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Subject: Re: [RFC][PATCH 6/6] objtool,x86: Rewrite retpoline thunk calls
To:     Peter Zijlstra <peterz@infradead.org>,
        Borislav Petkov <bp@alien8.de>
Cc:     Josh Poimboeuf <jpoimboe@redhat.com>, x86@kernel.org,
        pjt@google.com, mbenes@suze.cz, linux-kernel@vger.kernel.org
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Date:   Sun, 21 Feb 2021 06:45:54 +0100
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From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= <jgross@suse.com>
To: Peter Zijlstra <peterz@infradead.org>, Borislav Petkov <bp@alien8.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>, x86@kernel.org, pjt@google.com,
 mbenes@suze.cz, linux-kernel@vger.kernel.org
Message-ID: <1e498602-5319-6f12-b33e-d40a7735d316@suse.com>
Subject: Re: [RFC][PATCH 6/6] objtool,x86: Rewrite retpoline thunk calls
References: <20210219204300.749932493@infradead.org>
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In-Reply-To: <20210220223221.GB4746@worktop.programming.kicks-ass.net>

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On 20.02.21 23:32, Peter Zijlstra wrote:
> On Sat, Feb 20, 2021 at 06:41:01PM +0100, Borislav Petkov wrote:
>>>   - if we had negative alternatives objtool doesn't need to actually
>>>     rewrite code in this case. It could simply emit alternative entri=
es
>>>     and call it a day.
>>
>> I don't mind the negative alt per se - I mind the implementation I saw=
=2E
>> I'm sure we can come up with something nicer, like, for example, struc=
t
>> alt_instr.flags to denote that this feature is a NOT feature.
>=20
> So you don't like the ~ or - on cpuid? ISTR we talked about
> alt_instr::flags before, but Google isn't playing ball today so I can't=

> seem to find it.

If you want I can cook up a patch and include it in my paravirt
cleanup series.

Juergen

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