3 files changed, 75 insertions, 122 deletions

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 75e0cd847bd..2941b32ea66 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 c9f7f7c7b0e..5da472e434b 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 32e1018191b..2a47514f12f 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);
 }
 
 /**