From: "Jonathan (Zhixiong) Zhang" <[email protected]> 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. Reviewed-by: Catalin Marinas <[email protected]> Acked-by: Hanjun Guo <[email protected]> Signed-off-by: Jonathan (Zhixiong) Zhang <[email protected]> --- This patch as is does not build on current tip of next branch of git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi.git, a small tweak is needed. It builds on tip of linux-next/master of linus' repo and origin/master of arm64 repo. --- 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..1025d0401016 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 __pgprot(PROT_DEVICE_nGnRnE); + if (attr & EFI_MEMORY_WC) + return __pgprot(PROT_NORMAL_NC); + if (attr & EFI_MEMORY_WT) + return __pgprot(PROT_NORMAL_WT); + return __pgprot(PAGE_KERNEL); +} +#endif + #endif /*_ASM_ACPI_H*/ -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
