From mboxrd@z Thu Jan  1 00:00:00 1970
From: Hanjun Guo <guohanjun@huawei.com>
Subject: Re: [PATCH v3 05/12] arm64, acpi, numa: NUMA support based on SRAT
 and SLIT
Date: Wed, 27 Jan 2016 15:12:15 +0800
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To: Robert Richter <robert.richter@caviumnetworks.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>, Will Deacon <will.deacon@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Ganapatrao Kulkarni <gkulkarni@caviumnetworks.com>, Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>, Shannon Zhao <shannon.zhao@linaro.org>, Steve Capper <steve.capper@linaro.org>, Mark Rutland <mark.rutland@arm.com>, Hanjun Guo <hanjun.guo@linaro.org>

On 2016/1/25 18:21, Robert Richter wrote:
> On 23.01.16 17:39:20, Hanjun Guo wrote:
>> diff --git a/arch/arm64/kernel/acpi_numa.c b/arch/arm64/kernel/acpi_numa.c
>> new file mode 100644
>> index 0000000..f7f7533
>> --- /dev/null
>> +++ b/arch/arm64/kernel/acpi_numa.c
>> +/* Callback for parsing of the Proximity Domain <-> Memory Area mappings */
>> +int __init acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
>> +{
>> +	u64 start, end;
>> +	int node, pxm;
>> +
>> +	if (srat_disabled())
>> +		return -EINVAL;
>> +
>> +	if (ma->header.length != sizeof(struct acpi_srat_mem_affinity)) {
> Must be:
>
> 	ma->header.length < sizeof(struct acpi_srat_mem_affinity)) {
>
> Allow extensions to struct acpi_srat_mem_affinity in newer versions.

Hmm, I think we need to remove the check here now.

There are three cases:

 - firmware ACPI version is consistent with the ACPICA one, then
   ma->header.length == sizeof(struct acpi_srat_mem_affinity )

 - firmware ACPI version is not consistent with the ACPICA one,
   for example, struct acpi_srat_mem_affinity is extended in
   new ACI version, but the formware is using the older one,
  then it's ok to use
  ma->header.length < sizeof(struct acpi_srat_mem_affinity )

 - but if we use the older kernel + updated new firmware,
   then
   ma->header.length > sizeof(struct acpi_srat_mem_affinity )
  will be the case, right?

>
>> +		bad_srat();
>> +		return -EINVAL;
> We need a pr_err() here to avoid that numa setup fails silently due to
> bad fw. This applies to all error paths.
>
> See my delta patch below. You can merge it with your patch.

Thanks! I wil merge it into next version.

Hanjun