summaryrefslogtreecommitdiff
path: root/arch/arm64/kernel/efi-rt-wrapper.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm64/kernel/efi-rt-wrapper.S')
-rw-r--r--arch/arm64/kernel/efi-rt-wrapper.S11
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/arm64/kernel/efi-rt-wrapper.S b/arch/arm64/kernel/efi-rt-wrapper.S
index 1192c4bb48df..75691a2641c1 100644
--- a/arch/arm64/kernel/efi-rt-wrapper.S
+++ b/arch/arm64/kernel/efi-rt-wrapper.S
@@ -34,5 +34,14 @@ SYM_FUNC_START(__efi_rt_asm_wrapper)
ldp x29, x30, [sp], #32
b.ne 0f
ret
-0: b efi_handle_corrupted_x18 // tail call
+0:
+ /*
+ * With CONFIG_SHADOW_CALL_STACK, the kernel uses x18 to store a
+ * shadow stack pointer, which we need to restore before returning to
+ * potentially instrumented code. This is safe because the wrapper is
+ * called with preemption disabled and a separate shadow stack is used
+ * for interrupts.
+ */
+ mov x18, x2
+ b efi_handle_corrupted_x18 // tail call
SYM_FUNC_END(__efi_rt_asm_wrapper)