[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>

diff --git a/arch/ia64/kernel/jprobes.S b/arch/ia64/kernel/jprobes.S
index 5cd6226f44f291c2a9a4fd2fa42374148fc65ab9..621630256c4aa053b30dbb6e54d56e95dfd0e842 100644 (file)
--- 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 76e778951e20820208b7dea7ecc88c94e375d311..8406d24d516bc8a6d9813b6dff61b9c74d6e0a33 100644 (file)
--- 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 8167828edc4ba379d6381a678974d908e0c281dc..f034020398962d34987431971c4f9c33006597aa 100644 (file)
--- 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 1b45b71c79b98bfe0c0f9bc51855920e3b0b35a0..828ae00e47c1328e172cae15788dd73953f96de3 100644 (file)
--- 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,