---

yaml
---
r: 142771
b: refs/heads/master
c: a053958
h: refs/heads/master
i:
  142769: 3f326f0
  142767: bf2b500
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e2494e1b42ebac402324105d57646489d19e2b01
+refs/heads/master: a053958f073740219df1da596b42bfefdab634c4

trunk/Documentation/tracepoints.txt

@@ -103,13 +103,14 @@ used to export the defined tracepoints.
 
 * Probe / tracepoint example
 
-See the example provided in samples/tracepoints/src
+See the example provided in samples/tracepoints
 
-Compile them with your kernel.
+Compile them with your kernel.  They are built during 'make' (not
+'make modules') when CONFIG_SAMPLE_TRACEPOINTS=m.
 
 Run, as root :
-modprobe tracepoint-example (insmod order is not important)
-modprobe tracepoint-probe-example
-cat /proc/tracepoint-example (returns an expected error)
-rmmod tracepoint-example tracepoint-probe-example
+modprobe tracepoint-sample (insmod order is not important)
+modprobe tracepoint-probe-sample
+cat /proc/tracepoint-sample (returns an expected error)
+rmmod tracepoint-sample tracepoint-probe-sample
 dmesg

trunk/arch/x86/kernel/ftrace.c

@@ -79,11 +79,11 @@ static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
  *
  * 1) Put the instruction pointer into the IP buffer
  *    and the new code into the "code" buffer.
- * 2) Set a flag that says we are modifying code
- * 3) Wait for any running NMIs to finish.
- * 4) Write the code
- * 5) clear the flag.
- * 6) Wait for any running NMIs to finish.
+ * 2) Wait for any running NMIs to finish and set a flag that says
+ *    we are modifying code, it is done in an atomic operation.
+ * 3) Write the code
+ * 4) clear the flag.
+ * 5) Wait for any running NMIs to finish.
  *
  * If an NMI is executed, the first thing it does is to call
  * "ftrace_nmi_enter". This will check if the flag is set to write
@@ -95,9 +95,9 @@ static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
  * are the same as what exists.
  */
 
+#define MOD_CODE_WRITE_FLAG (1 << 31)	/* set when NMI should do the write */
 static atomic_t nmi_running = ATOMIC_INIT(0);
 static int mod_code_status;		/* holds return value of text write */
-static int mod_code_write;		/* set when NMI should do the write */
 static void *mod_code_ip;		/* holds the IP to write to */
 static void *mod_code_newcode;		/* holds the text to write to the IP */
 
@@ -114,6 +114,20 @@ int ftrace_arch_read_dyn_info(char *buf, int size)
 	return r;
 }
 
+static void clear_mod_flag(void)
+{
+	int old = atomic_read(&nmi_running);
+
+	for (;;) {
+		int new = old & ~MOD_CODE_WRITE_FLAG;
+
+		if (old == new)
+			break;
+
+		old = atomic_cmpxchg(&nmi_running, old, new);
+	}
+}
+
 static void ftrace_mod_code(void)
 {
 	/*
@@ -127,27 +141,39 @@ static void ftrace_mod_code(void)
 
 	/* if we fail, then kill any new writers */
 	if (mod_code_status)
-		mod_code_write = 0;
+		clear_mod_flag();
 }
 
 void ftrace_nmi_enter(void)
 {
-	atomic_inc(&nmi_running);
-	/* Must have nmi_running seen before reading write flag */
-	smp_mb();
-	if (mod_code_write) {
+	if (atomic_inc_return(&nmi_running) & MOD_CODE_WRITE_FLAG) {
+		smp_rmb();
 		ftrace_mod_code();
 		atomic_inc(&nmi_update_count);
 	}
+	/* Must have previous changes seen before executions */
+	smp_mb();
 }
 
 void ftrace_nmi_exit(void)
 {
 	/* Finish all executions before clearing nmi_running */
-	smp_wmb();
+	smp_mb();
 	atomic_dec(&nmi_running);
 }
 
+static void wait_for_nmi_and_set_mod_flag(void)
+{
+	if (!atomic_cmpxchg(&nmi_running, 0, MOD_CODE_WRITE_FLAG))
+		return;
+
+	do {
+		cpu_relax();
+	} while (atomic_cmpxchg(&nmi_running, 0, MOD_CODE_WRITE_FLAG));
+
+	nmi_wait_count++;
+}
+
 static void wait_for_nmi(void)
 {
 	if (!atomic_read(&nmi_running))
@@ -167,28 +193,19 @@ do_ftrace_mod_code(unsigned long ip, void *new_code)
 	mod_code_newcode = new_code;
 
 	/* The buffers need to be visible before we let NMIs write them */
-	smp_wmb();
-
-	mod_code_write = 1;
-
-	/* Make sure write bit is visible before we wait on NMIs */
 	smp_mb();
 
-	wait_for_nmi();
+	wait_for_nmi_and_set_mod_flag();
 
 	/* Make sure all running NMIs have finished before we write the code */
 	smp_mb();
 
 	ftrace_mod_code();
 
 	/* Make sure the write happens before clearing the bit */
-	smp_wmb();
-
-	mod_code_write = 0;
-
-	/* make sure NMIs see the cleared bit */
 	smp_mb();
 
+	clear_mod_flag();
 	wait_for_nmi();
 
 	return mod_code_status;
@@ -393,7 +410,6 @@ int ftrace_disable_ftrace_graph_caller(void)
 void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
 {
 	unsigned long old;
-	unsigned long long calltime;
 	int faulted;
 	struct ftrace_graph_ent trace;
 	unsigned long return_hooker = (unsigned long)
@@ -436,10 +452,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
 		return;
 	}
 
-	calltime = trace_clock_local();
-
-	if (ftrace_push_return_trace(old, calltime,
-				self_addr, &trace.depth) == -EBUSY) {
+	if (ftrace_push_return_trace(old, self_addr, &trace.depth) == -EBUSY) {
 		*parent = old;
 		return;
 	}

trunk/arch/x86/kernel/kprobes.c

@@ -638,13 +638,13 @@ static void __used __kprobes kretprobe_trampoline_holder(void)
 #else
 			"	pushf\n"
 			/*
-			 * Skip cs, ip, orig_ax.
+			 * Skip cs, ip, orig_ax and gs.
 			 * trampoline_handler() will plug in these values
 			 */
-			"	subl $12, %esp\n"
+			"	subl $16, %esp\n"
 			"	pushl %fs\n"
-			"	pushl %ds\n"
 			"	pushl %es\n"
+			"	pushl %ds\n"
 			"	pushl %eax\n"
 			"	pushl %ebp\n"
 			"	pushl %edi\n"
@@ -655,19 +655,19 @@ static void __used __kprobes kretprobe_trampoline_holder(void)
 			"	movl %esp, %eax\n"
 			"	call trampoline_handler\n"
 			/* Move flags to cs */
-			"	movl 52(%esp), %edx\n"
-			"	movl %edx, 48(%esp)\n"
+			"	movl 56(%esp), %edx\n"
+			"	movl %edx, 52(%esp)\n"
 			/* Replace saved flags with true return address. */
-			"	movl %eax, 52(%esp)\n"
+			"	movl %eax, 56(%esp)\n"
 			"	popl %ebx\n"
 			"	popl %ecx\n"
 			"	popl %edx\n"
 			"	popl %esi\n"
 			"	popl %edi\n"
 			"	popl %ebp\n"
 			"	popl %eax\n"
-			/* Skip ip, orig_ax, es, ds, fs */
-			"	addl $20, %esp\n"
+			/* Skip ds, es, fs, gs, orig_ax and ip */
+			"	addl $24, %esp\n"
 			"	popf\n"
 #endif
 			"	ret\n");
@@ -691,6 +691,7 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
 	regs->cs = __KERNEL_CS;
 #else
 	regs->cs = __KERNEL_CS | get_kernel_rpl();
+	regs->gs = 0;
 #endif
 	regs->ip = trampoline_address;
 	regs->orig_ax = ~0UL;

trunk/fs/debugfs/inode.c

@@ -30,6 +30,7 @@
 
 static struct vfsmount *debugfs_mount;
 static int debugfs_mount_count;
+static bool debugfs_registered;
 
 static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t dev)
 {
@@ -496,6 +497,16 @@ struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
 }
 EXPORT_SYMBOL_GPL(debugfs_rename);
 
+/**
+ * debugfs_initialized - Tells whether debugfs has been registered
+ */
+bool debugfs_initialized(void)
+{
+	return debugfs_registered;
+}
+EXPORT_SYMBOL_GPL(debugfs_initialized);
+
+
 static struct kobject *debug_kobj;
 
 static int __init debugfs_init(void)
@@ -509,11 +520,16 @@ static int __init debugfs_init(void)
 	retval = register_filesystem(&debug_fs_type);
 	if (retval)
 		kobject_put(debug_kobj);
+	else
+		debugfs_registered = true;
+
 	return retval;
 }
 
 static void __exit debugfs_exit(void)
 {
+	debugfs_registered = false;
+
 	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
 	unregister_filesystem(&debug_fs_type);
 	kobject_put(debug_kobj);

trunk/include/linux/debugfs.h

@@ -71,6 +71,9 @@ struct dentry *debugfs_create_bool(const char *name, mode_t mode,
 struct dentry *debugfs_create_blob(const char *name, mode_t mode,
 				  struct dentry *parent,
 				  struct debugfs_blob_wrapper *blob);
+
+bool debugfs_initialized(void);
+
 #else
 
 #include <linux/err.h>
@@ -183,6 +186,11 @@ static inline struct dentry *debugfs_create_blob(const char *name, mode_t mode,
 	return ERR_PTR(-ENODEV);
 }
 
+static inline bool debugfs_initialized(void)
+{
+	return false;
+}
+
 #endif
 
 #endif

trunk/include/linux/ftrace.h

@@ -145,9 +145,15 @@ enum {
 };
 
 struct dyn_ftrace {
-	unsigned long		ip; /* address of mcount call-site */
-	unsigned long		flags;
-	struct dyn_arch_ftrace	arch;
+	union {
+		unsigned long		ip; /* address of mcount call-site */
+		struct dyn_ftrace	*freelist;
+	};
+	union {
+		unsigned long		flags;
+		struct dyn_ftrace	*newlist;
+	};
+	struct dyn_arch_ftrace		arch;
 };
 
 int ftrace_force_update(void);
@@ -369,8 +375,7 @@ struct ftrace_ret_stack {
 extern void return_to_handler(void);
 
 extern int
-ftrace_push_return_trace(unsigned long ret, unsigned long long time,
-			 unsigned long func, int *depth);
+ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth);
 extern void
 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret);
 

trunk/include/linux/ring_buffer.h

@@ -18,10 +18,13 @@ struct ring_buffer_event {
 /**
  * enum ring_buffer_type - internal ring buffer types
  *
- * @RINGBUF_TYPE_PADDING:	Left over page padding
- *				 array is ignored
- *				 size is variable depending on how much
+ * @RINGBUF_TYPE_PADDING:	Left over page padding or discarded event
+ *				 If time_delta is 0:
+ *				  array is ignored
+ *				  size is variable depending on how much
  *				  padding is needed
+ *				 If time_delta is non zero:
+ *				  everything else same as RINGBUF_TYPE_DATA
  *
  * @RINGBUF_TYPE_TIME_EXTEND:	Extend the time delta
  *				 array[0] = time delta (28 .. 59)
@@ -65,6 +68,8 @@ ring_buffer_event_time_delta(struct ring_buffer_event *event)
 	return event->time_delta;
 }
 
+void ring_buffer_event_discard(struct ring_buffer_event *event);
+
 /*
  * size is in bytes for each per CPU buffer.
  */

trunk/include/linux/sched.h

@@ -1409,6 +1409,8 @@ struct task_struct {
 	int curr_ret_stack;
 	/* Stack of return addresses for return function tracing */
 	struct ftrace_ret_stack	*ret_stack;
+	/* time stamp for last schedule */
+	unsigned long long ftrace_timestamp;
 	/*
 	 * Number of functions that haven't been traced
 	 * because of depth overrun.

trunk/init/main.c

@@ -772,6 +772,7 @@ static void __init do_basic_setup(void)
 {
 	rcu_init_sched(); /* needed by module_init stage. */
 	init_workqueues();
+	cpuset_init_smp();
 	usermodehelper_init();
 	driver_init();
 	init_irq_proc();
@@ -865,8 +866,6 @@ static int __init kernel_init(void * unused)
 	smp_init();
 	sched_init_smp();
 
-	cpuset_init_smp();
-
 	do_basic_setup();
 
 	/*

trunk/kernel/extable.c

@@ -15,11 +15,22 @@
     along with this program; if not, write to the Free Software
     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
+#include <linux/ftrace.h>
+#include <linux/memory.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/init.h>
-#include <linux/ftrace.h>
-#include <asm/uaccess.h>
+
 #include <asm/sections.h>
+#include <asm/uaccess.h>
+
+/*
+ * mutex protecting text section modification (dynamic code patching).
+ * some users need to sleep (allocating memory...) while they hold this lock.
+ *
+ * NOT exported to modules - patching kernel text is a really delicate matter.
+ */
+DEFINE_MUTEX(text_mutex);
 
 extern struct exception_table_entry __start___ex_table[];
 extern struct exception_table_entry __stop___ex_table[];