[RFC PATCH v2 03/16] x86/kexec: Restore GDT on return from preserve_context kexec

[David Woodhouse]

From: David Woodhouse <dwmw at amazon.co.uk>

The restore_processor_state() function explicitly states that "the asm code
that gets us here will have restored a usable GDT". That wasn't true in the
case of returning from a preserve_context kexec. Make it so.

Without this, the kernel was depending on the called function to reload an
appropriate GDT.

Signed-off-by: David Woodhouse <dwmw at amazon.co.uk>
---
 arch/x86/kernel/relocate_kernel_64.S | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
index ca01e3e2f097..ed2ae50535dd 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -252,6 +252,11 @@ SYM_CODE_START_LOCAL_NOALIGN(virtual_mapped)
 	movq	CR0(%r8), %r8
 	movq	%rax, %cr3
 	movq	%r8, %cr0
+
+	/* Saved in save_processor_state. */
+	movq    $saved_context, %rax
+	lgdt    saved_context_gdt_desc(%rax)
+
 	movq	%rbp, %rax
 
 	popf
-- 
2.47.0