Commit ef9f643a authored by Pierre Gondois's avatar Pierre Gondois Committed by Sudeep Holla
Browse files

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



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: default avatarPierre Gondois <pierre.gondois@arm.com>
Link: https://lore.kernel.org/r/20230414081453.244787-5-pierre.gondois@arm.com


Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
parent 35223401

drivers/base/cacheinfo.c

+10 −2
Original line number Diff line number Diff line
@@ -28,6 +28,9 @@ static DEFINE_PER_CPU(struct cpu_cacheinfo, ci_cpu_cacheinfo); 
#define per_cpu_cacheinfo_idx(cpu, idx)		\

				(per_cpu_cacheinfo(cpu) + (idx))



/* Set if no cache information is found in DT/ACPI. */

static bool use_arch_info;



struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu)

{

	return ci_cacheinfo(cpu);
@@ -40,7 +43,8 @@ static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf, 
	 * For non DT/ACPI systems, assume unique level 1 caches,

	 * system-wide shared caches for all other levels.

	 */

	if (!(IS_ENABLED(CONFIG_OF) || IS_ENABLED(CONFIG_ACPI)))

	if (!(IS_ENABLED(CONFIG_OF) || IS_ENABLED(CONFIG_ACPI)) ||

	    use_arch_info)

		return (this_leaf->level != 1) && (sib_leaf->level != 1);



	if ((sib_leaf->attributes & CACHE_ID) &&
@@ -343,6 +347,10 @@ static int cache_setup_properties(unsigned int cpu) 
	else if (!acpi_disabled)

		ret = cache_setup_acpi(cpu);



	// Assume there is no cache information available in DT/ACPI from now.

	if (ret && use_arch_cache_info())

		use_arch_info = true;



	return ret;

}
@@ -361,7 +369,7 @@ static int cache_shared_cpu_map_setup(unsigned int cpu) 
	 * to update the shared cpu_map if the cache attributes were

	 * populated early before all the cpus are brought online

	 */

	if (!last_level_cache_is_valid(cpu)) {

	if (!last_level_cache_is_valid(cpu) && !use_arch_info) {

		ret = cache_setup_properties(cpu);

		if (ret)

			return ret;

include/linux/cacheinfo.h

+6 −0
Original line number Diff line number Diff line
@@ -131,4 +131,10 @@ static inline int get_cpu_cacheinfo_id(int cpu, int level) 
	return -1;

}



#ifdef CONFIG_ARM64

#define use_arch_cache_info()	(true)

#else

#define use_arch_cache_info()	(false)

#endif



#endif /* _LINUX_CACHEINFO_H */