linux-kernel - Re: [PATCH] sh: Avoid using IRQ0 on SH3 and SH4

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: <acad1156-4e60-9315-1bbb-9b569d05b410@omp.ru>
Date:   Wed, 12 Jul 2023 19:22:54 +0300
From:   Sergey Shtylyov <s.shtylyov@....ru>
To:     Guenter Roeck <linux@...ck-us.net>,
        Sergei Shtylyov <sergei.shtylyov@...il.com>,
        David Laight <David.Laight@...LAB.COM>,
        'John Paul Adrian Glaubitz' <glaubitz@...sik.fu-berlin.de>,
        Geert Uytterhoeven <geert@...ux-m68k.org>
CC:     Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Rich Felker <dalias@...c.org>,
        "linux-sh@...r.kernel.org" <linux-sh@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] sh: Avoid using IRQ0 on SH3 and SH4

On 7/12/23 6:38 PM, Guenter Roeck wrote:
[...]

>>>> Sent: 09 July 2023 00:13
>>> ....
>>>> Looking at arch/sh/boards/mach-r2d/irq.c, there is some IRQ translation going
>>>> on and maybe that's the part where we need to correct the offset by 16?
>>>
>>> Would it be less problematic to use (say) 16 for IRQ_0
>>> leaving IRQ_1+ as 1+ ?
>>
>>     I don't think so.
>>
>>> At least that would only cause issues for code that needed
>>> to use IRQ_0.
>>>
>>> (It has to be said that making IRQ 0 invalid seemed wrong
>>> to me. x86 (IBM PC) gets away with it because IRQ 0 is
>>> always assigned to platform specific hardware.)
>>
>>     Not only x86, IIRC.
>>     Have you seen the commit below?
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ce753ad1549cbe9ccaea4c06a1f5fa47432c8289
>>
> 
> Quoting:
> 
> using IRQ0 is considered invalid (according to Linus) outside the arch/ code
>                                                       ^^^^^^^^^^^^^^^^^^^^^^> The changes here were made _in_ the arch code. While there may be valid
> arguments for doing that, quoting the above commit as reason isn't really
> sufficient.

   It seems you still don't understand... The i8253 drivers using IRQ0 live in
the arch/{mips|x86}/kernel/ code, so they're allowed to claim IRQ0 via calling
request_irq() (MIPS still does it.  They are NOT the platform drivers we're
dealing with here...

> Guenter

MBR, Sergey