[PATCH V4 39/50] x86/debug, mce: Use C entry code

From: Lai Jiangshan
Date: Tue Oct 26 2021 - 10:36:37 EST


From: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>

Use DEFINE_IDTENTRY_IST_ETNRY to emit C entry function and use the function
directly in entry_64.S.

Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>
---
arch/x86/entry/entry_64.S | 10 +---------
arch/x86/include/asm/idtentry.h | 1 +
arch/x86/kernel/cpu/mce/Makefile | 3 +++
3 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index c9ee58e8e6d1..7c994bcde1b0 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -466,16 +466,8 @@ SYM_CODE_START(\asmsym)
testb $3, CS(%rsp)
jnz .Lfrom_usermode_switch_stack_\@

- /* paranoid_entry returns GS information for paranoid_exit in EBX. */
- call paranoid_entry
-
- UNWIND_HINT_REGS
-
movq %rsp, %rdi /* pt_regs pointer */
-
- call \cfunc
-
- call paranoid_exit
+ call ist_\cfunc
jmp restore_regs_and_return_to_kernel

/* Switch to the regular task stack and use the noist entry point */
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 0f615943a460..d0fd32288442 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -358,6 +358,7 @@ __visible __entry_text void ist_##func(struct pt_regs *regs) \
* Maps to DEFINE_IDTENTRY_RAW
*/
#define DEFINE_IDTENTRY_IST(func) \
+ DEFINE_IDTENTRY_IST_ETNRY(func) \
DEFINE_IDTENTRY_RAW(func)

/**
diff --git a/arch/x86/kernel/cpu/mce/Makefile b/arch/x86/kernel/cpu/mce/Makefile
index 015856abdbb1..555963416ec3 100644
--- a/arch/x86/kernel/cpu/mce/Makefile
+++ b/arch/x86/kernel/cpu/mce/Makefile
@@ -1,4 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
+
+CFLAGS_core.o += -fno-stack-protector
+
obj-y = core.o severity.o genpool.o

obj-$(CONFIG_X86_ANCIENT_MCE) += winchip.o p5.o
--
2.19.1.6.gb485710b