powerpc/sstep: Fix darn emulation

[ Upstream commit 22b89ba178dd0a66a26699ead014a3e73ff8e044 ]

Commit 8813ff49607e ("powerpc/sstep: Check instruction validity
against ISA version before emulation") introduced a proper way to skip
unknown instructions. This makes sure that the same is used for the
darn instruction when the range selection bits have a reserved value.

Fixes: a23987ef267a ("powerpc: sstep: Add support for darn instruction")
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210204080744.135785-2-sandipan@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 0f228ee..a2e067f 100644 (file)
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1853,7 +1853,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
                                goto compute_done;
                        }
 
-                       return -1;
+                       goto unknown_opcode;
 #ifdef __powerpc64__
                case 777:       /* modsd */
                        if (!cpu_has_feature(CPU_FTR_ARCH_300))