From: tip-bot for Andy Lutomirski <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: peterz@infradead.org, mingo@kernel.org, bp@alien8.de,
linux-kernel@vger.kernel.org, luto@kernel.org,
tglx@linutronix.de, hpa@zytor.com, chang.seok.bae@intel.com
Subject: [tip:x86/cpu] x86/entry/64: Don't compile ignore_sysret if 32-bit emulation is enabled
Date: Mon, 1 Jul 2019 23:49:45 -0700 [thread overview]
Message-ID: <tip-dffb3f9db6b593f3ed6ab4c8d8f10e0aa6aa7a88@git.kernel.org> (raw)
In-Reply-To: <0f7dafa72fe7194689de5ee8cfe5d83509fabcf5.1562035429.git.luto@kernel.org>
Commit-ID: dffb3f9db6b593f3ed6ab4c8d8f10e0aa6aa7a88
Gitweb: https://git.kernel.org/tip/dffb3f9db6b593f3ed6ab4c8d8f10e0aa6aa7a88
Author: Andy Lutomirski <luto@kernel.org>
AuthorDate: Mon, 1 Jul 2019 20:43:20 -0700
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 2 Jul 2019 08:45:20 +0200
x86/entry/64: Don't compile ignore_sysret if 32-bit emulation is enabled
It's only used if !CONFIG_IA32_EMULATION, so disable it in normal
configs. This will save a few bytes of text and reduce confusion.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "BaeChang Seok" <chang.seok.bae@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Bae, Chang Seok" <chang.seok.bae@intel.com>
Link: https://lkml.kernel.org/r/0f7dafa72fe7194689de5ee8cfe5d83509fabcf5.1562035429.git.luto@kernel.org
---
arch/x86/entry/entry_64.S | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 7f9f5119d6b1..54b1b0468b2b 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1743,11 +1743,17 @@ nmi_restore:
iretq
END(nmi)
+#ifndef CONFIG_IA32_EMULATION
+/*
+ * This handles SYSCALL from 32-bit code. There is no way to program
+ * MSRs to fully disable 32-bit SYSCALL.
+ */
ENTRY(ignore_sysret)
UNWIND_HINT_EMPTY
mov $-ENOSYS, %eax
sysret
END(ignore_sysret)
+#endif
ENTRY(rewind_stack_do_exit)
UNWIND_HINT_FUNC
next prev parent reply other threads:[~2019-07-02 6:50 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-02 3:43 [PATCH 0/3] FSGSBASE fix, test, and a semi-related cleanup Andy Lutomirski
2019-07-02 3:43 ` [PATCH 1/3] selftests/x86: Test SYSCALL and SYSENTER manually with TF set Andy Lutomirski
2019-07-02 6:49 ` [tip:x86/cpu] " tip-bot for Andy Lutomirski
2019-07-02 3:43 ` [PATCH 2/3] x86/entry/64: Don't compile ignore_sysret if 32-bit emulation is enabled Andy Lutomirski
2019-07-02 6:49 ` tip-bot for Andy Lutomirski [this message]
2019-07-02 3:43 ` [PATCH 3/3] x86/entry/64: Fix and clean up paranoid_exit Andy Lutomirski
2019-07-02 6:50 ` [tip:x86/cpu] " tip-bot for Andy Lutomirski
2019-07-02 3:57 ` [PATCH 0/3] FSGSBASE fix, test, and a semi-related cleanup Andy Lutomirski
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