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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2010-08-24 09:26:21 +0200
committerMartin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>2010-08-24 09:26:34 +0200
commit050eef364ad700590a605a0749f825cab4834b1e (patch)
tree2714c9cf7edcbf394971cc2c929e5ab2ea34d6a6 /arch/s390/mm
parent7af048dc7639db5202c56fecf2346c310647a218 (diff)
downloadlinux-linaro-android-050eef364ad700590a605a0749f825cab4834b1e.tar.gz
[S390] fix tlb flushing vs. concurrent /proc accesses
The tlb flushing code uses the mm_users field of the mm_struct to decide if each page table entry needs to be flushed individually with IPTE or if a global flush for the mm_struct is sufficient after all page table updates have been done. The comment for mm_users says "How many users with user space?" but the /proc code increases mm_users after it found the process structure by pid without creating a new user process. Which makes mm_users useless for the decision between the two tlb flusing methods. The current code can be confused to not flush tlb entries by a concurrent access to /proc files if e.g. a fork is in progres. The solution for this problem is to make the tlb flushing logic independent from the mm_users field. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r--arch/s390/mm/init.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index acc91c75bc9..30eb6d02ddb 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -74,6 +74,8 @@ void __init paging_init(void)
__ctl_load(S390_lowcore.kernel_asce, 13, 13);
__raw_local_irq_ssm(ssm_mask);
+ atomic_set(&init_mm.context.attach_count, 1);
+
sparse_memory_present_with_active_regions(MAX_NUMNODES);
sparse_init();
memset(max_zone_pfns, 0, sizeof(max_zone_pfns));