commit bd500361a937 ("ACPI: PPTT: Update acpi_find_last_cache_level()
to acpi_get_cache_info()")
updates the function acpi_get_cache_info().
If CONFIG_ACPI_PPTT is not defined, acpi_get_cache_info() doesn't
update its *levels and *split_levels parameters and returns 0.
This can lead to a faulty behaviour.
Make acpi_get_cache_info() return an error code if CONFIG_ACPI_PPTT
is not defined. Initialize levels and split_levels before passing
their address to acpi_get_cache_info().
Also, in init_cache_level():
- commit e75d18cecbb3 ("arm64: cacheinfo: Fix incorrect
assignment of signed error value to unsigned fw_level")
checks the fw_level value in init_cache_level() in case
the value is negative. Remove this check as the error code
is not returned through fw_level anymore.
- if no PPTT is present or CONFIG_ACPI_PPTT is not defined,
it is still possible to use the cache information from clidr_el1.
Instead of aborting if acpi_get_cache_info() returns an error
code, just continue.
Reported-by: Dan Carpenter <[email protected]>
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Pierre Gondois <[email protected]>
---
arch/arm64/kernel/cacheinfo.c | 5 +----
drivers/base/cacheinfo.c | 2 +-
include/linux/cacheinfo.h | 2 +-
3 files changed, 3 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kernel/cacheinfo.c b/arch/arm64/kernel/cacheinfo.c
index 36c3b07cdf2d..3ba70985e3a2 100644
--- a/arch/arm64/kernel/cacheinfo.c
+++ b/arch/arm64/kernel/cacheinfo.c
@@ -64,12 +64,9 @@ int init_cache_level(unsigned int cpu)
} else {
ret = acpi_get_cache_info(cpu, &fw_level, NULL);
if (ret < 0)
- return ret;
+ fw_level = 0;
}
- if (fw_level < 0)
- return fw_level;
-
if (level < fw_level) {
/*
* some external caches not specified in CLIDR_EL1
diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index b57fbd0d7114..f184ef7dc1d2 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -414,7 +414,7 @@ int allocate_cache_info(int cpu)
int fetch_cache_info(unsigned int cpu)
{
struct cpu_cacheinfo *this_cpu_ci;
- unsigned int levels, split_levels;
+ unsigned int levels = 0, split_levels = 0;
int ret;
if (acpi_disabled) {
diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h
index dfef57077cd0..908e19d17f49 100644
--- a/include/linux/cacheinfo.h
+++ b/include/linux/cacheinfo.h
@@ -100,7 +100,7 @@ static inline
int acpi_get_cache_info(unsigned int cpu,
unsigned int *levels, unsigned int *split_levels)
{
- return 0;
+ return -ENOENT;
}
#else
int acpi_get_cache_info(unsigned int cpu,
--
2.25.1
Hey!
On Tue, Jan 24, 2023 at 01:34:46PM +0100, Pierre Gondois wrote:
> commit bd500361a937 ("ACPI: PPTT: Update acpi_find_last_cache_level()
> to acpi_get_cache_info()")
> updates the function acpi_get_cache_info().
>
> If CONFIG_ACPI_PPTT is not defined, acpi_get_cache_info() doesn't
> update its *levels and *split_levels parameters and returns 0.
> This can lead to a faulty behaviour.
>
> Make acpi_get_cache_info() return an error code if CONFIG_ACPI_PPTT
> is not defined. Initialize levels and split_levels before passing
> their address to acpi_get_cache_info().
>
> Also, in init_cache_level():
Hmm...
> - commit e75d18cecbb3 ("arm64: cacheinfo: Fix incorrect
> assignment of signed error value to unsigned fw_level")
> checks the fw_level value in init_cache_level() in case
> the value is negative. Remove this check as the error code
> is not returned through fw_level anymore.
> - if no PPTT is present or CONFIG_ACPI_PPTT is not defined,
> it is still possible to use the cache information from clidr_el1.
> Instead of aborting if acpi_get_cache_info() returns an error
> code, just continue.
To be honest, these feel like entirely separate things that should be
in different patches. You've got:
- Dan's smatch fixes
- a redundant check being removed
- a behaviour change for if acpi_get_cache_info() returns an error
> Reported-by: Dan Carpenter <[email protected]>
> Reported-by: kernel test robot <[email protected]>
How about Link: to the LKP/Dan's report?
Link: https://lore.kernel.org/all/Y86iruJPuwNN7rZw@kili/
I did a quick check but didn't don't see the LKP report...
Also a Fixes: tag too, no?
Thanks,
Conor.
On Tue, Jan 24, 2023 at 01:31:06PM +0000, Conor Dooley wrote:
> Hey!
>
> On Tue, Jan 24, 2023 at 01:34:46PM +0100, Pierre Gondois wrote:
> > commit bd500361a937 ("ACPI: PPTT: Update acpi_find_last_cache_level()
> > to acpi_get_cache_info()")
> > updates the function acpi_get_cache_info().
> >
> > If CONFIG_ACPI_PPTT is not defined, acpi_get_cache_info() doesn't
> > update its *levels and *split_levels parameters and returns 0.
> > This can lead to a faulty behaviour.
> >
> > Make acpi_get_cache_info() return an error code if CONFIG_ACPI_PPTT
> > is not defined. Initialize levels and split_levels before passing
> > their address to acpi_get_cache_info().
> >
> > Also, in init_cache_level():
>
> Hmm...
>
> > - commit e75d18cecbb3 ("arm64: cacheinfo: Fix incorrect
> > assignment of signed error value to unsigned fw_level")
> > checks the fw_level value in init_cache_level() in case
> > the value is negative. Remove this check as the error code
> > is not returned through fw_level anymore.
> > - if no PPTT is present or CONFIG_ACPI_PPTT is not defined,
> > it is still possible to use the cache information from clidr_el1.
> > Instead of aborting if acpi_get_cache_info() returns an error
> > code, just continue.
>
> To be honest, these feel like entirely separate things that should be
> in different patches. You've got:
> - Dan's smatch fixes
> - a redundant check being removed
> - a behaviour change for if acpi_get_cache_info() returns an error
>
I am not too fussy about it, but for sure it would be cleaner for sure.
> > Reported-by: Dan Carpenter <[email protected]>
> > Reported-by: kernel test robot <[email protected]>
>
> How about Link: to the LKP/Dan's report?
> Link: https://lore.kernel.org/all/Y86iruJPuwNN7rZw@kili/
>
> I did a quick check but didn't don't see the LKP report...
>
Yes, LKP dropped all the cc when reported, even I saw after merging the
changes. I think this is the one:
https://lore.kernel.org/all/[email protected]/
> Also a Fixes: tag too, no?
>
+1, if you split make sure you tag fixes to the right one(mainly one
that changes return from acpi_get_cache_info())
> Thanks,
> Conor.
--
Regards,
Sudeep