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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 15:05:20 -0700	[thread overview]
Message-ID: <20211013220520.xzsp5q2amuwy6n6o@treble> (raw)
In-Reply-To: <YWdTDz8Qqs3jjCf1@hirez.programming.kicks-ass.net>

On Wed, Oct 13, 2021 at 11:43:43PM +0200, Peter Zijlstra wrote:
> On Wed, Oct 13, 2021 at 02:11:18PM -0700, Josh Poimboeuf wrote:
> > On Wed, Oct 13, 2021 at 02:22:21PM +0200, Peter Zijlstra wrote:
> > > +#ifdef CONFIG_X86_64
> > > +
> > > +/*
> > > + * CALL/JMP *%\reg
> > > + */
> > > +static int emit_indirect(int op, int reg, u8 *bytes)
> > 
> > X86_64 is already equivalent to STACK_VALIDATION these days, but might
> > as well clarify here where the retpoline_sites dependency comes from by
> > changing this to '#ifdef CONFIG_STACK_VALIDATION'.
> 
> Yeah, I was contemplating having x86_64 unconditionally select that.
> Maybe we should.

As far as I can tell, it already does that:

        select HAVE_STACK_VALIDATION            if X86_64
        select HAVE_STATIC_CALL_INLINE          if HAVE_STACK_VALIDATION
        select STACK_VALIDATION                 if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)

> Also, I think I've proposed it before, but what about:
> 
>  s/STACK_VALIDATION/OBJTOOL/
> 
> on all that?

How about keeping STACK_VALIDATION, but then having it depend on
OBJTOOL, in case anybody cares to extricate the two at some point.  Some
objtool features (like this one) don't rely on the full validation.

-- 
Josh


  reply	other threads:[~2021-10-13 22:05 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
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 [this message]
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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