From: Peter Zijlstra <peterz@infradead.org>
To: Alexandre Chartre <alexandre.chartre@oracle.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
jpoimboe@redhat.com, jthierry@redhat.com, tglx@linutronix.de
Subject: Re: [PATCH V2 9/9] x86/speculation: Remove all ANNOTATE_NOSPEC_ALTERNATIVE directives
Date: Tue, 7 Apr 2020 15:52:11 +0200 [thread overview]
Message-ID: <20200407135211.GB20730@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200407073142.20659-10-alexandre.chartre@oracle.com>
On Tue, Apr 07, 2020 at 09:31:42AM +0200, Alexandre Chartre wrote:
> - ANNOTATE_NOSPEC_ALTERNATIVE
> ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; jmp *\reg), \
> __stringify(RETPOLINE_JMP \reg), X86_FEATURE_RETPOLINE, \
> __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; jmp *\reg), X86_FEATURE_RETPOLINE_AMD
Possibly we can write this like:
ALTERNATIVE("", "lfence", X86_FEATURE_RETPOLINE_AMD);
ALTERNATIVE("jmp *\reg", "jmp __x86_retpoline_jmp_\reg", X86_FEATURE_RETPOLINE);
With an out-of-line copy of the retpoline, just like the THUNKs the
compiler uses, except of course, it can't be those, because we actually
want to use the alternative to implement those.
By moving the retpoline magic out-of-line we ensure it has a unique
address and the ORC stuff should work.
I'm just not sure what to do about the RETPOLINE_CALL variant.
next prev parent reply other threads:[~2020-04-07 13:52 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-07 7:31 [PATCH V2 0/9] objtool changes to remove all ANNOTATE_NOSPEC_ALTERNATIVE Alexandre Chartre
2020-04-07 7:31 ` [PATCH V2 1/9] objtool: Introduce HINT_RET_OFFSET Alexandre Chartre
2020-04-07 12:53 ` Peter Zijlstra
2020-04-07 13:17 ` Alexandre Chartre
2020-04-07 7:31 ` [PATCH V2 2/9] objtool: UNWIND_HINT_RET_OFFSET should not check registers Alexandre Chartre
2020-05-01 18:22 ` [tip: objtool/core] " tip-bot2 for Alexandre Chartre
2020-04-07 7:31 ` [PATCH V2 3/9] objtool: is_fentry_call() crashes if call has no destination Alexandre Chartre
2020-04-07 7:31 ` [PATCH V2 4/9] objtool: Allow branches within the same alternative Alexandre Chartre
2020-04-07 7:31 ` [PATCH V2 5/9] objtool: Add support for intra-function calls Alexandre Chartre
2020-04-07 13:07 ` Peter Zijlstra
2020-04-07 13:28 ` Alexandre Chartre
2020-04-08 14:06 ` Alexandre Chartre
2020-04-08 14:19 ` Julien Thierry
2020-04-08 16:03 ` Alexandre Chartre
2020-04-08 16:04 ` Julien Thierry
2020-04-08 17:06 ` Alexandre Chartre
2020-04-08 17:07 ` Julien Thierry
2020-04-07 7:31 ` [PATCH V2 6/9] x86/speculation: Change __FILL_RETURN_BUFFER to work with objtool Alexandre Chartre
2020-04-07 13:27 ` Josh Poimboeuf
2020-04-07 7:31 ` [PATCH V2 7/9] x86/speculation: Annotate intra-function calls Alexandre Chartre
2020-04-07 7:31 ` [PATCH V2 8/9] x86/speculation: Add unwind hint to trampoline return Alexandre Chartre
2020-04-07 7:31 ` [PATCH V2 9/9] x86/speculation: Remove all ANNOTATE_NOSPEC_ALTERNATIVE directives Alexandre Chartre
2020-04-07 13:28 ` Peter Zijlstra
2020-04-07 13:34 ` Josh Poimboeuf
2020-04-07 14:32 ` Alexandre Chartre
2020-04-07 16:18 ` Alexandre Chartre
2020-04-07 16:28 ` Josh Poimboeuf
2020-04-07 17:01 ` Alexandre Chartre
2020-04-07 17:26 ` Peter Zijlstra
2020-04-07 17:27 ` Peter Zijlstra
2020-04-08 21:35 ` Peter Zijlstra
2020-04-09 8:18 ` Alexandre Chartre
2020-04-09 10:34 ` Peter Zijlstra
2020-04-09 10:40 ` Peter Zijlstra
2020-04-07 16:41 ` Peter Zijlstra
2020-04-07 17:04 ` Alexandre Chartre
2020-04-07 13:52 ` Peter Zijlstra [this message]
2020-04-07 13:59 ` Peter Zijlstra
2020-04-07 13:35 ` [PATCH V2 0/9] objtool changes to remove all ANNOTATE_NOSPEC_ALTERNATIVE Josh Poimboeuf
2020-04-07 14:02 ` Alexandre Chartre
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200407135211.GB20730@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=alexandre.chartre@oracle.com \
--cc=jpoimboe@redhat.com \
--cc=jthierry@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox