From 8712783ddcba8851207e852b6acd2e0950e496b5 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Thu, 15 Jun 2017 09:46:39 +1000 Subject: [PATCH] powerpc: Fix emulation of mfocrf in emulate_step() commit 64e756c55aa46fc18fd53e8f3598b73b528d8637 upstream. From POWER4 onwards, mfocrf() only places the specified CR field into the destination GPR, and the rest of it is set to 0. The PowerPC AS from version 3.0 now requires this behaviour. The emulation code currently puts the entire CR into the destination GPR. Fix it. Fixes: 6888199f7fe5 ("[POWERPC] Emulate more instructions in software") Signed-off-by: Anton Blanchard Acked-by: Naveen N. Rao Signed-off-by: Michael Ellerman Signed-off-by: Ben Hutchings --- arch/powerpc/lib/sstep.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c index 9a52349874ee1..6ca7fe0bd420e 100644 --- a/arch/powerpc/lib/sstep.c +++ b/arch/powerpc/lib/sstep.c @@ -863,6 +863,19 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr) goto instr_done; #endif case 19: /* mfcr */ + if ((instr >> 20) & 1) { + imm = 0xf0000000UL; + for (sh = 0; sh < 8; ++sh) { + if (instr & (0x80000 >> sh)) { + regs->gpr[rd] = regs->ccr & imm; + break; + } + imm >>= 4; + } + + goto instr_done; + } + regs->gpr[rd] = regs->ccr; regs->gpr[rd] &= 0xffffffffUL; goto instr_done; -- 2.47.3