[PATCH v5 05/16] x86/pvh: Use fixed_percpu_data for early boot GSBASE
From: Brian Gerst
Date: Tue Nov 05 2024 - 10:59:14 EST
Instead of having a private area for the stack canary, use
fixed_percpu_data for GSBASE like the native kernel.
Signed-off-by: Brian Gerst <brgerst@xxxxxxxxx>
---
arch/x86/platform/pvh/head.S | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/arch/x86/platform/pvh/head.S b/arch/x86/platform/pvh/head.S
index 64fca49cd88f..b0a9a58952aa 100644
--- a/arch/x86/platform/pvh/head.S
+++ b/arch/x86/platform/pvh/head.S
@@ -159,10 +159,15 @@ SYM_CODE_START_LOCAL(pvh_start_xen)
1:
UNWIND_HINT_END_OF_STACK
- /* Set base address in stack canary descriptor. */
- mov $MSR_GS_BASE,%ecx
- leal canary(%rip), %eax
- xor %edx, %edx
+ /*
+ * Set up GSBASE.
+ * Note that, on SMP, the boot cpu uses init data section until
+ * the per cpu areas are set up.
+ */
+ movl $MSR_GS_BASE,%ecx
+ leaq INIT_PER_CPU_VAR(fixed_percpu_data)(%rip), %rdx
+ movq %edx, %eax
+ shrq $32, %rdx
wrmsr
/*
@@ -232,8 +237,6 @@ SYM_DATA_START_LOCAL(gdt_start)
SYM_DATA_END_LABEL(gdt_start, SYM_L_LOCAL, gdt_end)
.balign 16
-SYM_DATA_LOCAL(canary, .fill 48, 1, 0)
-
SYM_DATA_START_LOCAL(early_stack)
.fill BOOT_STACK_SIZE, 1, 0
SYM_DATA_END_LABEL(early_stack, SYM_L_LOCAL, early_stack_end)
--
2.47.0