diff options
| -rw-r--r-- | Documentation/trace/uprobetracer.txt | 95 | ||||
| -rw-r--r-- | arch/Kconfig | 2 | ||||
| -rw-r--r-- | kernel/trace/Kconfig | 16 | ||||
| -rw-r--r-- | kernel/trace/Makefile | 1 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 5 | ||||
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 2 | ||||
| -rw-r--r-- | kernel/trace/trace_probe.c | 14 | ||||
| -rw-r--r-- | kernel/trace/trace_probe.h | 3 | ||||
| -rw-r--r-- | kernel/trace/trace_uprobe.c | 788 |
9 files changed, 919 insertions, 7 deletions
diff --git a/Documentation/trace/uprobetracer.txt b/Documentation/trace/uprobetracer.txt new file mode 100644 index 00000000000..eae40a003ee --- /dev/null +++ b/Documentation/trace/uprobetracer.txt @@ -0,0 +1,95 @@ + Uprobe-tracer: Uprobe-based Event Tracing + ========================================= + Documentation written by Srikar Dronamraju + +Overview +-------- +Uprobe based trace events are similar to kprobe based trace events. +To enable this feature, build your kernel with CONFIG_UPROBE_EVENTS=y. + +Similar to the kprobe-event tracer, this doesn't need to be activated via +current_tracer. Instead of that, add probe points via +/sys/kernel/debug/tracing/uprobe_events, and enable it via +/sys/kernel/debug/tracing/events/uprobes/<EVENT>/enabled. + +However unlike kprobe-event tracer, the uprobe event interface expects the +user to calculate the offset of the probepoint in the object + +Synopsis of uprobe_tracer +------------------------- + p[:[GRP/]EVENT] PATH:SYMBOL[+offs] [FETCHARGS] : Set a probe + + GRP : Group name. If omitted, use "uprobes" for it. + EVENT : Event name. If omitted, the event name is generated + based on SYMBOL+offs. + PATH : path to an executable or a library. + SYMBOL[+offs] : Symbol+offset where the probe is inserted. + + FETCHARGS : Arguments. Each probe can have up to 128 args. + %REG : Fetch register REG + +Event Profiling +--------------- + You can check the total number of probe hits and probe miss-hits via +/sys/kernel/debug/tracing/uprobe_profile. + The first column is event name, the second is the number of probe hits, +the third is the number of probe miss-hits. + +Usage examples +-------------- +To add a probe as a new event, write a new definition to uprobe_events +as below. + + echo 'p: /bin/bash:0x4245c0' > /sys/kernel/debug/tracing/uprobe_events + + This sets a uprobe at an offset of 0x4245c0 in the executable /bin/bash + + echo > /sys/kernel/debug/tracing/uprobe_events + + This clears all probe points. + +The following example shows how to dump the instruction pointer and %ax +a register at the probed text address. Here we are trying to probe +function zfree in /bin/zsh + + # cd /sys/kernel/debug/tracing/ + # cat /proc/`pgrep zsh`/maps | grep /bin/zsh | grep r-xp + 00400000-0048a000 r-xp 00000000 08:03 130904 /bin/zsh + # objdump -T /bin/zsh | grep -w zfree + 0000000000446420 g DF .text 0000000000000012 Base zfree + +0x46420 is the offset of zfree in object /bin/zsh that is loaded at +0x00400000. Hence the command to probe would be : + + # echo 'p /bin/zsh:0x46420 %ip %ax' > uprobe_events + +Please note: User has to explicitly calculate the offset of the probepoint +in the object. We can see the events that are registered by looking at the +uprobe_events file. + + # cat uprobe_events + p:uprobes/p_zsh_0x46420 /bin/zsh:0x0000000000046420 + +Right after definition, each event is disabled by default. For tracing these +events, you need to enable it by: + + # echo 1 > events/uprobes/enable + +Lets disable the event after sleeping for some time. + # sleep 20 + # echo 0 > events/uprobes/enable + +And you can see the traced information via /sys/kernel/debug/tracing/trace. + + # cat trace + # tracer: nop + # + # TASK-PID CPU# TIMESTAMP FUNCTION + # | | | | | + zsh-24842 [006] 258544.995456: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79 + zsh-24842 [007] 258545.000270: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79 + zsh-24842 [002] 258545.043929: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79 + zsh-24842 [004] 258547.046129: p_zsh_0x46420: (0x446420) arg1=446421 arg2=79 + +Each line shows us probes were triggered for a pid 24842 with ip being +0x446421 and contents of ax register being 79. diff --git a/arch/Kconfig b/arch/Kconfig index e5d3778d555..0f8f968015e 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -78,7 +78,7 @@ config OPTPROBES config UPROBES bool "Transparent user-space probes (EXPERIMENTAL)" - depends on ARCH_SUPPORTS_UPROBES && PERF_EVENTS + depends on UPROBE_EVENTS && PERF_EVENTS default n help Uprobes is the user-space counterpart to kprobes: they diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index ce5a5c54ac8..ea4bff6295f 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -386,6 +386,22 @@ config KPROBE_EVENT This option is also required by perf-probe subcommand of perf tools. If you want to use perf tools, this option is strongly recommended. +config UPROBE_EVENT + bool "Enable uprobes-based dynamic events" + depends on ARCH_SUPPORTS_UPROBES + depends on MMU + select UPROBES + select PROBE_EVENTS + select TRACING + default n + help + This allows the user to add tracing events on top of userspace + dynamic events (similar to tracepoints) on the fly via the trace + events interface. Those events can be inserted wherever uprobes + can probe, and record various registers. + This option is required if you plan to use perf-probe subcommand + of perf tools on user space applications. + config PROBE_EVENTS def_bool n diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index fa10d5ca5ab..1734c03e048 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -62,5 +62,6 @@ ifeq ($(CONFIG_TRACING),y) obj-$(CONFIG_KGDB_KDB) += trace_kdb.o endif obj-$(CONFIG_PROBE_EVENTS) += trace_probe.o +obj-$(CONFIG_UPROBE_EVENT) += trace_uprobe.o libftrace-y := ftrace.o diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 95059f091a2..1bcdbec95a1 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -103,6 +103,11 @@ struct kretprobe_trace_entry_head { unsigned long ret_ip; }; +struct uprobe_trace_entry_head { + struct trace_entry ent; + unsigned long ip; +}; + /* * trace_flag_type is an enumeration that holds different * states when a trace occurs. These are: diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index f8b777367d8..b31d3d5699f 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -525,7 +525,7 @@ static int create_trace_probe(int argc, char **argv) /* Parse fetch argument */ ret = traceprobe_parse_probe_arg(arg, &tp->size, &tp->args[i], - is_return); + is_return, true); if (ret) { pr_info("Parse error at argument[%d]. (%d)\n", i, ret); goto error; diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 8e526b9286e..daa9980153a 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -550,7 +550,7 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t, /* Recursive argument parser */ static int parse_probe_arg(char *arg, const struct fetch_type *t, - struct fetch_param *f, bool is_return) + struct fetch_param *f, bool is_return, bool is_kprobe) { unsigned long param; long offset; @@ -558,6 +558,11 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t, int ret; ret = 0; + + /* Until uprobe_events supports only reg arguments */ + if (!is_kprobe && arg[0] != '%') + return -EINVAL; + switch (arg[0]) { case '$': ret = parse_probe_vars(arg + 1, t, f, is_return); @@ -619,7 +624,8 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t, return -ENOMEM; dprm->offset = offset; - ret = parse_probe_arg(arg, t2, &dprm->orig, is_return); + ret = parse_probe_arg(arg, t2, &dprm->orig, is_return, + is_kprobe); if (ret) kfree(dprm); else { @@ -677,7 +683,7 @@ static int __parse_bitfield_probe_arg(const char *bf, /* String length checking wrapper */ int traceprobe_parse_probe_arg(char *arg, ssize_t *size, - struct probe_arg *parg, bool is_return) + struct probe_arg *parg, bool is_return, bool is_kprobe) { const char *t; int ret; @@ -703,7 +709,7 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size, } parg->offset = *size; *size += parg->type->size; - ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return); + ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, is_kprobe); if (ret >= 0 && t != NULL) ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch); diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 2df9a18e025..93370867781 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -66,6 +66,7 @@ #define TP_FLAG_TRACE 1 #define TP_FLAG_PROFILE 2 #define TP_FLAG_REGISTERED 4 +#define TP_FLAG_UPROBE 8 /* data_rloc: data relative location, compatible with u32 */ @@ -143,7 +144,7 @@ static inline int is_good_name(const char *name) } extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size, - struct probe_arg *parg, bool is_return); + struct probe_arg *parg, bool is_return, bool is_kprobe); extern int traceprobe_conflict_field_name(const char *name, struct probe_arg *args, int narg); diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c new file mode 100644 index 00000000000..2b36ac68549 --- /dev/null +++ b/kernel/trace/trace_uprobe.c @@ -0,0 +1,788 @@ +/* + * 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, 2010-2012 + * Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com> + */ + +#include <linux/module.h> +#include <linux/uaccess.h> +#include <linux/uprobes.h> +#include <linux/namei.h> + +#include "trace_probe.h" + +#define UPROBE_EVENT_SYSTEM "uprobes" + +/* + * uprobe event core functions + */ +struct trace_uprobe; +struct uprobe_trace_consumer { + struct uprobe_consumer cons; + struct trace_uprobe *tu; +}; + +struct trace_uprobe { + struct list_head list; + struct ftrace_event_class class; + struct ftrace_event_call call; + struct uprobe_trace_consumer *consumer; + struct inode *inode; + char *filename; + unsigned long offset; + unsigned long nhit; + unsigned int flags; /* For TP_FLAG_* */ + ssize_t size; /* trace entry size */ + 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 register_uprobe_event(struct trace_uprobe *tu); +static void unregister_uprobe_event(struct trace_uprobe *tu); + +static DEFINE_MUTEX(uprobe_lock); +static LIST_HEAD(uprobe_list); + +static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); + +/* + * Allocate new trace_uprobe and initialize it (including uprobes). + */ +static struct trace_uprobe * +alloc_trace_uprobe(const char *group, const char *event, int nargs) +{ + struct trace_uprobe *tu; + + if (!event || !is_good_name(event)) + return ERR_PTR(-EINVAL); + + if (!group || !is_good_name(group)) + return ERR_PTR(-EINVAL); + + tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); + if (!tu) + return ERR_PTR(-ENOMEM); + + tu->call.class = &tu->class; + tu->call.name = kstrdup(event, GFP_KERNEL); + if (!tu->call.name) + goto error; + + tu->class.system = kstrdup(group, GFP_KERNEL); + if (!tu->class.system) + goto error; + + INIT_LIST_HEAD(&tu->list); + return tu; + +error: + kfree(tu->call.name); + kfree(tu); + + return ERR_PTR(-ENOMEM); +} + +static void free_trace_uprobe(struct trace_uprobe *tu) +{ + int i; + + for (i = 0; i < tu->nr_args; i++) + traceprobe_free_probe_arg(&tu->args[i]); + + iput(tu->inode); + kfree(tu->call.class->system); + kfree(tu->call.name); + kfree(tu->filename); + kfree(tu); +} + +static struct trace_uprobe *find_probe_event(const char *event, const char *group) +{ + struct trace_uprobe *tu; + + list_for_each_entry(tu, &uprobe_list, list) + if (strcmp(tu->call.name, event) == 0 && + strcmp(tu->call.class->system, group) == 0) + return tu; + + return NULL; +} + +/* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */ +static void unregister_trace_uprobe(struct trace_uprobe *tu) +{ + list_del(&tu->list); + unregister_uprobe_event(tu); + free_trace_uprobe(tu); +} + +/* Register a trace_uprobe and probe_event */ +static int register_trace_uprobe(struct trace_uprobe *tu) +{ + struct trace_uprobe *old_tp; + int ret; + + mutex_lock(&uprobe_lock); + + /* register as an event */ + old_tp = find_probe_event(tu->call.name, tu->call.class->system); + if (old_tp) + /* delete old event */ + unregister_trace_uprobe(old_tp); + + ret = register_uprobe_event(tu); + if (ret) { + pr_warning("Failed to register probe event(%d)\n", ret); + goto end; + } + + list_add_tail(&tu->list, &uprobe_list); + +end: + mutex_unlock(&uprobe_lock); + + return ret; +} + +/* + * Argument syntax: + * - Add uprobe: p[:[GRP/]EVENT] PATH:SYMBOL[+offs] [FETCHARGS] + * + * - Remove uprobe: -:[GRP/]EVENT + */ +static int create_trace_uprobe(int argc, char **argv) +{ + struct trace_uprobe *tu; + struct inode *inode; + char *arg, *event, *group, *filename; + char buf[MAX_EVENT_NAME_LEN]; + struct path path; + unsigned long offset; + bool is_delete; + int i, ret; + + inode = NULL; + ret = 0; + is_delete = false; + event = NULL; + group = NULL; + + /* argc must be >= 1 */ + if (argv[0][0] == '-') + is_delete = true; + 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]; + arg = strchr(event, '/'); + + if (arg) { + group = event; + event = arg + 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; + } + mutex_lock(&uprobe_lock); + tu = find_probe_event(event, group); + + if (!tu) { + mutex_unlock(&uprobe_lock); + pr_info("Event %s/%s doesn't exist.\n", group, event); + return -ENOENT; + } + /* delete an event */ + unregister_trace_uprobe(tu); + mutex_unlock(&uprobe_lock); + return 0; + } + + if (argc < 2) { + pr_info("Probe point is not specified.\n"); + return -EINVAL; + } + if (isdigit(argv[1][0])) { + pr_info("probe point must be have a filename.\n"); + return -EINVAL; + } + arg = strchr(argv[1], ':'); + if (!arg) + goto fail_address_parse; + + *arg++ = '\0'; + filename = argv[1]; + ret = kern_path(filename, LOOKUP_FOLLOW, &path); + if (ret) + goto fail_address_parse; + + ret = strict_strtoul(arg, 0, &offset); + if (ret) + goto fail_address_parse; + + inode = igrab(path.dentry->d_inode); + + argc -= 2; + argv += 2; + + /* setup a probe */ + if (!event) { + char *tail = strrchr(filename, '/'); + char *ptr; + + ptr = kstrdup((tail ? tail + 1 : filename), GFP_KERNEL); + if (!ptr) { + ret = -ENOMEM; + goto fail_address_parse; + } + + tail = ptr; + ptr = strpbrk(tail, ".-_"); + if (ptr) + *ptr = '\0'; + + snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); + event = buf; + kfree(tail); + } + + tu = alloc_trace_uprobe(group, event, argc); + if (IS_ERR(tu)) { + pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu)); + ret = PTR_ERR(tu); + goto fail_address_parse; + } + tu->offset = offset; + tu->inode = inode; + tu->filename = kstrdup(filename, GFP_KERNEL); + + if (!tu->filename) { + pr_info("Failed to allocate filename.\n"); + ret = -ENOMEM; + goto error; + } + + /* parse arguments */ + ret = 0; + for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { + /* Increment count for freeing args in error case */ + tu->nr_args++; + + /* Parse argument name */ + arg = strchr(argv[i], '='); + if (arg) { + *arg++ = '\0'; + tu->args[i].name = kstrdup(argv[i], GFP_KERNEL); + } else { + arg = argv[i]; + /* If argument name is omitted, set "argN" */ + snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1); + tu->args[i].name = kstrdup(buf, GFP_KERNEL); + } + + if (!tu->args[i].name) { + pr_info("Failed to allocate argument[%d] name.\n", i); + ret = -ENOMEM; + goto error; + } + + if (!is_good_name(tu->args[i].name)) { + pr_info("Invalid argument[%d] name: %s\n", i, tu->args[i].name); + ret = -EINVAL; + goto error; + } + + if (traceprobe_conflict_field_name(tu->args[i].name, tu->args, i)) { + pr_info("Argument[%d] name '%s' conflicts with " + "another field.\n", i, argv[i]); + ret = -EINVAL; + goto error; + } + + /* Parse fetch argument */ + ret = traceprobe_parse_probe_arg(arg, &tu->size, &tu->args[i], false, false); + if (ret) { + pr_info("Parse error at argument[%d]. (%d)\n", i, ret); + goto error; + } + } + + ret = register_trace_uprobe(tu); + if (ret) + goto error; + return 0; + +error: + free_trace_uprobe(tu); + return ret; + +fail_address_parse: + if (inode) + iput(inode); + + pr_info("Failed to parse address.\n"); + + return ret; +} + +static void cleanup_all_probes(void) +{ + struct trace_uprobe *tu; + + mutex_lock(&uprobe_lock); + while (!list_empty(&uprobe_list)) { + tu = list_entry(uprobe_list.next, struct trace_uprobe, list); + unregister_trace_uprobe(tu); + } + 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 *tu = v; + int i; + + seq_printf(m, "p:%s/%s", tu->call.class->system, tu->call.name); + seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset); + + for (i = 0; i < tu->nr_args; i++) + seq_printf(m, " %s=%s", tu->args[i].name, tu->args[i].comm); + + 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 ssize_t probes_write(struct file *file, const char __user *buffer, + size_t count, loff_t *ppos) +{ + return traceprobe_probes_write(file, buffer, count, ppos, create_trace_uprobe); +} + +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 *tu = v; + + seq_printf(m, " %s %-44s %15lu\n", tu->filename, tu->call.name, tu->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 trace_uprobe *tu, struct pt_regs *regs) +{ + struct uprobe_trace_entry_head *entry; + struct ring_buffer_event *event; + struct ring_buffer *buffer; + u8 *data; + int size, i, pc; + unsigned long irq_flags; + struct ftrace_event_call *call = &tu->call; + + tu->nhit++; + + local_save_flags(irq_flags); + pc = preempt_count(); + + size = sizeof(*entry) + tu->size; + + event = trace_current_buffer_lock_reserve(&buffer, call->event.type, + size, irq_flags, pc); + if (!event) + return; + + entry = ring_buffer_event_data(event); + entry->ip = uprobe_get_swbp_addr(task_pt_regs(current)); + data = (u8 *)&entry[1]; + for (i = 0; i < tu->nr_args; i++) + call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); + + if (!filter_current_check_discard(buffer, call, entry, event)) + trace_buffer_unlock_commit(buffer, event, irq_flags, pc); +} + +/* Event entry printers */ +static enum print_line_t +print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) +{ + struct uprobe_trace_entry_head *field; + struct trace_seq *s = &iter->seq; + struct trace_uprobe *tu; + u8 *data; + int i; + + field = (struct uprobe_trace_entry_head *)iter->ent; + tu = container_of(event, struct trace_uprobe, call.event); + + if (!trace_seq_printf(s, "%s: (", tu->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; + + data = (u8 *)&field[1]; + for (i = 0; i < tu->nr_args; i++) { + if (!tu->args[i].type->print(s, tu->args[i].name, + data + tu->args[i].offset, field)) + goto partial; + } + + if (trace_seq_puts(s, "\n")) + return TRACE_TYPE_HANDLED; + +partial: + return TRACE_TYPE_PARTIAL_LINE; +} + +static int probe_event_enable(struct trace_uprobe *tu, int flag) +{ + struct uprobe_trace_consumer *utc; + int ret = 0; + + if (!tu->inode || tu->consumer) + return -EINTR; + + utc = kzalloc(sizeof(struct uprobe_trace_consumer), GFP_KERNEL); + if (!utc) + return -EINTR; + + utc->cons.handler = uprobe_dispatcher; + utc->cons.filter = NULL; + ret = uprobe_register(tu->inode, tu->offset, &utc->cons); + if (ret) { + kfree(utc); + return ret; + } + + tu->flags |= flag; + utc->tu = tu; + tu->consumer = utc; + + return 0; +} + +static void probe_event_disable(struct trace_uprobe *tu, int flag) +{ + if (!tu->inode || !tu->consumer) + return; + + uprobe_unregister(tu->inode, tu->offset, &tu->consumer->cons); + tu->flags &= ~flag; + kfree(tu->consumer); + tu->consumer = NULL; +} + +static int uprobe_event_define_fields(struct ftrace_event_call *event_call) +{ + int ret, i; + struct uprobe_trace_entry_head field; + struct trace_uprobe *tu = (struct trace_uprobe *)event_call->data; + + DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); + /* Set argument names as fields */ + for (i = 0; i < tu->nr_args; i++) { + ret = trace_define_field(event_call, tu->args[i].type->fmttype, + tu->args[i].name, + sizeof(field) + tu->args[i].offset, + tu->args[i].type->size, + tu->args[i].type->is_signed, + FILTER_OTHER); + + if (ret) + return ret; + } + return 0; +} + +#define LEN_OR_ZERO (len ? len - pos : 0) +static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len) +{ + const char *fmt, *arg; + int i; + int pos = 0; + + fmt = "(%lx)"; + arg = "REC->" FIELD_STRING_IP; + + /* When len=0, we just calculate the needed length */ + + pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt); + + for (i = 0; i < tu->nr_args; i++) { + pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s", + tu->args[i].name, tu->args[i].type->fmt); + } + + pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg); + + for (i = 0; i < tu->nr_args; i++) { + pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s", + tu->args[i].name); + } + + return pos; /* return the length of print_fmt */ +} +#undef LEN_OR_ZERO + +static int set_print_fmt(struct trace_uprobe *tu) +{ + char *print_fmt; + int len; + + /* First: called with 0 length to calculate the needed length */ + len = __set_print_fmt(tu, NULL, 0); + print_fmt = kmalloc(len + 1, GFP_KERNEL); + if (!print_fmt) + return -ENOMEM; + + /* Second: actually write the @print_fmt */ + __set_print_fmt(tu, print_fmt, len + 1); + tu->call.print_fmt = print_fmt; + + return 0; +} + +#ifdef CONFIG_PERF_EVENTS +/* uprobe profile handler */ +static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs) +{ + struct ftrace_event_call *call = &tu->call; + struct uprobe_trace_entry_head *entry; + struct hlist_head *head; + u8 *data; + int size, __size, i; + int rctx; + + __size = sizeof(*entry) + tu->size; + size = ALIGN(__size + sizeof(u32), sizeof(u64)); + size -= sizeof(u32); + if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) + return; + + preempt_disable(); + + entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx); + if (!entry) + goto out; + + entry->ip = uprobe_get_swbp_addr(task_pt_regs(current)); + data = (u8 *)&entry[1]; + for (i = 0; i < tu->nr_args; i++) + call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); + + head = this_cpu_ptr(call->perf_events); + perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head); + + out: + preempt_enable(); +} +#endif /* CONFIG_PERF_EVENTS */ + +static +int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data) +{ + struct trace_uprobe *tu = (struct trace_uprobe *)event->data; + + switch (type) { + case TRACE_REG_REGISTER: + return probe_event_enable(tu, TP_FLAG_TRACE); + + case TRACE_REG_UNREGISTER: + probe_event_disable(tu, TP_FLAG_TRACE); + return 0; + +#ifdef CONFIG_PERF_EVENTS + case TRACE_REG_PERF_REGISTER: + return probe_event_enable(tu, TP_FLAG_PROFILE); + + case TRACE_REG_PERF_UNREGISTER: + probe_event_disable(tu, TP_FLAG_PROFILE); + return 0; +#endif + default: + return 0; + } + return 0; +} + +static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) +{ + struct uprobe_trace_consumer *utc; + struct trace_uprobe *tu; + + utc = container_of(con, struct uprobe_trace_consumer, cons); + tu = utc->tu; + if (!tu || tu->consumer != utc) + return 0; + + if (tu->flags & TP_FLAG_TRACE) + uprobe_trace_func(tu, regs); + +#ifdef CONFIG_PERF_EVENTS + if (tu->flags & TP_FLAG_PROFILE) + uprobe_perf_func(tu, regs); +#endif + return 0; +} + +static struct trace_event_functions uprobe_funcs = { + .trace = print_uprobe_event +}; + +static int register_uprobe_event(struct trace_uprobe *tu) +{ + struct ftrace_event_call *call = &tu->call; + int ret; + + /* Initialize ftrace_event_call */ + INIT_LIST_HEAD(&call->class->fields); + call->event.funcs = &uprobe_funcs; + call->class->define_fields = uprobe_event_define_fields; + + if (set_print_fmt(tu) < 0) + return -ENOMEM; + + ret = register_ftrace_event(&call->event); + if (!ret) { + kfree(call->print_fmt); + return -ENODEV; + } + call->flags = 0; + call->class->reg = trace_uprobe_register; + call->data = tu; + 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(&call->event); + } + + return ret; +} + +static void unregister_uprobe_event(struct trace_uprobe *tu) +{ + /* tu->event is unregistered in trace_remove_event_call() */ + trace_remove_event_call(&tu->call); + kfree(tu->call.print_fmt); + tu->call.print_fmt = NULL; +} + +/* Make a trace interface for controling probe points */ +static __init int init_uprobe_trace(void) +{ + struct dentry *d_tracer; + + d_tracer = tracing_init_dentry(); + if (!d_tracer) + return 0; + + trace_create_file("uprobe_events", 0644, d_tracer, + NULL, &uprobe_events_ops); + /* Profile interface */ + trace_create_file("uprobe_profile", 0444, d_tracer, + NULL, &uprobe_profile_ops); + return 0; +} + +fs_initcall(init_uprobe_trace); |