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-rw-r--r--arch/arm64/kernel/efi-entry.S27
1 files changed, 21 insertions, 6 deletions
diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S
index 619b1dd7bcde..d18a44940968 100644
--- a/arch/arm64/kernel/efi-entry.S
+++ b/arch/arm64/kernel/efi-entry.S
@@ -54,18 +54,17 @@ ENTRY(efi_stub_entry)
b.eq efi_load_fail
/*
- * efi_entry() will have relocated the kernel image if necessary
- * and we return here with device tree address in x0 and the kernel
- * entry point stored at *image_addr. Save those values in registers
- * which are callee preserved.
+ * efi_entry() will have copied the kernel image if necessary and we
+ * return here with device tree address in x0 and the kernel entry
+ * point stored at *image_addr. Save those values in registers which
+ * are callee preserved.
*/
mov x20, x0 // DTB address
ldr x0, [sp, #16] // relocated _text address
mov x21, x0
/*
- * Flush dcache covering current runtime addresses
- * of kernel text/data. Then flush all of icache.
+ * Calculate size of the kernel Image (same for original and copy).
*/
adrp x1, _text
add x1, x1, #:lo12:_text
@@ -73,9 +72,24 @@ ENTRY(efi_stub_entry)
add x2, x2, #:lo12:_edata
sub x1, x2, x1
+ /*
+ * Flush the copied Image to the PoC, and ensure it is not shadowed by
+ * stale icache entries from before relocation.
+ */
bl __flush_dcache_area
ic ialluis
+ /*
+ * Ensure that the rest of this function (in the original Image) is
+ * visible when the caches are disabled. The I-cache can't have stale
+ * entries for the VA range of the current image, so no maintenance is
+ * necessary.
+ */
+ adr x0, efi_stub_entry
+ adr x1, efi_stub_entry_end
+ sub x1, x1, x0
+ bl __flush_dcache_area
+
/* Turn off Dcache and MMU */
mrs x0, CurrentEL
cmp x0, #CurrentEL_EL2
@@ -105,4 +119,5 @@ efi_load_fail:
ldp x29, x30, [sp], #32
ret
+efi_stub_entry_end:
ENDPROC(efi_stub_entry)