2 files changed, 58 insertions, 2 deletions

diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 5d5344681555..51bc08bd0466 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -120,6 +120,41 @@ static void update_kprobe_inst_flag(uint template, uint  slot, uint major_opcode
 }
 
 /*
+ * In this function we check to see if the instruction
+ * (qp) cmpx.crel.ctype p1,p2=r2,r3
+ * on which we are inserting kprobe is cmp instruction
+ * with ctype as unc.
+ */
+static uint is_cmp_ctype_unc_inst(uint template, uint slot, uint major_opcode,
+unsigned long kprobe_inst)
+{
+        cmp_inst_t cmp_inst;
+        uint ctype_unc = 0;
+
+        if (!((bundle_encoding[template][slot] == I) ||
+                (bundle_encoding[template][slot] == M)))
+                goto out;
+
+        if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
+                (major_opcode == 0xE)))
+                goto out;
+
+        cmp_inst.l = kprobe_inst;
+        if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
+                /* Integere compare - Register Register (A6 type)*/
+                if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
+                                &&(cmp_inst.f.c == 1))
+                        ctype_unc = 1;
+        } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
+                /* Integere compare - Immediate Register (A8 type)*/
+                if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
+                        ctype_unc = 1;
+        }
+out:
+        return ctype_unc;
+}
+
+/*
  * In this function we override the bundle with
  * the break instruction at the given slot.
  */
@@ -131,9 +166,13 @@ static void prepare_break_inst(uint template, uint  slot, uint major_opcode,
 
         /*
          * Copy the original kprobe_inst qualifying predicate(qp)
-         * to the break instruction
+         * to the break instruction iff !is_cmp_ctype_unc_inst
+         * because for cmp instruction with ctype equal to unc,
+         * which is a special instruction always needs to be
+         * executed regradless of qp
          */
-        break_inst |= (0x3f & kprobe_inst);
+        if (!is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst))
+                break_inst |= (0x3f & kprobe_inst);
 
         switch (slot) {
           case 0:
diff --git a/include/asm-ia64/kprobes.h b/include/asm-ia64/kprobes.h
index cec4d9958307..7b700035e36d 100644
--- a/include/asm-ia64/kprobes.h
+++ b/include/asm-ia64/kprobes.h
@@ -30,6 +30,23 @@
 
 #define BREAK_INST      (long)(__IA64_BREAK_KPROBE << 6)
 
+typedef union cmp_inst {
+        struct {
+        unsigned long long qp : 6;
+        unsigned long long p1 : 6;
+        unsigned long long c  : 1;
+        unsigned long long r2 : 7;
+        unsigned long long r3 : 7;
+        unsigned long long p2 : 6;
+        unsigned long long ta : 1;
+        unsigned long long x2 : 2;
+        unsigned long long tb : 1;
+        unsigned long long opcode : 4;
+        unsigned long long reserved : 23;
+        }f;
+        unsigned long long l;
+} cmp_inst_t;
+
 struct kprobe;
 
 typedef struct _bundle {