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Subject[tip:core/efi] arm64, acpi/apei: Implement arch_apei_get_mem_attributes()
Commit-ID:  89e44b51cc0db50ea4b5bbb5d582c4db88bbaed8
Gitweb: http://git.kernel.org/tip/89e44b51cc0db50ea4b5bbb5d582c4db88bbaed8
Author: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
AuthorDate: Fri, 4 Sep 2015 14:11:41 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 14 Sep 2015 11:40:03 +0200

arm64, acpi/apei: Implement arch_apei_get_mem_attributes()

Table 8 of UEFI 2.5 section 2.3.6.1 defines mappings from EFI
memory types to MAIR attribute encodings for arm64.

If the physical address has memory attributes defined by EFI
memmap as EFI_MEMORY_[UC|WC|WT], return approprate page
protection type according to the UEFI spec. Otherwise, return
PAGE_KERNEL.

Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
[ Small stylistic tweaks. ]
Reviewed-by: Matt Fleming <matt.fleming@intel.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1441372302-23242-2-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/arm64/include/asm/acpi.h | 5 +++++
arch/arm64/kernel/acpi.c | 29 +++++++++++++++++++++++++++++
2 files changed, 34 insertions(+)

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index 406485e..5aa892a 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -92,4 +92,9 @@ static inline const char *acpi_get_enable_method(int cpu)
{
return acpi_psci_present() ? "psci" : NULL;
}
+
+#ifdef CONFIG_ACPI_APEI
+pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr);
+#endif
+
#endif /*_ASM_ACPI_H*/
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 19de753..137d537 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -29,6 +29,11 @@
#include <asm/cpu_ops.h>
#include <asm/smp_plat.h>

+#ifdef CONFIG_ACPI_APEI
+# include <linux/efi.h>
+# include <asm/pgtable.h>
+#endif
+
int acpi_noirq = 1; /* skip ACPI IRQ initialization */
int acpi_disabled = 1;
EXPORT_SYMBOL(acpi_disabled);
@@ -230,3 +235,27 @@ void __init acpi_gic_init(void)

early_acpi_os_unmap_memory((char *)table, tbl_size);
}
+
+#ifdef CONFIG_ACPI_APEI
+pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr)
+{
+ /*
+ * According to "Table 8 Map: EFI memory types to AArch64 memory
+ * types" of UEFI 2.5 section 2.3.6.1, each EFI memory type is
+ * mapped to a corresponding MAIR attribute encoding.
+ * The EFI memory attribute advises all possible capabilities
+ * of a memory region. We use the most efficient capability.
+ */
+
+ u64 attr;
+
+ attr = efi_mem_attributes(addr);
+ if (attr & EFI_MEMORY_WB)
+ return PAGE_KERNEL;
+ if (attr & EFI_MEMORY_WT)
+ return __pgprot(PROT_NORMAL_WT);
+ if (attr & EFI_MEMORY_WC)
+ return __pgprot(PROT_NORMAL_NC);
+ return __pgprot(PROT_DEVICE_nGnRnE);
+}
+#endif

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