Commit 50d93d38 authored by James Hogan's avatar James Hogan Committed by Sasha Levin

MIPS: smp.c: Fix uninitialised temp_foreign_map

[ Upstream commit d825c06b ]

When calculate_cpu_foreign_map() recalculates the cpu_foreign_map
cpumask it uses the local variable temp_foreign_map without initialising
it to zero. Since the calculation only ever sets bits in this cpumask
any existing bits at that memory location will remain set and find their
way into cpu_foreign_map too. This could potentially lead to cache
operations suboptimally doing smp calls to multiple VPEs in the same
core, even though the VPEs share primary caches.

Therefore initialise temp_foreign_map using cpumask_clear() before use.

Fixes: cccf34e9 ("MIPS: c-r4k: Fix cache flushing for MT cores")
Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12759/Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
parent 9c99016a
......@@ -120,6 +120,7 @@ static inline void calculate_cpu_foreign_map(void)
cpumask_t temp_foreign_map;
/* Re-calculate the mask */
cpumask_clear(&temp_foreign_map);
for_each_online_cpu(i) {
core_present = 0;
for_each_cpu(k, &temp_foreign_map)
......
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