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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Sandipan Das <sandipan@linux.ibm.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 087/157] powerpc/sstep: Fix darn emulation
Date:   Mon, 22 Mar 2021 13:27:24 +0100
Message-Id: <20210322121936.545824464@linuxfoundation.org>
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From: Sandipan Das <sandipan@linux.ibm.com>

[ 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>
---
 arch/powerpc/lib/sstep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 0f228ee11ca4..a2e067f68dee 100644
--- 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))
-- 
2.30.1