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SubjectRe: [PATCH v2 11/11] Uprobes traceevents patch.
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Date
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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