From 314f6c23dd8d417281eb9e8a516dd98036f2e7b3 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 22 Dec 2021 00:50:59 +1100 Subject: [PATCH] powerpc/64s: Mask NIP before checking against SRR0 When CONFIG_PPC_RFI_SRR_DEBUG=y we check that NIP and SRR0 match when returning from interrupts. This can trigger falsely if NIP has either of its two low bits set via sigreturn or ptrace, while SRR0 has its low two bits masked in hardware. As a quick fix make sure to mask the low bits before doing the check. Fixes: 59dc5bfca0cb ("powerpc/64s: avoid reloading (H)SRR registers if they are still valid") Reported-by: Sachin Sant Signed-off-by: Michael Ellerman Tested-by: Sachin Sant Link: https://lore.kernel.org/r/20211221135101.2085547-1-mpe@ellerman.id.au --- arch/powerpc/kernel/interrupt_64.S | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/powerpc/kernel/interrupt_64.S b/arch/powerpc/kernel/interrupt_64.S index d318013..d729c2e 100644 --- a/arch/powerpc/kernel/interrupt_64.S +++ b/arch/powerpc/kernel/interrupt_64.S @@ -30,6 +30,7 @@ COMPAT_SYS_CALL_TABLE: .ifc \srr,srr mfspr r11,SPRN_SRR0 ld r12,_NIP(r1) + clrrdi r12,r12,2 100: tdne r11,r12 EMIT_BUG_ENTRY 100b,__FILE__,__LINE__,(BUGFLAG_WARNING | BUGFLAG_ONCE) mfspr r11,SPRN_SRR1 @@ -39,6 +40,7 @@ COMPAT_SYS_CALL_TABLE: .else mfspr r11,SPRN_HSRR0 ld r12,_NIP(r1) + clrrdi r12,r12,2 100: tdne r11,r12 EMIT_BUG_ENTRY 100b,__FILE__,__LINE__,(BUGFLAG_WARNING | BUGFLAG_ONCE) mfspr r11,SPRN_HSRR1 -- 2.7.4