Re: [PATCH] ACPI/HMAT: Fix the parsing of Cache Associativity and Write Policy

Tao Xu
2019-12-10T01:04:24Z

On 12/9/2019 6:01 PM, Rafael J. Wysocki wrote:
> On Mon, Dec 2, 2019 at 8:03 AM Tao Xu <tao3.xu@intel.com> wrote:
>>
>> In chapter 5.2.27.5, Table 5-147: Field "Cache Attributes" of
>> ACPI 6.3 spec: 0 is "None", 1 is "Direct Mapped", 2 is "Complex Cache
>> Indexing" for Cache Associativity; 0 is "None", 1 is "Write Back",
>> 2 is "Write Through" for Write Policy.
>
> Well, I'm not sure what the connection between the above statement,
> which is correct AFAICS, and the changes made by the patch is.
>
> Is that the *_OTHER symbol names are confusing or something deeper?
>

Because in include/acpi/actbl1.h:

#define ACPI_HMAT_CA_NONE (0)

ACPI_HMAT_CA_NONE is 0, but in include/linux/node.h:

enum cache_indexing {
NODE_CACHE_DIRECT_MAP,
NODE_CACHE_INDEXED,
NODE_CACHE_OTHER,
};
NODE_CACHE_OTHER is 2, and for otner enum:

case ACPI_HMAT_CA_DIRECT_MAPPED:
tcache->cache_attrs.indexing = NODE_CACHE_DIRECT_MAP;
break;
case ACPI_HMAT_CA_COMPLEX_CACHE_INDEXING:
tcache->cache_attrs.indexing = NODE_CACHE_INDEXED;
break;
in include/acpi/actbl1.h:

#define ACPI_HMAT_CA_DIRECT_MAPPED (1)
#define ACPI_HMAT_CA_COMPLEX_CACHE_INDEXING (2)

but in include/linux/node.h:

NODE_CACHE_DIRECT_MAP is 0, NODE_CACHE_INDEXED is 1. This is incorrect.
And same for enum cache_write_policy.

>> Signed-off-by: Tao Xu <tao3.xu@intel.com>
>> ---
>> drivers/acpi/numa/hmat.c | 4 ++--
>> include/linux/node.h | 4 ++--
>> 2 files changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c
>> index 2c32cfb72370..719d0279563d 100644
>> --- a/drivers/acpi/numa/hmat.c
>> +++ b/drivers/acpi/numa/hmat.c
>> @@ -383,7 +383,7 @@ static __init int hmat_parse_cache(union acpi_subtable_headers *header,
>> break;
>> case ACPI_HMAT_CA_NONE:
>> default:
>> - tcache->cache_attrs.indexing = NODE_CACHE_OTHER;
>> + tcache->cache_attrs.indexing = NODE_CACHE_NONE;
>> break;
>> }
>>
>> @@ -396,7 +396,7 @@ static __init int hmat_parse_cache(union acpi_subtable_headers *header,
>> break;
>> case ACPI_HMAT_CP_NONE:
>> default:
>> - tcache->cache_attrs.write_policy = NODE_CACHE_WRITE_OTHER;
>> + tcache->cache_attrs.write_policy = NODE_CACHE_WRITE_NONE;
>> break;
>> }
>> list_add_tail(&tcache->node, &target->caches);
>> diff --git a/include/linux/node.h b/include/linux/node.h
>> index 4866f32a02d8..6dbd764d09ce 100644
>> --- a/include/linux/node.h
>> +++ b/include/linux/node.h
>> @@ -36,15 +36,15 @@ struct node_hmem_attrs {
>> };
>>
>> enum cache_indexing {
>> + NODE_CACHE_NONE,
>> NODE_CACHE_DIRECT_MAP,
>> NODE_CACHE_INDEXED,
>> - NODE_CACHE_OTHER,
>> };
>>
>> enum cache_write_policy {
>> + NODE_CACHE_WRITE_NONE,
>> NODE_CACHE_WRITE_BACK,
>> NODE_CACHE_WRITE_THROUGH,
>> - NODE_CACHE_WRITE_OTHER,
>> };
>>
>> /**