20 files changed, 528 insertions, 353 deletions

diff --git a/arch/arm/include/asm/kprobes.h b/arch/arm/include/asm/kprobes.h
index bb8a19bd5822..e46bdd0097eb 100644
--- a/arch/arm/include/asm/kprobes.h
+++ b/arch/arm/include/asm/kprobes.h
@@ -39,10 +39,13 @@ typedef u32 kprobe_opcode_t;
 struct kprobe;
 typedef void (kprobe_insn_handler_t)(struct kprobe *, struct pt_regs *);
 
+typedef unsigned long (kprobe_check_cc)(unsigned long);
+
 /* Architecture specific copy of original instruction. */
 struct arch_specific_insn {
         kprobe_opcode_t         *insn;
         kprobe_insn_handler_t   *insn_handler;
+        kprobe_check_cc         *insn_check_cc;
 };
 
 struct prev_kprobe {
diff --git a/arch/arm/kernel/kprobes-decode.c b/arch/arm/kernel/kprobes-decode.c
index 23891317dc4b..15eeff6aea0e 100644
--- a/arch/arm/kernel/kprobes-decode.c
+++ b/arch/arm/kernel/kprobes-decode.c
@@ -34,9 +34,6 @@
  *
  *   *) If the PC is written to by the instruction, the
  *      instruction must be fully simulated in software.
- *      If it is a conditional instruction, the handler
- *      will use insn[0] to copy its condition code to
- *      set r0 to 1 and insn[1] to "mov pc, lr" to return.
  *
  *   *) Otherwise, a modified form of the instruction is
  *      directly executed.  Its handler calls the
@@ -68,13 +65,17 @@
 
 #define branch_displacement(insn) sign_extend(((insn) & 0xffffff) << 2, 25)
 
+#define is_r15(insn, bitpos) (((insn) & (0xf << bitpos)) == (0xf << bitpos))
+
+/*
+ * Test if load/store instructions writeback the address register.
+ * if P (bit 24) == 0 or W (bit 21) == 1
+ */
+#define is_writeback(insn) ((insn ^ 0x01000000) & 0x01200000)
+
 #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 +420,10 @@ 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 +443,10 @@ 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;
 
@@ -463,9 +456,16 @@ static void __kprobes simulate_blx2bx(struct kprobe *p, struct pt_regs *regs)
                 regs->ARM_cpsr |= PSR_T_BIT;
 }
 
+static void __kprobes simulate_mrs(struct kprobe *p, struct pt_regs *regs)
+{
+        kprobe_opcode_t insn = p->opcode;
+        int rd = (insn >> 12) & 0xf;
+        unsigned long mask = 0xf8ff03df; /* Mask out execution state */
+        regs->uregs[rd] = regs->ARM_cpsr & mask;
+}
+
 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 +476,6 @@ 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 +507,6 @@ 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;
@@ -525,24 +517,16 @@ static void __kprobes simulate_mov_ipsp(struct kprobe *p, struct pt_regs *regs)
         regs->uregs[12] = regs->uregs[13];
 }
 
-static void __kprobes emulate_ldcstc(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;
-        long rnv = regs->uregs[rn];
-
-        /* Save Rn in case of writeback. */
-        regs->uregs[rn] = insnslot_1arg_rflags(rnv, regs->ARM_cpsr, i_fn);
-}
-