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From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: x86@kernel.org, andrew.cooper3@citrix.com,
	linux-kernel@vger.kernel.org, alexei.starovoitov@gmail.com,
	ndesaulniers@google.com
Subject: Re: [PATCH v2 14/14] bpf,x86: Respect X86_FEATURE_RETPOLINE*
Date: Wed, 20 Oct 2021 21:23:41 +0200	[thread overview]
Message-ID: <20211020192341.GQ174703@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20211020165655.632slp4ujsajis4j@treble>

On Wed, Oct 20, 2021 at 09:56:55AM -0700, Josh Poimboeuf wrote:
> On Wed, Oct 20, 2021 at 01:09:51PM +0200, Peter Zijlstra wrote:
> > Alexei; could the above not be further improved with something like the
> > below?
> > 
> > Despite several hours trying and Song helping, I can't seem to run
> > anything bpf, that stuff is cursed. So I've no idea if the below
> > actually works, but it seems reasonable.
> 
> The below fix gets it to run with test_verififer.

Argh, I;m fast running out of brown paper bags at this rate :/

> 
> I do like it, it does seem less fiddly and more robust against future
> changes, though it probably needs a comment for 'out_label' clarifying
> it only works because this function is always called at least twice for
> a given bpf_tail_call emission.

Right.

  reply	other threads:[~2021-10-20 19:23 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-20 10:44 [PATCH v2 00/14] x86: Rewrite the retpoline rewrite logic Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 01/14] objtool: Tag retpoline thunk symbols Peter Zijlstra
2021-10-20 15:17   ` Josh Poimboeuf
2021-10-26  7:55     ` Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 02/14] objtool: Explicitly avoid self modifying code in .altinstr_replacement Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 03/14] objtool: Shrink struct instruction Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 04/14] objtool,x86: Replace alternatives with .retpoline_sites Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 05/14] x86/retpoline: Remove unused replacement symbols Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 06/14] x86/asm: Fix register order Peter Zijlstra
2021-10-22 19:27   ` David Laight
2021-10-25 14:09   ` Borislav Petkov
2021-10-20 10:44 ` [PATCH v2 07/14] x86/asm: Fixup odd GEN-for-each-reg.h usage Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 08/14] x86/retpoline: Create a retpoline thunk array Peter Zijlstra
2021-10-20 15:57   ` Josh Poimboeuf
2021-10-20 16:46     ` Andrew Cooper
2021-10-20 17:09       ` Josh Poimboeuf
2021-10-20 19:22         ` Peter Zijlstra
2021-10-20 19:43           ` Josh Poimboeuf
2021-10-20 19:34       ` Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 09/14] x86/alternative: Implement .retpoline_sites support Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 10/14] x86/alternative: Handle Jcc __x86_indirect_thunk_\reg Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 11/14] x86/alternative: Try inline spectre_v2=retpoline,amd Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 12/14] x86/alternative: Add debug prints to apply_retpolines() Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 13/14] x86,bugs: Unconditionally allow spectre_v2=retpoline,amd Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 14/14] bpf,x86: Respect X86_FEATURE_RETPOLINE* Peter Zijlstra
2021-10-20 11:09   ` Peter Zijlstra
2021-10-20 16:56     ` Josh Poimboeuf
2021-10-20 19:23       ` Peter Zijlstra [this message]
2021-10-21  0:05     ` Alexei Starovoitov
2021-10-21  8:47       ` Peter Zijlstra
2021-10-21 18:03         ` Alexei Starovoitov
2021-10-21 22:37           ` Peter Zijlstra
2021-10-21 23:24             ` Alexei Starovoitov
2021-10-21 23:38               ` Josh Poimboeuf
2021-10-21 23:42                 ` Alexei Starovoitov
2021-10-22 11:31                   ` Peter Zijlstra
2021-10-22 15:22                     ` Alexei Starovoitov
2021-10-25 13:44                       ` Maciej Fijalkowski
2021-10-25 12:42                         ` Peter Zijlstra
2021-10-21 23:51         ` Zvi Effron
2021-10-22  8:33           ` Peter Zijlstra
2021-10-22 21:06             ` Zvi Effron
2021-10-21  0:07   ` Alexei Starovoitov
2021-10-21  0:18     ` Josh Poimboeuf
2021-10-21  8:53       ` Peter Zijlstra

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