[PATCH 18/24] powerpc/mm: Move/simplify faulthandler_disabled() and !mm check
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2017-07-19 04:57:09
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
Do the check before we re-enable interrupts and clean the code up a bit. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- arch/powerpc/mm/fault.c | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-)
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 6f3a2437008a..c5859ffd3a96 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c@@ -355,24 +355,23 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, if (unlikely(!is_user && bad_kernel_fault(is_exec, error_code, address))) return SIGSEGV; + /* + * If we're in an interrupt, have no user context or are running + * in a region with pagefaults disabled then we must not take the fault + */ + if (unlikely(faulthandler_disabled() || !mm)) { + if (is_user) + printk_ratelimited(KERN_ERR "Page fault in user mode" + " with faulthandler_disabled()=%d" + " mm=%=p\n", + faulthandler_disabled(), mm); + return bad_area_nosemaphore(regs, address); + } + /* We restore the interrupt state now */ if (!arch_irq_disabled_regs(regs)) local_irq_enable(); - if (faulthandler_disabled() || mm == NULL) { - if (!is_user) - return SIGSEGV; - - /* faulthandler_disabled() in user mode is really bad, - as is current->mm == NULL. */ - printk(KERN_EMERG "Page fault in user mode with " - "faulthandler_disabled() = %d mm = %p\n", - faulthandler_disabled(), mm); - printk(KERN_EMERG "NIP = %lx MSR = %lx\n", - regs->nip, regs->msr); - die("Weird page fault", regs, SIGSEGV); - } - perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); /*
--
2.13.3