All of lore.kernel.org
 help / color / mirror / Atom feed
From: Mark Brown <broonie@kernel.org>
To: Will Deacon <will@kernel.org>
Cc: Tamas Zsoldos <tamas.zsoldos@arm.com>,
	kernel-team@android.com, Dave Martin <dave.martin@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Daniel Kiss <daniel.kiss@arm.com>
Subject: Re: [PATCH v2 1/2] arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction
Date: Tue, 19 May 2020 17:33:08 +0100	[thread overview]
Message-ID: <20200519163308.GP4611@sirena.org.uk> (raw)
In-Reply-To: <20200519162821.16857-2-will@kernel.org>


[-- Attachment #1.1: Type: text/plain, Size: 572 bytes --]

On Tue, May 19, 2020 at 05:28:20PM +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.
> Commit c91db232da48 ("arm64: vdso: Convert to modern assembler annotations")
> unfortunately added a BTI C instruction to the start of __kernel_rt_sigreturn,
> which breaks this check. Thankfully, it's also not required, since the
> trampoline is called from a RET instruction when returning from the signal
> handler

Reviwed-by: Mark Brown <broonie@kernel.org>

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2020-05-19 16:33 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-19 16:28 [PATCH v2 0/2] arm64 sigreturn unwinding fixes Will Deacon
2020-05-19 16:28 ` [PATCH v2 1/2] arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction Will Deacon
2020-05-19 16:33   ` Mark Brown [this message]
2020-05-20  9:33   ` Dave Martin
2020-05-20  9:53     ` Will Deacon
2020-05-19 16:28 ` [PATCH v2 2/2] arm64: vdso: Fix CFI directives in sigreturn trampoline Will Deacon
2020-05-20  9:42   ` Dave Martin
2020-05-20  9:50     ` Will Deacon
2020-05-20 10:27       ` Dave Martin
2020-05-20 10:36         ` Will Deacon
2020-05-20 11:03           ` Dave Martin
2020-05-20 10:48   ` Will Deacon
2020-05-20 11:06     ` Dave Martin

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=20200519163308.GP4611@sirena.org.uk \
    --to=broonie@kernel.org \
    --cc=daniel.kiss@arm.com \
    --cc=dave.martin@arm.com \
    --cc=kernel-team@android.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=tamas.zsoldos@arm.com \
    --cc=will@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.