[PATCH] Check if cpu can be onlined before calling smp_prepare_cpu()

[linux-2.6-omap-h63xx.git] / arch / i386 / kernel / kprobes.c

diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index 32b0c24ab9a6dcca721414a7027635aa06d2c828..7a59050242a7ca58f5786ba11e4cd5c83077a51a 100644 (file)
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -58,13 +58,14 @@ static inline int is_IF_modifier(kprobe_opcode_t opcode)
 
 int __kprobes arch_prepare_kprobe(struct kprobe *p)
 {
-       return 0;
-}
+       /* insn: must be on special executable page on i386. */
+       p->ainsn.insn = get_insn_slot();
+       if (!p->ainsn.insn)
+               return -ENOMEM;
 
-void __kprobes arch_copy_kprobe(struct kprobe *p)
-{
        memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
        p->opcode = *p->addr;
+       return 0;
 }
 
 void __kprobes arch_arm_kprobe(struct kprobe *p)
@@ -83,6 +84,9 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
 
 void __kprobes arch_remove_kprobe(struct kprobe *p)
 {
+       mutex_lock(&kprobe_mutex);
+       free_insn_slot(p->ainsn.insn);
+       mutex_unlock(&kprobe_mutex);
 }
 
 static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb)
@@ -119,7 +123,7 @@ static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
        if (p->opcode == BREAKPOINT_INSTRUCTION)
                regs->eip = (unsigned long)p->addr;
        else
-               regs->eip = (unsigned long)&p->ainsn.insn;
+               regs->eip = (unsigned long)p->ainsn.insn;
 }
 
 /* Called with kretprobe_lock held */
@@ -191,11 +195,24 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
                         */
                        save_previous_kprobe(kcb);
                        set_current_kprobe(p, regs, kcb);
-                       p->nmissed++;
+                       kprobes_inc_nmissed_count(p);
                        prepare_singlestep(p, regs);
                        kcb->kprobe_status = KPROBE_REENTER;
                        return 1;
                } else {
+                       if (regs->eflags & VM_MASK) {
+                       /* We are in virtual-8086 mode. Return 0 */
+                               goto no_kprobe;
+                       }
+                       if (*addr != BREAKPOINT_INSTRUCTION) {
+                       /* The breakpoint instruction was removed by
+                        * another cpu right after we hit, no further
+                        * handling of this interrupt is appropriate
+                        */
+                               regs->eip -= sizeof(kprobe_opcode_t);
+                               ret = 1;
+                               goto no_kprobe;
+                       }
                        p = __get_cpu_var(current_kprobe);
                        if (p->break_handler && p->break_handler(p, regs)) {
                                goto ss_probe;
@@ -346,7 +363,7 @@ static void __kprobes resume_execution(struct kprobe *p,
 {
        unsigned long *tos = (unsigned long *)&regs->esp;
        unsigned long next_eip = 0;
-       unsigned long copy_eip = (unsigned long)&p->ainsn.insn;
+       unsigned long copy_eip = (unsigned long)p->ainsn.insn;
        unsigned long orig_eip = (unsigned long)p->addr;
 
        switch (p->ainsn.insn[0]) {