linux-kernel - [tip: x86/entry] x86/entry/32: Remove SEP test for SYSEXIT

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Date:   Thu, 05 Oct 2023 08:28:34 -0000
From:   "tip-bot2 for Brian Gerst" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Brian Gerst <brgerst@...il.com>, Ingo Molnar <mingo@...nel.org>,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/entry] x86/entry/32: Remove SEP test for SYSEXIT

The following commit has been merged into the x86/entry branch of tip:

Commit-ID:     bab9fa6dc5e4483749838877deebe038de3ce97e
Gitweb:        https://git.kernel.org/tip/bab9fa6dc5e4483749838877deebe038de3ce97e
Author:        Brian Gerst <brgerst@...il.com>
AuthorDate:    Fri, 21 Jul 2023 12:10:16 -04:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Thu, 05 Oct 2023 10:06:43 +02:00

x86/entry/32: Remove SEP test for SYSEXIT

SEP must be already be present in order for do_fast_syscall_32() to be
called on native 32-bit, so checking it again is unnecessary.

Signed-off-by: Brian Gerst <brgerst@...il.com>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Link: https://lore.kernel.org/r/20230721161018.50214-6-brgerst@gmail.com
---
 arch/x86/entry/common.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index f1f3bf1..0551bcb 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -238,8 +238,7 @@ __visible noinstr bool do_fast_syscall_32(struct pt_regs *regs)
 	 * We don't allow syscalls at all from VM86 mode, but we still
 	 * need to check VM, because we might be returning from sys_vm86.
 	 */
-	return static_cpu_has(X86_FEATURE_SEP) &&
-		regs->cs == __USER_CS && regs->ss == __USER_DS &&
+	return regs->cs == __USER_CS && regs->ss == __USER_DS &&
 		regs->ip == landing_pad &&
 		(regs->flags & (X86_EFLAGS_RF | X86_EFLAGS_TF | X86_EFLAGS_VM)) == 0;
 #endif