From: Borislav Petkov <b...@suse.de>
04633df0c43d ("x86/cpu: Call verify_cpu() after having entered long mode too")
added the call to verify_cpu() for sanitizing CPU configuration.
The latter uses the stack minimally and it can happen that we land in
startup_64() directly from a 64-bit bootloader. Then we want to use our
own, known good stack.
Do that.
APs don't need this as the trampoline sets up a stack for them.
Reported-by: Tom Lendacky <thomas.lenda...@amd.com>
Signed-off-by: Borislav Petkov <b...@suse.de>
---
arch/x86/kernel/head_64.S | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 22fbf9df61bb..d60a044c2fdc 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -64,6 +64,10 @@ startup_64:
* tables and then reload them.
*/
+ /* Setup a stack for verify_cpu */
+ movq stack_start - __START_KERNEL_map, %rsp
+ subq $__START_KERNEL_map, %rsp
+
/* Sanitize CPU configuration */
call verify_cpu
--
2.3.5
