Re: [PATCH 1/2] arm64: apei: implement arch_apei_get_mem_attributes()
From: Ingo Molnar <mingo@kernel.org>
Date: 2015-08-13 08:22:33
Also in:
lkml
* Matt Fleming [off-list ref] wrote:
quoted hunk ↗ jump to hunk
From: "Jonathan (Zhixiong) Zhang" <redacted> 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 <catalin.marinas@arm.com> Acked-by: Hanjun Guo <redacted> Reviewed-by: Ard Biesheuvel <redacted> Signed-off-by: Jonathan (Zhixiong) Zhang <redacted> Signed-off-by: Matt Fleming <redacted> --- arch/arm64/include/asm/acpi.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h index 406485ed110a..1cbad43e561d 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)@@ -92,4 +97,29 @@ 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) +{ + /* + * 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.
s/mapped to corresponding/ mapped to a corresponding
+ * 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
Also, this doesn't look like a small function - why is it inlined? Moving it to .c would also slightly improve compilation times for every .c file that includes asm/acpi.h. Thanks, Ingo