From: Andy Lutomirski <luto@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, "Bae, Chang Seok" <chang.seok.bae@intel.com>,
Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>
Subject: [PATCH 2/3] x86/entry/64: Don't compile ignore_sysret if 32-bit emulation is enabled
Date: Mon, 1 Jul 2019 20:43:20 -0700 [thread overview]
Message-ID: <0f7dafa72fe7194689de5ee8cfe5d83509fabcf5.1562035429.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1562035429.git.luto@kernel.org>
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.
Cc: "Bae, Chang Seok" <chang.seok.bae@intel.com>
Signed-off-by: Andy Lutomirski <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
--
2.21.0
next prev parent reply other threads:[~2019-07-02 3:43 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 ` Andy Lutomirski [this message]
2019-07-02 6:49 ` [tip:x86/cpu] x86/entry/64: Don't compile ignore_sysret if 32-bit emulation is enabled tip-bot for Andy Lutomirski
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=0f7dafa72fe7194689de5ee8cfe5d83509fabcf5.1562035429.git.luto@kernel.org \
--to=luto@kernel.org \
--cc=bp@alien8.de \
--cc=chang.seok.bae@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®