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Subject[PATCH V6 41/49] x86/nmi: Use C entry code
Date
From: Lai Jiangshan <laijs@linux.alibaba.com>

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

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
arch/x86/entry/entry_64.S | 17 ++---------------
arch/x86/include/asm/idtentry.h | 5 ++++-
arch/x86/kernel/Makefile | 1 +
3 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index ac05cbf894f5..cc552e23d691 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1306,21 +1306,8 @@ end_repeat_nmi:
PUSH_AND_CLEAR_REGS
ENCODE_FRAME_POINTER

- /*
- * Use paranoid_entry to handle SWAPGS and CR3.
- */
- call paranoid_entry
- UNWIND_HINT_REGS
-
- movq %rsp, %rdi
- movq $-1, %rsi
- call exc_nmi
-
- /*
- * Use paranoid_exit to handle SWAPGS and CR3, but no need to use
- * restore_regs_and_return_to_kernel as we must handle nested NMI.
- */
- call paranoid_exit
+ movq %rsp, %rdi /* pt_regs pointer */
+ call ist_exc_nmi

POP_REGS

diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 737fbbe19d84..b65cb61aafdc 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -372,6 +372,8 @@ __visible __entry_text void ist_##func(struct pt_regs *regs) \
#define DEFINE_IDTENTRY_NOIST(func) \
DEFINE_IDTENTRY_RAW(noist_##func)

+#define DEFINE_IDTENTRY_NMI DEFINE_IDTENTRY_IST
+
#define DECLARE_IDTENTRY_MCE DECLARE_IDTENTRY_IST
#define DEFINE_IDTENTRY_MCE DEFINE_IDTENTRY_IST
#define DEFINE_IDTENTRY_MCE_USER DEFINE_IDTENTRY_NOIST
@@ -421,6 +423,8 @@ __visible __entry_text void ist_##func(struct pt_regs *regs) \

#else /* CONFIG_X86_64 */

+#define DEFINE_IDTENTRY_NMI DEFINE_IDTENTRY_RAW
+
/**
* DECLARE_IDTENTRY_DF - Declare functions for double fault 32bit variant
* @vector: Vector number (ignored for C)
@@ -452,7 +456,6 @@ __visible noinstr void func(struct pt_regs *regs, \

/* C-Code mapping */
#define DECLARE_IDTENTRY_NMI DECLARE_IDTENTRY_RAW
-#define DEFINE_IDTENTRY_NMI DEFINE_IDTENTRY_RAW

#else /* !__ASSEMBLY__ */

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 8ac45801ba8b..28815c2e6cb2 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -51,6 +51,7 @@ KCOV_INSTRUMENT := n
CFLAGS_head$(BITS).o += -fno-stack-protector
CFLAGS_cc_platform.o += -fno-stack-protector
CFLAGS_traps.o += -fno-stack-protector
+CFLAGS_nmi.o += -fno-stack-protector

CFLAGS_irq.o := -I $(srctree)/$(src)/../include/asm/trace

--
2.19.1.6.gb485710b
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