From 28a1899db30a9325498aef114055506286dc8010 Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Mon, 5 Jan 2015 19:29:44 +0800 Subject: ARM: kprobes: check register usage for probed instruction. This patch utilizes the previously introduced checker to check register usage for probed ARM instruction and saves it in a mask. A further patch will use such information to avoid simulation or emulation. Signed-off-by: Wang Nan Reviewed-by: Jon Medhurst Signed-off-by: Jon Medhurst --- arch/arm/probes/kprobes/checkers-arm.c | 93 ++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) (limited to 'arch/arm/probes/kprobes/checkers-arm.c') diff --git a/arch/arm/probes/kprobes/checkers-arm.c b/arch/arm/probes/kprobes/checkers-arm.c index f817663..7b98173 100644 --- a/arch/arm/probes/kprobes/checkers-arm.c +++ b/arch/arm/probes/kprobes/checkers-arm.c @@ -97,3 +97,96 @@ const struct decode_checker arm_stack_checker[NUM_PROBES_ARM_ACTIONS] = { [PROBES_STORE] = {.checker = arm_check_stack}, [PROBES_LDMSTM] = {.checker = arm_check_stack}, }; + +static enum probes_insn __kprobes arm_check_regs_nouse(probes_opcode_t insn, + struct arch_probes_insn *asi, + const struct decode_header *h) +{ + asi->register_usage_flags = 0; + return INSN_GOOD; +} + +static enum probes_insn arm_check_regs_normal(probes_opcode_t insn, + struct arch_probes_insn *asi, + const struct decode_header *h) +{ + u32 regs = h->type_regs.bits >> DECODE_TYPE_BITS; + int i; + + asi->register_usage_flags = 0; + for (i = 0; i < 5; regs >>= 4, insn >>= 4, i++) + if (regs & 0xf) + asi->register_usage_flags |= 1 << (insn & 0xf); + + return INSN_GOOD; +} + + +static enum probes_insn arm_check_regs_ldmstm(probes_opcode_t insn, + struct arch_probes_insn *asi, + const struct decode_header *h) +{ + unsigned int reglist = insn & 0xffff; + unsigned int rn = (insn >> 16) & 0xf; + asi->register_usage_flags = reglist | (1 << rn); + return INSN_GOOD; +} + +static enum probes_insn arm_check_regs_mov_ip_sp(probes_opcode_t insn, + struct arch_probes_insn *asi, + const struct decode_header *h) +{ + /* Instruction is 'mov ip, sp' i.e. 'mov r12, r13' */ + asi->register_usage_flags = (1 << 12) | (1<< 13); + return INSN_GOOD; +} + +/* + * | Rn |Rt/d| | Rm | + * LDRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1101 xxxx + * STRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1111 xxxx + * | Rn |Rt/d| |imm4L| + * LDRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1101 xxxx + * STRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1111 xxxx + * + * Such instructions access Rt/d and its next register, so different + * from others, a specific checker is required to handle this extra + * implicit register usage. + */ +static enum probes_insn arm_check_regs_ldrdstrd(probes_opcode_t insn, + struct arch_probes_insn *asi, + const struct decode_header *h) +{ + int rdt = (insn >> 12) & 0xf; + arm_check_regs_normal(insn, asi, h); + asi->register_usage_flags |= 1 << (rdt + 1); + return INSN_GOOD; +} + + +const struct decode_checker arm_regs_checker[NUM_PROBES_ARM_ACTIONS] = { + [PROBES_MRS] = {.checker = arm_check_regs_normal}, + [PROBES_SATURATING_ARITHMETIC] = {.checker = arm_check_regs_normal}, + [PROBES_MUL1] = {.checker = arm_check_regs_normal}, + [PROBES_MUL2] = {.checker = arm_check_regs_normal}, + [PROBES_MUL_ADD_LONG] = {.checker = arm_check_regs_normal}, + [PROBES_MUL_ADD] = {.checker = arm_check_regs_normal}, + [PROBES_LOAD] = {.checker = arm_check_regs_normal}, + [PROBES_LOAD_EXTRA] = {.checker = arm_check_regs_normal}, + [PROBES_STORE] = {.checker = arm_check_regs_normal}, + [PROBES_STORE_EXTRA] = {.checker = arm_check_regs_normal}, + [PROBES_DATA_PROCESSING_REG] = {.checker = arm_check_regs_normal}, + [PROBES_DATA_PROCESSING_IMM] = {.checker = arm_check_regs_normal}, + [PROBES_SEV] = {.checker = arm_check_regs_nouse}, + [PROBES_WFE] = {.checker = arm_check_regs_nouse}, + [PROBES_SATURATE] = {.checker = arm_check_regs_normal}, + [PROBES_REV] = {.checker = arm_check_regs_normal}, + [PROBES_MMI] = {.checker = arm_check_regs_normal}, + [PROBES_PACK] = {.checker = arm_check_regs_normal}, + [PROBES_EXTEND] = {.checker = arm_check_regs_normal}, + [PROBES_EXTEND_ADD] = {.checker = arm_check_regs_normal}, + [PROBES_BITFIELD] = {.checker = arm_check_regs_normal}, + [PROBES_LDMSTM] = {.checker = arm_check_regs_ldmstm}, + [PROBES_MOV_IP_SP] = {.checker = arm_check_regs_mov_ip_sp}, + [PROBES_LDRSTRD] = {.checker = arm_check_regs_ldrdstrd}, +}; -- cgit v1.1