Commit b40227fb authored Aug 07, 2015 by Jonathan (Zhixiong) Zhang Committed by Ingo Molnar Aug 08, 2015

acpi, x86: Implement arch_apei_get_mem_attributes()



... 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>

parent 7bf79311

arch/x86/include/asm/acpi.h

+23 −0

Original line number	Diff line number	Diff line
		@@ -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 */

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