From: Markos Chandras <Markos.Chandras@imgtec.com>
To: Ralf Baechle <ralf@linux-mips.org>
Cc: <linux-mips@linux-mips.org>
Subject: Re: [PATCH] MIPS: Fix accessing to per-cpu data when flushing the cache
Date: Tue, 17 Sep 2013 11:55:55 +0100 [thread overview]
Message-ID: <5238353B.9050001@imgtec.com> (raw)
In-Reply-To: <20130917104431.GB22468@linux-mips.org>
On 09/17/13 11:44, Ralf Baechle wrote:
> On Tue, Sep 17, 2013 at 10:43:25AM +0100, Markos Chandras wrote:
>
>> The cache flushing code uses the current_cpu_data macro which
>> may cause problems in preemptive kernels because it relies on
>> smp_processor_id() to get the current cpu number. Per cpu-data
>> needs to be protected so we disable preemption around the flush
>> caching code. We enable it back when we are about to return.
>>
>> Fixes the following problem:
>>
>> BUG: using smp_processor_id() in preemptible [00000000] code: kjournald/1761
>> caller is blast_dcache32+0x30/0x254
>
> Just what I feared - these messages popping out from all over the tree.
>
> I'd prefer if we change the caller otherwise depending on the platform
> a single cache flush might involve several preempt_disable/-enable
> invocations. Something like below.
>
> And it also keeps the header file more usable outside the core kernel
> which Florian's recent zboot a little easier.
>
Hi Ralf,
Changing the caller instead of the function in the header file looks
good to me. Thanks for fixing it.
WARNING: multiple messages have this Message-ID (diff)
From: Markos Chandras <Markos.Chandras@imgtec.com>
To: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Subject: Re: [PATCH] MIPS: Fix accessing to per-cpu data when flushing the cache
Date: Tue, 17 Sep 2013 11:55:55 +0100 [thread overview]
Message-ID: <5238353B.9050001@imgtec.com> (raw)
Message-ID: <20130917105555.Id1aK8lhd5ynKJKFPVQI1OQtp4tNHbC_6LWMsgOCJT8@z> (raw)
In-Reply-To: <20130917104431.GB22468@linux-mips.org>
On 09/17/13 11:44, Ralf Baechle wrote:
> On Tue, Sep 17, 2013 at 10:43:25AM +0100, Markos Chandras wrote:
>
>> The cache flushing code uses the current_cpu_data macro which
>> may cause problems in preemptive kernels because it relies on
>> smp_processor_id() to get the current cpu number. Per cpu-data
>> needs to be protected so we disable preemption around the flush
>> caching code. We enable it back when we are about to return.
>>
>> Fixes the following problem:
>>
>> BUG: using smp_processor_id() in preemptible [00000000] code: kjournald/1761
>> caller is blast_dcache32+0x30/0x254
>
> Just what I feared - these messages popping out from all over the tree.
>
> I'd prefer if we change the caller otherwise depending on the platform
> a single cache flush might involve several preempt_disable/-enable
> invocations. Something like below.
>
> And it also keeps the header file more usable outside the core kernel
> which Florian's recent zboot a little easier.
>
Hi Ralf,
Changing the caller instead of the function in the header file looks
good to me. Thanks for fixing it.
next prev parent reply other threads:[~2013-09-17 10:56 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-17 9:43 [PATCH] MIPS: Fix accessing to per-cpu data when flushing the cache Markos Chandras
2013-09-17 9:43 ` Markos Chandras
2013-09-17 10:44 ` Ralf Baechle
2013-09-17 10:55 ` Markos Chandras [this message]
2013-09-17 10:55 ` Markos Chandras
2013-09-17 11:43 ` Ralf Baechle
2013-09-17 16:02 ` Ralf Baechle
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