[IA64] enable trap code on slot 1

Because slot 1 of one instr bundle crosses border of two consecutive
8-bytes, kprobe on slot 1 is disabled. This patch enables kprobe on
slot1, it only replaces higher 8-bytes of the instruction bundle and
changes the exception code to ignore the low 12 bits of the break
number (which is across the border in the lower 8-bytes of the bundle).

For those instructions which must execute regardless qp bits,
kprobe on slot 1 is still disabled.

Signed-off-by: bibo,mao <bibo.mao@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

4 files changed, 42 insertions, 17 deletions

diff --git a/arch/ia64/kernel/jprobes.S b/arch/ia64/kernel/jprobes.S
index 5cd6226f44f2..621630256c4a 100644
--- a/arch/ia64/kernel/jprobes.S
+++ b/arch/ia64/kernel/jprobes.S
@@ -45,13 +45,14 @@
  * to the correct location.
  */
 #include <asm/asmmacro.h>
+#include <asm-ia64/break.h>
 
         /*
          * void jprobe_break(void)
          */
         .section .kprobes.text, "ax"
 ENTRY(jprobe_break)
-        break.m 0x80300
+        break.m __IA64_BREAK_JPROBE
 END(jprobe_break)
 
         /*
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 76e778951e20..8406d24d516b 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -88,6 +88,7 @@ static void __kprobes update_kprobe_inst_flag(uint template, uint  slot,
 {
         p->ainsn.inst_flag = 0;
         p->ainsn.target_br_reg = 0;
+        p->ainsn.slot = slot;
 
         /* Check for Break instruction
          * Bits 37:40 Major opcode to be zero
@@ -296,12 +297,6 @@ static int __kprobes valid_kprobe_addr(int template, int slot,
                 return -EINVAL;
         }
 
-        if (slot == 1 && bundle_encoding[template][1] != L) {
-                printk(KERN_WARNING "Inserting kprobes on slot #1 "
-                       "is not supported\n");
-                return -EINVAL;
-        }
-
         return 0;
 }
 
@@ -458,23 +453,49 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 
 void __kprobes arch_arm_kprobe(struct kprobe *p)
 {
-        unsigned long addr = (unsigned long)p->addr;
-        unsigned long arm_addr = addr & ~0xFULL;
+        unsigned long arm_addr;
+        bundle_t *src, *dest;
+
+        arm_addr = ((unsigned long)p->addr) & ~0xFUL;
+        dest = &((kprobe_opcode_t *)arm_addr)->bundle;
+        src = &p->opcode.bundle;
 
         flush_icache_range((unsigned long)p->ainsn.insn,
                         (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
-        memcpy((char *)arm_addr, &p->opcode, sizeof(kprobe_opcode_t));
+        switch (p->ainsn.slot) {
+                case 0:
+                        dest->quad0.slot0 = src->quad0.slot0;
+                        break;
+                case 1:
+                        dest->quad1.slot1_p1 = src->quad1.slot1_p1;
+                        break;
+                case 2:
+                        dest->quad1.slot2 = src->quad1.slot2;
+                        break;
+        }
         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
 }
 
 void __kprobes arch_disarm_kprobe(struct kprobe *p)
 {
-        unsigned long addr = (unsigned long)p->addr;
-        unsigned long arm_addr = addr & ~0xFULL;
+        unsigned long arm_addr;
+        bundle_t *src, *dest;
 
+        arm_addr = ((unsigned long)p->addr) & ~0xFUL;
+        dest = &((kprobe_opcode_t *)arm_addr)->bundle;
         /* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
-        memcpy((char *) arm_addr, (char *) p->ainsn.insn,
-                                         sizeof(kprobe_opcode_t));
+        src = &p->ainsn.insn->bundle;
+        switch (p->ainsn.slot) {
+                case 0:
+                        dest->quad0.slot0 = src->quad0.slot0;
+                        break;
+                case 1:
+                        dest->quad1.slot1_p1 = src->quad1.slot1_p1;
+                        break;
+                case 2:
+                        dest->quad1.slot2 = src->quad1.slot2;
+                        break;
+        }
         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
 }
 
@@ -807,7 +828,9 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
         switch(val) {
         case DIE_BREAK:
                 /* err is break number from ia64_bad_break() */
-                if (args->err == 0x80200 || args->err == 0x80300 || args->err == 0)
+                if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
+                        || args->err == __IA64_BREAK_JPROBE
+                        || args->err == 0)
                         if (pre_kprobes_handler(args))
                                 ret = NOTIFY_STOP;
                 break;
diff --git a/include/asm-ia64/break.h b/include/asm-ia64/break.h
index 8167828edc4b..f03402039896 100644
--- a/include/asm-ia64/break.h
+++ b/include/asm-ia64/break.h
@@ -12,8 +12,8 @@
  * OS-specific debug break numbers:
  */
 #define __IA64_BREAK_KDB                0x80100
-#define __IA64_BREAK_KPROBE             0x80200
-#define __IA64_BREAK_JPROBE             0x80300
+#define __IA64_BREAK_KPROBE             0x81000 /* .. 0x81fff */
+#define __IA64_BREAK_JPROBE             0x82000
 
 /*
  * OS-specific break numbers:
diff --git a/include/asm-ia64/kprobes.h b/include/asm-ia64/kprobes.h
index 1b45b71c79b9..828ae00e47c1 100644
--- a/include/asm-ia64/kprobes.h
+++ b/include/asm-ia64/kprobes.h
@@ -115,6 +115,7 @@ struct arch_specific_insn {
  #define INST_FLAG_BREAK_INST                   4
         unsigned long inst_flag;
         unsigned short target_br_reg;
+        unsigned short slot;
 };
 
 extern int kprobe_exceptions_notify(struct notifier_block *self,