From c8ac1598ed8026c9a8cc862289b3bac776aeac5a Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Sat, 2 Mar 2024 20:22:09 +0100 Subject: [PATCH] s390/cache: prevent rebuild of shared_cpu_list BugLink: https://bugs.launchpad.net/bugs/2060097 [ Upstream commit cb0cd4ee11142339f2d47eef6db274290b7a482d ] With commit 36bbc5b4ffab ("cacheinfo: Allow early detection and population of cache attributes") the shared cpu list for each cache level higher than L1 is rebuilt even if the list already has been set up. This is caused by the removal of the cpumask_empty() check within cache_shared_cpu_map_setup(). However architectures can enforce that the shared cpu list is not rebuilt by simply setting cpu_map_populated of the per cpu cache info structure to true, which is also the fix for this problem. Before: $ cat /sys/devices/system/cpu/cpu1/cache/index2/shared_cpu_list 0-7 After: $ cat /sys/devices/system/cpu/cpu1/cache/index2/shared_cpu_list 1 Fixes: 36bbc5b4ffab ("cacheinfo: Allow early detection and population of cache attributes") Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin (cherry picked from commit db52c7c363d2dd85a90fb1690a2ee6e687c5cf68) Signed-off-by: Paolo Pisati --- arch/s390/kernel/cache.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/s390/kernel/cache.c b/arch/s390/kernel/cache.c index 56254fa06f99..4f2669030220 100644 --- a/arch/s390/kernel/cache.c +++ b/arch/s390/kernel/cache.c @@ -166,5 +166,6 @@ int populate_cache_leaves(unsigned int cpu) ci_leaf_init(this_leaf++, pvt, ctype, level, cpu); } } + this_cpu_ci->cpu_map_populated = true; return 0; }