[PATCH V4 21/50] x86/entry: Move cld to the start of idtentry
From: Lai Jiangshan
Date: Tue Oct 26 2021 - 10:30:41 EST
From: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>
Make it next to CLAC
Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>
---
arch/x86/entry/entry_64.S | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 1ec87d9e685d..52a08c4a0171 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -357,6 +357,7 @@ SYM_CODE_END(ret_from_fork)
SYM_CODE_START(\asmsym)
UNWIND_HINT_IRET_REGS offset=\has_error_code*8
ASM_CLAC
+ cld
.if \has_error_code == 0
pushq $-1 /* ORIG_RAX: no syscall to restart */
@@ -424,6 +425,7 @@ SYM_CODE_END(\asmsym)
SYM_CODE_START(\asmsym)
UNWIND_HINT_IRET_REGS
ASM_CLAC
+ cld
pushq $-1 /* ORIG_RAX: no syscall to restart */
@@ -479,6 +481,7 @@ SYM_CODE_END(\asmsym)
SYM_CODE_START(\asmsym)
UNWIND_HINT_IRET_REGS
ASM_CLAC
+ cld
/*
* If the entry is from userspace, switch stacks and treat it as
@@ -540,6 +543,7 @@ SYM_CODE_END(\asmsym)
SYM_CODE_START(\asmsym)
UNWIND_HINT_IRET_REGS offset=8
ASM_CLAC
+ cld
/* paranoid_entry returns GS information for paranoid_exit in EBX. */
call paranoid_entry
@@ -852,7 +856,6 @@ SYM_CODE_END(xen_failsafe_callback)
*/
SYM_CODE_START_LOCAL(paranoid_entry)
UNWIND_HINT_FUNC
- cld
PUSH_AND_CLEAR_REGS save_ret=1
ENCODE_FRAME_POINTER 8
@@ -977,7 +980,6 @@ SYM_CODE_END(paranoid_exit)
*/
SYM_CODE_START_LOCAL(error_entry)
UNWIND_HINT_FUNC
- cld
testb $3, CS+8(%rsp)
jz .Lerror_kernelspace
@@ -1112,6 +1114,7 @@ SYM_CODE_START(asm_exc_nmi)
*/
ASM_CLAC
+ cld
/* Use %rdx as our temp variable throughout */
pushq %rdx
@@ -1131,7 +1134,6 @@ SYM_CODE_START(asm_exc_nmi)
*/
swapgs
- cld
FENCE_SWAPGS_USER_ENTRY
SWITCH_TO_KERNEL_CR3 scratch_reg=%rdx
movq %rsp, %rdx
--
2.19.1.6.gb485710b