From: Will Deacon <will@kernel.org>
To: Dave Martin <Dave.Martin@arm.com>
Cc: Tamas Zsoldos <tamas.zsoldos@arm.com>,
Mark Brown <broonie@kernel.org>,
kernel-team@android.com, linux-arm-kernel@lists.infradead.org,
Daniel Kiss <daniel.kiss@arm.com>
Subject: Re: [PATCH 1/3] arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction
Date: Tue, 19 May 2020 14:29:56 +0100 [thread overview]
Message-ID: <20200519132955.GA14570@willie-the-truck> (raw)
In-Reply-To: <20200519132100.GD5031@arm.com>
On Tue, May 19, 2020 at 02:21:01PM +0100, Dave Martin wrote:
> On Tue, May 19, 2020 at 01:18:16PM +0100, Will Deacon wrote:
> > For better or worse, GDB relies on the exact instruction sequence in the
> > VDSO sigreturn trampoline in order to unwind from signals correctly.
>
> Are you sure? I'm struggling to find the relevant code in gdb.
It looks pretty damning:
https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=gdb/aarch64-linux-tdep.c;h=34ba0d87baaff12f1f9711e777ab15a0a394f59b;hb=HEAD#l361
(and also look at struct tramp_frame).
Will
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next prev parent reply other threads:[~2020-05-19 13:30 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 12:18 [PATCH 0/3] arm64 sigreturn unwinding fixes Will Deacon
2020-05-19 12:18 ` [PATCH 1/3] arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction Will Deacon
2020-05-19 12:38 ` Mark Brown
2020-05-19 13:25 ` Dave Martin
2020-05-19 14:35 ` Mark Brown
2020-05-19 14:55 ` Dave Martin
2020-05-19 15:42 ` Mark Brown
2020-05-20 9:48 ` Dave Martin
2020-05-20 10:46 ` Mark Brown
2020-05-20 11:08 ` Dave Martin
2020-05-19 15:26 ` Will Deacon
2020-05-19 13:21 ` Dave Martin
2020-05-19 13:29 ` Will Deacon [this message]
2020-05-19 12:18 ` [PATCH 2/3] arm64: vdso: Add a comment to justify the mysterious NOP in sigreturn Will Deacon
2020-05-19 13:26 ` Dave Martin
2020-05-19 12:18 ` [PATCH 3/3] arm64: vdso: Fix CFI directives in sigreturn trampoline Will Deacon
2020-05-19 13:09 ` Dave P Martin
2020-05-19 13:39 ` Will Deacon
2020-05-19 13:55 ` Dave Martin
2020-05-19 15:24 ` Will Deacon
2020-05-19 15:30 ` Daniel Kiss
2020-05-19 15:55 ` Will Deacon
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