From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Zack Rusin <zackr@vmware.com>,
linux-kernel@vger.kernel.org, Miroslav Benes <mbenes@suse.cz>,
x86@kernel.org,
VMware Graphics Reviewers <linux-graphics-maintainer@vmware.com>,
kernel test robot <lkp@intel.com>
Subject: Re: [PATCH] drm/vmwgfx: Silence RBP clobber warnings
Date: Fri, 2 Jun 2023 17:16:39 +0200 [thread overview]
Message-ID: <20230602151639.GK620383@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <e9388b1ad4d955b43b44e8a5dcd6cf6da7d260a0.1685717659.git.jpoimboe@kernel.org>
On Fri, Jun 02, 2023 at 07:56:34AM -0700, Josh Poimboeuf wrote:
> VMware hypercalls take the RBP register as input. This breaks basic
> frame pointer convention, as RBP should never be clobbered.
>
> So frame pointer unwinding is broken for the instructions surrounding
> the hypercall with the clobbered RBP. There's nothing that can be done
> about that. Just tell objtool to ignore it.
>
That's a pretty horrific ABI, one that violates the oldest x86 calling
convention in existence.
VMware folks, shame!!
next prev parent reply other threads:[~2023-06-02 15:16 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-02 14:56 Josh Poimboeuf
2023-06-02 15:16 ` Peter Zijlstra [this message]
2023-06-02 15:32 ` Josh Poimboeuf
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