Date:	Wed, 31 Mar 2010 17:24:51 -0400
From:	Steven Rostedt <rostedt@...dmis.org>
To:	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc:	Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Masami Hiramatsu <mhiramat@...hat.com>,
	Randy Dunlap <rdunlap@...otime.net>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Jim Keniston <jkenisto@...ux.vnet.ibm.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	"Frank Ch. Eigler" <fche@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 11/11] Uprobes traceevents patch.

On Wed, 2010-03-31 at 21:23 +0530, Srikar Dronamraju wrote:

>  libftrace-y := ftrace.o
> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> index 2825ef2..9fe02ab 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -126,6 +126,18 @@ struct kretprobe_trace_entry {
>  	(offsetof(struct kretprobe_trace_entry, args) +	\
>  	(sizeof(unsigned long) * (n)))
>  
> +struct uprobe_trace_entry {
> +	struct trace_entry	ent;
> +	pid_t			pid;

Unless pid is not the current pid, ent already records it.

> +	unsigned long		ip;
> +	int			nargs;
> +	unsigned long		args[];
> +};

Note, you want to really add this to trace_entries.h instead:

FTRACE_ENTRY(uprobe, uprobe_trace_entry,

	TRACE_GRAPH_ENT,

	F_STRUCT(
		__field(	unsigned long,	ip	)
		__field(	int,		nargs	)
		__dynamic_array(unsigned long,	args	)
	),

	F_printk("%lx nrargs:%u", __entry->ip, __entry->nargs)
);


This will put this event into the events/ftrace directory. Don't worry
about the printk format, we can write a plugin for it to override it if
need be.

By adding the above, other tools can know what it encountered instead of
having a "Unknown Event" show up.

> +
> +#define SIZEOF_UPROBE_TRACE_ENTRY(n)			\
> +	(offsetof(struct uprobe_trace_entry, args) +	\
> +	(sizeof(unsigned long) * (n)))
> +
>  /*
>   * trace_flag_type is an enumeration that holds different
>   * states when a trace occurs. These are:
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> new file mode 100644
> index 0000000..3e146ef
> --- /dev/null
> +++ b/kernel/trace/trace_uprobe.c
> @@ -0,0 +1,926 @@
> +/*
> + * Uprobes-based tracing events
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
> + *
> + * Copyright (C) IBM Corporation, 2010
> + * Author: 	Srikar Dronamraju
> + */
> +
> +#include <linux/module.h>
> +#include <linux/uaccess.h>
> +#include <linux/uprobes.h>
> +#include <linux/seq_file.h>
> +#include <linux/debugfs.h>
> +#include <linux/types.h>
> +#include <linux/string.h>
> +#include <linux/ctype.h>
> +#include <linux/ptrace.h>
> +#include <linux/perf_event.h>
> +
> +#include "trace.h"
> +#include "trace_output.h"
> +
> +#define MAX_TRACE_ARGS 128
> +#define MAX_ARGSTR_LEN 63
> +#define MAX_EVENT_NAME_LEN 64
> +#define UPROBE_EVENT_SYSTEM "uprobes"
> +
> +/* Reserved field names */
> +#define FIELD_STRING_IP "__probe_ip"
> +#define FIELD_STRING_NARGS "__probe_nargs"
> +#define FIELD_STRING_PID "__probe_pid"
> +
> +const char *ureserved_field_names[] = {
> +	"common_type",
> +	"common_flags",
> +	"common_preempt_count",
> +	"common_pid",
> +	"common_tgid",
> +	"common_lock_depth",
> +	FIELD_STRING_IP,
> +	FIELD_STRING_NARGS,
> +	FIELD_STRING_PID,
> +};
> +
> +struct fetch_func {
> +	unsigned long (*func)(struct pt_regs *, void *);
> +	void *data;
> +};
> +
> +static unsigned long call_fetch(struct fetch_func *f,
> +					  struct pt_regs *regs)
> +{
> +	return f->func(regs, f->data);
> +}
> +
> +/* fetch handlers */
> +static  unsigned long fetch_register(struct pt_regs *regs,
> +					      void *offset)
> +{
> +	return regs_get_register(regs, (unsigned int)((unsigned long)offset));
> +}
> +
> +/**
> + * Uprobe event core functions
> + */
> +
> +/* Flags for trace_probe */
> +#define TP_FLAG_TRACE	1
> +#define TP_FLAG_PROFILE	2
> +#define UPROBE_ENABLED	4
> +
> +struct probe_arg {
> +	struct fetch_func	fetch;
> +	const char		*name;
> +};
> +
> +struct trace_uprobe {
> +	struct list_head	list;
> +	struct uprobe		up;
> +	unsigned long 		nhit;
> +	unsigned int		flags;	/* For TP_FLAG_* */
> +	struct ftrace_event_call	call;
> +	struct trace_event		event;
> +	unsigned int		nr_args;
> +	struct probe_arg	args[];
> +};
> +
> +#define SIZEOF_TRACE_UPROBE(n)			\
> +	(offsetof(struct trace_uprobe, args) +	\
> +	(sizeof(struct probe_arg) * (n)))
> +
> +static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff)
> +{
> +	int ret = -EINVAL;
> +
> +	if (ff->func == fetch_register) {
> +		const char *name;
> +		name = regs_query_register_name((unsigned int)((long)ff->data));
> +		ret = snprintf(buf, n, "%%%s", name);
> +	}
> +	if (ret >= n)
> +		return -ENOSPC;
> +	return ret;
> +}
> +
> +static int register_uprobe_event(struct trace_uprobe *tp);
> +static void unregister_uprobe_event(struct trace_uprobe *tp);
> +
> +static DEFINE_MUTEX(uprobe_lock);
> +static LIST_HEAD(uprobe_list);
> +
> +static void uprobe_dispatcher(struct uprobe *up, struct pt_regs *regs);
> +
> +/* Check the name is good for event/group */
> +static int check_event_name(const char *name)
> +{
> +	if (!isalpha(*name) && *name != '_')
> +		return 0;
> +	while (*++name != '\0') {
> +		if (!isalpha(*name) && !isdigit(*name) && *name != '_')
> +			return 0;
> +	}
> +	return 1;
> +}
> +
> +/*
> + * Allocate new trace_uprobe and initialize it (including uprobes).
> + */
> +static struct trace_uprobe *alloc_trace_uprobe(const char * group,
> +					const char *event,
> +					void *addr,
> +					pid_t pid, int nargs)
> +{
> +	struct trace_uprobe *tp;
> +	int ret = -ENOMEM;
> +
> +	if (!event || !check_event_name(event))
> +		return ERR_PTR(-EINVAL);
> +	
> +	if (!group || !check_event_name(group))
> +		return ERR_PTR(-EINVAL);
> +
> +	tp = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
> +	if (!tp)
> +		return ERR_PTR(ret);
> +
> +	tp->up.vaddr = (unsigned long)addr;
> +	tp->up.pid = pid;
> +	tp->up.handler = uprobe_dispatcher;
> +
> +	tp->call.name = kstrdup(event, GFP_KERNEL);
> +	if (!tp->call.name)
> +		goto error;
> +
> +	tp->call.system = kstrdup(group, GFP_KERNEL);
> +	if (!tp->call.system)
> +		goto error;
> +
> +	INIT_LIST_HEAD(&tp->list);
> +	return tp;
> +error:
> +	kfree(tp->call.name);
> +	kfree(tp);
> +	return ERR_PTR(ret);
> +}
> +
> +static void free_probe_arg(struct probe_arg *arg)
> +{
> +	kfree(arg->name);
> +}
> +
> +static void free_trace_uprobe(struct trace_uprobe *tp)
> +{
> +	int i;
> +
> +	for (i = 0; i < tp->nr_args; i++)
> +		free_probe_arg(&tp->args[i]);
> +
> +	kfree(tp->call.system);
> +	kfree(tp->call.name);
> +	kfree(tp);
> +}
> +
> +static struct trace_uprobe *find_probe_event(const char *event,
> +					const char *group)
> +{
> +	struct trace_uprobe *tp;
> +
> +	list_for_each_entry(tp, &uprobe_list, list)
> +		if (strcmp(tp->call.name, event) == 0 &&
> +		    strcmp(tp->call.system, group) == 0)
> +			return tp;
> +	return NULL;
> +}
> +
> +/* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
> +static void unregister_trace_uprobe(struct trace_uprobe *tp)
> +{
> +	if (tp->flags & UPROBE_ENABLED)
> +		unregister_uprobe(&tp->up);
> +	list_del(&tp->list);
> +	unregister_uprobe_event(tp);
> +}
> +
> +/* Register a trace_uprobe and probe_event */
> +static int register_trace_uprobe(struct trace_uprobe *tp)
> +{
> +	struct trace_uprobe *old_tp;
> +	int ret;
> +
> +	mutex_lock(&uprobe_lock);
> +
> +	/* register as an event */
> +	old_tp = find_probe_event(tp->call.name, tp->call.system);
> +	if (old_tp) {
> +		/* delete old event */
> +		unregister_trace_uprobe(old_tp);
> +		free_trace_uprobe(old_tp);
> +	}
> +	ret = register_uprobe_event(tp);
> +	if (ret) {
> +		pr_warning("Faild to register probe event(%d)\n", ret);
> +		goto end;
> +	}
> +
> +	list_add_tail(&tp->list, &uprobe_list);
> +end:
> +	mutex_unlock(&uprobe_lock);
> +	return ret;
> +}
> +
> +#define PARAM_MAX_ARGS 16
> +#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
> +
> +/* Recursive argument parser */
> +static int __parse_probe_arg(char *arg, struct fetch_func *ff)
> +{
> +	int ret = 0;
> +
> +	switch (arg[0]) {
> +	case '%':	/* named register */
> +		ret = regs_query_register_offset(arg + 1);
> +		if (ret >= 0) {
> +			ff->func = fetch_register;
> +			ff->data = (void *)(unsigned long)ret;
> +			ret = 0;
> +		}
> +		break;
> +	default:
> +		/* TODO: support custom handler */
> +		ret = -EINVAL;
> +	}
> +	return ret;
> +}
> +
> +/* String length checking wrapper */
> +static int parse_probe_arg(char *arg, struct fetch_func *ff)
> +{
> +	if (strlen(arg) > MAX_ARGSTR_LEN) {
> +		pr_info("Argument is too long.: %s\n",  arg);
> +		return -ENOSPC;
> +	}
> +	return __parse_probe_arg(arg, ff);
> +}
> +
> +/* Return 1 if name is reserved or already used by another argument */
> +static int conflict_field_name(const char *name,
> +			       struct probe_arg *args, int narg)
> +{
> +	int i;
> +	for (i = 0; i < ARRAY_SIZE(ureserved_field_names); i++)
> +		if (strcmp(ureserved_field_names[i], name) == 0)
> +			return 1;
> +	for (i = 0; i < narg; i++)
> +		if (strcmp(args[i].name, name) == 0)
> +			return 1;
> +	return 0;
> +}
> +
> +static int create_trace_uprobe(int argc, char **argv)
> +{
> +	/*
> +	 * Argument syntax:
> +	 *  - Add uprobe: p[:[GRP/]EVENT] VADDR@PID [%REG]
> +	 *
> +	 *  - Remove uprobe: -:[GRP/]EVENT
> +	 */
> +	struct trace_uprobe *tp;
> +	int i, ret = 0;
> +	int is_delete = 0;
> +	char *arg = NULL, *event = NULL, *group = NULL;
> +	void *addr = NULL;
> +	pid_t pid = 0;
> +	char buf[MAX_EVENT_NAME_LEN];
> +
> +	/* argc must be >= 1 */
> +	if (argv[0][0] == '-')
> +		is_delete = 1;
> +	else if (argv[0][0] != 'p') {
> +		pr_info("Probe definition must be started with 'p', 'r' or"
> +			" '-'.\n");
> +		return -EINVAL;
> +	}
> +
> +	if (argv[0][1] == ':') {
> +		event = &argv[0][2];
> +		if (strchr(event, '/')) {
> +			group = event;
> +			event = strchr(group, '/') + 1;
> +			event[-1] = '\0';
> +			if (strlen(group) == 0) {
> +				pr_info("Group name is not specified\n");
> +				return -EINVAL;
> +			}
> +		}
> +		if (strlen(event) == 0) {
> +			pr_info("Event name is not specified\n");
> +			return -EINVAL;
> +		}
> +	}
> +	if (!group)
> +		group = UPROBE_EVENT_SYSTEM;
> +
> +	if (is_delete) {
> +		if (!event) {
> +			pr_info("Delete command needs an event name.\n");
> +			return -EINVAL;
> +		}
> +		tp = find_probe_event(event, group);
> +		if (!tp) {
> +			pr_info("Event %s/%s doesn't exist.\n", group, event);
> +			return -ENOENT;
> +		}
> +		/* delete an event */
> +		unregister_trace_uprobe(tp);
> +		free_trace_uprobe(tp);
> +		return 0;
> +	}
> +
> +	if (argc < 2) {
> +		pr_info("Probe point is not specified.\n");
> +		return -EINVAL;
> +	}
> +	if (isdigit(argv[1][0])) {
> +		/* an address specified */
> +		arg = strchr(argv[1], ':');
> +		if (!arg)
> +			goto fail_address_parse;
> +
> +		*arg++ = '\0';
> +		ret = strict_strtoul(&argv[1][0], 0, (unsigned long *)&pid);
> +		if (ret)
> +			goto fail_address_parse;
> +
> +		ret = strict_strtoul(arg, 0, (unsigned long *)&addr);
> +		if (ret)
> +			goto fail_address_parse;
> +	}
> +	argc -= 2; argv += 2;
> +
> +	/* setup a probe */
> +	if (!event) {
> +		snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%d_0x%p", 'p',
> +							pid, addr);
> +		event = buf;
> +	}
> +	tp = alloc_trace_uprobe(group, event, addr, pid, argc);
> +	if (IS_ERR(tp)) {
> +		pr_info("Failed to allocate trace_uprobe.(%d)\n",
> +			(int)PTR_ERR(tp));
> +		return PTR_ERR(tp);
> +	}
> +
> +	/* parse arguments */
> +	ret = 0;
> +	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
> +		/* Parse argument name */
> +		arg = strchr(argv[i], '=');
> +		if (arg)
> +			*arg++ = '\0';
> +		else
> +			arg = argv[i];
> +
> +		if (conflict_field_name(argv[i], tp->args, i)) {
> +			pr_info("Argument%d name '%s' conflicts with "
> +				"another field.\n", i, argv[i]);
> +			ret = -EINVAL;
> +			goto error;
> +		}
> +
> +		tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
> +		if (!tp->args[i].name) {
> +			pr_info("Failed to allocate argument%d name '%s'.\n",
> +				i, argv[i]);
> +			ret = -ENOMEM;
> +			goto error;
> +		}
> +
> +		/* Parse fetch argument */
> +		ret = parse_probe_arg(arg, &tp->args[i].fetch);
> +		if (ret) {
> +			pr_info("Parse error at argument%d. (%d)\n", i, ret);
> +			kfree(tp->args[i].name);
> +			goto error;
> +		}
> +
> +		tp->nr_args++;
> +	}
> +
> +	ret = register_trace_uprobe(tp);
> +	if (ret)
> +		goto error;
> +	return 0;
> +
> +error:
> +	free_trace_uprobe(tp);
> +	return ret;
> +
> +fail_address_parse:
> +	pr_info("Failed to parse address.\n");
> +	return ret;
> +}
> +
> +static void cleanup_all_probes(void)
> +{
> +	struct trace_uprobe *tp;
> +
> +	mutex_lock(&uprobe_lock);
> +	/* TODO: Use batch unregistration */
> +	while (!list_empty(&uprobe_list)) {
> +		tp = list_entry(uprobe_list.next, struct trace_uprobe, list);
> +		unregister_trace_uprobe(tp);
> +		free_trace_uprobe(tp);
> +	}
> +	mutex_unlock(&uprobe_lock);
> +}
> +
> +
> +/* Probes listing interfaces */
> +static void *probes_seq_start(struct seq_file *m, loff_t *pos)
> +{
> +	mutex_lock(&uprobe_lock);
> +	return seq_list_start(&uprobe_list, *pos);
> +}
> +
> +static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
> +{
> +	return seq_list_next(v, &uprobe_list, pos);
> +}
> +
> +static void probes_seq_stop(struct seq_file *m, void *v)
> +{
> +	mutex_unlock(&uprobe_lock);
> +}
> +
> +static int probes_seq_show(struct seq_file *m, void *v)
> +{
> +	struct trace_uprobe *tp = v;
> +	int i, ret;
> +	char buf[MAX_ARGSTR_LEN + 1];
> +
> +	seq_printf(m, "%c", 'p');
> +	seq_printf(m, ":%s/%s", tp->call.system, tp->call.name);
> +
> +	seq_printf(m, " %d:0x%p", tp->up.pid, (void *)tp->up.vaddr);
> +
> +	for (i = 0; i < tp->nr_args; i++) {
> +		ret = probe_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i].fetch);
> +		if (ret < 0) {
> +			pr_warning("Argument%d decoding error(%d).\n", i, ret);
> +			return ret;
> +		}
> +		seq_printf(m, " %s=%s", tp->args[i].name, buf);
> +	}
> +	seq_printf(m, "\n");
> +	return 0;
> +}
> +
> +static const struct seq_operations probes_seq_op = {
> +	.start  = probes_seq_start,
> +	.next   = probes_seq_next,
> +	.stop   = probes_seq_stop,
> +	.show   = probes_seq_show
> +};
> +
> +static int probes_open(struct inode *inode, struct file *file)
> +{
> +	if ((file->f_mode & FMODE_WRITE) &&
> +	    (file->f_flags & O_TRUNC))
> +		cleanup_all_probes();
> +
> +	return seq_open(file, &probes_seq_op);
> +}
> +
> +static int command_trace_uprobe(const char *buf)
> +{
> +	char **argv;
> +	int argc = 0, ret = 0;
> +
> +	argv = argv_split(GFP_KERNEL, buf, &argc);
> +	if (!argv)
> +		return -ENOMEM;
> +
> +	if (argc)
> +		ret = create_trace_uprobe(argc, argv);
> +
> +	argv_free(argv);
> +	return ret;
> +}
> +
> +#define WRITE_BUFSIZE 128
> +
> +static ssize_t probes_write(struct file *file, const char __user *buffer,
> +			    size_t count, loff_t *ppos)
> +{
> +	char *kbuf, *tmp;
> +	int ret;
> +	size_t done;
> +	size_t size;
> +
> +	kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
> +	if (!kbuf)
> +		return -ENOMEM;
> +
> +	ret = done = 0;
> +	while (done < count) {
> +		size = count - done;
> +		if (size >= WRITE_BUFSIZE)
> +			size = WRITE_BUFSIZE - 1;
> +		if (copy_from_user(kbuf, buffer + done, size)) {
> +			ret = -EFAULT;
> +			goto out;
> +		}
> +		kbuf[size] = '\0';
> +		tmp = strchr(kbuf, '\n');
> +		if (tmp) {
> +			*tmp = '\0';
> +			size = tmp - kbuf + 1;
> +		} else if (done + size < count) {
> +			pr_warning("Line length is too long: "
> +				   "Should be less than %d.", WRITE_BUFSIZE);
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +		done += size;
> +		/* Remove comments */
> +		tmp = strchr(kbuf, '#');
> +		if (tmp)
> +			*tmp = '\0';
> +
> +		ret = command_trace_uprobe(kbuf);
> +		if (ret)
> +			goto out;
> +	}
> +	ret = done;
> +out:
> +	kfree(kbuf);
> +	return ret;
> +}
> +
> +static const struct file_operations uprobe_events_ops = {
> +	.owner          = THIS_MODULE,
> +	.open           = probes_open,
> +	.read           = seq_read,
> +	.llseek         = seq_lseek,
> +	.release        = seq_release,
> +	.write		= probes_write,
> +};
> +
> +/* Probes profiling interfaces */
> +static int probes_profile_seq_show(struct seq_file *m, void *v)
> +{
> +	struct trace_uprobe *tp = v;
> +
> +	seq_printf(m, "  %d %-44s %15lu\n",tp->up.pid, tp->call.name, tp->nhit);
> +	return 0;
> +}
> +
> +static const struct seq_operations profile_seq_op = {
> +	.start  = probes_seq_start,
> +	.next   = probes_seq_next,
> +	.stop   = probes_seq_stop,
> +	.show   = probes_profile_seq_show
> +};
> +
> +static int profile_open(struct inode *inode, struct file *file)
> +{
> +	return seq_open(file, &profile_seq_op);
> +}
> +
> +static const struct file_operations uprobe_profile_ops = {
> +	.owner          = THIS_MODULE,
> +	.open           = profile_open,
> +	.read           = seq_read,
> +	.llseek         = seq_lseek,
> +	.release        = seq_release,
> +};
> +
> +/* Uprobe handler */
> +static void uprobe_trace_func(struct uprobe *up, struct pt_regs *regs)
> +{
> +	struct trace_uprobe *tp = container_of(up, struct trace_uprobe, up);
> +	struct uprobe_trace_entry *entry;
> +	struct ring_buffer_event *event;
> +	struct ring_buffer *buffer;
> +	int size, i, pc;
> +	unsigned long irq_flags;
> +	struct ftrace_event_call *call = &tp->call;
> +
> +	tp->nhit++;
> +
> +	local_save_flags(irq_flags);
> +	pc = preempt_count();
> +
> +	size = SIZEOF_UPROBE_TRACE_ENTRY(tp->nr_args);
> +
> +	event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
> +						  irq_flags, pc);
> +	if (!event)
> +		return;
> +
> +	entry = ring_buffer_event_data(event);
> +	entry->nargs = tp->nr_args;
> +	entry->ip = (unsigned long)up->vaddr;
> +	for (i = 0; i < tp->nr_args; i++)
> +		entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
> +
> +	if (!filter_current_check_discard(buffer, call, entry, event))
> +		trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
> +}
> +
> +/* Event entry printers */
> +enum print_line_t
> +print_uprobe_event(struct trace_iterator *iter, int flags)
> +{
> +	struct uprobe_trace_entry *field;
> +	struct trace_seq *s = &iter->seq;
> +	struct trace_event *event;
> +	struct trace_uprobe *tp;
> +	int i;
> +
> +	field = (struct uprobe_trace_entry *)iter->ent;
> +	event = ftrace_find_event(field->ent.type);
> +	tp = container_of(event, struct trace_uprobe, event);
> +
> +	if (!trace_seq_printf(s, "%s: (", tp->call.name))
> +		goto partial;
> +
> +	if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
> +		goto partial;
> +
> +	if (!trace_seq_puts(s, ")"))
> +		goto partial;
> +
> +	for (i = 0; i < field->nargs; i++)
> +		if (!trace_seq_printf(s, " %s=%lx",
> +				      tp->args[i].name, field->args[i]))
> +			goto partial;
> +
> +	if (!trace_seq_puts(s, "\n"))
> +		goto partial;
> +
> +	return TRACE_TYPE_HANDLED;
> +partial:
> +	return TRACE_TYPE_PARTIAL_LINE;
> +}
> +
> +
> +static int probe_event_enable(struct ftrace_event_call *call)
> +{
> +	int ret = 0;
> +	struct trace_uprobe *tp = (struct trace_uprobe *)call->data;
> +
> +	if (!(tp->flags & UPROBE_ENABLED)) {
> +		ret = register_uprobe(&tp->up);
> +		if (!ret)
> +			tp->flags |= (UPROBE_ENABLED | TP_FLAG_TRACE);
> +	}
> +	return ret;
> +}
> +
> +static void probe_event_disable(struct ftrace_event_call *call)
> +{
> +	struct trace_uprobe *tp = (struct trace_uprobe *)call->data;
> +
> +	if (tp->flags & UPROBE_ENABLED) {
> +		unregister_uprobe(&tp->up);
> +		tp->flags &= ~(UPROBE_ENABLED | TP_FLAG_TRACE);
> +	}
> +}
> +
> +static int probe_event_raw_init(struct ftrace_event_call *event_call)
> +{
> +	INIT_LIST_HEAD(&event_call->fields);
> +
> +	return 0;
> +}
> +
> +#undef DEFINE_FIELD
> +#define DEFINE_FIELD(type, item, name, is_signed)			\
> +	do {								\
> +		ret = trace_define_field(event_call, #type, name,	\
> +					 offsetof(typeof(field), item),	\
> +					 sizeof(field.item), is_signed, \
> +					 FILTER_OTHER);			\
> +		if (ret)						\
> +			return ret;					\
> +	} while (0)
> +
> +static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
> +{
> +	int ret, i;
> +	struct uprobe_trace_entry field;
> +	struct trace_uprobe *tp = (struct trace_uprobe *)event_call->data;
> +
> +	DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
> +	DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
> +	DEFINE_FIELD(pid_t, pid, FIELD_STRING_PID, 2);

If you added the event to trace_entries.h then this should be done
automatically in trace_export.c


> +	/* Set argument names as fields */
> +	for (i = 0; i < tp->nr_args; i++)
> +		DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0)

Hmm, we don't do it for dynamic arrays, well not yet anyway.

> ;
> +	return 0;
> +}
> +
> +static int __set_print_fmt(struct trace_uprobe *tp, char *buf, int len)
> +{
> +	int i;
> +	int pos = 0;
> +
> +	const char *fmt, *arg;
> +
> +	fmt = "(%lx)";
> +	arg = "REC->" FIELD_STRING_IP;
> +
> +	/* When len=0, we just calculate the needed length */
> +#define LEN_OR_ZERO (len ? len - pos : 0)
> +
> +	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
> +	for (i = 0; i < tp->nr_args; i++)
> +		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%%lx",
> +				tp->args[i].name);
> +
> +	pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
> +	for (i = 0; i < tp->nr_args; i++)
> +		pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
> +				tp->args[i].name);
> +
> +#undef LEN_OR_ZERO
> +
> +	/* return the length of print_fmt */
> +	return pos;
> +}
> +
> +static int set_print_fmt(struct trace_uprobe *tp)
> +{
> +	int len;
> +	char *print_fmt;
> +
> +	/* First: called with 0 length to calculate the needed length */
> +	len = __set_print_fmt(tp, NULL, 0);
> +	print_fmt = kmalloc(len + 1, GFP_KERNEL);
> +	if (!print_fmt)
> +		return -ENOMEM;
> +
> +	/* Second: actually write the @print_fmt */
> +	__set_print_fmt(tp, print_fmt, len + 1);
> +	tp->call.print_fmt = print_fmt;
> +
> +	return 0;
> +}

Or is it because of this special logic that you could not use the
trace_entries.h?

-- Steve

> +
> +#ifdef CONFIG_PERF_EVENTS
> +
> +/* Uprobe profile handler */
> +static void uprobe_perf_func(struct uprobe *up,
> +					 struct pt_regs *regs)
> +{
> +	struct trace_uprobe *tp = container_of(up, struct trace_uprobe, up);
> +	struct ftrace_event_call *call = &tp->call;
> +	struct uprobe_trace_entry *entry;
> +	int size, __size, i;
> +	unsigned long irq_flags;
> +	int rctx;
> +
> +	__size = SIZEOF_UPROBE_TRACE_ENTRY(tp->nr_args);
> +	size = ALIGN(__size + sizeof(u32), sizeof(u64));
> +	size -= sizeof(u32);
> +	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
> +		     "profile buffer not large enough"))
> +		return;
> +
> +	entry = perf_trace_buf_prepare(size, call->id, &rctx, &irq_flags);
> +	if (!entry)
> +		return;
> +
> +	entry->nargs = tp->nr_args;
> +	entry->ip = (unsigned long)up->vaddr;
> +	for (i = 0; i < tp->nr_args; i++)
> +		entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
> +
> +	perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, irq_flags, regs);
> +}
> +
> +static int probe_perf_enable(struct ftrace_event_call *call)
> +{
> +	int ret = 0;
> +	struct trace_uprobe *tp = (struct trace_uprobe *)call->data;
> +
> +	if (!(tp->flags & UPROBE_ENABLED)) {
> +		ret = register_uprobe(&tp->up);
> +		if (!ret) 
> +			tp->flags |= (UPROBE_ENABLED | TP_FLAG_PROFILE);
> +	}
> +	return ret;
> +}
> +
> +static void probe_perf_disable(struct ftrace_event_call *call)
> +{
> +	struct trace_uprobe *tp = (struct trace_uprobe *)call->data;
> +
> +	if (tp->flags & UPROBE_ENABLED) {
> +		unregister_uprobe(&tp->up);
> +		tp->flags &= ~(UPROBE_ENABLED | TP_FLAG_PROFILE);
> +	}
> +}
> +#endif	/* CONFIG_PERF_EVENTS */
> +
> +
> +static 
> +void uprobe_dispatcher(struct uprobe *up, struct pt_regs *regs)
> +{
> +	struct trace_uprobe *tp = container_of(up, struct trace_uprobe, up);
> +
> +	if (tp->flags & TP_FLAG_TRACE)
> +		uprobe_trace_func(up, regs);
> +#ifdef CONFIG_PERF_EVENTS
> +	if (tp->flags & TP_FLAG_PROFILE)
> +		uprobe_perf_func(up, regs);
> +#endif
> +}
> +
> +
> +static int register_uprobe_event(struct trace_uprobe *tp)
> +{
> +	struct ftrace_event_call *call = &tp->call;
> +	int ret;
> +
> +	/* Initialize ftrace_event_call */
> +	tp->event.trace = print_uprobe_event;
> +	call->raw_init = probe_event_raw_init;
> +	call->define_fields = uprobe_event_define_fields;
> +	if (set_print_fmt(tp) < 0)
> +		return -ENOMEM;
> +
> +	call->event = &tp->event;
> +	call->id = register_ftrace_event(&tp->event);
> +	if (!call->id) {
> +		kfree(call->print_fmt);
> +		return -ENODEV;
> +	}
> +
> +	call->enabled = 0;
> +	call->regfunc = probe_event_enable;
> +	call->unregfunc = probe_event_disable;
> +
> +#ifdef CONFIG_PERF_EVENTS
> +	call->perf_event_enable = probe_perf_enable;
> +	call->perf_event_disable = probe_perf_disable;
> +#endif
> +	call->data = tp;
> +	ret = trace_add_event_call(call);
> +	if (ret) {
> +		pr_info("Failed to register uprobe event: %s\n", call->name);
> +		kfree(call->print_fmt);
> +		unregister_ftrace_event(&tp->event);
> +	}
> +	return ret;
> +}
> +
> +static void unregister_uprobe_event(struct trace_uprobe *tp)
> +{
> +	/* tp->event is unregistered in trace_remove_event_call() */
> +	trace_remove_event_call(&tp->call);
> +	kfree(tp->call.print_fmt);
> +}
> +
> +/* Make a debugfs interface for controling probe points */
> +static __init int init_uprobe_trace(void)
> +{
> +	struct dentry *d_tracer;
> +	struct dentry *entry;
> +
> +	d_tracer = tracing_init_dentry();
> +	if (!d_tracer)
> +		return 0;
> +
> +	entry = debugfs_create_file("uprobe_events", 0644, d_tracer,
> +				    NULL, &uprobe_events_ops);
> +
> +	/* Event list interface */
> +	if (!entry)
> +		pr_warning("Could not create debugfs "
> +			   "'uprobe_events' entry\n");
> +
> +	/* Profile interface */
> +	entry = debugfs_create_file("uprobe_profile", 0444, d_tracer,
> +				    NULL, &uprobe_profile_ops);
> +
> +	if (!entry)
> +		pr_warning("Could not create debugfs "
> +			   "'uprobe_profile' entry\n");
> +	return 0;
> +}
> +fs_initcall(init_uprobe_trace);
> --
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