From: "Jonathan (Zhixiong) Zhang" zjzhang@codeaurora.org
If the physical address has memory attributes defined by EFI memmap as EFI_MEMORY_UC, the page protection type is PROT_DEVICE_nGnRE. Otherwise, the page protection type is PAGE_KERNEL.
Signed-off-by: Jonathan (Zhixiong) Zhang zjzhang@codeaurora.org --- This patch applies cleanly to efi-next-14364 of efi/next and arm64-upstream-13521 of arm64/master, but needed slight change to apply to next-20150720 of linux-next/master and pm+acpi-4.2-rc3 of linux-pm/master. The later two branches has newer arch/arm64/include/asm/acpi.h with following patch: b6cfb277378e ACPI / ARM64: add BAD_MADT_GICC_ENTRY() macro --- arch/arm64/include/asm/acpi.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h index 39248d3adf5d..42e4fd8aaf34 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 + /* Basic configuration for ACPI */ #ifdef CONFIG_ACPI /* ACPI table mapping after acpi_gbl_permanent_mmap is set */ @@ -84,4 +89,15 @@ static inline const char *acpi_get_enable_method(int cpu) { return acpi_psci_present() ? "psci" : NULL; } + +#ifdef CONFIG_ACPI_APEI +static inline pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr) +{ + if (efi_mem_attributes(addr) & EFI_MEMORY_UC) + return PROT_DEVICE_nGnRE; + + return PAGE_KERNEL; +} +#endif + #endif /*_ASM_ACPI_H*/