Re: [PATCH v6 07/12] drivers: base cacheinfo: Add support for ACPI based firmware tables

[Jeremy Linton]

Hi,

Thanks for taking a look at this.

On 01/22/2018 09:50 AM, Greg KH wrote:
> On Fri, Jan 12, 2018 at 06:59:15PM -0600, Jeremy Linton wrote:
> > Add a entry to to struct cacheinfo to maintain a reference to the PPTT
> > node which can be used to match identical caches across cores. Also
> > stub out cache_setup_acpi() so that individual architectures can
> > enable ACPI topology parsing.
> >
> > Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
> > ---
> >   drivers/acpi/pptt.c       |  1 +
> >   drivers/base/cacheinfo.c  | 20 +++++++++++++-------
> >   include/linux/cacheinfo.h |  9 +++++++++
> >   3 files changed, 23 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
> > index 2c4b3ed862a8..4f5ab19c3a08 100644
> > --- a/drivers/acpi/pptt.c
> > +++ b/drivers/acpi/pptt.c
> > @@ -329,6 +329,7 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
> >   {
> >   	int valid_flags = 0;
> >   
> > +	this_leaf->fw_unique = cpu_node;
> >   	if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID) {
> >   		this_leaf->size = found_cache->size;
> >   		valid_flags++;
> > diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
> > index 217aa90fb036..ee51e33cc37c 100644
> > --- a/drivers/base/cacheinfo.c
> > +++ b/drivers/base/cacheinfo.c
> > @@ -208,16 +208,16 @@ static int cache_setup_of_node(unsigned int cpu)
> >   
> >   	if (index != cache_leaves(cpu)) /* not all OF nodes populated */
> >   		return -ENOENT;
> > -
> >   	return 0;
> >   }
> > +
>
> Whitespace changes not needed for this patch :(

Sure.

> >   #else
> >   static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
> >   static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
> >   					   struct cacheinfo *sib_leaf)
> >   {
> >   	/*
> > -	 * For non-DT systems, assume unique level 1 cache, system-wide
> > +	 * For non-DT/ACPI systems, assume unique level 1 caches, system-wide
> >   	 * shared caches for all other levels. This will be used only if
> >   	 * arch specific code has not populated shared_cpu_map
> >   	 */
> > @@ -225,6 +225,11 @@ static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
> >   }
> >   #endif
> >   
> > +int __weak cache_setup_acpi(unsigned int cpu)
> > +{
> > +	return -ENOTSUPP;
> > +}
> > +
> >   static int cache_shared_cpu_map_setup(unsigned int cpu)
> >   {
> >   	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
> > @@ -235,11 +240,11 @@ static int cache_shared_cpu_map_setup(unsigned int cpu)
> >   	if (this_cpu_ci->cpu_map_populated)
> >   		return 0;
> >   
> > -	if (of_have_populated_dt())
> > +	if (!acpi_disabled)
> > +		ret = cache_setup_acpi(cpu);
>
> Why does acpi go first?  :)

This sounds like a joke i heard...

OTOH, given that we have machines with both ACPI and DT tables, it 
seemed a little clearer and a little more robust to code that so that if 
ACPI is enabled to prefer it over DT information. As long as the 
routines which set of of_root are protected by if (acpi_disabled) checks 
it should be safe to do it either way.


> > +	else if (of_have_populated_dt())
> >   		ret = cache_setup_of_node(cpu);
> > -	else if (!acpi_disabled)
> > -		/* No cache property/hierarchy support yet in ACPI */
> > -		ret = -ENOTSUPP;
> > +
> >   	if (ret)
> >   		return ret;
> >   
> > +int acpi_find_last_cache_level(unsigned int cpu)
> > +{
> > +	/*ACPI kernels should be built with PPTT support*/
>
> Here are some extra ' ' characters, you need them...

Oh ok, thanks! :)