3 files changed, 75 insertions, 122 deletions

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 75e0cd847bd6..2941b32ea666 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -593,6 +593,34 @@ static unsigned long ptrace_get_dr7(struct perf_event *bp[])
         return dr7;
 }
 
+static struct perf_event *
+ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
+                         struct task_struct *tsk)
+{
+        int err;
+        int gen_len, gen_type;
+        DEFINE_BREAKPOINT_ATTR(attr);
+
+        /*
+         * We shoud have at least an inactive breakpoint at this
+         * slot. It means the user is writing dr7 without having
+         * written the address register first
+         */
+        if (!bp)
+                return ERR_PTR(-EINVAL);
+
+        err = arch_bp_generic_fields(len, type, &gen_len, &gen_type);
+        if (err)
+                return ERR_PTR(err);
+
+        attr = bp->attr;
+        attr.bp_len = gen_len;
+        attr.bp_type = gen_type;
+        attr.disabled = 0;
+
+        return modify_user_hw_breakpoint(bp, &attr, bp->callback, tsk);
+}
+
 /*
  * Handle ptrace writes to debug register 7.
  */
@@ -603,7 +631,6 @@ static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
         int i, orig_ret = 0, rc = 0;
         int enabled, second_pass = 0;
         unsigned len, type;
-        int gen_len, gen_type;
         struct perf_event *bp;
 
         data &= ~DR_CONTROL_RESERVED;
@@ -634,33 +661,12 @@ restore:
                         continue;
                 }
 
-                /*
-                 * We shoud have at least an inactive breakpoint at this
-                 * slot. It means the user is writing dr7 without having
-                 * written the address register first
-                 */
-                if (!bp) {
-                        rc = -EINVAL;
-                        break;
-                }
-
-                rc = arch_bp_generic_fields(len, type, &gen_len, &gen_type);
-                if (rc)
-                        break;
-
-                /*
-                 * This is a temporary thing as bp is unregistered/registered
-                 * to simulate modification
-                 */
-                bp = modify_user_hw_breakpoint(bp, bp->attr.bp_addr, gen_len,
-                                               gen_type, bp->callback,
-                                               tsk, true);
-                thread->ptrace_bps[i] = NULL;
+                bp = ptrace_modify_breakpoint(bp, len, type, tsk);
 
                 /* Incorrect bp, or we have a bug in bp API */
                 if (IS_ERR(bp)) {
                         rc = PTR_ERR(bp);
-                        bp = NULL;
+                        thread->ptrace_bps[i] = NULL;
                         break;
                 }
                 thread->ptrace_bps[i] = bp;
@@ -707,24 +713,26 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
 {
         struct perf_event *bp;
         struct thread_struct *t = &tsk->thread;
+        DEFINE_BREAKPOINT_ATTR(attr);
 
         if (!t->ptrace_bps[nr]) {
                 /*
                  * Put stub len and type to register (reserve) an inactive but
                  * correct bp
                  */
-                bp = register_user_hw_breakpoint(addr, HW_BREAKPOINT_LEN_1,
-                                                 HW_BREAKPOINT_W,
-                                                 ptrace_triggered, tsk,
-                                                 false);
+                attr.bp_addr = addr;
+                attr.bp_len = HW_BREAKPOINT_LEN_1;
+                attr.bp_type = HW_BREAKPOINT_W;
+                attr.disabled = 1;
+
+                bp = register_user_hw_breakpoint(&attr, ptrace_triggered, tsk);
         } else {
                 bp = t->ptrace_bps[nr];
                 t->ptrace_bps[nr] = NULL;
-                bp = modify_user_hw_breakpoint(bp, addr, bp->attr.bp_len,
-                                               bp->attr.bp_type,
-                                               bp->callback,
-                                               tsk,
-                                               bp->attr.disabled);
+
+                attr = bp->attr;
+                attr.bp_addr = addr;
+                bp = modify_user_hw_breakpoint(bp, &attr, bp->callback, tsk);
         }
         /*
          * CHECKME: the previous code returned -EIO if the addr wasn't a
diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h
index c9f7f7c7b0e0..5da472e434b7 100644
--- a/include/linux/hw_breakpoint.h
+++ b/include/linux/hw_breakpoint.h
@@ -20,6 +20,14 @@ enum {
 
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 
+/* As it's for in-kernel or ptrace use, we want it to be pinned */
+#define DEFINE_BREAKPOINT_ATTR(name)    \
+struct perf_event_attr name = {         \
+        .type = PERF_TYPE_BREAKPOINT,   \
+        .size = sizeof(name),           \
+        .pinned = 1,                    \
+};
+
 static inline unsigned long hw_breakpoint_addr(struct perf_event *bp)
 {
         return bp->attr.bp_addr;
@@ -36,22 +44,16 @@ static inline int hw_breakpoint_len(struct perf_event *bp)
 }
 
 extern struct perf_event *
-register_user_hw_breakpoint(unsigned long addr,
-                            int len,
-                            int type,
+register_user_hw_breakpoint(struct perf_event_attr *attr,
                             perf_callback_t triggered,
-                            struct task_struct *tsk,
-                            bool active);
+                            struct task_struct *tsk);
 
 /* FIXME: only change from the attr, and don't unregister */
 extern struct perf_event *
 modify_user_hw_breakpoint(struct perf_event *bp,
-                          unsigned long addr,
-                          int len,
-                          int type,
+                          struct perf_event_attr *attr,
                           perf_callback_t triggered,
-                          struct task_struct *tsk,
-                          bool active);
+                          struct task_struct *tsk);
 
 /*
  * Kernel breakpoints are not associated with any particular thread.
@@ -89,20 +91,14 @@ static inline struct arch_hw_breakpoint *counter_arch_bp(struct perf_event *bp)
 #else /* !CONFIG_HAVE_HW_BREAKPOINT */
 
 static inline struct perf_event *
-register_user_hw_breakpoint(unsigned long addr,
-                            int len,
-                            int type,
+register_user_hw_breakpoint(struct perf_event_attr *attr,
                             perf_callback_t triggered,
-                            struct task_struct *tsk,
-                            bool active)                { return NULL; }
+                            struct task_struct *tsk)    { return NULL; }
 static inline struct perf_event *
 modify_user_hw_breakpoint(struct perf_event *bp,
-                          unsigned long addr,
-                          int len,
-                          int type,
+                          struct perf_event_attr *attr,
                           perf_callback_t triggered,
-                          struct task_struct *tsk,
-                          bool active)                  { return NULL; }
+                          struct task_struct *tsk)      { return NULL; }
 static inline struct perf_event *
 register_wide_hw_breakpoint_cpu(unsigned long addr,
                                 int len,
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
index 32e1018191be..2a47514f12fd 100644
--- a/kernel/hw_breakpoint.c
+++ b/kernel/hw_breakpoint.c
@@ -289,90 +289,32 @@ int register_perf_hw_breakpoint(struct perf_event *bp)
         return __register_perf_hw_breakpoint(bp);
 }
 
-/*
- * Register a breakpoint bound to a task and a given cpu.
- * If cpu is -1, the breakpoint is active for the task in every cpu
- * If the task is -1, the breakpoint is active for every tasks in the given
- * cpu.
- */
-static struct perf_event *
-register_user_hw_breakpoint_cpu(unsigned long addr,
-                                int len,
-                                int type,
-                                perf_callback_t triggered,
-                                pid_t pid,
-                                int cpu,
-                                bool active)
-{
-        struct perf_event_attr *attr;
-        struct perf_event *bp;
-
-        attr = kzalloc(sizeof(*attr), GFP_KERNEL);
-        if (!attr)
-                return ERR_PTR(-ENOMEM);
-
-        attr->type = PERF_TYPE_BREAKPOINT;
-        attr->size = sizeof(*attr);
-        attr->bp_addr = addr;
-        attr->bp_len = len;
-        attr->bp_type = type;
-        /*
-         * Such breakpoints are used by debuggers to trigger signals when
-         * we hit the excepted memory op. We can't miss such events, they
-         * must be pinned.
-         */
-        attr->pinned = 1;
-
-        if (!active)
-                attr->disabled = 1;
-
-        bp = perf_event_create_kernel_counter(attr, cpu, pid, triggered);
-        kfree(attr);
-
-        return bp;
-}
-
 /**
  * register_user_hw_breakpoint - register a hardware breakpoint for user space
- * @addr: is the memory address that triggers the breakpoint
- * @len: the length of the access to the memory (1 byte, 2 bytes etc...)
- * @type: the type of the access to the memory (read/write/exec)
+ * @attr: breakpoint attributes
  * @triggered: callback to trigger when we hit the breakpoint
  * @tsk: pointer to 'task_struct' of the process to which the address belongs
- * @active: should we activate it while registering it
- *
  */
 struct perf_event *
-register_user_hw_breakpoint(unsigned long addr,
-                            int len,
-                            int type,
+register_user_hw_breakpoint(struct perf_event_attr *attr,
                             perf_callback_t triggered,
-                            struct task_struct *tsk,
-                            bool active)
+                            struct task_struct *tsk)
 {
-        return register_user_hw_breakpoint_cpu(addr, len, type, triggered,
-                                               tsk->pid, -1, active);
+        return perf_event_create_kernel_counter(attr, -1, tsk->pid, triggered);
 }
 EXPORT_SYMBOL_GPL(register_user_hw_breakpoint);
 
 /**
  * modify_user_hw_breakpoint - modify a user-space hardware breakpoint
  * @bp: the breakpoint structure to modify
- * @addr: is the memory address that triggers the breakpoint
- * @len: the length of the access to the memory (1 byte, 2 bytes etc...)
- * @type: the type of the access to the memory (read/write/exec)
+ * @attr: new breakpoint attributes
  * @triggered: callback to trigger when we hit the breakpoint
  * @tsk: pointer to 'task_struct' of the process to which the address belongs
- * @active: should we activate it while registering it
  */
 struct perf_event *
-modify_user_hw_breakpoint(struct perf_event *bp,
-                          unsigned long addr,
-                          int len,
-                          int type,
+modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr,
                           perf_callback_t triggered,
-                          struct task_struct *tsk,
-                          bool active)
+                          struct task_struct *tsk)
 {
         /*
          * FIXME: do it without unregistering
@@ -381,8 +323,7 @@ modify_user_hw_breakpoint(struct perf_event *bp,
          */
         unregister_hw_breakpoint(bp);
 
-        return register_user_hw_breakpoint(addr, len, type, triggered,
-                                           tsk, active);
+        return perf_event_create_kernel_counter(attr, -1, tsk->pid, triggered);
 }
 EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint);
 
@@ -406,8 +347,16 @@ register_kernel_hw_breakpoint_cpu(unsigned long addr,
                                   int cpu,
                                   bool active)
 {
-        return register_user_hw_breakpoint_cpu(addr, len, type, triggered,
-                                               -1, cpu, active);
+        DEFINE_BREAKPOINT_ATTR(attr);
+
+        attr.bp_addr = addr;
+        attr.bp_len = len;
+        attr.bp_type = type;
+
+        if (!active)
+                attr.disabled = 1;
+
+        return perf_event_create_kernel_counter(&attr, cpu, -1, triggered);
 }
 
 /**