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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 /drivers/firmware | |
| parent | efi: capsule: use atomic kmap for transient sglist mappings (diff) | |
| download | linux-4dbe44fb538c59a4adae5abfa9ded2f310250315.tar.xz linux-4dbe44fb538c59a4adae5abfa9ded2f310250315.zip | |
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>
Diffstat (limited to 'drivers/firmware')
| -rw-r--r-- | drivers/firmware/efi/capsule.c | 12 |
1 files changed, 12 insertions, 0 deletions
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); } |