Merge branches 'tracing/branch-tracer', 'tracing/ftrace',...

Merge branches 'tracing/branch-tracer', 'tracing/ftrace', 'tracing/function-graph-tracer', 'tracing/markers', 'tracing/powerpc', 'tracing/stack-tracer' and 'tracing/tracepoints' into tracing/core

Documentation/ftrace.txt

@@ -1251,7 +1251,11 @@ These are the only wild cards which are supported.
 
   <match>*<match> will not work.
 
- # echo hrtimer_* > /debug/tracing/set_ftrace_filter
+Note: It is better to use quotes to enclose the wild cards, otherwise
+  the shell may expand the parameters into names of files in the local
+  directory.
+
+ # echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter
 
 Produces:
 
@@ -1306,7 +1310,7 @@ Again, now we want to append.
  # echo sys_nanosleep > /debug/tracing/set_ftrace_filter
  # cat /debug/tracing/set_ftrace_filter
 sys_nanosleep
- # echo hrtimer_* >> /debug/tracing/set_ftrace_filter
+ # echo 'hrtimer_*' >> /debug/tracing/set_ftrace_filter
  # cat /debug/tracing/set_ftrace_filter
 hrtimer_run_queues
 hrtimer_run_pending

Documentation/markers.txt

@@ -51,11 +51,16 @@ to call) for the specific marker through marker_probe_register() and can be
 activated by calling marker_arm(). Marker deactivation can be done by calling
 marker_disarm() as many times as marker_arm() has been called. Removing a probe
 is done through marker_probe_unregister(); it will disarm the probe.
-marker_synchronize_unregister() must be called before the end of the module exit
-function to make sure there is no caller left using the probe. This, and the
-fact that preemption is disabled around the probe call, make sure that probe
-removal and module unload are safe. See the "Probe example" section below for a
-sample probe module.
+
+marker_synchronize_unregister() must be called between probe unregistration and
+the first occurrence of
+- the end of module exit function,
+  to make sure there is no caller left using the probe;
+- the free of any resource used by the probes,
+  to make sure the probes wont be accessing invalid data.
+This, and the fact that preemption is disabled around the probe call, make sure
+that probe removal and module unload are safe. See the "Probe example" section
+below for a sample probe module.
 
 The marker mechanism supports inserting multiple instances of the same marker.
 Markers can be put in inline functions, inlined static functions, and

Documentation/tracepoints.txt

@@ -45,7 +45,7 @@ In include/trace/subsys.h :
 #include <linux/tracepoint.h>
 
 DECLARE_TRACE(subsys_eventname,
-	TPPTOTO(int firstarg, struct task_struct *p),
+	TPPROTO(int firstarg, struct task_struct *p),
 	TPARGS(firstarg, p));
 
 In subsys/file.c (where the tracing statement must be added) :
@@ -66,7 +66,7 @@ Where :
     - subsys is the name of your subsystem.
     - eventname is the name of the event to trace.
 
-- TPPTOTO(int firstarg, struct task_struct *p) is the prototype of the
+- TPPROTO(int firstarg, struct task_struct *p) is the prototype of the
   function called by this tracepoint.
 
 - TPARGS(firstarg, p) are the parameters names, same as found in the

arch/powerpc/kernel/Makefile

@@ -17,6 +17,7 @@ ifdef CONFIG_FUNCTION_TRACER
 CFLAGS_REMOVE_cputable.o = -pg -mno-sched-epilog
 CFLAGS_REMOVE_prom_init.o = -pg -mno-sched-epilog
 CFLAGS_REMOVE_btext.o = -pg -mno-sched-epilog
+CFLAGS_REMOVE_prom.o = -pg -mno-sched-epilog
 
 ifdef CONFIG_DYNAMIC_FTRACE
 # dynamic ftrace setup.

arch/powerpc/kernel/entry_32.S

@@ -1162,39 +1162,17 @@ machine_check_in_rtas:
 #ifdef CONFIG_DYNAMIC_FTRACE
 _GLOBAL(mcount)
 _GLOBAL(_mcount)
-	stwu	r1,-48(r1)
-	stw	r3, 12(r1)
-	stw	r4, 16(r1)
-	stw	r5, 20(r1)
-	stw	r6, 24(r1)
-	mflr	r3
-	stw	r7, 28(r1)
-	mfcr	r5
-	stw	r8, 32(r1)
-	stw	r9, 36(r1)
-	stw	r10,40(r1)
-	stw	r3, 44(r1)
-	stw	r5, 8(r1)
-	subi	r3, r3, MCOUNT_INSN_SIZE
-	.globl mcount_call
-mcount_call:
-	bl	ftrace_stub
-	nop
-	lwz	r6, 8(r1)
-	lwz	r0, 44(r1)
-	lwz	r3, 12(r1)
+	/*
+	 * It is required that _mcount on PPC32 must preserve the
+	 * link register. But we have r0 to play with. We use r0
+	 * to push the return address back to the caller of mcount
+	 * into the ctr register, restore the link register and
+	 * then jump back using the ctr register.
+	 */
+	mflr	r0
 	mtctr	r0
-	lwz	r4, 16(r1)
-	mtcr	r6
-	lwz	r5, 20(r1)
-	lwz	r6, 24(r1)
-	lwz	r0, 52(r1)
-	lwz	r7, 28(r1)
-	lwz	r8, 32(r1)
+	lwz	r0, 4(r1)
 	mtlr	r0
-	lwz	r9, 36(r1)
-	lwz	r10,40(r1)
-	addi	r1, r1, 48
 	bctr
 
 _GLOBAL(ftrace_caller)

arch/powerpc/kernel/entry_64.S

@@ -888,18 +888,6 @@ _GLOBAL(enter_prom)
 #ifdef CONFIG_DYNAMIC_FTRACE
 _GLOBAL(mcount)
 _GLOBAL(_mcount)
-	/* Taken from output of objdump from lib64/glibc */
-	mflr	r3
-	stdu	r1, -112(r1)
-	std	r3, 128(r1)
-	subi	r3, r3, MCOUNT_INSN_SIZE
-	.globl mcount_call
-mcount_call:
-	bl	ftrace_stub
-	nop
-	ld	r0, 128(r1)
-	mtlr	r0
-	addi	r1, r1, 112
 	blr
 
 _GLOBAL(ftrace_caller)

arch/powerpc/kernel/ftrace.c

@@ -114,19 +114,9 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
  */
 static int test_24bit_addr(unsigned long ip, unsigned long addr)
 {
-	long diff;
 
-	/*
-	 * Can we get to addr from ip in 24 bits?
-	 *  (26 really, since we mulitply by 4 for 4 byte alignment)
-	 */
-	diff = addr - ip;
-
-	/*
-	 * Return true if diff is less than 1 << 25
-	 *  and greater than -1 << 26.
-	 */
-	return (diff < (1 << 25)) && (diff > (-1 << 26));
+	/* use the create_branch to verify that this offset can be branched */
+	return create_branch((unsigned int *)ip, addr, 0);
 }
 
 static int is_bl_op(unsigned int op)
@@ -134,11 +124,6 @@ static int is_bl_op(unsigned int op)
 	return (op & 0xfc000003) == 0x48000001;
 }
 
-static int test_offset(unsigned long offset)
-{
-	return (offset + 0x2000000 > 0x3ffffff) || ((offset & 3) != 0);
-}
-
 static unsigned long find_bl_target(unsigned long ip, unsigned int op)
 {
 	static int offset;
@@ -151,37 +136,30 @@ static unsigned long find_bl_target(unsigned long ip, unsigned int op)
 	return ip + (long)offset;
 }
 
-static unsigned int branch_offset(unsigned long offset)
-{
-	/* return "bl ip+offset" */
-	return 0x48000001 | (offset & 0x03fffffc);
-}
-
 #ifdef CONFIG_PPC64
 static int
 __ftrace_make_nop(struct module *mod,
 		  struct dyn_ftrace *rec, unsigned long addr)
 {
-	unsigned char replaced[MCOUNT_INSN_SIZE * 2];
-	unsigned int *op = (unsigned *)&replaced;
-	unsigned char jmp[8];
-	unsigned long *ptr = (unsigned long *)&jmp;
+	unsigned int op;
+	unsigned int jmp[5];
+	unsigned long ptr;
 	unsigned long ip = rec->ip;
 	unsigned long tramp;
 	int offset;
 
 	/* read where this goes */
-	if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
+	if (probe_kernel_read(&op, (void *)ip, sizeof(int)))
 		return -EFAULT;
 
 	/* Make sure that that this is still a 24bit jump */
-	if (!is_bl_op(*op)) {
-		printk(KERN_ERR "Not expected bl: opcode is %x\n", *op);
+	if (!is_bl_op(op)) {
+		printk(KERN_ERR "Not expected bl: opcode is %x\n", op);
 		return -EINVAL;
 	}
 
 	/* lets find where the pointer goes */
-	tramp = find_bl_target(ip, *op);
+	tramp = find_bl_target(ip, op);
 
 	/*
 	 * On PPC64 the trampoline looks like:
@@ -200,19 +178,25 @@ __ftrace_make_nop(struct module *mod,
 	DEBUGP("ip:%lx jumps to %lx r2: %lx", ip, tramp, mod->arch.toc);
 
 	/* Find where the trampoline jumps to */
-	if (probe_kernel_read(jmp, (void *)tramp, 8)) {
+	if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
 		printk(KERN_ERR "Failed to read %lx\n", tramp);
 		return -EFAULT;
 	}
 
-	DEBUGP(" %08x %08x",
-	       (unsigned)(*ptr >> 32),
-	       (unsigned)*ptr);
+	DEBUGP(" %08x %08x", jmp[0], jmp[1]);
+
+	/* verify that this is what we expect it to be */
+	if (((jmp[0] & 0xffff0000) != 0x3d820000) ||
+	    ((jmp[1] & 0xffff0000) != 0x398c0000) ||
+	    (jmp[2] != 0xf8410028) ||
+	    (jmp[3] != 0xe96c0020) ||
+	    (jmp[4] != 0xe84c0028)) {
+		printk(KERN_ERR "Not a trampoline\n");
+		return -EINVAL;
+	}
 
-	offset = (unsigned)jmp[2] << 24 |
-		(unsigned)jmp[3] << 16 |
-		(unsigned)jmp[6] << 8 |
-		(unsigned)jmp[7];
+	offset = (unsigned)((unsigned short)jmp[0]) << 16 |
+		(unsigned)((unsigned short)jmp[1]);
 
 	DEBUGP(" %x ", offset);
 
@@ -225,13 +209,13 @@ __ftrace_make_nop(struct module *mod,
 		return -EFAULT;
 	}
 
-	DEBUGP(" %08x %08x\n",
-	       (unsigned)(*ptr >> 32),
-	       (unsigned)*ptr);
+	DEBUGP(" %08x %08x\n", jmp[0], jmp[1]);
+
+	ptr = ((unsigned long)jmp[0] << 32) + jmp[1];
 
 	/* This should match what was called */
-	if (*ptr != GET_ADDR(addr)) {
-		printk(KERN_ERR "addr does not match %lx\n", *ptr);
+	if (ptr != GET_ADDR(addr)) {
+		printk(KERN_ERR "addr does not match %lx\n", ptr);
 		return -EINVAL;
 	}
 
@@ -240,11 +224,11 @@ __ftrace_make_nop(struct module *mod,
 	 *  0xe8, 0x41, 0x00, 0x28   ld r2,40(r1)
 	 * This needs to be turned to a nop too.
 	 */
-	if (probe_kernel_read(replaced, (void *)(ip+4), MCOUNT_INSN_SIZE))
+	if (probe_kernel_read(&op, (void *)(ip+4), MCOUNT_INSN_SIZE))
 		return -EFAULT;
 
-	if (*op != 0xe8410028) {
-		printk(KERN_ERR "Next line is not ld! (%08x)\n", *op);
+	if (op != 0xe8410028) {
+		printk(KERN_ERR "Next line is not ld! (%08x)\n", op);
 		return -EINVAL;
 	}
 
@@ -261,11 +245,14 @@ __ftrace_make_nop(struct module *mod,
 	 *   ld r2,40(r1)
 	 *  1:
 	 */
-	op[0] = 0x48000008;	/* b +8 */
+	op = 0x48000008;	/* b +8 */
 
-	if (probe_kernel_write((void *)ip, replaced, MCOUNT_INSN_SIZE))
+	if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
 		return -EPERM;
 
+
+	flush_icache_range(ip, ip + 8);
+
 	return 0;
 }
 
@@ -274,46 +261,52 @@ static int
 __ftrace_make_nop(struct module *mod,
 		  struct dyn_ftrace *rec, unsigned long addr)
 {
-	unsigned char replaced[MCOUNT_INSN_SIZE];
-	unsigned int *op = (unsigned *)&replaced;
-	unsigned char jmp[8];
-	unsigned int *ptr = (unsigned int *)&jmp;
+	unsigned int op;
+	unsigned int jmp[4];
 	unsigned long ip = rec->ip;
 	unsigned long tramp;
-	int offset;
 
-	if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
+	if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE))
 		return -EFAULT;
 
 	/* Make sure that that this is still a 24bit jump */
-	if (!is_bl_op(*op)) {
-		printk(KERN_ERR "Not expected bl: opcode is %x\n", *op);
+	if (!is_bl_op(op)) {
+		printk(KERN_ERR "Not expected bl: opcode is %x\n", op);
 		return -EINVAL;
 	}
 
 	/* lets find where the pointer goes */
-	tramp = find_bl_target(ip, *op);
+	tramp = find_bl_target(ip, op);
 
 	/*
 	 * On PPC32 the trampoline looks like:
-	 * lis r11,sym@ha
-	 * addi r11,r11,sym@l
-	 * mtctr r11
-	 * bctr
+	 *  0x3d, 0x60, 0x00, 0x00  lis r11,sym@ha
+	 *  0x39, 0x6b, 0x00, 0x00  addi r11,r11,sym@l
+	 *  0x7d, 0x69, 0x03, 0xa6  mtctr r11
+	 *  0x4e, 0x80, 0x04, 0x20  bctr
 	 */
 
 	DEBUGP("ip:%lx jumps to %lx", ip, tramp);
 
 	/* Find where the trampoline jumps to */
-	if (probe_kernel_read(jmp, (void *)tramp, 8)) {
+	if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
 		printk(KERN_ERR "Failed to read %lx\n", tramp);
 		return -EFAULT;
 	}
 
-	DEBUGP(" %08x %08x ", ptr[0], ptr[1]);
+	DEBUGP(" %08x %08x ", jmp[0], jmp[1]);
+
+	/* verify that this is what we expect it to be */
+	if (((jmp[0] & 0xffff0000) != 0x3d600000) ||
+	    ((jmp[1] & 0xffff0000) != 0x396b0000) ||
+	    (jmp[2] != 0x7d6903a6) ||
+	    (jmp[3] != 0x4e800420)) {
+		printk(KERN_ERR "Not a trampoline\n");
+		return -EINVAL;
+	}
 
-	tramp = (ptr[1] & 0xffff) |
-		((ptr[0] & 0xffff) << 16);
+	tramp = (jmp[1] & 0xffff) |
+		((jmp[0] & 0xffff) << 16);
 	if (tramp & 0x8000)
 		tramp -= 0x10000;
 
@@ -326,11 +319,13 @@ __ftrace_make_nop(struct module *mod,
 		return -EINVAL;
 	}
 
-	op[0] = PPC_NOP_INSTR;
+	op = PPC_NOP_INSTR;
 
-	if (probe_kernel_write((void *)ip, replaced, MCOUNT_INSN_SIZE))
+	if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
 		return -EPERM;
 
+	flush_icache_range(ip, ip + 8);
+
 	return 0;
 }
 #endif /* PPC64 */
@@ -384,13 +379,11 @@ int ftrace_make_nop(struct module *mod,
 static int
 __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 {
-	unsigned char replaced[MCOUNT_INSN_SIZE * 2];
-	unsigned int *op = (unsigned *)&replaced;
+	unsigned int op[2];
 	unsigned long ip = rec->ip;
-	unsigned long offset;
 
 	/* read where this goes */
-	if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE * 2))
+	if (probe_kernel_read(op, (void *)ip, MCOUNT_INSN_SIZE * 2))
 		return -EFAULT;
 
 	/*
@@ -409,43 +402,40 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 		return -EINVAL;
 	}
 
-	/* now calculate a jump to the ftrace caller trampoline */
-	offset = rec->arch.mod->arch.tramp - ip;
-
-	if (test_offset(offset)) {
-		printk(KERN_ERR "REL24 %li out of range!\n",
-		       (long int)offset);
+	/* create the branch to the trampoline */
+	op[0] = create_branch((unsigned int *)ip,
+			      rec->arch.mod->arch.tramp, BRANCH_SET_LINK);
+	if (!op[0]) {
+		printk(KERN_ERR "REL24 out of range!\n");
 		return -EINVAL;
 	}
 
-	/* Set to "bl addr" */
-	op[0] = branch_offset(offset);
 	/* ld r2,40(r1) */
 	op[1] = 0xe8410028;
 
 	DEBUGP("write to %lx\n", rec->ip);
 
-	if (probe_kernel_write((void *)ip, replaced, MCOUNT_INSN_SIZE * 2))
+	if (probe_kernel_write((void *)ip, op, MCOUNT_INSN_SIZE * 2))
 		return -EPERM;
 
+	flush_icache_range(ip, ip + 8);
+
 	return 0;
 }
 #else
 static int
 __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 {
-	unsigned char replaced[MCOUNT_INSN_SIZE];
-	unsigned int *op = (unsigned *)&replaced;
+	unsigned int op;
 	unsigned long ip = rec->ip;
-	unsigned long offset;
 
 	/* read where this goes */
-	if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
+	if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE))
 		return -EFAULT;
 
 	/* It should be pointing to a nop */
-	if (op[0] != PPC_NOP_INSTR) {
-		printk(KERN_ERR "Expected NOP but have %x\n", op[0]);
+	if (op != PPC_NOP_INSTR) {
+		printk(KERN_ERR "Expected NOP but have %x\n", op);
 		return -EINVAL;
 	}
 
@@ -455,23 +445,21 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 		return -EINVAL;
 	}
 
-	/* now calculate a jump to the ftrace caller trampoline */
-	offset = rec->arch.mod->arch.tramp - ip;
-
-	if (test_offset(offset)) {
-		printk(KERN_ERR "REL24 %li out of range!\n",
-		       (long int)offset);
+	/* create the branch to the trampoline */
+	op = create_branch((unsigned int *)ip,
+			   rec->arch.mod->arch.tramp, BRANCH_SET_LINK);
+	if (!op) {
+		printk(KERN_ERR "REL24 out of range!\n");
 		return -EINVAL;
 	}
 
-	/* Set to "bl addr" */
-	op[0] = branch_offset(offset);
-
 	DEBUGP("write to %lx\n", rec->ip);
 
-	if (probe_kernel_write((void *)ip, replaced, MCOUNT_INSN_SIZE))
+	if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
 		return -EPERM;
 
+	flush_icache_range(ip, ip + 8);
+
 	return 0;
 }
 #endif /* CONFIG_PPC64 */

arch/powerpc/lib/Makefile

@@ -6,6 +6,9 @@ ifeq ($(CONFIG_PPC64),y)
 EXTRA_CFLAGS		+= -mno-minimal-toc
 endif
 
+CFLAGS_REMOVE_code-patching.o = -pg
+CFLAGS_REMOVE_feature-fixups.o = -pg
+
 obj-y			:= string.o alloc.o \
 			   checksum_$(CONFIG_WORD_SIZE).o
 obj-$(CONFIG_PPC32)	+= div64.o copy_32.o crtsavres.o

fs/seq_file.c

@@ -387,7 +387,7 @@ char *mangle_path(char *s, char *p, char *esc)
 	}
 	return NULL;
 }
-EXPORT_SYMBOL_GPL(mangle_path);
+EXPORT_SYMBOL(mangle_path);
 
 /*
  * return the absolute path of 'dentry' residing in mount 'mnt'.

include/linux/marker.h

@@ -211,8 +211,10 @@ extern void *marker_get_private_data(const char *name, marker_probe_func *probe,
 
 /*
  * marker_synchronize_unregister must be called between the last marker probe
- * unregistration and the end of module exit to make sure there is no caller
- * executing a probe when it is freed.
+ * unregistration and the first one of
+ * - the end of module exit function
+ * - the free of any resource used by the probes
+ * to ensure the code and data are valid for any possibly running probes.
  */
 #define marker_synchronize_unregister() synchronize_sched()
 

kernel/trace/ftrace.c

@@ -786,7 +786,6 @@ enum {
 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 
 struct ftrace_iterator {
-	loff_t			pos;
 	struct ftrace_page	*pg;
 	unsigned		idx;
 	unsigned		flags;
@@ -811,6 +810,8 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
 			iter->pg = iter->pg->next;
 			iter->idx = 0;
 			goto retry;
+		} else {
+			iter->idx = -1;
 		}
 	} else {
 		rec = &iter->pg->records[iter->idx++];
@@ -833,8 +834,6 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
 	}
 	spin_unlock(&ftrace_lock);
 
-	iter->pos = *pos;
-
 	return rec;
 }
 
@@ -842,13 +841,15 @@ static void *t_start(struct seq_file *m, loff_t *pos)
 {
 	struct ftrace_iterator *iter = m->private;
 	void *p = NULL;
-	loff_t l = -1;
 
-	if (*pos > iter->pos)
-		*pos = iter->pos;
+	if (*pos > 0) {
+		if (iter->idx < 0)
+			return p;
+		(*pos)--;
+		iter->idx--;
+	}
 
-	l = *pos;
-	p = t_next(m, p, &l);
+	p = t_next(m, p, pos);
 
 	return p;
 }
@@ -859,21 +860,15 @@ static void t_stop(struct seq_file *m, void *p)
 
 static int t_show(struct seq_file *m, void *v)
 {
-	struct ftrace_iterator *iter = m->private;
 	struct dyn_ftrace *rec = v;
 	char str[KSYM_SYMBOL_LEN];
-	int ret = 0;
 
 	if (!rec)
 		return 0;
 
 	kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 
-	ret = seq_printf(m, "%s\n", str);
-	if (ret < 0) {
-		iter->pos--;
-		iter->idx--;
-	}
+	seq_printf(m, "%s\n", str);
 
 	return 0;
 }
@@ -899,7 +894,6 @@ ftrace_avail_open(struct inode *inode, struct file *file)
 		return -ENOMEM;
 
 	iter->pg = ftrace_pages_start;
-	iter->pos = 0;
 
 	ret = seq_open(file, &show_ftrace_seq_ops);
 	if (!ret) {
@@ -986,7 +980,6 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 
 	if (file->f_mode & FMODE_READ) {
 		iter->pg = ftrace_pages_start;
-		iter->pos = 0;
 		iter->flags = enable ? FTRACE_ITER_FILTER :
 			FTRACE_ITER_NOTRACE;
 

kernel/trace/trace.c

@@ -983,6 +983,7 @@ static void ftrace_trace_userstack(struct trace_array *tr,
 		   struct trace_array_cpu *data,
 		   unsigned long flags, int pc)
 {
+#ifdef CONFIG_STACKTRACE
 	struct ring_buffer_event *event;
 	struct userstack_entry *entry;
 	struct stack_trace trace;
@@ -1008,6 +1009,7 @@ static void ftrace_trace_userstack(struct trace_array *tr,
 
 	save_stack_trace_user(&trace);
 	ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+#endif
 }
 
 void __trace_userstack(struct trace_array *tr,

kernel/trace/trace_branch.c

@@ -6,6 +6,7 @@
 #include <linux/kallsyms.h>
 #include <linux/seq_file.h>
 #include <linux/spinlock.h>
+#include <linux/irqflags.h>
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/module.h>

kernel/trace/trace_functions_graph.c

@@ -15,15 +15,24 @@
 
 #define TRACE_GRAPH_INDENT	2
 
+/* Flag options */
 #define TRACE_GRAPH_PRINT_OVERRUN	0x1
+#define TRACE_GRAPH_PRINT_CPU		0x2
+#define TRACE_GRAPH_PRINT_OVERHEAD	0x4
+
 static struct tracer_opt trace_opts[] = {
-	/* Display overruns or not */
-	{ TRACER_OPT(overrun, TRACE_GRAPH_PRINT_OVERRUN) },
+	/* Display overruns ? */
+	{ TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
+	/* Display CPU ? */
+	{ TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
+	/* Display Overhead ? */
+	{ TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
 	{ } /* Empty entry */
 };
 
 static struct tracer_flags tracer_flags = {
-	.val = 0, /* Don't display overruns by default */
+	/* Don't display overruns by default */
+	.val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD,
 	.opts = trace_opts
 };
 
@@ -52,37 +61,208 @@ static void graph_trace_reset(struct trace_array *tr)
 	unregister_ftrace_graph();
 }
 
+static inline int log10_cpu(int nb)
+{
+	if (nb / 100)
+		return 3;
+	if (nb / 10)
+		return 2;
+	return 1;
+}
+
+static enum print_line_t
+print_graph_cpu(struct trace_seq *s, int cpu)
+{
+	int i;
+	int ret;
+	int log10_this = log10_cpu(cpu);
+	int log10_all = log10_cpu(cpus_weight_nr(cpu_online_map));
+
+
+	/*
+	 * Start with a space character - to make it stand out
+	 * to the right a bit when trace output is pasted into
+	 * email:
+	 */
+	ret = trace_seq_printf(s, " ");
+
+	/*
+	 * Tricky - we space the CPU field according to the max
+	 * number of online CPUs. On a 2-cpu system it would take
+	 * a maximum of 1 digit - on a 128 cpu system it would
+	 * take up to 3 digits:
+	 */
+	for (i = 0; i < log10_all - log10_this; i++) {
+		ret = trace_seq_printf(s, " ");
+		if (!ret)
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+	ret = trace_seq_printf(s, "%d) ", cpu);
+	if (!ret)
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	return TRACE_TYPE_HANDLED;
+}
+
+
 /* If the pid changed since the last trace, output this event */
 static int verif_pid(struct trace_seq *s, pid_t pid, int cpu)
 {
-	char *comm;
+	char *comm, *prev_comm;
+	pid_t prev_pid;
+	int ret;
 
 	if (last_pid[cpu] != -1 && last_pid[cpu] == pid)
 		return 1;
 
+	prev_pid = last_pid[cpu];
 	last_pid[cpu] = pid;
+
 	comm = trace_find_cmdline(pid);
+	prev_comm = trace_find_cmdline(prev_pid);
 
-	return trace_seq_printf(s, "\nCPU[%03d]"
-				    " ------------8<---------- thread %s-%d"
-				    " ------------8<----------\n\n",
-				    cpu, comm, pid);
+/*
+ * Context-switch trace line:
+
+ ------------------------------------------
+ | 1)  migration/0--1  =>  sshd-1755
+ ------------------------------------------
+
+ */
+	ret = trace_seq_printf(s,
+		" ------------------------------------------\n");
+	ret += trace_seq_printf(s, " | %d)  %s-%d  =>  %s-%d\n",
+				  cpu, prev_comm, prev_pid, comm, pid);
+	ret += trace_seq_printf(s,
+		" ------------------------------------------\n\n");
+	return ret;
 }
 
+static bool
+trace_branch_is_leaf(struct trace_iterator *iter,
+		struct ftrace_graph_ent_entry *curr)
+{
+	struct ring_buffer_iter *ring_iter;
+	struct ring_buffer_event *event;
+	struct ftrace_graph_ret_entry *next;
+
+	ring_iter = iter->buffer_iter[iter->cpu];
+
+	if (!ring_iter)
+		return false;
+
+	event = ring_buffer_iter_peek(ring_iter, NULL);
+
+	if (!event)
+		return false;
+
+	next = ring_buffer_event_data(event);
+
+	if (next->ent.type != TRACE_GRAPH_RET)
+		return false;
+
+	if (curr->ent.pid != next->ent.pid ||
+			curr->graph_ent.func != next->ret.func)
+		return false;
+
+	return true;
+}
+
+
+static inline int
+print_graph_duration(unsigned long long duration, struct trace_seq *s)
+{
+	unsigned long nsecs_rem = do_div(duration, 1000);
+	return trace_seq_printf(s, "%4llu.%3lu us |  ", duration, nsecs_rem);
+}
+
+/* Signal a overhead of time execution to the output */
+static int
+print_graph_overhead(unsigned long long duration, struct trace_seq *s)
+{
+	/* Duration exceeded 100 msecs */
+	if (duration > 100000ULL)
+		return trace_seq_printf(s, "! ");
+
+	/* Duration exceeded 10 msecs */
+	if (duration > 10000ULL)
+		return trace_seq_printf(s, "+ ");
+
+	return trace_seq_printf(s, "  ");
+}
+
+/* Case of a leaf function on its call entry */
 static enum print_line_t
-print_graph_entry(struct ftrace_graph_ent *call, struct trace_seq *s,
-		  struct trace_entry *ent, int cpu)
+print_graph_entry_leaf(struct trace_iterator *iter,
+		struct ftrace_graph_ent_entry *entry, struct trace_seq *s)
 {
-	int i;
+	struct ftrace_graph_ret_entry *ret_entry;
+	struct ftrace_graph_ret *graph_ret;
+	struct ring_buffer_event *event;
+	struct ftrace_graph_ent *call;
+	unsigned long long duration;
 	int ret;
+	int i;
 
-	if (!verif_pid(s, ent->pid, cpu))
+	event = ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
+	ret_entry = ring_buffer_event_data(event);
+	graph_ret = &ret_entry->ret;
+	call = &entry->graph_ent;
+	duration = graph_ret->rettime - graph_ret->calltime;
+
+	/* Must not exceed 8 characters: 9999.999 us */
+	if (duration > 10000000ULL)
+		duration = 9999999ULL;
+
+	/* Overhead */
+	if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
+		ret = print_graph_overhead(duration, s);
+		if (!ret)
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+
+	/* Duration */
+	ret = print_graph_duration(duration, s);
+	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 
-	ret = trace_seq_printf(s, "CPU[%03d] ", cpu);
+	/* Function */
+	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
+		ret = trace_seq_printf(s, " ");
+		if (!ret)
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+
+	ret = seq_print_ip_sym(s, call->func, 0);
+	if (!ret)
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	ret = trace_seq_printf(s, "();\n");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 
+	return TRACE_TYPE_HANDLED;
+}
+
+static enum print_line_t
+print_graph_entry_nested(struct ftrace_graph_ent_entry *entry,
+			struct trace_seq *s)
+{
+	int i;
+	int ret;
+	struct ftrace_graph_ent *call = &entry->graph_ent;
+
+	/* No overhead */
+	if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
+		ret = trace_seq_printf(s, "  ");
+		if (!ret)
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+
+	/* No time */
+	ret = trace_seq_printf(s, "            |  ");
+
+	/* Function */
 	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 		ret = trace_seq_printf(s, " ");
 		if (!ret)
@@ -96,37 +276,82 @@ print_graph_entry(struct ftrace_graph_ent *call, struct trace_seq *s,
 	ret = trace_seq_printf(s, "() {\n");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
+
 	return TRACE_TYPE_HANDLED;
 }
 
+static enum print_line_t
+print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
+			struct trace_iterator *iter, int cpu)
+{
+	int ret;
+	struct trace_entry *ent = iter->ent;
+
+	/* Pid */
+	if (!verif_pid(s, ent->pid, cpu))
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	/* Cpu */
+	if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
+		ret = print_graph_cpu(s, cpu);
+		if (!ret)
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+
+	if (trace_branch_is_leaf(iter, field))
+		return print_graph_entry_leaf(iter, field, s);
+	else
+		return print_graph_entry_nested(field, s);
+
+}
+
 static enum print_line_t
 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 		   struct trace_entry *ent, int cpu)
 {
 	int i;
 	int ret;
+	unsigned long long duration = trace->rettime - trace->calltime;
+
+	/* Must not exceed 8 characters: xxxx.yyy us */
+	if (duration > 10000000ULL)
+		duration = 9999999ULL;
 
+	/* Pid */
 	if (!verif_pid(s, ent->pid, cpu))
 		return TRACE_TYPE_PARTIAL_LINE;
 
-	ret = trace_seq_printf(s, "CPU[%03d] ", cpu);
+	/* Cpu */
+	if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
+		ret = print_graph_cpu(s, cpu);
+		if (!ret)
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+
+	/* Overhead */
+	if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
+		ret = print_graph_overhead(duration, s);
+		if (!ret)
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+
+	/* Duration */
+	ret = print_graph_duration(duration, s);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 
+	/* Closing brace */
 	for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
 		ret = trace_seq_printf(s, " ");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 
-	ret = trace_seq_printf(s, "} ");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = trace_seq_printf(s, "%llu\n", trace->rettime - trace->calltime);
+	ret = trace_seq_printf(s, "}\n");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 
+	/* Overrun */
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {
 		ret = trace_seq_printf(s, " (Overruns: %lu)\n",
 					trace->overrun);
@@ -146,7 +371,7 @@ print_graph_function(struct trace_iterator *iter)
 	case TRACE_GRAPH_ENT: {
 		struct ftrace_graph_ent_entry *field;
 		trace_assign_type(field, entry);
-		return print_graph_entry(&field->graph_ent, s, entry,
+		return print_graph_entry(field, s, iter,
 					 iter->cpu);
 	}
 	case TRACE_GRAPH_RET: {
@@ -160,7 +385,7 @@ print_graph_function(struct trace_iterator *iter)
 }
 
 static struct tracer graph_trace __read_mostly = {
-	.name	     = "function-graph",
+	.name	     = "function_graph",
 	.init	     = graph_trace_init,
 	.reset	     = graph_trace_reset,
 	.print_line = print_graph_function,