ARM: use a function table for determining instruction interpreter action

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>

1 files changed, 107 insertions, 42 deletions

diff --git a/arch/arm/kernel/kprobes-thumb.c b/arch/arm/kernel/kprobes-thumb.c
index 977f21723a9c..d83f6092920a 100644
--- a/arch/arm/kernel/kprobes-thumb.c
+++ b/arch/arm/kernel/kprobes-thumb.c
@@ -16,6 +16,10 @@
 #include "kprobes.h"
 #include "probes-thumb.h"
 
+/* These emulation encodings are functionally equivalent... */
+#define t32_emulate_rd8rn16rm0ra12_noflags \
+		t32_emulate_rdlo12rdhi8rn16rm0_noflags
+
 /*
  * Return the PC value for a probe in thumb code.
  * This is the address of the probed instruction plus 4.
@@ -29,7 +33,7 @@ static inline unsigned long __kprobes thumb_probe_pc(struct kprobe *p)
 
 /* t32 thumb actions */
 
-void __kprobes
+static void __kprobes
 t32_simulate_table_branch(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -49,7 +53,7 @@ t32_simulate_table_branch(struct kprobe *p, struct pt_regs *regs)
 	regs->ARM_pc = pc + 2 * halfwords;
 }
 
-void __kprobes
+static void __kprobes
 t32_simulate_mrs(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -58,7 +62,7 @@ t32_simulate_mrs(struct kprobe *p, struct pt_regs *regs)
 	regs->uregs[rd] = regs->ARM_cpsr & mask;
 }
 
-void __kprobes
+static void __kprobes
 t32_simulate_cond_branch(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -73,8 +77,9 @@ t32_simulate_cond_branch(struct kprobe *p, struct pt_regs *regs)
 	regs->ARM_pc = pc + (offset * 2);
 }
 
-enum kprobe_insn __kprobes
-t32_decode_cond_branch(kprobe_opcode_t insn, struct arch_specific_insn *asi)
+static enum kprobe_insn __kprobes
+t32_decode_cond_branch(kprobe_opcode_t insn, struct arch_specific_insn *asi,
+		const struct decode_header *d)
 {
 	int cc = (insn >> 22) & 0xf;
 	asi->insn_check_cc = kprobe_condition_checks[cc];
@@ -82,7 +87,7 @@ t32_decode_cond_branch(kprobe_opcode_t insn, struct arch_specific_insn *asi)
 	return INSN_GOOD_NO_SLOT;
 }
 
-void __kprobes
+static void __kprobes
 t32_simulate_branch(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -110,7 +115,7 @@ t32_simulate_branch(struct kprobe *p, struct pt_regs *regs)
 	regs->ARM_pc = pc + (offset * 2);
 }
 
-void __kprobes
+static void __kprobes
 t32_simulate_ldr_literal(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -148,10 +153,11 @@ t32_simulate_ldr_literal(struct kprobe *p, struct pt_regs *regs)
 	regs->uregs[rt] = rtv;
 }
 
-enum kprobe_insn __kprobes
-t32_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi)
+static enum kprobe_insn __kprobes
+t32_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi,
+		const struct decode_header *d)
 {
-	enum kprobe_insn ret = kprobe_decode_ldmstm(insn, asi);
+	enum kprobe_insn ret = kprobe_decode_ldmstm(insn, asi, d);
 
 	/* Fixup modified instruction to have halfwords in correct order...*/
 	insn = asi->insn[0];
@@ -161,7 +167,7 @@ t32_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi)
 	return ret;
 }
 
-void __kprobes
+static void __kprobes
 t32_emulate_ldrdstrd(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -188,7 +194,7 @@ t32_emulate_ldrdstrd(struct kprobe *p, struct pt_regs *regs)
 	regs->uregs[rt2] = rt2v;
 }
 
-void __kprobes
+static void __kprobes
 t32_emulate_ldrstr(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -214,7 +220,7 @@ t32_emulate_ldrstr(struct kprobe *p, struct pt_regs *regs)
 		regs->uregs[rt] = rtv;
 }
 
-void __kprobes
+static void __kprobes
 t32_emulate_rd8rn16rm0_rwflags(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -241,7 +247,7 @@ t32_emulate_rd8rn16rm0_rwflags(struct kprobe *p, struct pt_regs *regs)
 	regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
 }
 
-void __kprobes
+static void __kprobes
 t32_emulate_rd8pc16_noflags(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -261,7 +267,7 @@ t32_emulate_rd8pc16_noflags(struct kprobe *p, struct pt_regs *regs)
 	regs->uregs[rd] = rdv;
 }
 
-void __kprobes
+static void __kprobes
 t32_emulate_rd8rn16_noflags(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -281,7 +287,7 @@ t32_emulate_rd8rn16_noflags(struct kprobe *p, struct pt_regs *regs)
 	regs->uregs[rd] = rdv;
 }
 
-void __kprobes
+static void __kprobes
 t32_emulate_rdlo12rdhi8rn16rm0_noflags(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -308,7 +314,7 @@ t32_emulate_rdlo12rdhi8rn16rm0_noflags(struct kprobe *p, struct pt_regs *regs)
 }
 /* t16 thumb actions */
 
-void __kprobes
+static void __kprobes
 t16_simulate_bxblx(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -322,7 +328,7 @@ t16_simulate_bxblx(struct kprobe *p, struct pt_regs *regs)
 	bx_write_pc(rmv, regs);
 }
 
-void __kprobes
+static void __kprobes
 t16_simulate_ldr_literal(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -332,7 +338,7 @@ t16_simulate_ldr_literal(struct kprobe *p, struct pt_regs *regs)
 	regs->uregs[rt] = base[index];
 }
 
-void __kprobes
+static void __kprobes
 t16_simulate_ldrstr_sp_relative(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -345,7 +351,7 @@ t16_simulate_ldrstr_sp_relative(struct kprobe *p, struct pt_regs *regs)
 		base[index] = regs->uregs[rt];
 }
 
-void __kprobes
+static void __kprobes
 t16_simulate_reladr(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -356,7 +362,7 @@ t16_simulate_reladr(struct kprobe *p, struct pt_regs *regs)
 	regs->uregs[rt] = base + offset * 4;
 }
 
-void __kprobes
+static void __kprobes
 t16_simulate_add_sp_imm(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -367,7 +373,7 @@ t16_simulate_add_sp_imm(struct kprobe *p, struct pt_regs *regs)
 		regs->ARM_sp += imm * 4;
 }
 
-void __kprobes
+static void __kprobes
 t16_simulate_cbz(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -381,7 +387,7 @@ t16_simulate_cbz(struct kprobe *p, struct pt_regs *regs)
 	}
 }
 
-void __kprobes
+static void __kprobes
 t16_simulate_it(struct kprobe *p, struct pt_regs *regs)
 {
 	/*
@@ -398,21 +404,22 @@ t16_simulate_it(struct kprobe *p, struct pt_regs *regs)
 	regs->ARM_cpsr = cpsr;
 }
 
-void __kprobes
+static void __kprobes
 t16_singlestep_it(struct kprobe *p, struct pt_regs *regs)
 {
 	regs->ARM_pc += 2;
 	t16_simulate_it(p, regs);
 }
 
-enum kprobe_insn __kprobes
-t16_decode_it(kprobe_opcode_t insn, struct arch_specific_insn *asi)
+static enum kprobe_insn __kprobes
+t16_decode_it(kprobe_opcode_t insn, struct arch_specific_insn *asi,
+		const struct decode_header *d)
 {
 	asi->insn_singlestep = t16_singlestep_it;
 	return INSN_GOOD_NO_SLOT;
 }
 
-void __kprobes
+static void __kprobes
 t16_simulate_cond_branch(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -422,8 +429,9 @@ t16_simulate_cond_branch(struct kprobe *p, struct pt_regs *regs)
 	regs->ARM_pc = pc + (offset * 2);
 }
 
-enum kprobe_insn __kprobes
-t16_decode_cond_branch(kprobe_opcode_t insn, struct arch_specific_insn *asi)
+static enum kprobe_insn __kprobes
+t16_decode_cond_branch(kprobe_opcode_t insn, struct arch_specific_insn *asi,
+		const struct decode_header *d)
 {
 	int cc = (insn >> 8) & 0xf;
 	asi->insn_check_cc = kprobe_condition_checks[cc];
@@ -431,7 +439,7 @@ t16_decode_cond_branch(kprobe_opcode_t insn, struct arch_specific_insn *asi)
 	return INSN_GOOD_NO_SLOT;
 }
 
-void __kprobes
+static void __kprobes
 t16_simulate_branch(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -463,13 +471,13 @@ t16_emulate_loregs(struct kprobe *p, struct pt_regs *regs)
 	return (oldcpsr & ~APSR_MASK) | (newcpsr & APSR_MASK);
 }
 
-void __kprobes
+static void __kprobes
 t16_emulate_loregs_rwflags(struct kprobe *p, struct pt_regs *regs)
 {
 	regs->ARM_cpsr = t16_emulate_loregs(p, regs);
 }
 
-void __kprobes
+static void __kprobes
 t16_emulate_loregs_noitrwflags(struct kprobe *p, struct pt_regs *regs)
 {
 	unsigned long cpsr = t16_emulate_loregs(p, regs);
@@ -477,7 +485,7 @@ t16_emulate_loregs_noitrwflags(struct kprobe *p, struct pt_regs *regs)
 		regs->ARM_cpsr = cpsr;
 }
 
-void __kprobes
+static void __kprobes
 t16_emulate_hiregs(struct kprobe *p, struct pt_regs *regs)
 {
 	kprobe_opcode_t insn = p->opcode;
@@ -508,8 +516,9 @@ t16_emulate_hiregs(struct kprobe *p, struct pt_regs *regs)
 	regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
 }
 
-enum kprobe_insn __kprobes
-t16_decode_hiregs(kprobe_opcode_t insn, struct arch_specific_insn *asi)
+static enum kprobe_insn __kprobes
+t16_decode_hiregs(kprobe_opcode_t insn, struct arch_specific_insn *asi,
+		const struct decode_header *d)
 {
 	insn &= ~0x00ff;
 	insn |= 0x001; /* Set Rdn = R1 and Rm = R0 */
@@ -518,7 +527,7 @@ t16_decode_hiregs(kprobe_opcode_t insn, struct arch_specific_insn *asi)
 	return INSN_GOOD;
 }
 
-void __kprobes
+static void __kprobes
 t16_emulate_push(struct kprobe *p, struct pt_regs *regs)
 {
 	__asm__ __volatile__ (
@@ -534,8 +543,9 @@ t16_emulate_push(struct kprobe *p, struct pt_regs *regs)
 		);
 }
 
-enum kprobe_insn __kprobes
-t16_decode_push(kprobe_opcode_t insn, struct arch_specific_insn *asi)
+static enum kprobe_insn __kprobes
+t16_decode_push(kprobe_opcode_t insn, struct arch_specific_insn *asi,
+		const struct decode_header *d)
 {
 	/*
 	 * To simulate a PUSH we use a Thumb-2 "STMDB R9!, {registers}"
@@ -548,7 +558,7 @@ t16_decode_push(kprobe_opcode_t insn, struct arch_specific_insn *asi)
 	return INSN_GOOD;
 }
 
-void __kprobes
+static void __kprobes
 t16_emulate_pop_nopc(struct kprobe *p, struct pt_regs *regs)
 {
 	__asm__ __volatile__ (
@@ -564,7 +574,7 @@ t16_emulate_pop_nopc(struct kprobe *p, struct pt_regs *regs)
 		);
 }
 
-void __kprobes
+static void __kprobes
 t16_emulate_pop_pc(struct kprobe *p, struct pt_regs *regs)
 {
 	register unsigned long pc asm("r8");
@@ -584,8 +594,9 @@ t16_emulate_pop_pc(struct kprobe *p, struct pt_regs *regs)
 	bx_write_pc(pc, regs);
 }
 
-enum kprobe_insn __kprobes
-t16_decode_pop(kprobe_opcode_t insn, struct arch_specific_insn *asi)
+static enum kprobe_insn __kprobes
+t16_decode_pop(kprobe_opcode_t insn, struct arch_specific_insn *asi,
+		const struct decode_header *d)
 {
 	/*
 	 * To simulate a POP we use a Thumb-2 "LDMDB R9!, {registers}"
@@ -598,3 +609,57 @@ t16_decode_pop(kprobe_opcode_t insn, struct arch_specific_insn *asi)
 					 : t16_emulate_pop_nopc;
 	return INSN_GOOD;
 }
+
+const union decode_action kprobes_t16_actions[NUM_PROBES_T16_ACTIONS] = {
+	[PROBES_T16_ADD_SP] = {.handler = t16_simulate_add_sp_imm},
+	[PROBES_T16_CBZ] = {.handler = t16_simulate_cbz},
+	[PROBES_T16_SIGN_EXTEND] = {.handler = t16_emulate_loregs_rwflags},
+	[PROBES_T16_PUSH] = {.decoder = t16_decode_push},
+	[PROBES_T16_POP] = {.decoder = t16_decode_pop},
+	[PROBES_T16_SEV] = {.handler = kprobe_emulate_none},
+	[PROBES_T16_WFE] = {.handler = kprobe_simulate_nop},
+	[PROBES_T16_IT] = {.decoder = t16_decode_it},
+	[PROBES_T16_CMP] = {.handler = t16_emulate_loregs_rwflags},
+	[PROBES_T16_ADDSUB] = {.handler = t16_emulate_loregs_noitrwflags},
+	[PROBES_T16_LOGICAL] = {.handler = t16_emulate_loregs_noitrwflags},
+	[PROBES_T16_LDR_LIT] = {.handler = t16_simulate_ldr_literal},
+	[PROBES_T16_BLX] = {.handler = t16_simulate_bxblx},
+	[PROBES_T16_HIREGOPS] = {.decoder = t16_decode_hiregs},
+	[PROBES_T16_LDRHSTRH] = {.handler = t16_emulate_loregs_rwflags},
+	[PROBES_T16_LDRSTR] = {.handler = t16_simulate_ldrstr_sp_relative},
+	[PROBES_T16_ADR] = {.handler = t16_simulate_reladr},
+	[PROBES_T16_LDMSTM] = {.handler = t16_emulate_loregs_rwflags},
+	[PROBES_T16_BRANCH_COND] = {.decoder = t16_decode_cond_branch},
+	[PROBES_T16_BRANCH] = {.handler = t16_simulate_branch},
+};
+
+const union decode_action kprobes_t32_actions[NUM_PROBES_T32_ACTIONS] = {
+	[PROBES_T32_LDMSTM] = {.decoder = t32_decode_ldmstm},
+	[PROBES_T32_LDRDSTRD] = {.handler = t32_emulate_ldrdstrd},
+	[PROBES_T32_TABLE_BRANCH] = {.handler = t32_simulate_table_branch},
+	[PROBES_T32_TST] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
+	[PROBES_T32_MOV] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
+	[PROBES_T32_ADDSUB] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
+	[PROBES_T32_LOGICAL] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
+	[PROBES_T32_CMP] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
+	[PROBES_T32_ADDWSUBW_PC] = {.handler = t32_emulate_rd8pc16_noflags,},
+	[PROBES_T32_ADDWSUBW] = {.handler = t32_emulate_rd8rn16_noflags},
+	[PROBES_T32_MOVW] = {.handler = t32_emulate_rd8rn16_noflags},
+	[PROBES_T32_SAT] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
+	[PROBES_T32_BITFIELD] = {.handler = t32_emulate_rd8rn16_noflags},
+	[PROBES_T32_SEV] = {.handler = kprobe_emulate_none},
+	[PROBES_T32_WFE] = {.handler = kprobe_simulate_nop},
+	[PROBES_T32_MRS] = {.handler = t32_simulate_mrs},
+	[PROBES_T32_BRANCH_COND] = {.decoder = t32_decode_cond_branch},
+	[PROBES_T32_BRANCH] = {.handler = t32_simulate_branch},
+	[PROBES_T32_PLDI] = {.handler = kprobe_simulate_nop},
+	[PROBES_T32_LDR_LIT] = {.handler = t32_simulate_ldr_literal},
+	[PROBES_T32_LDRSTR] = {.handler = t32_emulate_ldrstr},
+	[PROBES_T32_SIGN_EXTEND] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
+	[PROBES_T32_MEDIA] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
+	[PROBES_T32_REVERSE] = {.handler = t32_emulate_rd8rn16_noflags},
+	[PROBES_T32_MUL_ADD] = {.handler = t32_emulate_rd8rn16rm0_rwflags},
+	[PROBES_T32_MUL_ADD2] = {.handler = t32_emulate_rd8rn16rm0ra12_noflags},
+	[PROBES_T32_MUL_ADD_LONG] = {
+		.handler = t32_emulate_rdlo12rdhi8rn16rm0_noflags},
+};