[PATCH 13/18] arm64: preserve x18 when CPU is suspended

Sami Tolvanen
2019-10-18T16:14:47Z

Don't lose the current task's shadow stack when the CPU is suspended.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
arch/arm64/mm/proc.S | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index fdabf40a83c8..9a8bd4bc8549 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -73,6 +73,9 @@ alternative_endif
stp x8, x9, [x0, #48]
stp x10, x11, [x0, #64]
stp x12, x13, [x0, #80]
+#ifdef CONFIG_SHADOW_CALL_STACK
+ stp x18, xzr, [x0, #96]
+#endif
ret
ENDPROC(cpu_do_suspend)

@@ -89,6 +92,9 @@ ENTRY(cpu_do_resume)
ldp x9, x10, [x0, #48]
ldp x11, x12, [x0, #64]
ldp x13, x14, [x0, #80]
+#ifdef CONFIG_SHADOW_CALL_STACK
+ ldp x18, x19, [x0, #96]
+#endif
msr tpidr_el0, x2
msr tpidrro_el0, x3
msr contextidr_el1, x4
--
2.23.0.866.gb869b98d4c-goog