ARM: kprobes: Remove redundant condition checks from simulation routines

Now we have the framework code handling conditionally executed
instructions we can remove redundant checks in individual simulation
routines.

Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>

1 files changed, 3 insertions, 27 deletions

diff --git a/arch/arm/kernel/kprobes-decode.c b/arch/arm/kernel/kprobes-decode.c
index 2e84169b9e91..f52fac0c59f0 100644
--- a/arch/arm/kernel/kprobes-decode.c
+++ b/arch/arm/kernel/kprobes-decode.c
@@ -71,10 +71,6 @@
 #define PSR_fs  (PSR_f|PSR_s)
 
 #define KPROBE_RETURN_INSTRUCTION       0xe1a0f00e      /* mov pc, lr */
-#define SET_R0_TRUE_INSTRUCTION         0xe3a00001      /* mov  r0, #1 */
-
-#define truecc_insn(insn)       (((insn) & 0xf0000000) | \
-                                 (SET_R0_TRUE_INSTRUCTION & 0x0fffffff))
 
 typedef long (insn_0arg_fn_t)(void);
 typedef long (insn_1arg_fn_t)(long);
@@ -419,14 +415,10 @@ insnslot_llret_4arg_rwflags(long r0, long r1, long r2, long r3, long *cpsr,
 
 static void __kprobes simulate_bbl(struct kprobe *p, struct pt_regs *regs)
 {
-        insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
         kprobe_opcode_t insn = p->opcode;
         long iaddr = (long)p->addr;
         int disp  = branch_displacement(insn);
 
-        if (!insnslot_1arg_rflags(0, regs->ARM_cpsr, i_fn))
-                return;
-
         if (insn & (1 << 24))
                 regs->ARM_lr = iaddr + 4;
 
@@ -446,14 +438,10 @@ static void __kprobes simulate_blx1(struct kprobe *p, struct pt_regs *regs)
 
 static void __kprobes simulate_blx2bx(struct kprobe *p, struct pt_regs *regs)
 {
-        insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
         kprobe_opcode_t insn = p->opcode;
         int rm = insn & 0xf;
         long rmv = regs->uregs[rm];
 
-        if (!insnslot_1arg_rflags(0, regs->ARM_cpsr, i_fn))
-                return;
-
         if (insn & (1 << 5))
                 regs->ARM_lr = (long)p->addr + 4;
 
@@ -465,7 +453,6 @@ static void __kprobes simulate_blx2bx(struct kprobe *p, struct pt_regs *regs)
 
 static void __kprobes simulate_ldm1stm1(struct kprobe *p, struct pt_regs *regs)
 {
-        insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
         kprobe_opcode_t insn = p->opcode;
         int rn = (insn >> 16) & 0xf;
         int lbit = insn & (1 << 20);
@@ -476,9 +463,6 @@ static void __kprobes simulate_ldm1stm1(struct kprobe *p, struct pt_regs *regs)
         int reg_bit_vector;
         int reg_count;
 
-        if (!insnslot_1arg_rflags(0, regs->ARM_cpsr, i_fn))
-                return;
-
         reg_count = 0;
         reg_bit_vector = insn & 0xffff;
         while (reg_bit_vector) {
@@ -510,11 +494,6 @@ static void __kprobes simulate_ldm1stm1(struct kprobe *p, struct pt_regs *regs)
 
 static void __kprobes simulate_stm1_pc(struct kprobe *p, struct pt_regs *regs)
 {
-        insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];
-
-        if (!insnslot_1arg_rflags(0, regs->ARM_cpsr, i_fn))
-                return;
-
         regs->ARM_pc = (long)p->addr + str_pc_offset;
         simulate_ldm1stm1(p, regs);
         regs->ARM_pc = (long)p->addr + 4;
@@ -1056,9 +1035,8 @@ space_cccc_000x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
                 /* BLX(2) : cccc 0001 0010 xxxx xxxx xxxx 0011 xxxx */
                 /* BX     : cccc 0001 0010 xxxx xxxx xxxx 0001 xxxx */
                 if ((insn & 0x0ff000d0) == 0x01200010) {
-                        asi->insn[0] = truecc_insn(insn);
                         asi->insn_handler = simulate_blx2bx;
-                        return INSN_GOOD;
+                        return INSN_GOOD_NO_SLOT;
                 }
 
                 /* CLZ : cccc 0001 0110 xxxx xxxx xxxx 0001 xxxx */
@@ -1333,10 +1311,9 @@ space_cccc_100x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
 
         /* LDM(1) : cccc 100x x0x1 xxxx xxxx xxxx xxxx xxxx */
         /* STM(1) : cccc 100x x0x0 xxxx xxxx xxxx xxxx xxxx */
-        asi->insn[0] = truecc_insn(insn);
         asi->insn_handler = ((insn & 0x108000) == 0x008000) ? /* STM & R15 */
                                 simulate_stm1_pc : simulate_ldm1stm1;
-        return INSN_GOOD;
+        return INSN_GOOD_NO_SLOT;
 }
 
 static enum kprobe_insn __kprobes
@@ -1344,9 +1321,8 @@ space_cccc_101x(kprobe_opcode_t insn, struct arch_specific_insn *asi)
 {
         /* B  : cccc 1010 xxxx xxxx xxxx xxxx xxxx xxxx */
         /* BL : cccc 1011 xxxx xxxx xxxx xxxx xxxx xxxx */
-        asi->insn[0] = truecc_insn(insn);
         asi->insn_handler = simulate_bbl;
-        return INSN_GOOD;
+        return INSN_GOOD_NO_SLOT;
 }
 
 static enum kprobe_insn __kprobes