Commit 198102c9 authored by Yong-Xuan Wang's avatar Yong-Xuan Wang Committed by Sudeep Holla
Browse files

cacheinfo: Fix shared_cpu_map to handle shared caches at different levels 



The cacheinfo sets up the shared_cpu_map by checking whether the caches
with the same index are shared between CPUs. However, this will trigger
slab-out-of-bounds access if the CPUs do not have the same cache hierarchy.
Another problem is the mismatched shared_cpu_map when the shared cache does
not have the same index between CPUs.

CPU0	I	D	L3
index	0	1	2	x
	^	^	^	^
index	0	1	2	3
CPU1	I	D	L2	L3

This patch checks each cache is shared with all caches on other CPUs.

Reviewed-by: default avatarPierre Gondois <pierre.gondois@arm.com>
Signed-off-by: default avatarYong-Xuan Wang <yongxuan.wang@sifive.com>
Link: https://lore.kernel.org/r/20230117105133.4445-2-yongxuan.wang@sifive.com


Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
parent 5944ce09

drivers/base/cacheinfo.c

+17 −10
Original line number Diff line number Diff line
@@ -319,7 +319,7 @@ static int cache_shared_cpu_map_setup(unsigned int cpu) 
{

	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);

	struct cacheinfo *this_leaf, *sib_leaf;

	unsigned int index;

	unsigned int index, sib_index;

	int ret = 0;



	if (this_cpu_ci->cpu_map_populated)
@@ -347,11 +347,13 @@ static int cache_shared_cpu_map_setup(unsigned int cpu) 


			if (i == cpu || !sib_cpu_ci->info_list)

				continue;/* skip if itself or no cacheinfo */



			sib_leaf = per_cpu_cacheinfo_idx(i, index);

			for (sib_index = 0; sib_index < cache_leaves(i); sib_index++) {

				sib_leaf = per_cpu_cacheinfo_idx(i, sib_index);

				if (cache_leaves_are_shared(this_leaf, sib_leaf)) {

					cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map);

					cpumask_set_cpu(i, &this_leaf->shared_cpu_map);

					break;

				}

			}

		}

		/* record the maximum cache line size */
@@ -365,7 +367,7 @@ static int cache_shared_cpu_map_setup(unsigned int cpu) 
static void cache_shared_cpu_map_remove(unsigned int cpu)

{

	struct cacheinfo *this_leaf, *sib_leaf;

	unsigned int sibling, index;

	unsigned int sibling, index, sib_index;



	for (index = 0; index < cache_leaves(cpu); index++) {

		this_leaf = per_cpu_cacheinfo_idx(cpu, index);
@@ -376,9 +378,14 @@ static void cache_shared_cpu_map_remove(unsigned int cpu) 
			if (sibling == cpu || !sib_cpu_ci->info_list)

				continue;/* skip if itself or no cacheinfo */



			sib_leaf = per_cpu_cacheinfo_idx(sibling, index);

			for (sib_index = 0; sib_index < cache_leaves(sibling); sib_index++) {

				sib_leaf = per_cpu_cacheinfo_idx(sibling, sib_index);

				if (cache_leaves_are_shared(this_leaf, sib_leaf)) {

					cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);

					cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);

					break;

				}

			}

		}

	}

}