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: Pierre Gondois <pierre.gondois@arm.com>
Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Link: https://lore.kernel.org/r/20230117105133.4445-2-yongxuan.wang@sifive.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index c9bcecf..418a18a 100644 (file)
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -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);
-                       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);
+                       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);
-                       cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
-                       cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
+                       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;
+                               }
+                       }
                }
        }
 }