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ARM: use a function table for determining instruction interpreter action
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Make the instruction interpreter call back to semantic action functions
through a function pointer array provided by the invoker.  The interpreter
decodes the instructions into groups and uses the group number to index
into the supplied array.  kprobes and uprobes code will each supply their
own array of functions.

Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Jon Medhurst <tixy@linaro.org>
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David A. Long committed Mar 18, 2014
1 parent 87abef6 commit 3e6cd39
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Showing 11 changed files with 441 additions and 271 deletions.
57 changes: 49 additions & 8 deletions arch/arm/kernel/kprobes-arm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -73,7 +73,7 @@
#endif


void __kprobes
static void __kprobes
emulate_ldrdstrd(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
Expand Down Expand Up @@ -102,7 +102,7 @@ emulate_ldrdstrd(struct kprobe *p, struct pt_regs *regs)
regs->uregs[rn] = rnv;
}

void __kprobes
static void __kprobes
emulate_ldr(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
Expand Down Expand Up @@ -132,7 +132,7 @@ emulate_ldr(struct kprobe *p, struct pt_regs *regs)
regs->uregs[rn] = rnv;
}

void __kprobes
static void __kprobes
emulate_str(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
Expand All @@ -159,7 +159,7 @@ emulate_str(struct kprobe *p, struct pt_regs *regs)
regs->uregs[rn] = rnv;
}

void __kprobes
static void __kprobes
emulate_rd12rn16rm0rs8_rwflags(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
Expand Down Expand Up @@ -194,7 +194,7 @@ emulate_rd12rn16rm0rs8_rwflags(struct kprobe *p, struct pt_regs *regs)
regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
}

void __kprobes
static void __kprobes
emulate_rd12rn16rm0_rwflags_nopc(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
Expand All @@ -221,7 +221,7 @@ emulate_rd12rn16rm0_rwflags_nopc(struct kprobe *p, struct pt_regs *regs)
regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
}

void __kprobes
static void __kprobes
emulate_rd16rn12rm0rs8_rwflags_nopc(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
Expand Down Expand Up @@ -250,7 +250,7 @@ emulate_rd16rn12rm0rs8_rwflags_nopc(struct kprobe *p, struct pt_regs *regs)
regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
}

void __kprobes
static void __kprobes
emulate_rd12rm0_noflags_nopc(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
Expand All @@ -270,7 +270,7 @@ emulate_rd12rm0_noflags_nopc(struct kprobe *p, struct pt_regs *regs)
regs->uregs[rd] = rdv;
}

void __kprobes
static void __kprobes
emulate_rdlo12rdhi16rn0rm8_rwflags_nopc(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
Expand Down Expand Up @@ -299,3 +299,44 @@ emulate_rdlo12rdhi16rn0rm8_rwflags_nopc(struct kprobe *p, struct pt_regs *regs)
regs->uregs[rdhi] = rdhiv;
regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
}

const union decode_action kprobes_arm_actions[NUM_PROBES_ARM_ACTIONS] = {
[PROBES_EMULATE_NONE] = {.handler = kprobe_emulate_none},
[PROBES_SIMULATE_NOP] = {.handler = kprobe_simulate_nop},
[PROBES_PRELOAD_IMM] = {.handler = kprobe_simulate_nop},
[PROBES_PRELOAD_REG] = {.handler = kprobe_simulate_nop},
[PROBES_BRANCH_IMM] = {.handler = simulate_blx1},
[PROBES_MRS] = {.handler = simulate_mrs},
[PROBES_BRANCH_REG] = {.handler = simulate_blx2bx},
[PROBES_CLZ] = {.handler = emulate_rd12rm0_noflags_nopc},
[PROBES_SATURATING_ARITHMETIC] = {
.handler = emulate_rd12rn16rm0_rwflags_nopc},
[PROBES_MUL1] = {.handler = emulate_rdlo12rdhi16rn0rm8_rwflags_nopc},
[PROBES_MUL2] = {.handler = emulate_rd16rn12rm0rs8_rwflags_nopc},
[PROBES_SWP] = {.handler = emulate_rd12rn16rm0_rwflags_nopc},
[PROBES_LDRSTRD] = {.handler = emulate_ldrdstrd},
[PROBES_LOAD_EXTRA] = {.handler = emulate_ldr},
[PROBES_LOAD] = {.handler = emulate_ldr},
[PROBES_STORE_EXTRA] = {.handler = emulate_str},
[PROBES_STORE] = {.handler = emulate_str},
[PROBES_MOV_IP_SP] = {.handler = simulate_mov_ipsp},
[PROBES_DATA_PROCESSING_REG] = {
.handler = emulate_rd12rn16rm0rs8_rwflags},
[PROBES_DATA_PROCESSING_IMM] = {
.handler = emulate_rd12rn16rm0rs8_rwflags},
[PROBES_MOV_HALFWORD] = {.handler = emulate_rd12rm0_noflags_nopc},
[PROBES_SEV] = {.handler = kprobe_emulate_none},
[PROBES_WFE] = {.handler = kprobe_simulate_nop},
[PROBES_SATURATE] = {.handler = emulate_rd12rn16rm0_rwflags_nopc},
[PROBES_REV] = {.handler = emulate_rd12rm0_noflags_nopc},
[PROBES_MMI] = {.handler = emulate_rd12rn16rm0_rwflags_nopc},
[PROBES_PACK] = {.handler = emulate_rd12rn16rm0_rwflags_nopc},
[PROBES_EXTEND] = {.handler = emulate_rd12rm0_noflags_nopc},
[PROBES_EXTEND_ADD] = {.handler = emulate_rd12rn16rm0_rwflags_nopc},
[PROBES_MUL_ADD_LONG] = {
.handler = emulate_rdlo12rdhi16rn0rm8_rwflags_nopc},
[PROBES_MUL_ADD] = {.handler = emulate_rd16rn12rm0rs8_rwflags_nopc},
[PROBES_BITFIELD] = {.handler = emulate_rd12rm0_noflags_nopc},
[PROBES_BRANCH] = {.handler = simulate_bbl},
[PROBES_LDMSTM] = {.decoder = kprobe_decode_ldmstm}
};
3 changes: 2 additions & 1 deletion arch/arm/kernel/kprobes-common.c
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Original file line number Diff line number Diff line change
Expand Up @@ -112,7 +112,8 @@ emulate_ldm_r3_15(struct kprobe *p, struct pt_regs *regs)
}

enum kprobe_insn __kprobes
kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi)
kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi,
const struct decode_header *h)
{
kprobe_insn_handler_t *handler = 0;
unsigned reglist = insn & 0xffff;
Expand Down
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