From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Alexandre Chartre <alexandre.chartre@oracle.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
peterz@infradead.org, jthierry@redhat.com, tglx@linutronix.de
Subject: Re: [PATCH 5/7] x86/speculation: Annotate intra-function calls
Date: Fri, 3 Apr 2020 11:05:38 -0500 [thread overview]
Message-ID: <20200403160538.qwu237amhanr6pyi@treble> (raw)
In-Reply-To: <20200402082220.808-6-alexandre.chartre@oracle.com>
On Thu, Apr 02, 2020 at 10:22:18AM +0200, Alexandre Chartre wrote:
> .macro RETPOLINE_JMP reg:req
> - call .Ldo_rop_\@
> + INTRA_FUNCTION_CALL .Ldo_rop_\@
> .Lspec_trap_\@:
> pause
> lfence
> @@ -102,7 +116,7 @@
> .Ldo_retpoline_jmp_\@:
> RETPOLINE_JMP \reg
> .Ldo_call_\@:
> - call .Ldo_retpoline_jmp_\@
> + INTRA_FUNCTION_CALL .Ldo_retpoline_jmp_\@
> .endm
There's a catch: this is part of an alternative. Which means if
X86_FEATURE_RETPOLINE isn't set at runtime, then the retpoline won't be
there and the ORC data will be wrong.
In fact objtool should probably be made smart enough to warn about this
situation, when an alternative changes the stack state.
The only way I can think of to fix this is to have ORC alternatives :-/
--
Josh
next prev parent reply other threads:[~2020-04-03 16:05 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-02 8:22 [PATCH 0/7] objtool changes to remove most ANNOTATE_NOSPEC_ALTERNATIVE Alexandre Chartre
2020-04-02 8:22 ` [PATCH 1/7] objtool: is_fentry_call() crashes if call has no destination Alexandre Chartre
2020-04-02 8:22 ` [PATCH 2/7] objtool: Allow branches within the same alternative Alexandre Chartre
2020-04-02 12:03 ` Julien Thierry
2020-04-02 12:38 ` Alexandre Chartre
2020-04-02 8:22 ` [PATCH 3/7] objtool: Add support for intra-function calls Alexandre Chartre
2020-04-02 12:53 ` Julien Thierry
2020-04-02 13:24 ` Alexandre Chartre
2020-04-02 13:38 ` Julien Thierry
2020-04-02 14:56 ` Alexandre Chartre
2020-04-02 15:04 ` Peter Zijlstra
2020-04-02 15:54 ` Josh Poimboeuf
2020-04-03 7:06 ` Alexandre Chartre
2020-04-02 15:49 ` Josh Poimboeuf
2020-04-02 17:27 ` Josh Poimboeuf
2020-04-03 8:01 ` Julien Thierry
2020-04-03 12:41 ` Peter Zijlstra
2020-04-03 12:49 ` Julien Thierry
2020-04-03 14:37 ` Peter Zijlstra
2020-04-03 14:44 ` Josh Poimboeuf
2020-04-02 8:22 ` [PATCH 4/7] objtool: Add support for return trampoline call Alexandre Chartre
2020-04-02 13:26 ` Julien Thierry
2020-04-02 14:46 ` Alexandre Chartre
2020-04-02 15:31 ` Julien Thierry
2020-04-02 15:40 ` Peter Zijlstra
2020-04-03 8:11 ` Julien Thierry
2020-04-03 15:17 ` Josh Poimboeuf
2020-04-03 15:22 ` Josh Poimboeuf
2020-04-03 15:32 ` Josh Poimboeuf
2020-04-03 15:46 ` Peter Zijlstra
2020-04-03 15:55 ` Josh Poimboeuf
2020-04-04 13:32 ` Peter Zijlstra
2020-04-04 14:22 ` Josh Poimboeuf
2020-04-04 15:51 ` Peter Zijlstra
2020-04-06 8:19 ` Alexandre Chartre
2020-04-06 9:31 ` Peter Zijlstra
2020-04-06 11:03 ` Alexandre Chartre
2020-04-06 14:16 ` Josh Poimboeuf
2020-04-02 15:27 ` Peter Zijlstra
2020-04-03 7:19 ` Alexandre Chartre
2020-04-06 14:34 ` Alexandre Chartre
2020-04-06 14:55 ` Alexandre Chartre
2020-04-02 8:22 ` [PATCH 5/7] x86/speculation: Annotate intra-function calls Alexandre Chartre
2020-04-03 16:05 ` Josh Poimboeuf [this message]
2020-04-03 16:16 ` Josh Poimboeuf
2020-04-03 17:14 ` Alexandre Chartre
2020-04-03 17:18 ` Peter Zijlstra
2020-04-03 17:24 ` Josh Poimboeuf
2020-04-03 18:20 ` Peter Zijlstra
2020-04-02 8:22 ` [PATCH 6/7] x86/speculation: Annotate retpoline return instructions Alexandre Chartre
2020-04-02 8:22 ` [PATCH 7/7] x86/speculation: Remove most ANNOTATE_NOSPEC_ALTERNATIVE Alexandre Chartre
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