From: "Jonathan (Zhixiong) Zhang" <zjzh...@codeaurora.org>
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. Otherwise, return PAGE_KERNEL.
Change-Id: I7f836cae0fb3e74a34e27ac695c2637ffc4cddc6
Acked-by: Hanjun Guo <hanjun....@linaro.org>
Signed-off-by: Jonathan (Zhixiong) Zhang <zjzh...@codeaurora.org>
---
arch/arm64/include/asm/acpi.h | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index 1ff9e6eb5e02..04720f819f0a 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -19,6 +19,11 @@
#include <asm/psci.h>
#include <asm/smp_plat.h>
+#ifdef CONFIG_ACPI_APEI
+#include <linux/efi.h>
+#include <asm/pgtable.h>
+#endif
+
/* Macros for consistency checks of the GICC subtable of MADT */
#define ACPI_MADT_GICC_LENGTH \
(acpi_gbl_FADT.header.revision < 6 ? 76 : 80)
@@ -91,4 +95,26 @@ static inline const char *acpi_get_enable_method(int cpu)
{
return acpi_psci_present() ? "psci" : NULL;
}
+
+#ifdef CONFIG_ACPI_APEI
+/*
+ * 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
+ * corresponding MAIR attribute encoding.
+ */
+static inline pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr)
+{
+ u64 attr;
+
+ attr = efi_mem_attributes(addr);
+ if (attr & EFI_MEMORY_UC)
+ return PROT_DEVICE_nGnRnE;
+ if (attr & EFI_MEMORY_WC)
+ return PROT_NORMAL_NC;
+ if (attr & EFI_MEMORY_WT)
+ return PROT_NORMAL_WT;
+ return PAGE_KERNEL;
+}
+#endif
+
#endif /*_ASM_ACPI_H*/
--
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