Re: [PATCH 8/9] ARM: kernel: add support for cpu cache information

From: Sudeep Holla
Date: Fri Jun 27 2014 - 05:38:32 EST


Hi,

On 26/06/14 19:45, Stephen Boyd wrote:
On 06/26/14 04:36, Sudeep Holla wrote:
Hi Stephen,

On 26/06/14 01:19, Stephen Boyd wrote:
On 06/25/14 10:30, Sudeep Holla wrote:
+
+/*
+ * Which cache CCSIDR represents depends on CSSELR value
+ * Make sure no one else changes CSSELR during this
+ * smp_call_function_single prevents preemption for us
+ */

Where's the smp_call_function_single() or preemption disable happening?


init_cache_level is called using smp_call_function_single in
drivers/base/cacheinfo.c(PATCH 2/9)

Oh that's unexpected. Do other architectures require the use of
smp_call_function_single() to read their cache information? It seems
like an ARM architecture specific detail that has been pushed up into
the generic layer.


Right, since I started with x86 as reference and it requires it, I missed to
see others. So x86,ARM{32,64} requires it while ppc,s390 and ia64 doesn't.
I see how to fix that. Thanks for spotting it.

Regards,
Sudeep

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