diff options
Diffstat (limited to 'drivers/misc/cxl/fault.c')
| -rw-r--r-- | drivers/misc/cxl/fault.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/misc/cxl/fault.c b/drivers/misc/cxl/fault.c index 6eed7d03e2b5..f17f72ea0545 100644 --- a/drivers/misc/cxl/fault.c +++ b/drivers/misc/cxl/fault.c @@ -138,6 +138,22 @@ int cxl_handle_mm_fault(struct mm_struct *mm, u64 dsisr, u64 dar) int result; unsigned long access, flags, inv_flags = 0; + /* + * Add the fault handling cpu to task mm cpumask so that we + * can do a safe lockless page table walk when inserting the + * hash page table entry. This function get called with a + * valid mm for user space addresses. Hence using the if (mm) + * check is sufficient here. + */ + if (mm && !cpumask_test_cpu(smp_processor_id(), mm_cpumask(mm))) { + cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm)); + /* + * We need to make sure we walk the table only after + * we update the cpumask. The other side of the barrier + * is explained in serialize_against_pte_lookup() + */ + smp_mb(); + } if ((result = copro_handle_mm_fault(mm, dar, dsisr, &flt))) { pr_devel("copro_handle_mm_fault failed: %#x\n", result); return result; |