[PATCH V2 37/41] x86/sev: Use C entry code

From: Lai Jiangshan
Date: Sun Sep 26 2021 - 11:13:06 EST


From: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>

Use DEFINE_IDTENTRY_IST_ETNRY_ERRORCODE 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 | 22 +---------------------
arch/x86/include/asm/idtentry.h | 1 +
2 files changed, 2 insertions(+), 21 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 8871f8ccf117..63cafeeaf27d 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -498,28 +498,8 @@ SYM_CODE_START(\asmsym)

UNWIND_HINT_REGS

- /*
- * paranoid_entry returns SWAPGS flag for paranoid_exit in EBX.
- * EBX == 0 -> SWAPGS, EBX == 1 -> no SWAPGS
- */
- call paranoid_entry
-
- UNWIND_HINT_REGS
-
- /* Update pt_regs */
- movq ORIG_RAX(%rsp), %rsi /* get error code into 2nd argument*/
- movq $-1, ORIG_RAX(%rsp) /* no syscall to restart */
-
movq %rsp, %rdi /* pt_regs pointer */
-
- call kernel_\cfunc
-
- /*
- * No need to switch back to the IST stack. The current stack is either
- * identical to the stack in the IRET frame or the VC fall-back stack,
- * so it is definitely mapped even with PTI enabled.
- */
- call paranoid_exit
+ call ist_kernel_\cfunc
jmp restore_regs_and_return_to_kernel

/* Switch to the regular task stack */
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 99e1ae3f5c7d..c8837bb3991f 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -412,6 +412,7 @@ __visible __entry_text void ist_##func(struct pt_regs *regs) \
* Maps to DEFINE_IDTENTRY_RAW_ERRORCODE
*/
#define DEFINE_IDTENTRY_VC_KERNEL(func) \
+ DEFINE_IDTENTRY_IST_ETNRY_ERRORCODE(kernel_##func) \
DEFINE_IDTENTRY_RAW_ERRORCODE(kernel_##func)

/**
--
2.19.1.6.gb485710b