diff options
Diffstat (limited to 'arch/powerpc/mm/book3s64/hash_utils.c')
| -rw-r--r-- | arch/powerpc/mm/book3s64/hash_utils.c | 54 |
1 files changed, 8 insertions, 46 deletions
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index 7abf82a698d3..985cabdd7f67 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -1621,8 +1621,7 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap, } EXPORT_SYMBOL_GPL(hash_page); -DECLARE_INTERRUPT_HANDLER(__do_hash_fault); -DEFINE_INTERRUPT_HANDLER(__do_hash_fault) +DEFINE_INTERRUPT_HANDLER(do_hash_fault) { unsigned long ea = regs->dar; unsigned long dsisr = regs->dsisr; @@ -1681,35 +1680,6 @@ DEFINE_INTERRUPT_HANDLER(__do_hash_fault) } } -/* - * The _RAW interrupt entry checks for the in_nmi() case before - * running the full handler. - */ -DEFINE_INTERRUPT_HANDLER_RAW(do_hash_fault) -{ - /* - * If we are in an "NMI" (e.g., an interrupt when soft-disabled), then - * don't call hash_page, just fail the fault. This is required to - * prevent re-entrancy problems in the hash code, namely perf - * interrupts hitting while something holds H_PAGE_BUSY, and taking a - * hash fault. See the comment in hash_preload(). - * - * We come here as a result of a DSI at a point where we don't want - * to call hash_page, such as when we are accessing memory (possibly - * user memory) inside a PMU interrupt that occurred while interrupts - * were soft-disabled. We want to invoke the exception handler for - * the access, or panic if there isn't a handler. - */ - if (unlikely(in_nmi())) { - do_bad_page_fault_segv(regs); - return 0; - } - - __do_hash_fault(regs); - - return 0; -} - #ifdef CONFIG_PPC_MM_SLICES static bool should_hash_preload(struct mm_struct *mm, unsigned long ea) { @@ -1776,26 +1746,18 @@ static void hash_preload(struct mm_struct *mm, pte_t *ptep, unsigned long ea, #endif /* CONFIG_PPC_64K_PAGES */ /* - * __hash_page_* must run with interrupts off, as it sets the - * H_PAGE_BUSY bit. It's possible for perf interrupts to hit at any - * time and may take a hash fault reading the user stack, see - * read_user_stack_slow() in the powerpc/perf code. - * - * If that takes a hash fault on the same page as we lock here, it - * will bail out when seeing H_PAGE_BUSY set, and retry the access - * leading to an infinite loop. + * __hash_page_* must run with interrupts off, including PMI interrupts + * off, as it sets the H_PAGE_BUSY bit. * - * Disabling interrupts here does not prevent perf interrupts, but it - * will prevent them taking hash faults (see the NMI test in - * do_hash_page), then read_user_stack's copy_from_user_nofault will - * fail and perf will fall back to read_user_stack_slow(), which - * walks the Linux page tables. + * It's otherwise possible for perf interrupts to hit at any time and + * may take a hash fault reading the user stack, which could take a + * hash miss and deadlock on the same H_PAGE_BUSY bit. * * Interrupts must also be off for the duration of the * mm_is_thread_local test and update, to prevent preempt running the * mm on another CPU (XXX: this may be racy vs kthread_use_mm). */ - local_irq_save(flags); + powerpc_local_irq_pmu_save(flags); /* Is that local to this CPU ? */ if (mm_is_thread_local(mm)) @@ -1820,7 +1782,7 @@ static void hash_preload(struct mm_struct *mm, pte_t *ptep, unsigned long ea, mm_ctx_user_psize(&mm->context), pte_val(*ptep)); - local_irq_restore(flags); + powerpc_local_irq_pmu_restore(flags); } /* |