From: guohanjun@huawei•com (Hanjun Guo)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM64 / SMP: Switch pr_err() to pr_debug() for disabled GICC entry
Date: Fri, 3 Jul 2015 09:15:38 +0800 [thread overview]
Message-ID: <5595E23A.9040901@huawei.com> (raw)
In-Reply-To: <20150702162940.GF1354@e104818-lin.cambridge.arm.com>
On 2015/7/3 0:29, Catalin Marinas wrote:
> On Wed, Jul 01, 2015 at 09:37:23PM +0800, Hanjun Guo wrote:
>> It is normal that firmware presents GICC entry or entries (processors)
>> with disabled flag in ACPI MADT, taking a system of 16 cpus for example,
>> ACPI firmware may present 8 enabled first with another 8 cpus disabled
>> in MADT, the disabled cpus can be hot-added later.
>>
>> Firmware may also present more cpus than the hardware actually has, but
>> disabled the unused ones, and easily enable it when the hardware has such
>> cpus to make the firmware code scalable.
>>
>> So that's not an error for disabled cpus in MADT, we can switch
>> pr_err() to pr_debug() instead.
>>
>> Signed-off-by: Hanjun Guo <hanjun.guo@linaro•org>
>> ---
>> arch/arm64/kernel/smp.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
>> index 4b2121b..5caf04a 100644
>> --- a/arch/arm64/kernel/smp.c
>> +++ b/arch/arm64/kernel/smp.c
>> @@ -402,7 +402,7 @@ acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor)
>> }
>>
>> if (!(processor->flags & ACPI_MADT_ENABLED)) {
>> - pr_err("skipping disabled CPU entry with 0x%llx MPIDR\n", hwid);
>> + pr_debug("skipping disabled CPU entry with 0x%llx MPIDR\n", hwid);
> That's a pretty harmless change. But looking at the use-case, would we
> expect the disabled entries to have a valid hwid? I guess such hwid is
> not known, especially if we can hot-plug some CPU at a later time. If
Good point, usually it's invalid hwid.
> that's the case, can we also move this check before the hwid one?
Yes, fully agree, thanks for catching this, will update the patch.
Thanks
Hanjun
next prev parent reply other threads:[~2015-07-03 1:15 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-01 13:37 [PATCH] ARM64 / SMP: Switch pr_err() to pr_debug() for disabled GICC entry Hanjun Guo
2015-07-01 17:02 ` Al Stone
2015-07-02 16:29 ` Catalin Marinas
2015-07-02 17:40 ` Mark Salter
2015-07-03 1:15 ` Hanjun Guo [this message]
2015-07-02 17:38 ` Mark Salter
2015-07-03 1:18 ` Hanjun Guo
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