From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: x86@kernel.org, andrew.cooper3@citrix.com,
linux-kernel@vger.kernel.org, alexei.starovoitov@gmail.com,
ndesaulniers@google.com
Subject: Re: [PATCH 4/9] x86/alternative: Implement .retpoline_sites support
Date: Wed, 13 Oct 2021 13:52:59 -0700 [thread overview]
Message-ID: <20211013205259.44cvvaxiexiff5w5@treble> (raw)
In-Reply-To: <20211013123645.002402102@infradead.org>
On Wed, Oct 13, 2021 at 02:22:21PM +0200, Peter Zijlstra wrote:
> /*
> + * Rewrite the retpolines, must be done before alternatives since
> + * those can rewrite the retpoline thunks.
> + */
Why exactly is that a problem? This code doesn't read the thunks.
BTW, CALL_NOSPEC results in a retpoline site in .altinstr_replacement:
Relocation section [40] '.rela.retpoline_sites' for section [39] '.retpoline_sites' at offset 0x8d28 contains 1 entry:
Offset Type Value Addend Name
000000000000000000 X86_64_PC32 000000000000000000 +10 .altinstr_replacement
Which I assume we don't want.
--
Josh
next prev parent reply other threads:[~2021-10-13 20:53 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-13 12:22 [PATCH 0/9] x86: Rewrite the retpoline rewrite logic Peter Zijlstra
2021-10-13 12:22 ` [PATCH 1/9] objtool,x86: Replace alternatives with .retpoline_sites Peter Zijlstra
2021-10-13 13:29 ` Borislav Petkov
2021-10-13 20:11 ` Josh Poimboeuf
2021-10-14 15:43 ` Peter Zijlstra
2021-10-13 12:22 ` [PATCH 2/9] x86/retpoline: Remove unused replacement symbols Peter Zijlstra
2021-10-13 12:22 ` [PATCH 3/9] x86/asm: Fix register order Peter Zijlstra
2021-10-13 20:15 ` Josh Poimboeuf
2021-10-13 12:22 ` [PATCH 4/9] x86/alternative: Implement .retpoline_sites support Peter Zijlstra
2021-10-13 14:38 ` Andrew Cooper
2021-10-13 15:12 ` Peter Zijlstra
2021-10-13 17:11 ` Andrew Cooper
2021-10-14 10:05 ` Peter Zijlstra
2021-10-13 20:39 ` Josh Poimboeuf
2021-10-13 21:20 ` Peter Zijlstra
2021-10-13 21:49 ` Josh Poimboeuf
2021-10-13 21:52 ` Josh Poimboeuf
2021-10-13 22:10 ` Peter Zijlstra
2021-10-13 22:47 ` Andrew Cooper
2021-10-13 20:52 ` Josh Poimboeuf [this message]
2021-10-13 21:00 ` Peter Zijlstra
2021-10-19 11:37 ` Peter Zijlstra
2021-10-19 16:46 ` Josh Poimboeuf
2021-10-19 16:49 ` Josh Poimboeuf
2021-10-20 8:25 ` Peter Zijlstra
2021-10-20 8:30 ` Peter Zijlstra
2021-10-13 21:11 ` Josh Poimboeuf
2021-10-13 21:43 ` Peter Zijlstra
2021-10-13 22:05 ` Josh Poimboeuf
2021-10-13 22:14 ` Peter Zijlstra
2021-10-15 14:24 ` Borislav Petkov
2021-10-15 16:56 ` Peter Zijlstra
2021-10-18 23:06 ` Alexander Lobakin
2021-10-19 0:25 ` Alexander Lobakin
2021-10-19 9:47 ` Alexander Lobakin
2021-10-19 10:16 ` Peter Zijlstra
2021-10-19 15:37 ` Sami Tolvanen
2021-10-19 18:00 ` Alexander Lobakin
2021-10-19 9:40 ` Peter Zijlstra
2021-10-19 10:02 ` Peter Zijlstra
2021-10-13 12:22 ` [PATCH 5/9] x86/alternative: Handle Jcc __x86_indirect_thunk_\reg Peter Zijlstra
2021-10-13 20:11 ` Nick Desaulniers
2021-10-13 21:08 ` Peter Zijlstra
2021-10-13 12:22 ` [PATCH 6/9] x86/alternative: Try inline spectre_v2=retpoline,amd Peter Zijlstra
2021-10-13 12:22 ` [PATCH 7/9] x86/alternative: Add debug prints to apply_retpolines() Peter Zijlstra
2021-10-13 12:22 ` [PATCH 8/9] x86,bugs: Unconditionally allow spectre_v2=retpoline,amd Peter Zijlstra
2021-10-13 12:22 ` [PATCH 9/9] bpf,x86: Respect X86_FEATURE_RETPOLINE* Peter Zijlstra
2021-10-13 21:06 ` Josh Poimboeuf
2021-10-13 21:54 ` Peter Zijlstra
2021-10-14 9:46 ` Peter Zijlstra
2021-10-14 9:48 ` Peter Zijlstra
2021-10-20 7:34 ` Peter Zijlstra
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