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From: guohanjun@huawei•com (Hanjun Guo)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v3 05/12] arm64, acpi, numa: NUMA support based on SRAT and SLIT
Date: Thu, 28 Jan 2016 11:16:34 +0800	[thread overview]
Message-ID: <56A98812.4060506@huawei.com> (raw)
In-Reply-To: <20160127140109.GQ24726@rric.localdomain>

On 2016/1/27 22:01, Robert Richter wrote:
> On 27.01.16 15:12:15, Hanjun Guo wrote:
>> 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.
> No, we might have an out-of-bound access then.
>
>> 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 )
> The check above is ok as we need at least struct
> acpi_srat_mem_affinity as it is now.
>
> If we later change the kernel to support multiple versions of struct
> acpi_srat_mem_affinity, i.e. use data from an extended section, we
> will need to add code to handle that. This will include support of
> data with length < acpi_srat_mem_affinity, in this case we may not use
> extended data.

I checked the ACPI spec about memory affinity structure, it still have 10 bytes
reserved for future use, so I think it's safe as you suggested for next few years.

>
>>  - 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?
> Right, and this is a valid case not resulting in an error with my
> suggestion above.

Yes, I just mixed up those two cases.

I will sync with Ganapat to prepare a new version and test it on x86 and
IA64 to make sure this patch set don't break anything.

Thanks
Hanjun

  reply	other threads:[~2016-01-28  3:16 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-23  9:39 [PATCH v3 00/12] ACPI NUMA support for ARM64 Hanjun Guo
2016-01-23  9:39 ` [PATCH v3 01/12] acpi, numa: Use pr_fmt() instead of printk Hanjun Guo
2016-01-23  9:39 ` [PATCH v3 02/12] acpi, numa: Replace ACPI_DEBUG_PRINT() with pr_debug() Hanjun Guo
2016-01-23  9:39 ` [PATCH v3 03/12] acpi, numa: remove duplicate NULL check Hanjun Guo
2016-01-23  9:39 ` [PATCH v3 04/12] acpi, numa: introduce ACPI_HAS_NUMA_ARCH_FIXUP Hanjun Guo
2016-01-23 10:25   ` Robert Richter
2016-01-24  4:56     ` Hanjun Guo
2016-01-23  9:39 ` [PATCH v3 05/12] arm64, acpi, numa: NUMA support based on SRAT and SLIT Hanjun Guo
2016-01-25 10:21   ` Robert Richter
2016-01-27  7:12     ` Hanjun Guo
2016-01-27 14:01       ` Robert Richter
2016-01-28  3:16         ` Hanjun Guo [this message]
2016-02-01 18:09   ` Robert Richter
2016-02-02 11:30     ` Hanjun Guo
2016-02-02 17:00       ` Lorenzo Pieralisi
2016-03-02 14:10     ` Matthias Brugger
2016-03-02 14:10     ` Matthias Brugger
2016-03-02 14:08   ` Matthias Brugger
2016-03-10  9:50     ` Hanjun Guo
2016-01-23  9:39 ` [PATCH v3 06/12] acpi, numa: Enable ACPI based NUMA on ARM64 Hanjun Guo
2016-01-29 16:37   ` Robert Richter
2016-01-23  9:39 ` [PATCH v3 07/12] acpi, numa: move acpi_numa_slit_init() to common place Hanjun Guo
2016-01-23  9:39 ` [PATCH v3 08/12] arm64, numa: rework numa_add_memblk() Hanjun Guo
2016-01-25  9:34   ` Robert Richter
2016-01-27  6:20     ` Hanjun Guo
2016-03-09 12:27   ` Robert Richter
2016-03-10 10:10     ` Hanjun Guo
2016-01-23  9:39 ` [PATCH v3 09/12] x86, acpi, numa: cleanup acpi_numa_processor_affinity_init() Hanjun Guo
2016-01-23  9:39 ` [PATCH v3 10/12] acpi, numa: move bad_srat() and srat_disabled() to common place Hanjun Guo
2016-01-23  9:39 ` [PATCH v3 11/12] acpi, numa: remove unneeded acpi_numa=1 Hanjun Guo
2016-01-23  9:39 ` [PATCH v3 12/12] acpi, numa: reuse acpi_numa_memory_affinity_init() Hanjun Guo
2016-01-25 10:26   ` Robert Richter
2016-01-27  6:15     ` Hanjun Guo
2016-01-27 14:18       ` Robert Richter
2016-01-28  2:48         ` Hanjun Guo
2016-01-28 13:31           ` Robert Richter

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