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powerpc/mm: Move/simplify faulthandler_disabled() and !mm check 

Do the check before we re-enable interrupts and clean the code
up a bit.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Benjamin Herrenschmidt 2017-07-19 14:49:40 +10:00 committed by Michael Ellerman
parent 2865d08dd9
commit 11ccdd33d6
1 changed files with 13 additions and 14 deletions
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27
arch/powerpc/mm/fault.c
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@ -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))) if (unlikely(!is_user && bad_kernel_fault(is_exec, error_code, address)))
return SIGSEGV; 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 */ /* We restore the interrupt state now */
if (!arch_irq_disabled_regs(regs)) if (!arch_irq_disabled_regs(regs))
local_irq_enable(); 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); perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
/* /*