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From: f.fainelli@gmail.com (Florian Fainelli)
To: linux-arm-kernel@lists.infradead.org
Subject: [CFT] Always enable SMP mode on MP capable CPUs
Date: Thu, 25 May 2017 10:24:46 -0700	[thread overview]
Message-ID: <0eac2f9f-8af7-b991-6021-320b91f3f98a@gmail.com> (raw)
In-Reply-To: <20170525165651.GK22219@n2100.armlinux.org.uk>

On 05/25/2017 09:56 AM, Russell King - ARM Linux wrote:
> On Thu, May 25, 2017 at 09:15:19AM -0700, Florian Fainelli wrote:
>> On 05/18/2017 03:52 AM, Russell King - ARM Linux wrote:
>>> As a result of a recent bug report, it has been found that certain CPUs
>>> must always have SMP mode enabled in order for the caches to work.
>>>
>>> Remove the conditional on setting the SMP bit(s).
>>>
>>> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
>>> ---
>>> This needs to be tested on:
>>>
>>> - Cortex A5MP
>>> - Cortex A9MP
>>> - Cortex R7MP
>>> - Cortex A7MP
>>> - Cortex A12MP
>>> - Cortex A15MP
>>> - Cortex A17MP
>>> - Brahma B15
>>
>> Sorry just saw this, what kind of test do you want me to run on B15?
>> Should I build a !SMP kernel, or force a SMP kernel with maxcpus=1?
> 
> What I'm after is testing on any single-core systems with these SMP
> capable cores.  If the core never appears in a single-core configuration,
> then please let me know so it can be crossed off the list.

We have chips like the 7250 that are single core, and we do run a
CONFIG_SMP kernel on this guy as well. Feel free to add:

Tested-by: Florian Fainelli <f.fainelli@gmail.com>

on 7250 (single core), 7445 (core core) and 7278 (quad core Brahma B53
in 32-bit mode) as well. If you are curious about what we report, B15
report:

7250, 7445: CPU: ARMv7 Processor [420f00f3] revision 3 (ARMv7), cr=30c5387d
7278: CPU: ARMv7 Processor [420f1000] revision 0 (ARMv7), cr=30c5383d

> 
> With the bug that crept in fixed (as pointed out by Tony) there is no
> difference for kernels built with SMP enabled and detected as a SMP
> capable CPU.
> 

Got it, thanks!
-- 
Florian

  parent reply	other threads:[~2017-05-25 17:24 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-18 10:52 [CFT] Always enable SMP mode on MP capable CPUs Russell King - ARM Linux
2017-05-18 18:09 ` Fabio Estevam
2017-05-19 17:07   ` Fabio Estevam
2017-05-19 17:15     ` Russell King - ARM Linux
2017-05-24 15:38       ` Tony Lindgren
2017-05-24 15:38         ` Tony Lindgren
2017-05-25 14:48         ` Russell King - ARM Linux
2017-05-25 14:48           ` Russell King - ARM Linux
2017-05-25 15:11           ` Tony Lindgren
2017-05-25 15:11             ` Tony Lindgren
2017-05-25 18:05             ` Russell King - ARM Linux
2017-05-25 18:05               ` Russell King - ARM Linux
2017-05-25 22:13               ` Tony Lindgren
2017-05-25 22:13                 ` Tony Lindgren
2017-05-26 11:22                 ` afzal mohammed
2017-05-26 11:22                   ` afzal mohammed
2017-05-27 13:22                   ` Russell King - ARM Linux
2017-05-27 13:22                     ` Russell King - ARM Linux
2017-05-31 14:39                     ` Tony Lindgren
2017-05-31 14:39                       ` Tony Lindgren
2017-05-31 14:59                       ` Russell King - ARM Linux
2017-05-31 14:59                         ` Russell King - ARM Linux
2017-05-31 15:07                         ` Tony Lindgren
2017-05-31 15:07                           ` Tony Lindgren
2017-05-24 15:50 ` afzal mohammed
2017-05-24 15:50   ` afzal mohammed
2017-05-25 16:15 ` Florian Fainelli
2017-05-25 16:56   ` Russell King - ARM Linux
2017-05-25 17:10     ` Tony Lindgren
2017-05-25 17:10       ` Tony Lindgren
2017-05-25 17:24     ` Florian Fainelli [this message]
2017-05-26  9:44 ` Vladimir Murzin

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