linux-kernel - [PATCH V4 30/50] x86/entry: move PUSH_AND_CLEAR_REGS out of paranoid

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Date:   Tue, 26 Oct 2021 22:34:16 +0800
From:   Lai Jiangshan <jiangshanlai@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     x86@...nel.org, Lai Jiangshan <laijs@...ux.alibaba.com>,
        Andy Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH V4 30/50] x86/entry: move PUSH_AND_CLEAR_REGS out of paranoid_entry

From: Lai Jiangshan <laijs@...ux.alibaba.com>

It is prepared for converting the whole paranoid_entry() into C code.

No functional change intended.

Signed-off-by: Lai Jiangshan <laijs@...ux.alibaba.com>
---
 arch/x86/entry/entry_64.S | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 8d873b778681..c9ee58e8e6d1 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -323,9 +323,6 @@ SYM_CODE_END(ret_from_fork)
  */
 .macro idtentry_body cfunc has_error_code:req
 
-	PUSH_AND_CLEAR_REGS
-	ENCODE_FRAME_POINTER
-
 	/*
 	 * Call error_entry and switch stack settled by sync_regs().
 	 *
@@ -404,6 +401,9 @@ SYM_CODE_START(\asmsym)
 .Lfrom_usermode_no_gap_\@:
 	.endif
 
+	PUSH_AND_CLEAR_REGS
+	ENCODE_FRAME_POINTER
+
 	idtentry_body \cfunc \has_error_code
 
 _ASM_NOKPROBE(\asmsym)
@@ -456,11 +456,14 @@ SYM_CODE_START(\asmsym)
 
 	pushq	$-1			/* ORIG_RAX: no syscall to restart */
 
+	PUSH_AND_CLEAR_REGS
+	ENCODE_FRAME_POINTER
+
 	/*
 	 * If the entry is from userspace, switch stacks and treat it as
 	 * a normal entry.
 	 */
-	testb	$3, CS-ORIG_RAX(%rsp)
+	testb	$3, CS(%rsp)
 	jnz	.Lfrom_usermode_switch_stack_\@
 
 	/* paranoid_entry returns GS information for paranoid_exit in EBX. */
@@ -511,11 +514,14 @@ SYM_CODE_START(\asmsym)
 	ASM_CLAC
 	cld
 
+	PUSH_AND_CLEAR_REGS
+	ENCODE_FRAME_POINTER
+
 	/*
 	 * If the entry is from userspace, switch stacks and treat it as
 	 * a normal entry.
 	 */
-	testb	$3, CS-ORIG_RAX(%rsp)
+	testb	$3, CS(%rsp)
 	jnz	.Lfrom_usermode_switch_stack_\@
 
 	/*
@@ -574,6 +580,9 @@ SYM_CODE_START(\asmsym)
 	ASM_CLAC
 	cld
 
+	PUSH_AND_CLEAR_REGS
+	ENCODE_FRAME_POINTER
+
 	/* paranoid_entry returns GS information for paranoid_exit in EBX. */
 	call	paranoid_entry
 	UNWIND_HINT_REGS
@@ -886,8 +895,6 @@ SYM_CODE_END(xen_failsafe_callback)
  */
 SYM_CODE_START_LOCAL(paranoid_entry)
 	UNWIND_HINT_FUNC
-	PUSH_AND_CLEAR_REGS save_ret=1
-	ENCODE_FRAME_POINTER 8
 
 	/*
 	 * Always stash CR3 in %r14.  This value will be restored,
@@ -1307,6 +1314,9 @@ end_repeat_nmi:
 	 */
 	pushq	$-1				/* ORIG_RAX: no syscall to restart */
 
+	PUSH_AND_CLEAR_REGS
+	ENCODE_FRAME_POINTER
+
 	/*
 	 * Use paranoid_entry to handle SWAPGS and CR3.
 	 */
-- 
2.19.1.6.gb485710b