From: Oliver O'Halloran <oohall@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Oliver O'Halloran <oohall@gmail.com>
Subject: [PATCH] powerpc/lib/sstep.c - Fix emulation fall-through
Date: Tue, 16 Feb 2016 10:28:49 +1100 [thread overview]
Message-ID: <1455578929-29599-1-git-send-email-oohall@gmail.com> (raw)
In-Reply-To: <1453704952-11197-1-git-send-email-oohall@gmail.com>
There is a switch fallthough in instr_analyze() which can cause
an invalid instruction to be emulated as a different, valid,
instruction. The rld* (opcode 30) case extracts a sub-opcode from
bits 3:1 of the instruction word. However, the only valid values
of this field a 001 and 000. These cases are correctly handled,
but the others are not which causes execution to fall through
into case 31.
Breaking out of the switch causes the instruction to be marked as
unknown and allows the caller to deal with the invalid instruction
in a manner consistent with other invalid instructions.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
---
arch/powerpc/lib/sstep.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index dc885b3..e25f73c 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -925,6 +925,7 @@ int __kprobes analyse_instr(struct instruction_op *op, struct pt_regs *regs,
}
}
#endif
+ break; /* illegal instruction */
case 31:
switch ((instr >> 1) & 0x3ff) {
--
2.5.0
next prev parent reply other threads:[~2016-02-15 23:29 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-25 6:55 [PATCH] Fix fall-through from case 30 (rld*) to case 31 Oliver O'Halloran
2016-01-27 0:52 ` Andrew Donnellan
2016-01-27 5:29 ` oliver
2016-01-27 7:00 ` Andrew Donnellan
2016-02-15 23:28 ` Oliver O'Halloran [this message]
2016-02-16 0:59 ` [PATCH] powerpc/lib/sstep.c - Fix emulation fall-through Andrew Donnellan
2016-02-16 6:31 ` [PATCH v2] powerpc/sstep.c " Oliver O'Halloran
2016-05-10 21:48 ` [v2] " Michael Ellerman
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