* Added validity checking for early_ioremap pgd, pud, and pmd in arm64

Mark Salter (5):
mm: create generic early_ioremap() support
x86: use generic early_ioremap
arm: add early_ioremap support
arm64: initialize pgprot info earlier in boot
arm64: add early_ioremap support

 Documentation/arm64/memory.txt      |   4 +-
 arch/arm/Kconfig                    |  11 ++
 arch/arm/include/asm/Kbuild         |   1 +
 arch/arm/include/asm/fixmap.h       |  18 +++
 arch/arm/include/asm/io.h           |   1 +
 arch/arm/kernel/setup.c             |   3 +
 arch/arm/mm/Makefile                |   1 +
 arch/arm/mm/early_ioremap.c         |  93 ++++++++++++++
 arch/arm/mm/mmu.c                   |   2 +
 arch/arm64/Kconfig                  |   1 +
 arch/arm64/include/asm/Kbuild       |   1 +
 arch/arm64/include/asm/fixmap.h     |  68 ++++++++++
 arch/arm64/include/asm/io.h         |   1 +
 arch/arm64/include/asm/memory.h     |   2 +-
 arch/arm64/include/asm/mmu.h        |   1 +
 arch/arm64/kernel/early_printk.c    |   8 +-
 arch/arm64/kernel/head.S            |   9 +-
 arch/arm64/kernel/setup.c           |   4 +
 arch/arm64/mm/ioremap.c             |  85 ++++++++++++
 arch/arm64/mm/mmu.c                 |  44 +------
 arch/x86/Kconfig                    |   1 +
 arch/x86/include/asm/Kbuild         |   1 +
 arch/x86/include/asm/fixmap.h       |   6 +
 arch/x86/include/asm/io.h           |  14 +-
 arch/x86/mm/ioremap.c               | 224 +-------------------------------
 arch/x86/mm/pgtable_32.c            |   2 +-
 include/asm-generic/early_ioremap.h |  41 ++++++
 mm/Kconfig                          |   3 +
 mm/Makefile                         |   1 +
 mm/early_ioremap.c                  | 249 ++++++++++++++++++++++++++++++++++++
 30 files changed, 611 insertions(+), 289 deletions(-)
 create mode 100644 arch/arm/mm/early_ioremap.c
 create mode 100644 arch/arm64/include/asm/fixmap.h
 create mode 100644 include/asm-generic/early_ioremap.h
 create mode 100644 mm/early_ioremap.c

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Mark Salter

author

2014-01-07 02:35 UTC #1 lore raw

PATCH v2 1/5 mm: create generic early_ioremap() support

This patch creates a generic implementation of early_ioremap() support based on the existing x86 implementation. early_ioremp() is useful for early boot code which needs to temporarily map I/O or memory regions before normal mapping functions such as ioremap() are available.

There is one difference from the existing x86 implementation which should be noted. The generic early_memremap() function does not return an __iomem pointer and a new early_memunmap() function has been added to act as a wrapper for early_iounmap() but with a non __iomem pointer passed in. This is in line with the first patch of this series:

https://lkml.org/lkml/2013/12/22/69

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

CC [email protected]

CC Andrew Morton <[email protected]>

CC Arnd Bergmann <[email protected]>

CC Ingo Molnar <[email protected]>

CC Thomas Gleixner <[email protected]>

CC "H. Peter Anvin" <[email protected]>

CC Russell King <[email protected]>

CC Catalin Marinas <[email protected]>

CC Will Deacon <[email protected]>

---
 include/asm-generic/early_ioremap.h |  41 ++++++
 mm/Kconfig                          |   3 +
 mm/Makefile                         |   1 +
 mm/early_ioremap.c                  | 249 ++++++++++++++++++++++++++++++++++++
 4 files changed, 294 insertions(+)
 create mode 100644 include/asm-generic/early_ioremap.h
 create mode 100644 mm/early_ioremap.c

include/asm-generic/early_ioremap.h new file +41 -0

new file mode 100644
index 0000000..d43e187
@@ -0,0 +1,41 @@
+#ifndef _ASM_EARLY_IOREMAP_H_
+#define _ASM_EARLY_IOREMAP_H_
+
+#include <linux/types.h>
+
+#ifdef CONFIG_GENERIC_EARLY_IOREMAP
+/*
+ * early_ioremap() and early_iounmap() are for temporary early boot-time
+ * mappings, before the real ioremap() is functional.
+ */
+extern void __iomem *early_ioremap(resource_size_t phys_addr,
+				   unsigned long size);
+extern void *early_memremap(resource_size_t phys_addr,
+			    unsigned long size);
+extern void early_iounmap(void __iomem *addr, unsigned long size);
+extern void early_memunmap(void *addr, unsigned long size);
+
+/* Arch-specific initialization */
+extern void early_ioremap_init(void);
+
+/* Generic initialization called by architecture code */
+extern void early_ioremap_setup(void);
+
+/*
+ * Called as last step in paging_init() so library can act
+ * accordingly for subsequent map/unmap requests.
+ */
+extern void early_ioremap_reset(void);
+
+/*
+ * Weak function called by early_ioremap_reset(). It does nothing, but
+ * architectures may provide their own version to do any needed cleanups.
+ */
+extern void early_ioremap_shutdown(void);
+#else
+static inline void early_ioremap_init(void) { }
+static inline void early_ioremap_setup(void) { }
+static inline void early_ioremap_reset(void) { }
+#endif
+
+#endif /* _ASM_EARLY_IOREMAP_H_ */

mm/Kconfig +3 -0

index 723bbe0..0dcebf2a 100644
@@ -552,3 +552,6 @@ config MEM_SOFT_DIRTY
 	  it can be cleared by hands.
 
 	  See Documentation/vm/soft-dirty.txt for more details.
+
+config GENERIC_EARLY_IOREMAP
+	bool

mm/Makefile +1 -0

index 305d10a..4e102e9 100644
@@ -60,3 +60,4 @@ obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o
 obj-$(CONFIG_CLEANCACHE) += cleancache.o
 obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
 obj-$(CONFIG_ZBUD)	+= zbud.o
+obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o

mm/early_ioremap.c new file +249 -0

249 lines not on this page · raw message

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Catalin Marinas

maintainer Acked-by on v2 1/5

2014-01-07 15:25 UTC #2 lore raw

Re: [PATCH v2 1/5] mm: create generic early_ioremap() support

Quoted 13 lines · Mark Salter

This patch creates a generic implementation of early_ioremap() support based on the existing x86 implementation. early_ioremp() is useful for early boot code which needs to temporarily map I/O or memory regions before normal mapping functions such as ioremap() are available.
There is one difference from the existing x86 implementation which should be noted. The generic early_memremap() function does not return an __iomem pointer and a new early_memunmap() function has been added to act as a wrapper for early_iounmap() but with a non __iomem pointer passed in. This is in line with the first patch of this series:
https://lkml.org/lkml/2013/12/22/69

Quoted 11 lines

Signed-off-by Mark Salter <[email protected]>
CC [email protected]
CC [email protected]
CC Andrew Morton <[email protected]>
CC Arnd Bergmann <[email protected]>
CC Ingo Molnar <[email protected]>
CC Thomas Gleixner <[email protected]>
CC "H. Peter Anvin" <[email protected]>
CC Russell King <[email protected]>
CC Catalin Marinas <[email protected]>
CC Will Deacon <[email protected]>

Acked-by Catalin Marinas <[email protected]>

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H. Peter Anvin

reviewer

2014-01-07 23:11 UTC #3 lore raw

Re: [PATCH v2 1/5] mm: create generic early_ioremap() support

In reply to Mark Salter

Quoted 7 lines · Mark Salter

There is one difference from the existing x86 implementation which should be noted. The generic early_memremap() function does not return an __iomem pointer and a new early_memunmap() function has been added to act as a wrapper for early_iounmap() but with a non __iomem pointer passed in. This is in line with the first patch of this series:

This makes a lot of sense. However, I would suggest that we preface the patch series with a single patch changing the signature for the existing x86 function, that way this change becomes bisectable.

-hpa

Mark Salter

author

2014-01-08 16:09 UTC #4 lore raw

Re: [PATCH v2 1/5] mm: create generic early_ioremap() support

Quoted 9 lines · H. Peter Anvin

Quoted 7 lines · Mark Salter
There is one difference from the existing x86 implementation which should be noted. The generic early_memremap() function does not return an __iomem pointer and a new early_memunmap() function has been added to act as a wrapper for early_iounmap() but with a non __iomem pointer passed in. This is in line with the first patch of this series:

Quoted 3 lines

This makes a lot of sense. However, I would suggest that we preface the patch series with a single patch changing the signature for the existing x86 function, that way this change becomes bisectable.

Ok, that sounds like a good idea. I'm uncertain how best to coordinate with Dave Young's patch series to avoid conflicts. His first patch does the signature change (and adds the early_memunmap function but that isn't used anywhere):

https://lkml.org/lkml/2013/12/20/143

Any thoughts on how best to avoid potential merge conflicts here?

Matt Fleming

2014-01-09 10:15 UTC #5 lore raw

Re: [PATCH v2 1/5] mm: create generic early_ioremap() support

Quoted 9 lines · Mark Salter

Ok, that sounds like a good idea. I'm uncertain how best to coordinate with Dave Young's patch series to avoid conflicts. His first patch does the signature change (and adds the early_memunmap function but that isn't used anywhere):
https://lkml.org/lkml/2013/12/20/143
Any thoughts on how best to avoid potential merge conflicts here?

Dave's patch hasn't been picked up by anyone so far, so you could incorporate it into your series.

Signature · 7 lines

Matt Fleming, Intel Open Source Technology Center

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Mark Salter

author

2014-01-07 02:35 UTC #6 lore raw

PATCH v2 2/5 x86: use generic early_ioremap

In reply to Mark Salter

Move x86 over to the generic early ioremap implementation. The generic implementation is functionally the same except that the early_memremap() function returns a normal pointer instead of an __iomem pointer. This is in line with sparse warning cleanups in this patch series:

https://lkml.org/lkml/2013/12/22/69

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

CC [email protected]

CC Andrew Morton <[email protected]>

CC Arnd Bergmann <[email protected]>

CC Ingo Molnar <[email protected]>

CC Thomas Gleixner <[email protected]>

CC "H. Peter Anvin" <[email protected]>

---
 arch/x86/Kconfig              |   1 +
 arch/x86/include/asm/Kbuild   |   1 +
 arch/x86/include/asm/fixmap.h |   6 ++
 arch/x86/include/asm/io.h     |  14 +--
 arch/x86/mm/ioremap.c         | 224 +-----------------------------------------
 arch/x86/mm/pgtable_32.c      |   2 +-
 6 files changed, 13 insertions(+), 235 deletions(-)

arch/x86/Kconfig +1 -0

index 0952ecd..50e1eab 100644
@@ -125,6 +125,7 @@ config X86
 	select RTC_LIB
 	select HAVE_DEBUG_STACKOVERFLOW
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
+	select GENERIC_EARLY_IOREMAP
 
 config INSTRUCTION_DECODER
 	def_bool y

arch/x86/include/asm/Kbuild +1 -0

index 7f66985..203f5f9 100644
@@ -5,3 +5,4 @@ genhdr-y += unistd_64.h
 genhdr-y += unistd_x32.h
 
 generic-y += clkdev.h
+generic-y += early_ioremap.h

arch/x86/include/asm/fixmap.h +6 -0

index 7252cd3..e5f236d 100644
@@ -177,5 +177,11 @@ static inline void __set_fixmap(enum fixed_addresses idx,
 
 #include <asm-generic/fixmap.h>
 
+#define __late_set_fixmap(idx, phys, flags) __set_fixmap(idx, phys, flags)
+#define __late_clear_fixmap(idx) __set_fixmap(idx, 0, __pgprot(0))
+
+void __early_set_fixmap(enum fixed_addresses idx,
+			phys_addr_t phys, pgprot_t flags);
+
 #endif /* !__ASSEMBLY__ */
 #endif /* _ASM_X86_FIXMAP_H */

arch/x86/include/asm/io.h +1 ~~-13~~

index 34f69cb..aae7010 100644
@@ -39,6 +39,7 @@
 #include <linux/string.h>
 #include <linux/compiler.h>
 #include <asm/page.h>
+#include <asm/early_ioremap.h>
 
 #define build_mmio_read(name, size, type, reg, barrier) \
 static inline type name(const volatile void __iomem *addr) \

@@ -316,19 +317,6 @@ extern int ioremap_change_attr(unsigned long vaddr, unsigned long size,
 				unsigned long prot_val);
 extern void __iomem *ioremap_wc(resource_size_t offset, unsigned long size);
 
-/*
- * early_ioremap() and early_iounmap() are for temporary early boot-time
- * mappings, before the real ioremap() is functional.
- * A boot-time mapping is currently limited to at most 16 pages.
- */
-extern void early_ioremap_init(void);
-extern void early_ioremap_reset(void);
-extern void __iomem *early_ioremap(resource_size_t phys_addr,
-				   unsigned long size);
-extern void __iomem *early_memremap(resource_size_t phys_addr,
-				    unsigned long size);
-extern void early_iounmap(void __iomem *addr, unsigned long size);
-extern void fixup_early_ioremap(void);
 extern bool is_early_ioremap_ptep(pte_t *ptep);
 
 #ifdef CONFIG_XEN

arch/x86/mm/ioremap.c +3 ~~-221~~

249 lines not on this page · raw message

arch/x86/mm/pgtable_32.c +1 -1

index a69bcb8..4dd8cf6 100644
@@ -127,7 +127,7 @@ static int __init parse_reservetop(char *arg)
 
 	address = memparse(arg, &arg);
 	reserve_top_address(address);
-	fixup_early_ioremap();
+	early_ioremap_init();
 	return 0;
 }
 early_param("reservetop", parse_reservetop);

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Mark Salter

author

2014-01-07 02:35 UTC #7 lore raw

PATCH v2 3/5 arm: add early_ioremap support

In reply to Mark Salter

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]>

Tested-by Leif Lindholm <[email protected]>

CC [email protected]

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/fixmap.h | 18 +++++++++
 arch/arm/include/asm/io.h     |  1 +
 arch/arm/kernel/setup.c       |  3 ++
 arch/arm/mm/Makefile          |  1 +
 arch/arm/mm/early_ioremap.c   | 93 +++++++++++++++++++++++++++++++++++++++++++
 arch/arm/mm/mmu.c             |  2 +
 8 files changed, 130 insertions(+)
 create mode 100644 arch/arm/mm/early_ioremap.c

arch/arm/Kconfig +11 -0

index c1f1a7e..78a79a6a 100644
@@ -1842,6 +1842,17 @@ 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 unapped before paging_init() is called.
+
 config SECCOMP
 	bool
 	prompt "Enable seccomp to safely compute untrusted bytecode"

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

index c38b58c..49ec506 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/fixmap.h +18 -0

index 68ea615..e92b7a4 100644
@@ -21,8 +21,26 @@ enum fixed_addresses {
 	FIX_KMAP_BEGIN,
 	FIX_KMAP_END = (FIXADDR_TOP - FIXADDR_START) >> PAGE_SHIFT,
 	__end_of_fixed_addresses
+/*
+ * 224 temporary boot-time mappings, used by early_ioremap(),
+ * before ioremap() is functional.
+ *
+ * (P)re-using the FIXADDR region, which is used for highmem
+ * later on, and statically aligned to 1MB.
+ */
+#define NR_FIX_BTMAPS		32
+#define FIX_BTMAPS_SLOTS	7
+#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)
 };
 
+#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)
+
+extern void __early_set_fixmap(enum fixed_addresses idx,
+			       phys_addr_t phys, pgprot_t flags);
+
 #include <asm-generic/fixmap.h>
 
 #endif

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

index 3c597c2..131e0ba 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 987a7f5..038fb75 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>

@@ -887,6 +888,8 @@ void __init setup_arch(char **cmdline_p)
 
 	parse_early_param();
 
+	early_ioremap_init();
+
 	sort(&meminfo.bank, meminfo.nr_banks, sizeof(meminfo.bank[0]), meminfo_cmp, NULL);
 
 	early_paging_init(mdesc, lookup_processor_type(read_cpuid_id()));

arch/arm/mm/Makefile +1 -0

index ecfe6e5..fea855e 100644
@@ -15,6 +15,7 @@ endif
 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 +93 -0

93 lines not on this page · raw message

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

index 580ef2d..bef59b9 100644
@@ -34,6 +34,7 @@
 #include <asm/mach/arch.h>
 #include <asm/mach/map.h>
 #include <asm/mach/pci.h>
+#include <asm/early_ioremap.h>
 
 #include "mm.h"
 #include "tcm.h"

@@ -1405,6 +1406,7 @@ void __init paging_init(const struct machine_desc *mdesc)
 {
 	void *zero_page;
 
+	early_ioremap_reset();
 	build_mem_type_table();
 	prepare_page_table();
 	map_lowmem();

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1.8.3.1

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Catalin Marinas

maintainer Acked-by on v2 3/5

2014-01-07 17:23 UTC #8 lore raw

Re: [PATCH v2 3/5] arm: add early_ioremap support

Quoted 7 lines · Mark Salter

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

Quoted 7 lines

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

Acked-by Catalin Marinas <[email protected]>

Mark Salter

author

2014-01-07 02:35 UTC #9 lore raw

PATCH v2 4/5 arm64: initialize pgprot info earlier in boot

In reply to Mark Salter

Presently, paging_init() calls init_mem_pgprot() to initialize pgprot values used by macros such as PAGE_KERNEL, PAGE_KERNEL_EXEC, etc. The new fixmap and early_ioremap support also needs to use these macros before paging_init() is called. This patch moves the init_mem_pgprot() call out of paging_init() and into setup_arch() so that pgprot_default gets initialized in time for fixmap and early_ioremap.

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

CC [email protected]

CC Catalin Marinas <[email protected]>

CC Will Deacon <[email protected]>

---
 arch/arm64/include/asm/mmu.h | 1 +
 arch/arm64/kernel/setup.c    | 2 ++
 arch/arm64/mm/mmu.c          | 3 +--
 3 files changed, 4 insertions(+), 2 deletions(-)

arch/arm64/include/asm/mmu.h +1 -0

index 2494fc0..f600d40 100644
@@ -27,5 +27,6 @@ typedef struct {
 extern void paging_init(void);
 extern void setup_mm_for_reboot(void);
 extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
+extern void init_mem_pgprot(void);
 
 #endif

arch/arm64/kernel/setup.c +2 -0

index bd9bbd0..029ecfe 100644
@@ -221,6 +221,8 @@ void __init setup_arch(char **cmdline_p)
 
 	*cmdline_p = boot_command_line;
 
+	init_mem_pgprot();
+
 	parse_early_param();
 
 	arm64_memblock_init();

arch/arm64/mm/mmu.c +1 -2

index f557ebb..541c782 100644
@@ -125,7 +125,7 @@ early_param("cachepolicy", early_cachepolicy);
 /*
  * Adjust the PMD section entries according to the CPU in use.
  */
-static void __init init_mem_pgprot(void)
+void __init init_mem_pgprot(void)
 {
 	pteval_t default_pgprot;
 	int i;

@@ -349,7 +349,6 @@ void __init paging_init(void)
 {
 	void *zero_page;
 
-	init_mem_pgprot();
 	map_mem();
 
 	/*

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1.8.3.1

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Mark Salter

author

2014-01-07 02:35 UTC #10 lore raw

PATCH v2 5/5 arm64: add early_ioremap support

In reply to Mark Salter

Add support for early IO or memory mappings which are needed before the normal ioremap() is usable. This also adds fixmap support for permanent fixed mappings such as that used by the earlyprintk device register region.

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

CC [email protected]

CC Catalin Marinas <[email protected]>

CC Will Deacon <[email protected]>

---
 Documentation/arm64/memory.txt   |  4 +-
 arch/arm64/Kconfig               |  1 +
 arch/arm64/include/asm/Kbuild    |  1 +
 arch/arm64/include/asm/fixmap.h  | 68 ++++++++++++++++++++++++++++++++
 arch/arm64/include/asm/io.h      |  1 +
 arch/arm64/include/asm/memory.h  |  2 +-
 arch/arm64/kernel/early_printk.c |  8 +++-
 arch/arm64/kernel/head.S         |  9 ++---
 arch/arm64/kernel/setup.c        |  2 +
 arch/arm64/mm/ioremap.c          | 85 ++++++++++++++++++++++++++++++++++++++++
 arch/arm64/mm/mmu.c              | 41 -------------------
 11 files changed, 170 insertions(+), 52 deletions(-)
 create mode 100644 arch/arm64/include/asm/fixmap.h

Documentation/arm64/memory.txt +2 -2

index 5e054bf..953c81e 100644
@@ -35,7 +35,7 @@ ffffffbc00000000	ffffffbdffffffff	   8GB		vmemmap
 
 ffffffbe00000000	ffffffbffbbfffff	  ~8GB		[guard, future vmmemap]
 
-ffffffbffbc00000	ffffffbffbdfffff	   2MB		earlyprintk device
+ffffffbffbc00000	ffffffbffbdfffff	   2MB		fixed mappings
 
 ffffffbffbe00000	ffffffbffbe0ffff	  64KB		PCI I/O space

@@ -60,7 +60,7 @@ fffffdfc00000000	fffffdfdffffffff	   8GB		vmemmap
 
 fffffdfe00000000	fffffdfffbbfffff	  ~8GB		[guard, future vmmemap]
 
-fffffdfffbc00000	fffffdfffbdfffff	   2MB		earlyprintk device
+fffffdfffbc00000	fffffdfffbdfffff	   2MB		fixed mappings
 
 fffffdfffbe00000	fffffdfffbe0ffff	  64KB		PCI I/O space

arch/arm64/Kconfig +1 -0

index 6d4dd22..e66a317 100644
@@ -12,6 +12,7 @@ config ARM64
 	select CLONE_BACKWARDS
 	select COMMON_CLK
 	select GENERIC_CLOCKEVENTS
+	select GENERIC_EARLY_IOREMAP
 	select GENERIC_IOMAP
 	select GENERIC_IRQ_PROBE
 	select GENERIC_IRQ_SHOW

arch/arm64/include/asm/Kbuild +1 -0

index 519f89f..b7f99a3 100644
@@ -10,6 +10,7 @@ generic-y += delay.h
 generic-y += div64.h
 generic-y += dma.h
 generic-y += emergency-restart.h
+generic-y += early_ioremap.h
 generic-y += errno.h
 generic-y += ftrace.h
 generic-y += hw_irq.h

arch/arm64/include/asm/fixmap.h new file +68 -0

68 lines not on this page · raw message

arch/arm64/include/asm/io.h +1 -0

index 5727697..1e34831 100644
@@ -27,6 +27,7 @@
 #include <asm/byteorder.h>
 #include <asm/barrier.h>
 #include <asm/pgtable.h>
+#include <asm/early_ioremap.h>
 
 #include <xen/xen.h>

arch/arm64/include/asm/memory.h +1 -1

index 3776217..50a97df 100644
@@ -49,7 +49,7 @@
 #define PAGE_OFFSET		(UL(0xffffffffffffffff) << (VA_BITS - 1))
 #define MODULES_END		(PAGE_OFFSET)
 #define MODULES_VADDR		(MODULES_END - SZ_64M)
-#define EARLYCON_IOBASE		(MODULES_VADDR - SZ_4M)
+#define FIXADDR_TOP		(MODULES_VADDR - SZ_2M - PAGE_SIZE)
 #define TASK_SIZE_64		(UL(1) << VA_BITS)
 
 #ifdef CONFIG_COMPAT

arch/arm64/kernel/early_printk.c +6 -2

index fbb6e18..850d9a4 100644
@@ -26,6 +26,8 @@
 #include <linux/amba/serial.h>
 #include <linux/serial_reg.h>
 
+#include <asm/fixmap.h>
+
 static void __iomem *early_base;
 static void (*printch)(char ch);

@@ -141,8 +143,10 @@ static int __init setup_early_printk(char *buf)
 	}
 	/* no options parsing yet */
 
-	if (paddr)
-		early_base = early_io_map(paddr, EARLYCON_IOBASE);
+	if (paddr) {
+		set_fixmap_io(FIX_EARLYCON, paddr);
+		early_base = (void __iomem *)fix_to_virt(FIX_EARLYCON);
+	}
 
 	printch = match->printch;
 	early_console = &early_console_dev;

arch/arm64/kernel/head.S +3 -6

index c68cca5..4b47dcb 100644
@@ -412,7 +412,7 @@ ENDPROC(__calc_phys_offset)
  *   - identity mapping to enable the MMU (low address, TTBR0)
  *   - first few MB of the kernel linear mapping to jump to once the MMU has
  *     been enabled, including the FDT blob (TTBR1)
- *   - UART mapping if CONFIG_EARLY_PRINTK is enabled (TTBR1)
+ *   - pgd entry for fixed mappings (TTBR1)
  */
 __create_page_tables:
 	pgtbl	x25, x26, x24			// idmap_pg_dir and swapper_pg_dir addresses

@@ -465,15 +465,12 @@ __create_page_tables:
 	sub	x6, x6, #1			// inclusive range
 	create_block_map x0, x7, x3, x5, x6
 1:
-#ifdef CONFIG_EARLY_PRINTK
 	/*
-	 * Create the pgd entry for the UART mapping. The full mapping is done
-	 * later based earlyprintk kernel parameter.
+	 * Create the pgd entry for the fixed mappings.
 	 */
-	ldr	x5, =EARLYCON_IOBASE		// UART virtual address
+	ldr	x5, =FIXADDR_TOP		// Fixed mapping virtual address
 	add	x0, x26, #2 * PAGE_SIZE		// section table address
 	create_pgd_entry x26, x0, x5, x6, x7
-#endif
 	ret
 ENDPROC(__create_page_tables)
 	.ltorg

arch/arm64/kernel/setup.c +2 -0

index 029ecfe..5516f54 100644
@@ -42,6 +42,7 @@
 #include <linux/of_fdt.h>
 #include <linux/of_platform.h>
 
+#include <asm/fixmap.h>
 #include <asm/cputype.h>
 #include <asm/elf.h>
 #include <asm/cputable.h>

@@ -222,6 +223,7 @@ void __init setup_arch(char **cmdline_p)
 	*cmdline_p = boot_command_line;
 
 	init_mem_pgprot();
+	early_ioremap_init();
 
 	parse_early_param();

arch/arm64/mm/ioremap.c +85 -0

94 lines not on this page · raw message

arch/arm64/mm/mmu.c +0 ~~-41~~

47 lines not on this page · raw message

Signature · 7 lines

1.8.3.1

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Catalin Marinas

maintainer

2014-01-07 17:26 UTC #11 lore raw

In reply to Mark Salter

Quoted 10 lines · Mark Salter

This patch series takes the common bits from the x86 early ioremap implementation and creates a generic implementation which may be used by other architectures. The early ioremap interfaces are intended for situations where boot code needs to make temporary virtual mappings before the normal ioremap interfaces are available. Typically, this means before paging_init() has run.
These patches are layered on top of generic fixmap patches which were discussed here (and are in the akpm tree):

Quoted 6 lines

http://lkml.org/lkml/2013/11/25/474
This is version 2 of the patch series. These patches (and underlying fixmap patches) may be found at:
git://github.com/mosalter/linux.git (early-ioremap-v2 branch)

The patches look fine to me. I haven't acked the arm64 patches as I'll eventually merge/sign them off once the first patch in the series goes in.

Thanks.

Signature · 7 lines

Catalin

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