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

[Tao Xu]

On 12/9/2019 6:01 PM, Rafael J. Wysocki wrote:
> On Mon, Dec 2, 2019 at 8:03 AM Tao Xu <tao3.xu@xxxxxxxxx> 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@xxxxxxxxx>
> > ---
> >   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,
> >   };
> >
> >   /**