From: Andy Whitcroft <apw@canonical.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
David Woodhouse <dwmw@amazon.co.uk>,
Peter Zijlstra <peterz@infradead.org>
Cc: Andy Whitcroft <apw@canonical.com>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/1] x86/speculation, objtool: Annotate indirect calls/jumps for objtool on 32bit
Date: Wed, 14 Mar 2018 11:24:27 +0000 [thread overview]
Message-ID: <20180314112427.22351-1-apw@canonical.com> (raw)
In 9e0e3c5130e9 ("x86/speculation, objtool: Annotate indirect calls/jumps
for objtool") we added annotations for CALL_NOSPEC/JMP_NOSPEC on x86 64bit.
We did not annotate the 32bit path. Annotate it similarly.
Signed-off-by: Andy Whitcroft <apw@canonical.com>
---
arch/x86/include/asm/nospec-branch.h | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
While reviewing indirect calls in our builds I noted that the
i386 retpoline CALL_NOSPEC is not annotated safe even though
its amd64 equivalent is. I cannot see any reason this is not
also inherantly safe. Peter was there a reason that you did
not annotate this one too? Anyhow, on the assumption this was
just missed, this patch annotates it.
-apw
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index d0dabeae0505..07886162bdf8 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -183,7 +183,10 @@
* otherwise we'll run out of registers. We don't care about CET
* here, anyway.
*/
-# define CALL_NOSPEC ALTERNATIVE("call *%[thunk_target]\n", \
+# define CALL_NOSPEC \
+ ALTERNATIVE( \
+ ANNOTATE_RETPOLINE_SAFE \
+ "call *%[thunk_target]\n", \
" jmp 904f;\n" \
" .align 16\n" \
"901: call 903f;\n" \
--
2.15.1
next reply other threads:[~2018-03-14 11:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-14 11:24 Andy Whitcroft [this message]
2018-03-14 11:51 ` Peter Zijlstra
2018-03-14 12:24 ` Ingo Molnar
2018-03-14 12:28 ` [tip:x86/pti] x86/speculation, objtool: Annotate indirect calls/jumps for objtool on 32-bit kernels tip-bot for Andy Whitcroft
2018-03-14 13:03 ` Josh Poimboeuf
2018-03-14 13:39 ` Ingo Molnar
2018-03-14 13:51 ` Josh Poimboeuf
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