1 files changed, 73 insertions, 65 deletions

diff --git a/arch/ppc64/kernel/kprobes.c b/arch/ppc64/kernel/kprobes.c
index ed876a5178ae..511af54e6230 100644
--- a/arch/ppc64/kernel/kprobes.c
+++ b/arch/ppc64/kernel/kprobes.c
@@ -30,19 +30,14 @@
 #include <linux/config.h>
 #include <linux/kprobes.h>
 #include <linux/ptrace.h>
-#include <linux/spinlock.h>
 #include <linux/preempt.h>
 #include <asm/cacheflush.h>
 #include <asm/kdebug.h>
 #include <asm/sstep.h>
 
 static DECLARE_MUTEX(kprobe_mutex);
-
-static struct kprobe *current_kprobe;
-static unsigned long kprobe_status, kprobe_saved_msr;
-static struct kprobe *kprobe_prev;
-static unsigned long kprobe_status_prev, kprobe_saved_msr_prev;
-static struct pt_regs jprobe_saved_regs;
+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
 int __kprobes arch_prepare_kprobe(struct kprobe *p)
 {
@@ -108,20 +103,28 @@ static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
                 regs->nip = (unsigned long)p->ainsn.insn;
 }
 
-static inline void save_previous_kprobe(void)
+static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+        kcb->prev_kprobe.kp = kprobe_running();
+        kcb->prev_kprobe.status = kcb->kprobe_status;
+        kcb->prev_kprobe.saved_msr = kcb->kprobe_saved_msr;
+}
+
+static inline void restore_previous_kprobe(struct kprobe_ctlblk *kcb)
 {
-        kprobe_prev = current_kprobe;
-        kprobe_status_prev = kprobe_status;
-        kprobe_saved_msr_prev = kprobe_saved_msr;
+        __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
+        kcb->kprobe_status = kcb->prev_kprobe.status;
+        kcb->kprobe_saved_msr = kcb->prev_kprobe.saved_msr;
 }
 
-static inline void restore_previous_kprobe(void)
+static inline void set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
+                                struct kprobe_ctlblk *kcb)
 {
-        current_kprobe = kprobe_prev;
-        kprobe_status = kprobe_status_prev;
-        kprobe_saved_msr = kprobe_saved_msr_prev;
+        __get_cpu_var(current_kprobe) = p;
+        kcb->kprobe_saved_msr = regs->msr;
 }
 
+/* Called with kretprobe_lock held */
 void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
                                       struct pt_regs *regs)
 {
@@ -145,19 +148,24 @@ static inline int kprobe_handler(struct pt_regs *regs)
         struct kprobe *p;
         int ret = 0;
         unsigned int *addr = (unsigned int *)regs->nip;
+        struct kprobe_ctlblk *kcb;
+
+        /*
+         * We don't want to be preempted for the entire
+         * duration of kprobe processing
+         */
+        preempt_disable();
+        kcb = get_kprobe_ctlblk();
 
         /* Check we're not actually recursing */
         if (kprobe_running()) {
-                /* We *are* holding lock here, so this is safe.
-                   Disarm the probe we just hit, and ignore it. */
                 p = get_kprobe(addr);
                 if (p) {
                         kprobe_opcode_t insn = *p->ainsn.insn;
-                        if (kprobe_status == KPROBE_HIT_SS &&
+                        if (kcb->kprobe_status == KPROBE_HIT_SS &&
                                         is_trap(insn)) {
                                 regs->msr &= ~MSR_SE;
-                                regs->msr |= kprobe_saved_msr;
-                                unlock_kprobes();
+                                regs->msr |= kcb->kprobe_saved_msr;
                                 goto no_kprobe;
                         }
                         /* We have reentered the kprobe_handler(), since
@@ -166,27 +174,24 @@ static inline int kprobe_handler(struct pt_regs *regs)
                          * just single step on the instruction of the new probe
                          * without calling any user handlers.
                          */
-                        save_previous_kprobe();
-                        current_kprobe = p;
-                        kprobe_saved_msr = regs->msr;
+                        save_previous_kprobe(kcb);
+                        set_current_kprobe(p, regs, kcb);
+                        kcb->kprobe_saved_msr = regs->msr;
                         p->nmissed++;
                         prepare_singlestep(p, regs);
-                        kprobe_status = KPROBE_REENTER;
+                        kcb->kprobe_status = KPROBE_REENTER;
                         return 1;
                 } else {
-                        p = current_kprobe;
+                        p = __get_cpu_var(current_kprobe);
                         if (p->break_handler && p->break_handler(p, regs)) {
                                 goto ss_probe;
                         }
                 }
-                /* If it's not ours, can't be delete race, (we hold lock). */
                 goto no_kprobe;
         }
 
-        lock_kprobes();
         p = get_kprobe(addr);
         if (!p) {
-                unlock_kprobes();
                 if (*addr != BREAKPOINT_INSTRUCTION) {
                         /*
                          * PowerPC has multiple variants of the "trap"
@@ -209,24 +214,19 @@ static inline int kprobe_handler(struct pt_regs *regs)
                 goto no_kprobe;
         }
 
-        kprobe_status = KPROBE_HIT_ACTIVE;
-        current_kprobe = p;
-        kprobe_saved_msr = regs->msr;
+        kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+        set_current_kprobe(p, regs, kcb);
         if (p->pre_handler && p->pre_handler(p, regs))
                 /* handler has already set things up, so skip ss setup */
                 return 1;
 
 ss_probe:
         prepare_singlestep(p, regs);
-        kprobe_status = KPROBE_HIT_SS;
-        /*
-         * This preempt_disable() matches the preempt_enable_no_resched()
-         * in post_kprobe_handler().
-         */
-        preempt_disable();
+        kcb->kprobe_status = KPROBE_HIT_SS;
         return 1;
 
 no_kprobe:
+        preempt_enable_no_resched();
         return ret;
 }
 
@@ -251,9 +251,10 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         struct kretprobe_instance *ri = NULL;
         struct hlist_head *head;
         struct hlist_node *node, *tmp;
-        unsigned long orig_ret_address = 0;
+        unsigned long flags, orig_ret_address = 0;
         unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
 
+        spin_lock_irqsave(&kretprobe_lock, flags);
         head = kretprobe_inst_table_head(current);
 
         /*
@@ -292,12 +293,14 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
         regs->nip = orig_ret_address;
 
-        unlock_kprobes();
+        reset_current_kprobe();
+        spin_unlock_irqrestore(&kretprobe_lock, flags);
+        preempt_enable_no_resched();
 
         /*
          * By returning a non-zero value, we are telling
-         * kprobe_handler() that we have handled unlocking
-         * and re-enabling preemption.
+         * kprobe_handler() that we don't want the post_handler
+         * to run (and have re-enabled preemption)
          */
         return 1;
 }
@@ -323,23 +326,26 @@ static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
 
 static inline int post_kprobe_handler(struct pt_regs *regs)
 {
-        if (!kprobe_running())
+        struct kprobe *cur = kprobe_running();
+        struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+        if (!cur)
                 return 0;
 
-        if ((kprobe_status != KPROBE_REENTER) && current_kprobe->post_handler) {
-                kprobe_status = KPROBE_HIT_SSDONE;
-                current_kprobe->post_handler(current_kprobe, regs, 0);
+        if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
+                kcb->kprobe_status = KPROBE_HIT_SSDONE;
+                cur->post_handler(cur, regs, 0);
         }
 
-        resume_execution(current_kprobe, regs);
-        regs->msr |= kprobe_saved_msr;
+        resume_execution(cur, regs);
+        regs->msr |= kcb->kprobe_saved_msr;
 
         /*Restore back the original saved kprobes variables and continue. */
-        if (kprobe_status == KPROBE_REENTER) {
-                restore_previous_kprobe();
+        if (kcb->kprobe_status == KPROBE_REENTER) {
+                restore_previous_kprobe(kcb);
                 goto out;
         }
-        unlock_kprobes();
+        reset_current_kprobe();
 out:
         preempt_enable_no_resched();
 
@@ -354,19 +360,20 @@ out:
         return 1;
 }
 
-/* Interrupts disabled, kprobe_lock held. */
 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 {
-        if (current_kprobe->fault_handler
-            && current_kprobe->fault_handler(current_kprobe, regs, trapnr))
+        struct kprobe *cur = kprobe_running();
+        struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+        if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
                 return 1;
 
-        if (kprobe_status & KPROBE_HIT_SS) {
-                resume_execution(current_kprobe, regs);
+        if (kcb->kprobe_status & KPROBE_HIT_SS) {
+                resume_execution(cur, regs);
                 regs->msr &= ~MSR_SE;
-                regs->msr |= kprobe_saved_msr;
+                regs->msr |= kcb->kprobe_saved_msr;
 
-                unlock_kprobes();
+                reset_current_kprobe();
                 preempt_enable_no_resched();
         }
         return 0;
@@ -381,11 +388,6 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
         struct die_args *args = (struct die_args *)data;
         int ret = NOTIFY_DONE;
 
-        /*
-         * Interrupts are not disabled here.  We need to disable
-         * preemption, because kprobe_running() uses smp_processor_id().
-         */
-        preempt_disable();
         switch (val) {
         case DIE_BPT:
                 if (kprobe_handler(args->regs))
@@ -396,22 +398,25 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
                         ret = NOTIFY_STOP;
                 break;
         case DIE_PAGE_FAULT:
+                /* kprobe_running() needs smp_processor_id() */
+                preempt_disable();
                 if (kprobe_running() &&
                     kprobe_fault_handler(args->regs, args->trapnr))
                         ret = NOTIFY_STOP;
+                preempt_enable();
                 break;
         default:
                 break;
         }
-        preempt_enable_no_resched();
         return ret;
 }
 
 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();
 
-        memcpy(&jprobe_saved_regs, regs, sizeof(struct pt_regs));
+        memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs));
 
         /* setup return addr to the jprobe handler routine */
         regs->nip = (unsigned long)(((func_descr_t *)jp->entry)->entry);
@@ -431,12 +436,15 @@ void __kprobes jprobe_return_end(void)
 
 int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
 {
+        struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
         /*
          * FIXME - we should ideally be validating that we got here 'cos
          * of the "trap" in jprobe_return() above, before restoring the
          * saved regs...
          */
-        memcpy(regs, &jprobe_saved_regs, sizeof(struct pt_regs));
+        memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
+        preempt_enable_no_resched();
         return 1;
 }