From: vladimir.murzin@arm•com (Vladimir Murzin)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM: SWP emulation: Restore original *data when failed
Date: Thu, 15 Oct 2015 14:25:28 +0100 [thread overview]
Message-ID: <561FA948.5080505@arm.com> (raw)
In-Reply-To: <20151015130247.GB29301@arm.com>
On 15/10/15 14:02, Will Deacon wrote:
> On Thu, Oct 15, 2015 at 10:17:47AM +0100, Vladimir Murzin wrote:
>> We might need the same change for arm64 counterpart (see
>> arch/arm64/kernel/armv8_deprecated.c).
>
> Something like below?
Looks good. Should these two go to stable?
Vladimir
>
> Will
>
>>From 63c3e83073cfac2e011adf0ed6f335275cc977a7 Mon Sep 17 00:00:00 2001
> From: Will Deacon <will.deacon@arm•com>
> Date: Thu, 15 Oct 2015 13:55:53 +0100
> Subject: [PATCH] arm64: compat: fix stxr failure case in SWP emulation
>
> If the STXR instruction fails in the SWP emulation code, we leave *data
> overwritten with the loaded value, therefore corrupting the data written
> by a subsequent, successful attempt.
>
> This patch re-jigs the code so that we only write back to *data once we
> know that the update has happened.
>
> Reported-by: Shengjiu Wang <shengjiu.wang@freescale•com>
> Reported-by: Vladimir Murzin <vladimir.murzin@arm•com>
> Signed-off-by: Will Deacon <will.deacon@arm•com>
> ---
> arch/arm64/kernel/armv8_deprecated.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c
> index bcee7abac68e..6039d1eb5912 100644
> --- a/arch/arm64/kernel/armv8_deprecated.c
> +++ b/arch/arm64/kernel/armv8_deprecated.c
> @@ -284,12 +284,12 @@ static void register_insn_emulation_sysctl(struct ctl_table *table)
> __asm__ __volatile__( \
> ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \
> CONFIG_ARM64_PAN) \
> - " mov %w2, %w1\n" \
> - "0: ldxr"B" %w1, [%3]\n" \
> - "1: stxr"B" %w0, %w2, [%3]\n" \
> + "0: ldxr"B" %w2, [%3]\n" \
> + "1: stxr"B" %w0, %w1, [%3]\n" \
> " cbz %w0, 2f\n" \
> " mov %w0, %w4\n" \
> "2:\n" \
> + " mov %w1, %w2\n" \
> " .pushsection .fixup,\"ax\"\n" \
> " .align 2\n" \
> "3: mov %w0, %w5\n" \
>
next prev parent reply other threads:[~2015-10-15 13:25 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-14 2:51 [PATCH] ARM: SWP emulation: Restore original *data when failed Shengjiu Wang
2015-10-15 8:24 ` Russell King - ARM Linux
2015-10-15 8:36 ` Shengjiu Wang
2015-10-15 8:57 ` Russell King - ARM Linux
2015-10-15 9:17 ` Vladimir Murzin
2015-10-15 13:02 ` Will Deacon
2015-10-15 13:25 ` Vladimir Murzin [this message]
2015-10-16 7:52 ` Vladimir Murzin
2015-10-16 10:37 ` Catalin Marinas
2015-10-27 15:44 ` Will Deacon
2015-10-28 16:16 ` Will Deacon
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=561FA948.5080505@arm.com \
--to=vladimir.murzin@arm$(echo .)com \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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