1 files changed, 43 insertions, 48 deletions

diff --git a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c
index 8e75ed762fd8..ae221f0d4a6f 100644
--- a/arch/sparc64/kernel/kprobes.c
+++ b/arch/sparc64/kernel/kprobes.c
@@ -45,7 +45,11 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 int __kprobes arch_prepare_kprobe(struct kprobe *p)
 {
         p->ainsn.insn[0] = *p->addr;
+        flushi(&p->ainsn.insn[0]);
+
         p->ainsn.insn[1] = BREAKPOINT_INSTRUCTION_2;
+        flushi(&p->ainsn.insn[1]);
+
         p->opcode = *p->addr;
         return 0;
 }
@@ -185,16 +189,19 @@ no_kprobe:
 /* If INSN is a relative control transfer instruction,
  * return the corrected branch destination value.
  *
- * The original INSN location was REAL_PC, it actually
- * executed at PC and produced destination address NPC.
+ * regs->tpc and regs->tnpc still hold the values of the
+ * program counters at the time of trap due to the execution
+ * of the BREAKPOINT_INSTRUCTION_2 at p->ainsn.insn[1]
+ * 
  */
-static unsigned long __kprobes relbranch_fixup(u32 insn, unsigned long real_pc,
-                                               unsigned long pc,
-                                               unsigned long npc)
+static unsigned long __kprobes relbranch_fixup(u32 insn, struct kprobe *p,
+                                               struct pt_regs *regs)
 {
+        unsigned long real_pc = (unsigned long) p->addr;
+
         /* Branch not taken, no mods necessary.  */
-        if (npc == pc + 0x4UL)
-                return real_pc + 0x4UL;
+        if (regs->tnpc == regs->tpc + 0x4UL)
+                return real_pc + 0x8UL;
 
         /* The three cases are call, branch w/prediction,
          * and traditional branch.
@@ -202,14 +209,21 @@ static unsigned long __kprobes relbranch_fixup(u32 insn, unsigned long real_pc,
         if ((insn & 0xc0000000) == 0x40000000 ||
             (insn & 0xc1c00000) == 0x00400000 ||
             (insn & 0xc1c00000) == 0x00800000) {
+                unsigned long ainsn_addr;
+
+                ainsn_addr = (unsigned long) &p->ainsn.insn[0];
+
                 /* The instruction did all the work for us
                  * already, just apply the offset to the correct
                  * instruction location.
                  */
-                return (real_pc + (npc - pc));
+                return (real_pc + (regs->tnpc - ainsn_addr));
         }
 
-        return real_pc + 0x4UL;
+        /* It is jmpl or some other absolute PC modification instruction,
+         * leave NPC as-is.
+         */
+        return regs->tnpc;
 }
 
 /* If INSN is an instruction which writes it's PC location
@@ -220,12 +234,12 @@ static void __kprobes retpc_fixup(struct pt_regs *regs, u32 insn,
 {
         unsigned long *slot = NULL;
 
-        /* Simplest cast is call, which always uses %o7 */
+        /* Simplest case is 'call', which always uses %o7 */
         if ((insn & 0xc0000000) == 0x40000000) {
                 slot = &regs->u_regs[UREG_I7];
         }
 
-        /* Jmpl encodes the register inside of the opcode */
+        /* 'jmpl' encodes the register inside of the opcode */
         if ((insn & 0xc1f80000) == 0x81c00000) {
                 unsigned long rd = ((insn >> 25) & 0x1f);
 
@@ -247,11 +261,11 @@ static void __kprobes retpc_fixup(struct pt_regs *regs, u32 insn,
 
 /*
  * Called after single-stepping.  p->addr is the address of the
- * instruction whose first byte has been replaced by the breakpoint
+ * instruction which has been replaced by the breakpoint
  * instruction.  To avoid the SMP problems that can occur when we
  * temporarily put back the original opcode to single-step, we
  * single-stepped a copy of the instruction.  The address of this
- * copy is p->ainsn.insn.
+ * copy is &p->ainsn.insn[0].
  *
  * This function prepares to return from the post-single-step
  * breakpoint trap.
@@ -261,11 +275,11 @@ static void __kprobes resume_execution(struct kprobe *p,
 {
         u32 insn = p->ainsn.insn[0];
 
+        regs->tnpc = relbranch_fixup(insn, p, regs);
+
+        /* This assignment must occur after relbranch_fixup() */
         regs->tpc = kcb->kprobe_orig_tnpc;
-        regs->tnpc = relbranch_fixup(insn,
-                                     (unsigned long) p->addr,
-                                     (unsigned long) &p->ainsn.insn[0],
-                                     regs->tnpc);
+
         retpc_fixup(regs, insn, (unsigned long) p->addr);
 
         regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
@@ -430,17 +444,8 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
         struct jprobe *jp = container_of(p, struct jprobe, kp);
         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 
-        kcb->jprobe_saved_regs_location = regs;
         memcpy(&(kcb->jprobe_saved_regs), regs, sizeof(*regs));
 
-        /* Save a whole stack frame, this gets arguments
-         * pushed onto the stack after using up all the
-         * arg registers.
-         */
-        memcpy(&(kcb->jprobe_saved_stack),
-               (char *) (regs->u_regs[UREG_FP] + STACK_BIAS),
-               sizeof(kcb->jprobe_saved_stack));
-
         regs->tpc  = (unsigned long) jp->entry;
         regs->tnpc = ((unsigned long) jp->entry) + 0x4UL;
         regs->tstate |= TSTATE_PIL;
@@ -450,10 +455,19 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
 
 void __kprobes jprobe_return(void)
 {
-        __asm__ __volatile__(
-                ".globl jprobe_return_trap_instruction\n"
+        struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+        register unsigned long orig_fp asm("g1");
+
+        orig_fp = kcb->jprobe_saved_regs.u_regs[UREG_FP];
+        __asm__ __volatile__("\n"
+"1:     cmp             %%sp, %0\n\t"
+        "blu,a,pt       %%xcc, 1b\n\t"
+        " restore\n\t"
+        ".globl         jprobe_return_trap_instruction\n"
 "jprobe_return_trap_instruction:\n\t"
-                "ta 0x70");
+        "ta             0x70"
+        : /* no outputs */
+        : "r" (orig_fp));
 }
 
 extern void jprobe_return_trap_instruction(void);
@@ -466,26 +480,7 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 
         if (addr == (u32 *) jprobe_return_trap_instruction) {
-                if (kcb->jprobe_saved_regs_location != regs) {
-                        printk("JPROBE: Current regs (%p) does not match "
-                               "saved regs (%p).\n",
-                               regs, kcb->jprobe_saved_regs_location);
-                        printk("JPROBE: Saved registers\n");
-                        __show_regs(kcb->jprobe_saved_regs_location);
-                        printk("JPROBE: Current registers\n");
-                        __show_regs(regs);
-                        BUG();
-                }
-                /* Restore old register state.  Do pt_regs
-                 * first so that UREG_FP is the original one for
-                 * the stack frame restore.
-                 */
                 memcpy(regs, &(kcb->jprobe_saved_regs), sizeof(*regs));
-
-                memcpy((char *) (regs->u_regs[UREG_FP] + STACK_BIAS),
-                       &(kcb->jprobe_saved_stack),
-                       sizeof(kcb->jprobe_saved_stack));
-
                 preempt_enable_no_resched();
                 return 1;
         }