From c44dc6323cd49d8d742c37e234b952e822c35de4 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Wed, 29 Apr 2020 16:56:53 +1000 Subject: [PATCH] powerpc/64s/kuap: Restore AMR in fast_interrupt_return Interrupts that use fast_interrupt_return actually do lock AMR, but they have been ones which tend to come from userspace (or kernel bugs) in radix mode. With kuap on hash, segment interrupts are taken in kernel often, which quickly breaks due to the missing restore. Fixes: 890274c2dc4c ("powerpc/64s: Implement KUAP for Radix MMU") Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200429065654.1677541-6-npiggin@gmail.com --- arch/powerpc/kernel/entry_64.S | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 9a1e5d6..b3c9f15 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -472,15 +472,17 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S) #ifdef CONFIG_PPC_BOOK3S /* * If MSR EE/RI was never enabled, IRQs not reconciled, NVGPRs not - * touched, AMR not set, no exit work created, then this can be used. + * touched, no exit work created, then this can be used. */ .balign IFETCH_ALIGN_BYTES .globl fast_interrupt_return fast_interrupt_return: _ASM_NOKPROBE_SYMBOL(fast_interrupt_return) + kuap_check_amr r3, r4 ld r4,_MSR(r1) andi. r0,r4,MSR_PR bne .Lfast_user_interrupt_return + kuap_restore_amr r3 andi. r0,r4,MSR_RI li r3,0 /* 0 return value, no EMULATE_STACK_STORE */ bne+ .Lfast_kernel_interrupt_return -- 2.7.4