x18 must be preserved on HVC/SMC calls per arm's convention.
Change-Id: I3e2ebe9b283617c2c8d7b3f2aa0780d4c91b6443
diff --git a/src/arch/aarch64/exceptions.S b/src/arch/aarch64/exceptions.S
index efb7ed5..54e3882 100644
--- a/src/arch/aarch64/exceptions.S
+++ b/src/arch/aarch64/exceptions.S
@@ -41,8 +41,11 @@
.balign 0x80
/* sync_lower_64 */
- /* Save x18 since we're about to clobber it. */
- str x18, [sp, #-8]
+ /*
+ * Save x18 since we're about to clobber it. We subtract 16 instead of
+ * 8 from the stack pointer to keep it 16-byte aligned.
+ */
+ str x18, [sp, #-16]!
/* Extract the exception class (EC) from exception syndrome register. */
mrs x18, esr_el2
@@ -71,7 +74,7 @@
ldp x11, x12, [sp, #-16]
ldp x13, x14, [sp, #-16]
ldp x15, x16, [sp, #-16]
- ldp x17, x18, [sp, #-16]
+ mov x17, xzr
eret
.balign 0x80
@@ -329,7 +332,8 @@
stp x16, x17, [x18, #8 * 16]
stp x29, x30, [x18, #8 * 29]
- ldr x0, [sp, #-8]
+ /* x18 was saved on the stack, so we move it to vcpu regs buffer. */
+ ldr x0, [sp], #16
str x0, [x18, #8 * 18]
/* Save return address & mode. */
