@@ -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 */
@@ -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 */
@@ -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);
}
The UEFI spec 2.9 has recently been updated to include a requirement that 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 it enables the MMU. On ARM and arm64 systems, this implies a D-cache clean by virtual address to the point of coherency. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- arch/arm/include/asm/efi.h | 5 +++++ arch/arm64/include/asm/efi.h | 5 +++++ drivers/firmware/efi/capsule.c | 12 ++++++++++++ 3 files changed, 22 insertions(+)