Re: [PATCH 3/3] cacheinfo: Add use_arch[|_cache]_info field/function

[Pierre Gondois]

Hello Will,

On 3/27/23 14:17, Will Deacon wrote:
> On Mon, Mar 27, 2023 at 01:59:51PM +0200, Pierre Gondois wrote:
> > The cache information can be extracted from either a Device
> > Tree (DT), the PPTT ACPI table, or arch registers (clidr_el1
> > for arm64).
> >
> > The clidr_el1 register is used only if DT/ACPI information is not
> > available. It does not states how caches are shared among CPUs.
> >
> > Add a use_arch_cache_info field/function to identify when the
> > DT/ACPI doesn't provide cache information. Use this information
> > to assume L1 caches are privates and L2 and higher are shared among
> > all CPUs.
> >
> > Signed-off-by: Pierre Gondois <pierre.gondois@xxxxxxx>
> > ---
> >   arch/arm64/kernel/cacheinfo.c |  5 +++++
> >   drivers/base/cacheinfo.c      | 20 ++++++++++++++++++--
> >   include/linux/cacheinfo.h     |  2 ++
> >   3 files changed, 25 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm64/kernel/cacheinfo.c b/arch/arm64/kernel/cacheinfo.c
> > index c307f69e9b55..b6306cda0fa7 100644
> > --- a/arch/arm64/kernel/cacheinfo.c
> > +++ b/arch/arm64/kernel/cacheinfo.c
> > @@ -96,3 +96,8 @@ int populate_cache_leaves(unsigned int cpu)
> >   	}
> >   	return 0;
> >   }
> > +
> > +bool use_arch_cache_info(unsigned int cpu)
> > +{
> > +	return true;
> > +}
>
> It would be a lot nicer if this was a static inline function in a header
> rather than a weak symbol.

I am not sure I see where the static inline function should be added.
Do you prefer to have function like the following in
include/linux/cacheinfo.h ?

static inline bool use_arch_cache_info(unsigned int cpu)
{
#if defined(CONFIG_ARM64)
	return true;
#else
	return false;
#endif
}

Regards,
Pierre

> Will