linux-kernel - [PATCH 1/3] x86/entry: remove unneeded kernel cr3 switching

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Date:   Sun, 19 Apr 2020 14:40:47 +0000
From:   Lai Jiangshan <laijs@...ux.alibaba.com>
To:     linux-kernel@...r.kernel.org
Cc:     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>,
        x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH 1/3] x86/entry: remove unneeded kernel cr3 switching

When native_load_gs_index() fails on .Lgs_change, the cr3
must be kernel cr3. Don't need to switch it.

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

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 0e9504fabe52..b789835afbab 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1339,7 +1339,6 @@ SYM_CODE_START_LOCAL(error_entry)
 	 */
 	SWAPGS
 	FENCE_SWAPGS_USER_ENTRY
-	SWITCH_TO_KERNEL_CR3 scratch_reg=%rax
 	jmp .Lerror_entry_done
 
 .Lbstep_iret:
-- 
2.20.1