s390/cache: prevent rebuild of shared_cpu_list

BugLink: https://bugs.launchpad.net/bugs/2060097

[ Upstream commit cb0cd4ee11142339f2d47eef6db274290b7a482d ]

With commit 36bbc5b4ff ("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: 36bbc5b4ff ("cacheinfo: Allow early detection and population of cache attributes")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit db52c7c363d2dd85a90fb1690a2ee6e687c5cf68)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

This commit is contained in:

Heiko Carstens

2024-03-02 20:22:09 +01:00

committed by

Roxana Nicolescu

parent 838b4d0a4e

commit c8ac1598ed

1 changed files with 1 additions and 0 deletions

									
										arch/s390/kernel/cache.c
									
		+1
		
												View File
												
				@@ -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;

				}