From: David Woodhouse <d...@amazon.co.uk>
All writes to the relocate_kernel control page are now done *after* the
%cr3 switch via simple %rip-relative addressing, which means the DATA()
macro with its pointer arithmetic can also now be removed.
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
---
arch/x86/kernel/relocate_kernel_64.S | 29 ++++++++++++++--------------
1 file changed, 14 insertions(+), 15 deletions(-)
diff --git a/arch/x86/kernel/relocate_kernel_64.S
b/arch/x86/kernel/relocate_kernel_64.S
index 16f123527406..288dfc08c63d 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -61,21 +61,24 @@ SYM_CODE_START_NOALIGN(relocate_kernel)
pushq %r15
pushf
- movq %rsp, saved_rsp(%rip)
- movq %cr0, %rax
- movq %rax, saved_cr0(%rip)
- movq %cr3, %rax
- movq %rax, saved_cr3(%rip)
- movq %cr4, %rax
- movq %rax, saved_cr4(%rip)
-
- /* Save CR4. Required to enable the right paging mode later. */
- movq %rax, %r13
-
/* zero out flags, and disable interrupts */
pushq $0
popfq
+ /* Switch to the identity mapped page tables */
+ movq %cr3, %rax
+ movq kexec_pa_table_page(%rip), %r9
+ movq %r9, %cr3
+
+ /* Save %rsp and CRs. */
+ movq %rsp, saved_rsp(%rip)
+ movq %rax, saved_cr3(%rip)
+ movq %cr0, %rax
+ movq %rax, saved_cr0(%rip)
+ /* Leave CR4 in %r13 to enable the right paging mode later. */
+ movq %cr4, %r13
+ movq %r13, saved_cr4(%rip)
+
/* Save SME active flag */
movq %r8, %r12
@@ -85,10 +88,6 @@ SYM_CODE_START_NOALIGN(relocate_kernel)
/* Save the preserve_context to %r11 as swap_pages clobbers %rcx. */
movq %rcx, %r11
- /* Switch to the identity mapped page tables */
- movq kexec_pa_table_page(%rip), %r9
- movq %r9, %cr3
-
/* Physical address of control page */
movq %rsi, %r8
--
2.47.0
