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From: Brian Gerst <brgerst@gmail.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>, "H . Peter Anvin" <hpa@zytor.com>,
	Andy Lutomirski <luto@kernel.org>,
	Brian Gerst <brgerst@gmail.com>
Subject: [PATCH 5/6] x86/entry/32: Remove SEP test for SYSEXIT
Date: Tue, 18 Jul 2023 09:44:45 -0400	[thread overview]
Message-ID: <20230718134446.168654-6-brgerst@gmail.com> (raw)
In-Reply-To: <20230718134446.168654-1-brgerst@gmail.com>

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@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 15660f936ede..fca6f2b7daf3 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -275,8 +275,7 @@ __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
-- 
2.41.0


  parent reply	other threads:[~2023-07-18 13:45 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-18 13:44 [PATCH 0/6] x86: Clean up fast syscall return validation Brian Gerst
2023-07-18 13:44 ` [PATCH 1/6] x86/entry/64: Remove obsolete comment on tracing vs. SYSRET Brian Gerst
2023-07-18 13:44 ` [PATCH 2/6] x86/entry/64: Convert SYSRET validation tests to C Brian Gerst
2023-07-18 14:16   ` Mika Penttilä
2023-07-18 14:25     ` Brian Gerst
2023-07-18 14:49       ` Mika Penttilä
2023-07-18 15:21         ` Brian Gerst
2023-07-18 15:46           ` Brian Gerst
2023-07-18 13:44 ` [PATCH 3/6] x86/entry/compat: Combine return value test from syscall handler Brian Gerst
2023-07-18 13:44 ` [PATCH 4/6] x86/entry/32: Convert do_fast_syscall_32() to bool return type Brian Gerst
2023-07-18 13:44 ` Brian Gerst [this message]
2023-07-18 13:44 ` [PATCH 6/6] x86/entry/32: Clean up syscall fast exit tests Brian Gerst

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