linux-kernel - Re: [PATCH] MIPS: cavium_octeon: Fix syncw generation.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5e4876ff.1c69fb81.7b887.cb6e@mx.google.com>
Date:   Sat, 15 Feb 2020 14:55:58 -0800
From:   Paul Burton <paulburton@...nel.org>
To:     Mark Tomlinson <mark.tomlinson@...iedtelesis.co.nz>
CC:     linux-mips@...r.kernel.org
Subject: Re: [PATCH] MIPS: cavium_octeon: Fix syncw generation.

Hello,

Mark Tomlinson wrote:
> The Cavium Octeon CPU uses a special sync instruction for implementing
> wmb, and due to a CPU bug, the instruction must appear twice. A macro
> had been defined to hide this:
> 
>  #define __SYNC_rpt(type)     (1 + (type == __SYNC_wmb))
> 
> which was intended to evaluate to 2 for __SYNC_wmb, and 1 for any other
> type of sync. However, this expression is evaluated by the assembler,
> and not the compiler, and the result of '==' in the assembler is 0 or
> -1, not 0 or 1 as it is in C. The net result was wmb() producing no code
> at all. The simple fix in this patch is to change the '+' to '-'.

Applied to mips-fixes.

> commit 97e914b7de3c
> https://git.kernel.org/mips/c/97e914b7de3c
> 
> Fixes: bf92927251b3 ("MIPS: barrier: Add __SYNC() infrastructure")
> Signed-off-by: Mark Tomlinson <mark.tomlinson@...iedtelesis.co.nz>
> Tested-by: Chris Packham <chris.packham@...iedtelesis.co.nz>
> Signed-off-by: Paul Burton <paulburton@...nel.org>

Thanks,
    Paul

[ This message was auto-generated; if you believe anything is incorrect
  then please email paulburton@...nel.org to report it. ]