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author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-08-16 14:10:01 +0200 |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-09-06 09:24:42 +0200 |
commit | b3e5dc45fd1ec2aa1de6b80008f9295eb17e0659 (patch) | |
tree | 5dbf5cd01b249aabf7dd212aae89a0c881699126 /arch/s390/include/asm/mmu_context.h | |
parent | 46fde9a9d204e322cf4fda391c30213633dcc17f (diff) | |
download | op-kernel-dev-b3e5dc45fd1ec2aa1de6b80008f9295eb17e0659.zip op-kernel-dev-b3e5dc45fd1ec2aa1de6b80008f9295eb17e0659.tar.gz |
s390/mm: fix local TLB flushing vs. detach of an mm address space
The local TLB flushing code keeps an additional mask in the mm.context,
the cpu_attach_mask. At the time a global flush of an address space is
done the cpu_attach_mask is copied to the mm_cpumask in order to avoid
future global flushes in case the mm is used by a single CPU only after
the flush.
Trouble is that the reset of the mm_cpumask is racy against the detach
of an mm address space by switch_mm. The current order is first the
global TLB flush and then the copy of the cpu_attach_mask to the
mm_cpumask. The order needs to be the other way around.
Cc: <stable@vger.kernel.org>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/mmu_context.h')
-rw-r--r-- | arch/s390/include/asm/mmu_context.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h index 72e9ca8..8823e35 100644 --- a/arch/s390/include/asm/mmu_context.h +++ b/arch/s390/include/asm/mmu_context.h @@ -103,7 +103,6 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, if (prev == next) return; cpumask_set_cpu(cpu, &next->context.cpu_attach_mask); - cpumask_set_cpu(cpu, mm_cpumask(next)); /* Clear old ASCE by loading the kernel ASCE. */ __ctl_load(S390_lowcore.kernel_asce, 1, 1); __ctl_load(S390_lowcore.kernel_asce, 7, 7); @@ -121,7 +120,7 @@ static inline void finish_arch_post_lock_switch(void) preempt_disable(); while (atomic_read(&mm->context.flush_count)) cpu_relax(); - + cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm)); if (mm->context.flush_mm) __tlb_flush_mm(mm); preempt_enable(); @@ -136,6 +135,7 @@ static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next) { switch_mm(prev, next, current); + cpumask_set_cpu(smp_processor_id(), mm_cpumask(next)); set_user_asce(next); } |