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: <CAK8P3a0OS+4XTG9VmfPwbuQoT+_G5-fSatbJ0g8Y7Y+O6-3YLQ@mail.gmail.com>
Date:   Tue, 10 May 2022 15:01:26 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     "Verdun, Jean-Marie" <verdun@....com>
Cc:     Arnd Bergmann <arnd@...db.de>,
        "Hawkins, Nick" <nick.hawkins@....com>,
        Russell King - ARM Linux <linux@...linux.org.uk>,
        Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Joel Stanley <joel@....id.au>
Subject: Re: [PATCH v1] ARM: A9: Add ARM ERRATA 764319 workaround

On Tue, May 10, 2022 at 1:53 PM Verdun, Jean-Marie <verdun@....com> wrote:
>
> Hi Arnd,
>
> >    Hi Nick,
>
> >    This seems a bit more complex than necessary. Can't you just use a custom
> >    inline asm with an ex_table entry to catch the fault? Have a look at
> >    __get_user_asm() for an example.
> >
> >           Arnd
>
> We got inspired from debug_reg_hook within the same source file
>( ./arch/arm/kernel/hw_breakpoint.c ). We chose that path to keep coherency
> within the source code. We can implement the same fix by using an ex_table
> entry, but this will create two different ways at catching unknown instruction
> within the same source file. Will that be ok ?

I got a little lost trying to find where the breakpoint instruction comes
from that gets trapped here, but I would guess that they had to do this
using an undef_hook because the ex_table approach does not work
there for some reason.

I would still pick the ex_table method here if that works.

       Arnd

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ