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| author | Ard Biesheuvel <ardb@kernel.org> | 2020-12-07 18:40:53 +0100 |
|---|---|---|
| committer | Ard Biesheuvel <ardb@kernel.org> | 2020-12-09 08:37:27 +0100 |
| commit | 4dbe44fb538c59a4adae5abfa9ded2f310250315 (patch) | |
| tree | da4f681ca5b596a899337141cf3cfadc185a98b9 | |
| parent | 91c1c092f27da4164d55ca81e0a483108f8a3235 (diff) | |
| download | linux-4dbe44fb538c59a4adae5abfa9ded2f310250315.tar.bz2 | |
efi: capsule: clean scatter-gather entries from the D-cache
Scatter-gather lists passed to UpdateCapsule() should be cleaned
from the D-cache to ensure that they are visible to the CPU after a
warm reboot before the MMU is enabled. On ARM and arm64 systems, this
implies a D-cache clean by virtual address to the point of coherency.
However, due to the fact that the firmware itself is not able to map
physical addresses back to virtual addresses when running under the OS,
this must be done by the caller.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
| -rw-r--r-- | arch/arm/include/asm/efi.h | 5 | ||||
| -rw-r--r-- | arch/arm64/include/asm/efi.h | 5 | ||||
| -rw-r--r-- | drivers/firmware/efi/capsule.c | 12 |
3 files changed, 22 insertions, 0 deletions
diff --git a/arch/arm/include/asm/efi.h b/arch/arm/include/asm/efi.h index 3ee4f4381985..e9a06e164e06 100644 --- a/arch/arm/include/asm/efi.h +++ b/arch/arm/include/asm/efi.h @@ -93,4 +93,9 @@ struct efi_arm_entry_state { u32 sctlr_after_ebs; }; +static inline void efi_capsule_flush_cache_range(void *addr, int size) +{ + __cpuc_flush_dcache_area(addr, size); +} + #endif /* _ASM_ARM_EFI_H */ diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h index 973b14415271..00bd1e179d36 100644 --- a/arch/arm64/include/asm/efi.h +++ b/arch/arm64/include/asm/efi.h @@ -141,4 +141,9 @@ static inline void efi_set_pgd(struct mm_struct *mm) void efi_virtmap_load(void); void efi_virtmap_unload(void); +static inline void efi_capsule_flush_cache_range(void *addr, int size) +{ + __flush_dcache_area(addr, size); +} + #endif /* _ASM_EFI_H */ diff --git a/drivers/firmware/efi/capsule.c b/drivers/firmware/efi/capsule.c index 43f6fe7bfe80..768430293669 100644 --- a/drivers/firmware/efi/capsule.c +++ b/drivers/firmware/efi/capsule.c @@ -12,6 +12,7 @@ #include <linux/highmem.h> #include <linux/efi.h> #include <linux/vmalloc.h> +#include <asm/efi.h> #include <asm/io.h> typedef struct { @@ -265,6 +266,17 @@ int efi_capsule_update(efi_capsule_header_t *capsule, phys_addr_t *pages) else sglist[j].data = page_to_phys(sg_pages[i + 1]); +#if defined(CONFIG_ARM) || defined(CONFIG_ARM64) + /* + * At runtime, the firmware has no way to find out where the + * sglist elements are mapped, if they are mapped in the first + * place. Therefore, on architectures that can only perform + * cache maintenance by virtual address, the firmware is unable + * to perform this maintenance, and so it is up to the OS to do + * it instead. + */ + efi_capsule_flush_cache_range(sglist, PAGE_SIZE); +#endif kunmap_atomic(sglist); } |