On 7/31/25 21:29, alex@xxxxxxxx wrote:
> > From: Jessica Liu <liu.xuemei1@xxxxxxxxxx>
> >
> > As described in commit 1845d381f280 ("riscv: cacheinfo: Add back
> > init_cache_level() function"), when CONFIG_SMP is undefined, the cache
> > hierarchy detection needs to be performed through the init_cache_level(),
> > whereas when CONFIG_SMP is defined, this detection is handled during the
> > init_cpu_topology() process.
> >
> > Furthermore, while commit 66381d36771e ("RISC-V: Select ACPI PPTT drivers")
> > enables cache information retrieval through the ACPI PPTT table, the
> > init_of_cache_level() called within init_cache_level() cannot support cache
> > hierarchy detection through ACPI PPTT. Therefore, when CONFIG_SMP is
> > undefined, we directly invoke the fetch_cache_info function to initialize
> > the cache levels.
> >
> > Signed-off-by: Jessica Liu <liu.xuemei1@xxxxxxxxxx>
> > ---
> > arch/riscv/kernel/cacheinfo.c | 6 +++++-
> > 1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/riscv/kernel/cacheinfo.c b/arch/riscv/kernel/cacheinfo.c
> > index 26b085dbdd07..f81ca963d177 100644
> > --- a/arch/riscv/kernel/cacheinfo.c
> > +++ b/arch/riscv/kernel/cacheinfo.c
> > @@ -73,7 +73,11 @@ static void ci_leaf_init(struct cacheinfo *this_leaf,
> >
> > int init_cache_level(unsigned int cpu)
> > {
> > - return init_of_cache_level(cpu);
> > +#ifdef CONFIG_SMP
> > + return 0;
> > +#endif
> > +
> > + return fetch_cache_info(cpu);
> > }
> >
> > int populate_cache_leaves(unsigned int cpu)
>
>
> Is the current behaviour wrong or just redundant? If wrong, I'll add a
> Fixes tag to backport, otherwise I won't.
>
> Thanks,
>
> Alex
Hi Alex,
The current behavior is actually wrong when using ACPI on !CONFIG_SMP
systems. The original init_of_cache_level() cannot detect cache hierarchy
through ACPI PPTT table, which means cache information would be missing
in this configuration.
The patch fixes this by directly calling fetch_cache_info() when
CONFIG_SMP is undefined, which properly handles both DT and ACPI cases.
So yes, it would be appropriate to add a Fixes tag. The commit being
fixed is 1845d381f280 ("riscv: cacheinfo: Add back init_cache_level() function").
Please let me know if you need any additional information.
Best regards,
Jessica