[net-next-2.6.git] / kernel / profile.c

/*
 *  linux/kernel/profile.c
 *  Simple profiling. Manages a direct-mapped profile hit count buffer,
 *  with configurable resolution, support for restricting the cpus on
 *  which profiling is done, and switching between cpu time and
 *  schedule() calls via kernel command line parameters passed at boot.
 *
 *  Scheduler profiling support, Arjan van de Ven and Ingo Molnar,
 *	Red Hat, July 2004
 *  Consolidation of architecture support code for profiling,
 *	William Irwin, Oracle, July 2004
 *  Amortized hit count accounting via per-cpu open-addressed hashtables
 *	to resolve timer interrupt livelocks, William Irwin, Oracle, 2004
 */

#include <linux/module.h>
#include <linux/profile.h>
#include <linux/bootmem.h>
#include <linux/notifier.h>
#include <linux/mm.h>
#include <linux/cpumask.h>
#include <linux/cpu.h>
#include <linux/profile.h>
#include <linux/highmem.h>
#include <linux/mutex.h>
#include <asm/sections.h>
#include <asm/semaphore.h>
#include <asm/irq_regs.h>

struct profile_hit {
	u32 pc, hits;
};
#define PROFILE_GRPSHIFT	3
#define PROFILE_GRPSZ		(1 << PROFILE_GRPSHIFT)
#define NR_PROFILE_HIT		(PAGE_SIZE/sizeof(struct profile_hit))
#define NR_PROFILE_GRP		(NR_PROFILE_HIT/PROFILE_GRPSZ)

/* Oprofile timer tick hook */
int (*timer_hook)(struct pt_regs *) __read_mostly;

static atomic_t *prof_buffer;
static unsigned long prof_len, prof_shift;

int prof_on __read_mostly;
EXPORT_SYMBOL_GPL(prof_on);

static cpumask_t prof_cpu_mask = CPU_MASK_ALL;
#ifdef CONFIG_SMP
static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
static DEFINE_PER_CPU(int, cpu_profile_flip);
static DEFINE_MUTEX(profile_flip_mutex);
#endif /* CONFIG_SMP */

static int __init profile_setup(char * str)
{
	static char __initdata schedstr[] = "schedule";
	static char __initdata sleepstr[] = "sleep";
	static char __initdata kvmstr[] = "kvm";
	int par;

	if (!strncmp(str, sleepstr, strlen(sleepstr))) {
		prof_on = SLEEP_PROFILING;
		if (str[strlen(sleepstr)] == ',')
			str += strlen(sleepstr) + 1;
		if (get_option(&str, &par))
			prof_shift = par;
		printk(KERN_INFO
			"kernel sleep profiling enabled (shift: %ld)\n",
			prof_shift);
	} else if (!strncmp(str, schedstr, strlen(schedstr))) {
		prof_on = SCHED_PROFILING;
		if (str[strlen(schedstr)] == ',')
			str += strlen(schedstr) + 1;
		if (get_option(&str, &par))
			prof_shift = par;
		printk(KERN_INFO
			"kernel schedule profiling enabled (shift: %ld)\n",
			prof_shift);
	} else if (!strncmp(str, kvmstr, strlen(kvmstr))) {
		prof_on = KVM_PROFILING;
		if (str[strlen(kvmstr)] == ',')
			str += strlen(kvmstr) + 1;
		if (get_option(&str, &par))
			prof_shift = par;
		printk(KERN_INFO
			"kernel KVM profiling enabled (shift: %ld)\n",
			prof_shift);
	} else if (get_option(&str, &par)) {
		prof_shift = par;
		prof_on = CPU_PROFILING;
		printk(KERN_INFO "kernel profiling enabled (shift: %ld)\n",
			prof_shift);
	}
	return 1;
}
__setup("profile=", profile_setup);


void __init profile_init(void)
{
	if (!prof_on) 
		return;
 
	/* only text is profiled */
	prof_len = (_etext - _stext) >> prof_shift;
	prof_buffer = alloc_bootmem(prof_len*sizeof(atomic_t));
}

/* Profile event notifications */
 
#ifdef CONFIG_PROFILING
 
static BLOCKING_NOTIFIER_HEAD(task_exit_notifier);
static ATOMIC_NOTIFIER_HEAD(task_free_notifier);
static BLOCKING_NOTIFIER_HEAD(munmap_notifier);
 
void profile_task_exit(struct task_struct * task)
{
	blocking_notifier_call_chain(&task_exit_notifier, 0, task);
}
 
int profile_handoff_task(struct task_struct * task)
{
	int ret;
	ret = atomic_notifier_call_chain(&task_free_notifier, 0, task);
	return (ret == NOTIFY_OK) ? 1 : 0;
}

void profile_munmap(unsigned long addr)
{
	blocking_notifier_call_chain(&munmap_notifier, 0, (void *)addr);
}

int task_handoff_register(struct notifier_block * n)
{
	return atomic_notifier_chain_register(&task_free_notifier, n);
}

int task_handoff_unregister(struct notifier_block * n)
{
	return atomic_notifier_chain_unregister(&task_free_notifier, n);
}

int profile_event_register(enum profile_type type, struct notifier_block * n)
{
	int err = -EINVAL;
 
	switch (type) {
		case PROFILE_TASK_EXIT:
			err = blocking_notifier_chain_register(
					&task_exit_notifier, n);
			break;
		case PROFILE_MUNMAP:
			err = blocking_notifier_chain_register(
					&munmap_notifier, n);
			break;
	}
 
	return err;
}

 
int profile_event_unregister(enum profile_type type, struct notifier_block * n)
{
	int err = -EINVAL;
 
	switch (type) {
		case PROFILE_TASK_EXIT:
			err = blocking_notifier_chain_unregister(
					&task_exit_notifier, n);
			break;
		case PROFILE_MUNMAP:
			err = blocking_notifier_chain_unregister(
					&munmap_notifier, n);
			break;
	}

	return err;
}

int register_timer_hook(int (*hook)(struct pt_regs *))
{
	if (timer_hook)
		return -EBUSY;
	timer_hook = hook;
	return 0;
}

void unregister_timer_hook(int (*hook)(struct pt_regs *))
{
	WARN_ON(hook != timer_hook);
	timer_hook = NULL;
	/* make sure all CPUs see the NULL hook */
	synchronize_sched();  /* Allow ongoing interrupts to complete. */
}

EXPORT_SYMBOL_GPL(register_timer_hook);
EXPORT_SYMBOL_GPL(unregister_timer_hook);
EXPORT_SYMBOL_GPL(task_handoff_register);
EXPORT_SYMBOL_GPL(task_handoff_unregister);

#endif /* CONFIG_PROFILING */

EXPORT_SYMBOL_GPL(profile_event_register);
EXPORT_SYMBOL_GPL(profile_event_unregister);

#ifdef CONFIG_SMP
/*
 * Each cpu has a pair of open-addressed hashtables for pending
 * profile hits. read_profile() IPI's all cpus to request them
 * to flip buffers and flushes their contents to prof_buffer itself.
 * Flip requests are serialized by the profile_flip_mutex. The sole
 * use of having a second hashtable is for avoiding cacheline
 * contention that would otherwise happen during flushes of pending
 * profile hits required for the accuracy of reported profile hits
 * and so resurrect the interrupt livelock issue.
 *
 * The open-addressed hashtables are indexed by profile buffer slot
 * and hold the number of pending hits to that profile buffer slot on
 * a cpu in an entry. When the hashtable overflows, all pending hits
 * are accounted to their corresponding profile buffer slots with
 * atomic_add() and the hashtable emptied. As numerous pending hits
 * may be accounted to a profile buffer slot in a hashtable entry,
 * this amortizes a number of atomic profile buffer increments likely
 * to be far larger than the number of entries in the hashtable,
 * particularly given that the number of distinct profile buffer
 * positions to which hits are accounted during short intervals (e.g.
 * several seconds) is usually very small. Exclusion from buffer
 * flipping is provided by interrupt disablement (note that for
 * SCHED_PROFILING or SLEEP_PROFILING profile_hit() may be called from
 * process context).
 * The hash function is meant to be lightweight as opposed to strong,
 * and was vaguely inspired by ppc64 firmware-supported inverted
 * pagetable hash functions, but uses a full hashtable full of finite
 * collision chains, not just pairs of them.
 *
 * -- wli
 */
static void __profile_flip_buffers(void *unused)
{
	int cpu = smp_processor_id();

	per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu);
}

static void profile_flip_buffers(void)
{
	int i, j, cpu;

	mutex_lock(&profile_flip_mutex);
	j = per_cpu(cpu_profile_flip, get_cpu());
	put_cpu();
	on_each_cpu(__profile_flip_buffers, NULL, 0, 1);
	for_each_online_cpu(cpu) {
		struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[j];
		for (i = 0; i < NR_PROFILE_HIT; ++i) {
			if (!hits[i].hits) {
				if (hits[i].pc)
					hits[i].pc = 0;
				continue;
			}
			atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
			hits[i].hits = hits[i].pc = 0;
		}
	}
	mutex_unlock(&profile_flip_mutex);
}

static void profile_discard_flip_buffers(void)
{
	int i, cpu;

	mutex_lock(&profile_flip_mutex);
	i = per_cpu(cpu_profile_flip, get_cpu());
	put_cpu();
	on_each_cpu(__profile_flip_buffers, NULL, 0, 1);
	for_each_online_cpu(cpu) {
		struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[i];
		memset(hits, 0, NR_PROFILE_HIT*sizeof(struct profile_hit));
	}
	mutex_unlock(&profile_flip_mutex);
}

void profile_hits(int type, void *__pc, unsigned int nr_hits)
{
	unsigned long primary, secondary, flags, pc = (unsigned long)__pc;
	int i, j, cpu;
	struct profile_hit *hits;

	if (prof_on != type || !prof_buffer)
		return;
	pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1);
	i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
	secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
	cpu = get_cpu();
	hits = per_cpu(cpu_profile_hits, cpu)[per_cpu(cpu_profile_flip, cpu)];
	if (!hits) {
		put_cpu();
		return;
	}
	/*
	 * We buffer the global profiler buffer into a per-CPU
	 * queue and thus reduce the number of global (and possibly
	 * NUMA-alien) accesses. The write-queue is self-coalescing:
	 */
	local_irq_save(flags);
	do {
		for (j = 0; j < PROFILE_GRPSZ; ++j) {
			if (hits[i + j].pc == pc) {
				hits[i + j].hits += nr_hits;
				goto out;
			} else if (!hits[i + j].hits) {
				hits[i + j].pc = pc;
				hits[i + j].hits = nr_hits;
				goto out;
			}
		}
		i = (i + secondary) & (NR_PROFILE_HIT - 1);
	} while (i != primary);

	/*
	 * Add the current hit(s) and flush the write-queue out
	 * to the global buffer:
	 */
	atomic_add(nr_hits, &prof_buffer[pc]);
	for (i = 0; i < NR_PROFILE_HIT; ++i) {
		atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
		hits[i].pc = hits[i].hits = 0;
	}
out:
	local_irq_restore(flags);
	put_cpu();
}

static int __devinit profile_cpu_callback(struct notifier_block *info,
					unsigned long action, void *__cpu)
{
	int node, cpu = (unsigned long)__cpu;
	struct page *page;

	switch (action) {
	case CPU_UP_PREPARE:
	case CPU_UP_PREPARE_FROZEN:
		node = cpu_to_node(cpu);
		per_cpu(cpu_profile_flip, cpu) = 0;
		if (!per_cpu(cpu_profile_hits, cpu)[1]) {
			page = alloc_pages_node(node,
					GFP_KERNEL | __GFP_ZERO | GFP_THISNODE,
					0);
			if (!page)
				return NOTIFY_BAD;
			per_cpu(cpu_profile_hits, cpu)[1] = page_address(page);
		}
		if (!per_cpu(cpu_profile_hits, cpu)[0]) {
			page = alloc_pages_node(node,
					GFP_KERNEL | __GFP_ZERO | GFP_THISNODE,
					0);
			if (!page)
				goto out_free;
			per_cpu(cpu_profile_hits, cpu)[0] = page_address(page);
		}
		break;
	out_free:
		page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
		per_cpu(cpu_profile_hits, cpu)[1] = NULL;
		__free_page(page);
		return NOTIFY_BAD;
	case CPU_ONLINE:
	case CPU_ONLINE_FROZEN:
		cpu_set(cpu, prof_cpu_mask);
		break;
	case CPU_UP_CANCELED:
	case CPU_UP_CANCELED_FROZEN:
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		cpu_clear(cpu, prof_cpu_mask);
		if (per_cpu(cpu_profile_hits, cpu)[0]) {
			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
			per_cpu(cpu_profile_hits, cpu)[0] = NULL;
			__free_page(page);
		}
		if (per_cpu(cpu_profile_hits, cpu)[1]) {
			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
			per_cpu(cpu_profile_hits, cpu)[1] = NULL;
			__free_page(page);
		}
		break;
	}
	return NOTIFY_OK;
}
#else /* !CONFIG_SMP */
#define profile_flip_buffers()		do { } while (0)
#define profile_discard_flip_buffers()	do { } while (0)
#define profile_cpu_callback		NULL

void profile_hits(int type, void *__pc, unsigned int nr_hits)
{
	unsigned long pc;

	if (prof_on != type || !prof_buffer)
		return;
	pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
	atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]);
}
#endif /* !CONFIG_SMP */

EXPORT_SYMBOL_GPL(profile_hits);

void profile_tick(int type)
{
	struct pt_regs *regs = get_irq_regs();

	if (type == CPU_PROFILING && timer_hook)
		timer_hook(regs);
	if (!user_mode(regs) && cpu_isset(smp_processor_id(), prof_cpu_mask))
		profile_hit(type, (void *)profile_pc(regs));
}

#ifdef CONFIG_PROC_FS
#include <linux/proc_fs.h>
#include <asm/uaccess.h>
#include <asm/ptrace.h>

static int prof_cpu_mask_read_proc (char *page, char **start, off_t off,
			int count, int *eof, void *data)
{
	int len = cpumask_scnprintf(page, count, *(cpumask_t *)data);
	if (count - len < 2)
		return -EINVAL;
	len += sprintf(page + len, "\n");
	return len;
}

static int prof_cpu_mask_write_proc (struct file *file, const char __user *buffer,
					unsigned long count, void *data)
{
	cpumask_t *mask = (cpumask_t *)data;
	unsigned long full_count = count, err;
	cpumask_t new_value;

	err = cpumask_parse_user(buffer, count, new_value);
	if (err)
		return err;

	*mask = new_value;
	return full_count;
}

void create_prof_cpu_mask(struct proc_dir_entry *root_irq_dir)
{
	struct proc_dir_entry *entry;

	/* create /proc/irq/prof_cpu_mask */
	if (!(entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir)))
		return;
	entry->data = (void *)&prof_cpu_mask;
	entry->read_proc = prof_cpu_mask_read_proc;
	entry->write_proc = prof_cpu_mask_write_proc;
}

/*
 * This function accesses profiling information. The returned data is
 * binary: the sampling step and the actual contents of the profile
 * buffer. Use of the program readprofile is recommended in order to
 * get meaningful info out of these data.
 */
static ssize_t
read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
	unsigned long p = *ppos;
	ssize_t read;
	char * pnt;
	unsigned int sample_step = 1 << prof_shift;

	profile_flip_buffers();
	if (p >= (prof_len+1)*sizeof(unsigned int))
		return 0;
	if (count > (prof_len+1)*sizeof(unsigned int) - p)
		count = (prof_len+1)*sizeof(unsigned int) - p;
	read = 0;

	while (p < sizeof(unsigned int) && count > 0) {
		if (put_user(*((char *)(&sample_step)+p),buf))
			return -EFAULT;
		buf++; p++; count--; read++;
	}
	pnt = (char *)prof_buffer + p - sizeof(atomic_t);
	if (copy_to_user(buf,(void *)pnt,count))
		return -EFAULT;
	read += count;
	*ppos += read;
	return read;
}

/*
 * Writing to /proc/profile resets the counters
 *
 * Writing a 'profiling multiplier' value into it also re-sets the profiling
 * interrupt frequency, on architectures that support this.
 */
static ssize_t write_profile(struct file *file, const char __user *buf,
			     size_t count, loff_t *ppos)
{
#ifdef CONFIG_SMP
	extern int setup_profiling_timer (unsigned int multiplier);

	if (count == sizeof(int)) {
		unsigned int multiplier;

		if (copy_from_user(&multiplier, buf, sizeof(int)))
			return -EFAULT;

		if (setup_profiling_timer(multiplier))
			return -EINVAL;
	}
#endif
	profile_discard_flip_buffers();
	memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
	return count;
}

static const struct file_operations proc_profile_operations = {
	.read		= read_profile,
	.write		= write_profile,
};

#ifdef CONFIG_SMP
static void __init profile_nop(void *unused)
{
}

static int __init create_hash_tables(void)
{
	int cpu;

	for_each_online_cpu(cpu) {
		int node = cpu_to_node(cpu);
		struct page *page;

		page = alloc_pages_node(node,
				GFP_KERNEL | __GFP_ZERO | GFP_THISNODE,
				0);
		if (!page)
			goto out_cleanup;
		per_cpu(cpu_profile_hits, cpu)[1]
				= (struct profile_hit *)page_address(page);
		page = alloc_pages_node(node,
				GFP_KERNEL | __GFP_ZERO | GFP_THISNODE,
				0);
		if (!page)
			goto out_cleanup;
		per_cpu(cpu_profile_hits, cpu)[0]
				= (struct profile_hit *)page_address(page);
	}
	return 0;
out_cleanup:
	prof_on = 0;
	smp_mb();
	on_each_cpu(profile_nop, NULL, 0, 1);
	for_each_online_cpu(cpu) {
		struct page *page;

		if (per_cpu(cpu_profile_hits, cpu)[0]) {
			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
			per_cpu(cpu_profile_hits, cpu)[0] = NULL;
			__free_page(page);
		}
		if (per_cpu(cpu_profile_hits, cpu)[1]) {
			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
			per_cpu(cpu_profile_hits, cpu)[1] = NULL;
			__free_page(page);
		}
	}
	return -1;
}
#else
#define create_hash_tables()			({ 0; })
#endif

static int __init create_proc_profile(void)
{
	struct proc_dir_entry *entry;

	if (!prof_on)
		return 0;
	if (create_hash_tables())
		return -1;
	if (!(entry = create_proc_entry("profile", S_IWUSR | S_IRUGO, NULL)))
		return 0;
	entry->proc_fops = &proc_profile_operations;
	entry->size = (1+prof_len) * sizeof(atomic_t);
	hotcpu_notifier(profile_cpu_callback, 0);
	return 0;
}
module_init(create_proc_profile);
#endif /* CONFIG_PROC_FS */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/kernel/profile.c
	3	* Simple profiling. Manages a direct-mapped profile hit count buffer,
	4	* with configurable resolution, support for restricting the cpus on
	5	* which profiling is done, and switching between cpu time and
	6	* schedule() calls via kernel command line parameters passed at boot.
	7	*
	8	* Scheduler profiling support, Arjan van de Ven and Ingo Molnar,
	9	* Red Hat, July 2004
	10	* Consolidation of architecture support code for profiling,
	11	* William Irwin, Oracle, July 2004
	12	* Amortized hit count accounting via per-cpu open-addressed hashtables
	13	* to resolve timer interrupt livelocks, William Irwin, Oracle, 2004
	14	*/
	15
1da177e4 LT	16	#include <linux/module.h>
	17	#include <linux/profile.h>
	18	#include <linux/bootmem.h>
	19	#include <linux/notifier.h>
	20	#include <linux/mm.h>
	21	#include <linux/cpumask.h>
	22	#include <linux/cpu.h>
	23	#include <linux/profile.h>
	24	#include <linux/highmem.h>
97d1f15b	25	#include <linux/mutex.h>
1da177e4 LT	26	#include <asm/sections.h>
1da177e4 LT	27	#include <asm/semaphore.h>
7d12e780	28	#include <asm/irq_regs.h>
1da177e4 LT	29
	30	struct profile_hit {
	31	u32 pc, hits;
	32	};
	33	#define PROFILE_GRPSHIFT 3
	34	#define PROFILE_GRPSZ (1 << PROFILE_GRPSHIFT)
	35	#define NR_PROFILE_HIT (PAGE_SIZE/sizeof(struct profile_hit))
	36	#define NR_PROFILE_GRP (NR_PROFILE_HIT/PROFILE_GRPSZ)
	37
	38	/* Oprofile timer tick hook */
6c036527	39	int (timer_hook)(struct pt_regs ) __read_mostly;
1da177e4 LT	40
	41	static atomic_t *prof_buffer;
	42	static unsigned long prof_len, prof_shift;
07031e14	43
ece8a684	44	int prof_on __read_mostly;
07031e14 IM	45	EXPORT_SYMBOL_GPL(prof_on);
07031e14 IM	46
1da177e4 LT	47	static cpumask_t prof_cpu_mask = CPU_MASK_ALL;
	48	#ifdef CONFIG_SMP
	49	static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
	50	static DEFINE_PER_CPU(int, cpu_profile_flip);
97d1f15b	51	static DEFINE_MUTEX(profile_flip_mutex);
1da177e4 LT	52	#endif /* CONFIG_SMP */
	53
	54	static int __init profile_setup(char * str)
	55	{
dfaa9c94	56	static char __initdata schedstr[] = "schedule";
ece8a684	57	static char __initdata sleepstr[] = "sleep";
07031e14	58	static char __initdata kvmstr[] = "kvm";
1da177e4 LT	59	int par;
1da177e4 LT	60
ece8a684 IM	61	if (!strncmp(str, sleepstr, strlen(sleepstr))) {
	62	prof_on = SLEEP_PROFILING;
	63	if (str[strlen(sleepstr)] == ',')
	64	str += strlen(sleepstr) + 1;
	65	if (get_option(&str, &par))
	66	prof_shift = par;
	67	printk(KERN_INFO
	68	"kernel sleep profiling enabled (shift: %ld)\n",
	69	prof_shift);
a75acf85	70	} else if (!strncmp(str, schedstr, strlen(schedstr))) {
1da177e4	71	prof_on = SCHED_PROFILING;
dfaa9c94 WLII	72	if (str[strlen(schedstr)] == ',')
	73	str += strlen(schedstr) + 1;
	74	if (get_option(&str, &par))
	75	prof_shift = par;
	76	printk(KERN_INFO
	77	"kernel schedule profiling enabled (shift: %ld)\n",
	78	prof_shift);
07031e14 IM	79	} else if (!strncmp(str, kvmstr, strlen(kvmstr))) {
	80	prof_on = KVM_PROFILING;
	81	if (str[strlen(kvmstr)] == ',')
	82	str += strlen(kvmstr) + 1;
	83	if (get_option(&str, &par))
	84	prof_shift = par;
	85	printk(KERN_INFO
	86	"kernel KVM profiling enabled (shift: %ld)\n",
	87	prof_shift);
dfaa9c94	88	} else if (get_option(&str, &par)) {
1da177e4 LT	89	prof_shift = par;
	90	prof_on = CPU_PROFILING;
	91	printk(KERN_INFO "kernel profiling enabled (shift: %ld)\n",
	92	prof_shift);
	93	}
	94	return 1;
	95	}
	96	__setup("profile=", profile_setup);
	97
	98
	99	void __init profile_init(void)
	100	{
	101	if (!prof_on)
	102	return;
	103
	104	/* only text is profiled */
	105	prof_len = (_etext - _stext) >> prof_shift;
	106	prof_buffer = alloc_bootmem(prof_len*sizeof(atomic_t));
	107	}
	108
	109	/* Profile event notifications */
	110
	111	#ifdef CONFIG_PROFILING
	112
e041c683 AS	113	static BLOCKING_NOTIFIER_HEAD(task_exit_notifier);
	114	static ATOMIC_NOTIFIER_HEAD(task_free_notifier);
	115	static BLOCKING_NOTIFIER_HEAD(munmap_notifier);
1da177e4 LT	116
	117	void profile_task_exit(struct task_struct * task)
	118	{
e041c683	119	blocking_notifier_call_chain(&task_exit_notifier, 0, task);
1da177e4 LT	120	}
	121
	122	int profile_handoff_task(struct task_struct * task)
	123	{
	124	int ret;
e041c683	125	ret = atomic_notifier_call_chain(&task_free_notifier, 0, task);
1da177e4 LT	126	return (ret == NOTIFY_OK) ? 1 : 0;
	127	}
	128
	129	void profile_munmap(unsigned long addr)
	130	{
e041c683	131	blocking_notifier_call_chain(&munmap_notifier, 0, (void *)addr);
1da177e4 LT	132	}
	133
	134	int task_handoff_register(struct notifier_block * n)
	135	{
e041c683	136	return atomic_notifier_chain_register(&task_free_notifier, n);
1da177e4 LT	137	}
	138
	139	int task_handoff_unregister(struct notifier_block * n)
	140	{
e041c683	141	return atomic_notifier_chain_unregister(&task_free_notifier, n);
1da177e4 LT	142	}
	143
	144	int profile_event_register(enum profile_type type, struct notifier_block * n)
	145	{
	146	int err = -EINVAL;
	147
1da177e4 LT	148	switch (type) {
1da177e4 LT	149	case PROFILE_TASK_EXIT:
e041c683 AS	150	err = blocking_notifier_chain_register(
e041c683 AS	151	&task_exit_notifier, n);
1da177e4 LT	152	break;
1da177e4 LT	153	case PROFILE_MUNMAP:
e041c683 AS	154	err = blocking_notifier_chain_register(
e041c683 AS	155	&munmap_notifier, n);
1da177e4 LT	156	break;
	157	}
	158
1da177e4 LT	159	return err;
	160	}
	161
	162
	163	int profile_event_unregister(enum profile_type type, struct notifier_block * n)
	164	{
	165	int err = -EINVAL;
	166
1da177e4 LT	167	switch (type) {
1da177e4 LT	168	case PROFILE_TASK_EXIT:
e041c683 AS	169	err = blocking_notifier_chain_unregister(
e041c683 AS	170	&task_exit_notifier, n);
1da177e4 LT	171	break;
1da177e4 LT	172	case PROFILE_MUNMAP:
e041c683 AS	173	err = blocking_notifier_chain_unregister(
e041c683 AS	174	&munmap_notifier, n);
1da177e4 LT	175	break;
	176	}
	177
1da177e4 LT	178	return err;
	179	}
	180
	181	int register_timer_hook(int (hook)(struct pt_regs ))
	182	{
	183	if (timer_hook)
	184	return -EBUSY;
	185	timer_hook = hook;
	186	return 0;
	187	}
	188
	189	void unregister_timer_hook(int (hook)(struct pt_regs ))
	190	{
	191	WARN_ON(hook != timer_hook);
	192	timer_hook = NULL;
	193	/* make sure all CPUs see the NULL hook */
fbd568a3	194	synchronize_sched(); /* Allow ongoing interrupts to complete. */
1da177e4 LT	195	}
	196
	197	EXPORT_SYMBOL_GPL(register_timer_hook);
	198	EXPORT_SYMBOL_GPL(unregister_timer_hook);
	199	EXPORT_SYMBOL_GPL(task_handoff_register);
	200	EXPORT_SYMBOL_GPL(task_handoff_unregister);
	201
	202	#endif /* CONFIG_PROFILING */
	203
	204	EXPORT_SYMBOL_GPL(profile_event_register);
	205	EXPORT_SYMBOL_GPL(profile_event_unregister);
	206
	207	#ifdef CONFIG_SMP
	208	/*
	209	* Each cpu has a pair of open-addressed hashtables for pending
	210	* profile hits. read_profile() IPI's all cpus to request them
	211	* to flip buffers and flushes their contents to prof_buffer itself.
	212	* Flip requests are serialized by the profile_flip_mutex. The sole
	213	* use of having a second hashtable is for avoiding cacheline
	214	* contention that would otherwise happen during flushes of pending
	215	* profile hits required for the accuracy of reported profile hits
	216	* and so resurrect the interrupt livelock issue.
	217	*
	218	* The open-addressed hashtables are indexed by profile buffer slot
	219	* and hold the number of pending hits to that profile buffer slot on
	220	* a cpu in an entry. When the hashtable overflows, all pending hits
	221	* are accounted to their corresponding profile buffer slots with
	222	* atomic_add() and the hashtable emptied. As numerous pending hits
	223	* may be accounted to a profile buffer slot in a hashtable entry,
	224	* this amortizes a number of atomic profile buffer increments likely
	225	* to be far larger than the number of entries in the hashtable,
	226	* particularly given that the number of distinct profile buffer
	227	* positions to which hits are accounted during short intervals (e.g.
	228	* several seconds) is usually very small. Exclusion from buffer
	229	* flipping is provided by interrupt disablement (note that for
ece8a684 IM	230	* SCHED_PROFILING or SLEEP_PROFILING profile_hit() may be called from
ece8a684 IM	231	* process context).
1da177e4 LT	232	* The hash function is meant to be lightweight as opposed to strong,
	233	* and was vaguely inspired by ppc64 firmware-supported inverted
	234	* pagetable hash functions, but uses a full hashtable full of finite
	235	* collision chains, not just pairs of them.
	236	*
	237	* -- wli
	238	*/
	239	static void __profile_flip_buffers(void *unused)
	240	{
	241	int cpu = smp_processor_id();
	242
	243	per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu);
	244	}
	245
	246	static void profile_flip_buffers(void)
	247	{
	248	int i, j, cpu;
	249
97d1f15b	250	mutex_lock(&profile_flip_mutex);
1da177e4 LT	251	j = per_cpu(cpu_profile_flip, get_cpu());
	252	put_cpu();
	253	on_each_cpu(__profile_flip_buffers, NULL, 0, 1);
	254	for_each_online_cpu(cpu) {
	255	struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[j];
	256	for (i = 0; i < NR_PROFILE_HIT; ++i) {
	257	if (!hits[i].hits) {
	258	if (hits[i].pc)
	259	hits[i].pc = 0;
	260	continue;
	261	}
	262	atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
	263	hits[i].hits = hits[i].pc = 0;
	264	}
	265	}
97d1f15b	266	mutex_unlock(&profile_flip_mutex);
1da177e4 LT	267	}
	268
	269	static void profile_discard_flip_buffers(void)
	270	{
	271	int i, cpu;
	272
97d1f15b	273	mutex_lock(&profile_flip_mutex);
1da177e4 LT	274	i = per_cpu(cpu_profile_flip, get_cpu());
	275	put_cpu();
	276	on_each_cpu(__profile_flip_buffers, NULL, 0, 1);
	277	for_each_online_cpu(cpu) {
	278	struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[i];
	279	memset(hits, 0, NR_PROFILE_HIT*sizeof(struct profile_hit));
	280	}
97d1f15b	281	mutex_unlock(&profile_flip_mutex);
1da177e4 LT	282	}
1da177e4 LT	283
ece8a684	284	void profile_hits(int type, void *__pc, unsigned int nr_hits)
1da177e4 LT	285	{
	286	unsigned long primary, secondary, flags, pc = (unsigned long)__pc;
	287	int i, j, cpu;
	288	struct profile_hit *hits;
	289
	290	if (prof_on != type \|\| !prof_buffer)
	291	return;
	292	pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1);
	293	i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
	294	secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
	295	cpu = get_cpu();
	296	hits = per_cpu(cpu_profile_hits, cpu)[per_cpu(cpu_profile_flip, cpu)];
	297	if (!hits) {
	298	put_cpu();
	299	return;
	300	}
ece8a684 IM	301	/*
	302	* We buffer the global profiler buffer into a per-CPU
	303	* queue and thus reduce the number of global (and possibly
	304	* NUMA-alien) accesses. The write-queue is self-coalescing:
	305	*/
1da177e4 LT	306	local_irq_save(flags);
	307	do {
	308	for (j = 0; j < PROFILE_GRPSZ; ++j) {
	309	if (hits[i + j].pc == pc) {
ece8a684	310	hits[i + j].hits += nr_hits;
1da177e4 LT	311	goto out;
	312	} else if (!hits[i + j].hits) {
	313	hits[i + j].pc = pc;
ece8a684	314	hits[i + j].hits = nr_hits;
1da177e4 LT	315	goto out;
	316	}
	317	}
	318	i = (i + secondary) & (NR_PROFILE_HIT - 1);
	319	} while (i != primary);
ece8a684 IM	320
	321	/*
	322	* Add the current hit(s) and flush the write-queue out
	323	* to the global buffer:
	324	*/
	325	atomic_add(nr_hits, &prof_buffer[pc]);
1da177e4 LT	326	for (i = 0; i < NR_PROFILE_HIT; ++i) {
	327	atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
	328	hits[i].pc = hits[i].hits = 0;
	329	}
	330	out:
	331	local_irq_restore(flags);
	332	put_cpu();
	333	}
	334
9c7b216d	335	static int __devinit profile_cpu_callback(struct notifier_block *info,
1da177e4 LT	336	unsigned long action, void *__cpu)
	337	{
	338	int node, cpu = (unsigned long)__cpu;
	339	struct page *page;
	340
	341	switch (action) {
	342	case CPU_UP_PREPARE:
8bb78442	343	case CPU_UP_PREPARE_FROZEN:
1da177e4 LT	344	node = cpu_to_node(cpu);
	345	per_cpu(cpu_profile_flip, cpu) = 0;
	346	if (!per_cpu(cpu_profile_hits, cpu)[1]) {
fbd98167 CL	347	page = alloc_pages_node(node,
	348	GFP_KERNEL \| __GFP_ZERO \| GFP_THISNODE,
	349	0);
1da177e4 LT	350	if (!page)
	351	return NOTIFY_BAD;
	352	per_cpu(cpu_profile_hits, cpu)[1] = page_address(page);
	353	}
	354	if (!per_cpu(cpu_profile_hits, cpu)[0]) {
fbd98167 CL	355	page = alloc_pages_node(node,
	356	GFP_KERNEL \| __GFP_ZERO \| GFP_THISNODE,
	357	0);
1da177e4 LT	358	if (!page)
	359	goto out_free;
	360	per_cpu(cpu_profile_hits, cpu)[0] = page_address(page);
	361	}
	362	break;
	363	out_free:
	364	page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
	365	per_cpu(cpu_profile_hits, cpu)[1] = NULL;
	366	__free_page(page);
	367	return NOTIFY_BAD;
	368	case CPU_ONLINE:
8bb78442	369	case CPU_ONLINE_FROZEN:
1da177e4 LT	370	cpu_set(cpu, prof_cpu_mask);
	371	break;
	372	case CPU_UP_CANCELED:
8bb78442	373	case CPU_UP_CANCELED_FROZEN:
1da177e4	374	case CPU_DEAD:
8bb78442	375	case CPU_DEAD_FROZEN:
1da177e4 LT	376	cpu_clear(cpu, prof_cpu_mask);
	377	if (per_cpu(cpu_profile_hits, cpu)[0]) {
	378	page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
	379	per_cpu(cpu_profile_hits, cpu)[0] = NULL;
	380	__free_page(page);
	381	}
	382	if (per_cpu(cpu_profile_hits, cpu)[1]) {
	383	page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
	384	per_cpu(cpu_profile_hits, cpu)[1] = NULL;
	385	__free_page(page);
	386	}
	387	break;
	388	}
	389	return NOTIFY_OK;
	390	}
1da177e4 LT	391	#else /* !CONFIG_SMP */
	392	#define profile_flip_buffers() do { } while (0)
	393	#define profile_discard_flip_buffers() do { } while (0)
02316067	394	#define profile_cpu_callback NULL
1da177e4	395
ece8a684	396	void profile_hits(int type, void *__pc, unsigned int nr_hits)
1da177e4 LT	397	{
	398	unsigned long pc;
	399
	400	if (prof_on != type \|\| !prof_buffer)
	401	return;
	402	pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
ece8a684	403	atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]);
1da177e4 LT	404	}
	405	#endif /* !CONFIG_SMP */
	406
bbe1a59b AM	407	EXPORT_SYMBOL_GPL(profile_hits);
bbe1a59b AM	408
7d12e780	409	void profile_tick(int type)
1da177e4	410	{
7d12e780 DH	411	struct pt_regs *regs = get_irq_regs();
7d12e780 DH	412
1da177e4 LT	413	if (type == CPU_PROFILING && timer_hook)
	414	timer_hook(regs);
	415	if (!user_mode(regs) && cpu_isset(smp_processor_id(), prof_cpu_mask))
	416	profile_hit(type, (void *)profile_pc(regs));
	417	}
	418
	419	#ifdef CONFIG_PROC_FS
	420	#include <linux/proc_fs.h>
	421	#include <asm/uaccess.h>
	422	#include <asm/ptrace.h>
	423
	424	static int prof_cpu_mask_read_proc (char page, char *start, off_t off,
	425	int count, int eof, void data)
	426	{
	427	int len = cpumask_scnprintf(page, count, (cpumask_t )data);
	428	if (count - len < 2)
	429	return -EINVAL;
	430	len += sprintf(page + len, "\n");
	431	return len;
	432	}
	433
	434	static int prof_cpu_mask_write_proc (struct file file, const char __user buffer,
	435	unsigned long count, void *data)
	436	{
	437	cpumask_t mask = (cpumask_t )data;
	438	unsigned long full_count = count, err;
	439	cpumask_t new_value;
	440
01a3ee2b	441	err = cpumask_parse_user(buffer, count, new_value);
1da177e4 LT	442	if (err)
	443	return err;
	444
	445	*mask = new_value;
	446	return full_count;
	447	}
	448
	449	void create_prof_cpu_mask(struct proc_dir_entry *root_irq_dir)
	450	{
	451	struct proc_dir_entry *entry;
	452
	453	/* create /proc/irq/prof_cpu_mask */
	454	if (!(entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir)))
	455	return;
1da177e4 LT	456	entry->data = (void *)&prof_cpu_mask;
	457	entry->read_proc = prof_cpu_mask_read_proc;
	458	entry->write_proc = prof_cpu_mask_write_proc;
	459	}
	460
	461	/*
	462	* This function accesses profiling information. The returned data is
	463	* binary: the sampling step and the actual contents of the profile
	464	* buffer. Use of the program readprofile is recommended in order to
	465	* get meaningful info out of these data.
	466	*/
	467	static ssize_t
	468	read_profile(struct file file, char __user buf, size_t count, loff_t *ppos)
	469	{
	470	unsigned long p = *ppos;
	471	ssize_t read;
	472	char * pnt;
	473	unsigned int sample_step = 1 << prof_shift;
	474
	475	profile_flip_buffers();
	476	if (p >= (prof_len+1)*sizeof(unsigned int))
	477	return 0;
	478	if (count > (prof_len+1)*sizeof(unsigned int) - p)
	479	count = (prof_len+1)*sizeof(unsigned int) - p;
	480	read = 0;
	481
	482	while (p < sizeof(unsigned int) && count > 0) {
064b022c HC	483	if (put_user(((char )(&sample_step)+p),buf))
064b022c HC	484	return -EFAULT;
1da177e4 LT	485	buf++; p++; count--; read++;
	486	}
	487	pnt = (char *)prof_buffer + p - sizeof(atomic_t);
	488	if (copy_to_user(buf,(void *)pnt,count))
	489	return -EFAULT;
	490	read += count;
	491	*ppos += read;
	492	return read;
	493	}
	494
	495	/*
	496	* Writing to /proc/profile resets the counters
	497	*
	498	* Writing a 'profiling multiplier' value into it also re-sets the profiling
	499	* interrupt frequency, on architectures that support this.
	500	*/
	501	static ssize_t write_profile(struct file file, const char __user buf,
	502	size_t count, loff_t *ppos)
	503	{
	504	#ifdef CONFIG_SMP
	505	extern int setup_profiling_timer (unsigned int multiplier);
	506
	507	if (count == sizeof(int)) {
	508	unsigned int multiplier;
	509
	510	if (copy_from_user(&multiplier, buf, sizeof(int)))
	511	return -EFAULT;
	512
	513	if (setup_profiling_timer(multiplier))
	514	return -EINVAL;
	515	}
	516	#endif
	517	profile_discard_flip_buffers();
	518	memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
	519	return count;
	520	}
	521
15ad7cdc	522	static const struct file_operations proc_profile_operations = {
1da177e4 LT	523	.read = read_profile,
	524	.write = write_profile,
	525	};
	526
	527	#ifdef CONFIG_SMP
	528	static void __init profile_nop(void *unused)
	529	{
	530	}
	531
	532	static int __init create_hash_tables(void)
	533	{
	534	int cpu;
	535
	536	for_each_online_cpu(cpu) {
	537	int node = cpu_to_node(cpu);
	538	struct page *page;
	539
fbd98167 CL	540	page = alloc_pages_node(node,
	541	GFP_KERNEL \| __GFP_ZERO \| GFP_THISNODE,
	542	0);
1da177e4 LT	543	if (!page)
	544	goto out_cleanup;
	545	per_cpu(cpu_profile_hits, cpu)[1]
	546	= (struct profile_hit *)page_address(page);
fbd98167 CL	547	page = alloc_pages_node(node,
	548	GFP_KERNEL \| __GFP_ZERO \| GFP_THISNODE,
	549	0);
1da177e4 LT	550	if (!page)
	551	goto out_cleanup;
	552	per_cpu(cpu_profile_hits, cpu)[0]
	553	= (struct profile_hit *)page_address(page);
	554	}
	555	return 0;
	556	out_cleanup:
	557	prof_on = 0;
d59dd462	558	smp_mb();
1da177e4 LT	559	on_each_cpu(profile_nop, NULL, 0, 1);
	560	for_each_online_cpu(cpu) {
	561	struct page *page;
	562
	563	if (per_cpu(cpu_profile_hits, cpu)[0]) {
	564	page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
	565	per_cpu(cpu_profile_hits, cpu)[0] = NULL;
	566	__free_page(page);
	567	}
	568	if (per_cpu(cpu_profile_hits, cpu)[1]) {
	569	page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
	570	per_cpu(cpu_profile_hits, cpu)[1] = NULL;
	571	__free_page(page);
	572	}
	573	}
	574	return -1;
	575	}
	576	#else
	577	#define create_hash_tables() ({ 0; })
	578	#endif
	579
	580	static int __init create_proc_profile(void)
	581	{
	582	struct proc_dir_entry *entry;
	583
	584	if (!prof_on)
	585	return 0;
	586	if (create_hash_tables())
	587	return -1;
	588	if (!(entry = create_proc_entry("profile", S_IWUSR \| S_IRUGO, NULL)))
	589	return 0;
	590	entry->proc_fops = &proc_profile_operations;
	591	entry->size = (1+prof_len) * sizeof(atomic_t);
	592	hotcpu_notifier(profile_cpu_callback, 0);
	593	return 0;
	594	}
	595	module_init(create_proc_profile);
	596	#endif /* CONFIG_PROC_FS */