From mboxrd@z Thu Jan 1 00:00:00 1970 From: james.morse@arm.com (James Morse) Date: Tue, 8 Nov 2016 10:27:14 +0000 Subject: [PATCH] arm64: acpi: arch_apei_get_mem_attributes() should use memblock Message-ID: <20161108102714.29931-1-james.morse@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org arm64's arch_apei_get_mem_attributes() tries to use efi_mem_attributes() to read the memory attributes from the efi memory map. drivers/firmware/efi/arm-init.c:efi_init() calls efi_memmap_unmap(), which clears the EFI_MEMMAP bit from efi.flags once efi_init() has finished with the memory map. This causes efi_mem_attributes() to return 0 meaning PROT_DEVICE_nGnRnE is the chosen memory type for all ACPI APEI mappings. APEI may call this from NMI context, so we can't re-map the EFI memory map as this may need to allocate virtual address space. 'ghes_ioremap_area' is APEIs cache of virtual address space to access the buffer once we tell it the memory attributes. Do as acpi_os_ioremap() does, and consult memblock to learn if the provided address is memory, or not. Signed-off-by: James Morse Cc: Jonathan (Zhixiong) Zhang Cc: Ard Biesheuvel --- Fixes: 89e44b51cc0d ("arm64, acpi/apei: Implement arch_apei_get_mem_attributes()") This doesn't code even get built on mainline as HAVE_ACPI_APEI isn't defined, until https://lkml.org/lkml/2016/8/10/231 gets merged. I don't think this should go to stable. I also took the opportunity to remove some unnecessarily ifdef'd includes. arch/arm64/kernel/acpi.c | 28 ++++++++-------------------- 1 file changed, 8 insertions(+), 20 deletions(-) diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index 252a6d9c1da5..985f721f3bdd 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -28,13 +29,9 @@ #include #include +#include #include -#ifdef CONFIG_ACPI_APEI -# include -# include -#endif - int acpi_noirq = 1; /* skip ACPI IRQ initialization */ int acpi_disabled = 1; EXPORT_SYMBOL(acpi_disabled); @@ -241,22 +238,13 @@ void __init acpi_boot_table_init(void) 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. + * The EFI memmap isn't mapped, instead read the version exported + * into memblock. EFI's reserve_regions() call adds memory with the + * WB attribute to memblock via early_init_dt_add_memory_arch(). */ + if (!memblock_is_memory(addr)) + return __pgprot(PROT_DEVICE_nGnRnE); - 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); + return PAGE_KERNEL; } #endif -- 2.10.1