cacheinfo: Make default acpi_get_cache_info() return an error

commit bd500361a937 ("ACPI: PPTT: Update acpi_find_last_cache_level()
to acpi_get_cache_info()")
updates the prototype of acpi_get_cache_info(). The cache 'levels'
is update through a pointer and not the return value of the function.

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.
Also,

In init_cache_level(), if no PPTT is present or CONFIG_ACPI_PPTT is
not defined, instead of aborting if acpi_get_cache_info() returns an
error code, just continue. This allows to try fetching the cache
information from clidr_el1.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Link: https://lore.kernel.org/r/20230124154053.355376-3-pierre.gondois@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm64/kernel/cacheinfo.c b/arch/arm64/kernel/cacheinfo.c
index 36c3b07..91677f4 100644 (file)
--- a/arch/arm64/kernel/cacheinfo.c
+++ b/arch/arm64/kernel/cacheinfo.c
@@ -64,7 +64,7 @@ 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)

diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h
index dfef570..908e19d 100644 (file)
--- 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,