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acpi, x86: Implement arch_apei_get_mem_attributes()

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... to allow an arch specific implementation of getting page
protection type associated with a physical address.

On x86, we currently have no way to look up the EFI memory map
attributes for a region in a consistent way, because the
memmap is discarded after efi_free_boot_services(). So if
you call efi_mem_attributes() during boot and at runtime,
you could theoretically see different attributes.

Since we are yet to see any x86 platforms that require
anything other than PAGE_KERNEL (some arm64 platforms
require the equivalent of PAGE_KERNEL_NOCACHE), return that
until we know differently.

Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1438936621-5215-5-git-send-email-matt@codeblueprint.co.uk
[ Small fixes to spelling. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Jonathan (Zhixiong) Zhang 2015-08-07 09:36:58 +01:00 committed by Ingo Molnar
parent 7bf793115d
commit b40227fbfb
1 changed files with 23 additions and 0 deletions
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23
arch/x86/include/asm/acpi.h
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@ -32,6 +32,10 @@
#include <asm/mpspec.h>
#include <asm/realmode.h>
#ifdef CONFIG_ACPI_APEI
# include <asm/pgtable_types.h>
#endif
#ifdef CONFIG_ACPI
extern int acpi_lapic;
extern int acpi_ioapic;
@ -147,4 +151,23 @@ extern int x86_acpi_numa_init(void);
#define acpi_unlazy_tlb(x) leave_mm(x)
#ifdef CONFIG_ACPI_APEI
static inline pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr)
{
/*
* We currently have no way to look up the EFI memory map
* attributes for a region in a consistent way, because the
* memmap is discarded after efi_free_boot_services(). So if
* you call efi_mem_attributes() during boot and at runtime,
* you could theoretically see different attributes.
*
* Since we are yet to see any x86 platforms that require
* anything other than PAGE_KERNEL (some arm64 platforms
* require the equivalent of PAGE_KERNEL_NOCACHE), return that
* until we know differently.
*/
return PAGE_KERNEL;
}
#endif
#endif /* _ASM_X86_ACPI_H */