From ba48d40713ae5afe758dd5525a0f8740cce71d22 Mon Sep 17 00:00:00 2001 From: Jon Medhurst Date: Thu, 7 Apr 2011 13:25:19 +0100 Subject: [PATCH] ARM: kprobes: Reject probing of undefined multiply instructions The instructions space for 'Multiply and multiply-accumulate' instructions contains some undefined patterns. We need to reject probing of these because they may in future become defined and the kprobes code may then emulate them faultily. This has already happened with the new MLS instruction which this patch also adds correct decoding for as well as tightening up other decoding tests. (Before this patch the wrong emulation routine was being called for MLS though it still produced correct results.) Signed-off-by: Jon Medhurst Signed-off-by: Nicolas Pitre --- arch/arm/kernel/kprobes-decode.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/arch/arm/kernel/kprobes-decode.c b/arch/arm/kernel/kprobes-decode.c index 54c175906787..8f3f03e46ace 100644 --- a/arch/arm/kernel/kprobes-decode.c +++ b/arch/arm/kernel/kprobes-decode.c @@ -1102,13 +1102,16 @@ space_cccc_000x(kprobe_opcode_t insn, struct arch_specific_insn *asi) } /* cccc 0000 xxxx xxxx xxxx xxxx xxxx 1001 xxxx */ - else if ((insn & 0x0f000090) == 0x00000090) { + else if ((insn & 0x0f0000f0) == 0x00000090) { /* MUL : cccc 0000 0000 xxxx xxxx xxxx 1001 xxxx : */ /* MULS : cccc 0000 0001 xxxx xxxx xxxx 1001 xxxx :cc */ /* MLA : cccc 0000 0010 xxxx xxxx xxxx 1001 xxxx : */ /* MLAS : cccc 0000 0011 xxxx xxxx xxxx 1001 xxxx :cc */ /* UMAAL : cccc 0000 0100 xxxx xxxx xxxx 1001 xxxx : */ + /* undef : cccc 0000 0101 xxxx xxxx xxxx 1001 xxxx : */ + /* MLS : cccc 0000 0110 xxxx xxxx xxxx 1001 xxxx : */ + /* undef : cccc 0000 0111 xxxx xxxx xxxx 1001 xxxx : */ /* UMULL : cccc 0000 1000 xxxx xxxx xxxx 1001 xxxx : */ /* UMULLS : cccc 0000 1001 xxxx xxxx xxxx 1001 xxxx :cc */ /* UMLAL : cccc 0000 1010 xxxx xxxx xxxx 1001 xxxx : */ @@ -1117,9 +1120,11 @@ space_cccc_000x(kprobe_opcode_t insn, struct arch_specific_insn *asi) /* SMULLS : cccc 0000 1101 xxxx xxxx xxxx 1001 xxxx :cc */ /* SMLAL : cccc 0000 1110 xxxx xxxx xxxx 1001 xxxx : */ /* SMLALS : cccc 0000 1111 xxxx xxxx xxxx 1001 xxxx :cc */ - if ((insn & 0x0fe000f0) == 0x00000090) { + if ((insn & 0x00d00000) == 0x00500000) { + return INSN_REJECTED; + } else if ((insn & 0x00e00000) == 0x00000000) { return prep_emulate_rd16rs8rm0_wflags(insn, asi); - } else if ((insn & 0x0fe000f0) == 0x00200090) { + } else if ((insn & 0x00a00000) == 0x00200000) { return prep_emulate_rd16rn12rs8rm0_wflags(insn, asi); } else { return prep_emulate_rdhi16rdlo12rs8rm0_wflags(insn, asi); -- 2.39.2