On 17. 12. 24 00:24, David Woodhouse wrote:
From: David Woodhouse <dwmw@xxxxxxxxxxxx>
The swap_pages function will only actually *swap*, as its name implies,
if the preserve_context flag in the %r11 register is non-zero. On the
way back from a ::preserve_context kexec, ensure that the %r11 register
is non-zero so that the pages get swapped back.
Fixes: 9e5683e2d0b5 ("x86/kexec: Only swap pages for ::preserve_context mode")
Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
---
arch/x86/kernel/relocate_kernel_64.S | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
index 9bd601dd8659..1a52e4339c1d 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -220,6 +220,7 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
movq kexec_pa_table_page(%rip), %rax
movq %rax, %cr3
lea PAGE_SIZE(%r8), %rsp
+ movq $1, %r11 /* Ensure preserve_context flag is set */
You can save a byte here by using "movl $1, %r11d".
call swap_pages
movq kexec_va_control_page(%rip), %rax
addq $(virtual_mapped - relocate_kernel), %rax
Uros.
