From: behanw@converseincode.com (Behan Webster)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm, vt8500, LLVMLlinux: Use mcr instead of mcr% for mach-vt8500
Date: Wed, 24 Sep 2014 11:11:43 -0700 [thread overview]
Message-ID: <5423095F.9030802@converseincode.com> (raw)
In-Reply-To: <7810937.UX61PvX9nB@wuerfel>
On 09/24/14 02:16, Arnd Bergmann wrote:
> On Tuesday 23 September 2014 20:44:44 Behan Webster wrote:
>> The ASM below does not compile with clang and is not the way that the mcr
>> command is used in other parts of the kernel.
>>
>> arch/arm/mach-vt8500/vt8500.c:72:11: error: invalid % escape in inline assembly string
>> asm("mcr%? p15, 0, %0, c7, c0, 4" : : "r" (0));
>> ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
>> 1 error generated.
>>
>> There are other forms that are supported on different ARM instruction sets but
>> generally the kernel just uses mcr as it is supported in all ARM instruction
>> sets.
> Just for confirm: both forms are actually correct and we don't need this
> backported for stable, right?
My understanding is that the %? carries a condition code to the next
instruction (which in this case is then ignored). So essentially in this
situation both are equivalent.
>> Signed-off-by: Behan Webster <behanw@converseincode.com>
>> Reviewed-by: Mark Charlebois <charlebm@gmail.com>
>> Acked-by: Will Deacon <will.deacon@arm.com>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
>
> Tony, would you like to pick this one up and send it in a pull request
> to arm-soc, or should we apply it to fixes-non-critical directly?
Thanks,
Behan
--
Behan Webster
behanw at converseincode.com
WARNING: multiple messages have this Message-ID (diff)
From: Behan Webster <behanw@converseincode.com>
To: Arnd Bergmann <arnd@arndb.de>, linux-arm-kernel@lists.infradead.org
Cc: linux@arm.linux.org.uk, linux@prisktech.co.nz,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm, vt8500, LLVMLlinux: Use mcr instead of mcr% for mach-vt8500
Date: Wed, 24 Sep 2014 11:11:43 -0700 [thread overview]
Message-ID: <5423095F.9030802@converseincode.com> (raw)
In-Reply-To: <7810937.UX61PvX9nB@wuerfel>
On 09/24/14 02:16, Arnd Bergmann wrote:
> On Tuesday 23 September 2014 20:44:44 Behan Webster wrote:
>> The ASM below does not compile with clang and is not the way that the mcr
>> command is used in other parts of the kernel.
>>
>> arch/arm/mach-vt8500/vt8500.c:72:11: error: invalid % escape in inline assembly string
>> asm("mcr%? p15, 0, %0, c7, c0, 4" : : "r" (0));
>> ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
>> 1 error generated.
>>
>> There are other forms that are supported on different ARM instruction sets but
>> generally the kernel just uses mcr as it is supported in all ARM instruction
>> sets.
> Just for confirm: both forms are actually correct and we don't need this
> backported for stable, right?
My understanding is that the %? carries a condition code to the next
instruction (which in this case is then ignored). So essentially in this
situation both are equivalent.
>> Signed-off-by: Behan Webster <behanw@converseincode.com>
>> Reviewed-by: Mark Charlebois <charlebm@gmail.com>
>> Acked-by: Will Deacon <will.deacon@arm.com>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
>
> Tony, would you like to pick this one up and send it in a pull request
> to arm-soc, or should we apply it to fixes-non-critical directly?
Thanks,
Behan
--
Behan Webster
behanw@converseincode.com
next prev parent reply other threads:[~2014-09-24 18:11 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-24 3:44 [PATCH] arm, vt8500, LLVMLlinux: Use mcr instead of mcr% for mach-vt8500 Behan Webster
2014-09-24 3:44 ` Behan Webster
2014-09-24 9:16 ` Arnd Bergmann
2014-09-24 9:16 ` Arnd Bergmann
2014-09-24 18:11 ` Behan Webster [this message]
2014-09-24 18:11 ` Behan Webster
2014-09-24 18:23 ` Tony Prisk
2014-09-24 18:23 ` Tony Prisk
2014-09-25 23:26 ` Arnd Bergmann
2014-09-25 23:26 ` Arnd Bergmann
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