diff options
Diffstat (limited to 'kernel/trace/trace_kprobe.c')
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 1510 |
1 files changed, 1510 insertions, 0 deletions
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c new file mode 100644 index 000000000..64abc8ca9 --- /dev/null +++ b/kernel/trace/trace_kprobe.c @@ -0,0 +1,1510 @@ +/* + * Kprobes-based tracing events + * + * Created by Masami Hiramatsu <mhiramat@redhat.com> + * + * 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 + */ + +#include <linux/module.h> +#include <linux/uaccess.h> + +#include "trace_probe.h" + +#define KPROBE_EVENT_SYSTEM "kprobes" + +/** + * Kprobe event core functions + */ +struct trace_probe { + struct list_head list; + struct kretprobe rp; /* Use rp.kp for kprobe use */ + unsigned long nhit; + unsigned int flags; /* For TP_FLAG_* */ + const char *symbol; /* symbol name */ + struct ftrace_event_class class; + struct ftrace_event_call call; + struct ftrace_event_file * __rcu *files; + ssize_t size; /* trace entry size */ + unsigned int nr_args; + struct probe_arg args[]; +}; + +#define SIZEOF_TRACE_PROBE(n) \ + (offsetof(struct trace_probe, args) + \ + (sizeof(struct probe_arg) * (n))) + + +static __kprobes bool trace_probe_is_return(struct trace_probe *tp) +{ + return tp->rp.handler != NULL; +} + +static __kprobes const char *trace_probe_symbol(struct trace_probe *tp) +{ + return tp->symbol ? tp->symbol : "unknown"; +} + +static __kprobes unsigned long trace_probe_offset(struct trace_probe *tp) +{ + return tp->rp.kp.offset; +} + +static __kprobes bool trace_probe_is_enabled(struct trace_probe *tp) +{ + return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE)); +} + +static __kprobes bool trace_probe_is_registered(struct trace_probe *tp) +{ + return !!(tp->flags & TP_FLAG_REGISTERED); +} + +static __kprobes bool trace_probe_has_gone(struct trace_probe *tp) +{ + return !!(kprobe_gone(&tp->rp.kp)); +} + +static __kprobes bool trace_probe_within_module(struct trace_probe *tp, + struct module *mod) +{ + int len = strlen(mod->name); + const char *name = trace_probe_symbol(tp); + return strncmp(mod->name, name, len) == 0 && name[len] == ':'; +} + +static __kprobes bool trace_probe_is_on_module(struct trace_probe *tp) +{ + return !!strchr(trace_probe_symbol(tp), ':'); +} + +static int register_probe_event(struct trace_probe *tp); +static int unregister_probe_event(struct trace_probe *tp); + +static DEFINE_MUTEX(probe_lock); +static LIST_HEAD(probe_list); + +static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs); +static int kretprobe_dispatcher(struct kretprobe_instance *ri, + struct pt_regs *regs); + +/* + * Allocate new trace_probe and initialize it (including kprobes). + */ +static struct trace_probe *alloc_trace_probe(const char *group, + const char *event, + void *addr, + const char *symbol, + unsigned long offs, + int nargs, bool is_return) +{ + struct trace_probe *tp; + int ret = -ENOMEM; + + tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL); + if (!tp) + return ERR_PTR(ret); + + if (symbol) { + tp->symbol = kstrdup(symbol, GFP_KERNEL); + if (!tp->symbol) + goto error; + tp->rp.kp.symbol_name = tp->symbol; + tp->rp.kp.offset = offs; + } else + tp->rp.kp.addr = addr; + + if (is_return) + tp->rp.handler = kretprobe_dispatcher; + else + tp->rp.kp.pre_handler = kprobe_dispatcher; + + if (!event || !is_good_name(event)) { + ret = -EINVAL; + goto error; + } + + tp->call.class = &tp->class; + tp->call.name = kstrdup(event, GFP_KERNEL); + if (!tp->call.name) + goto error; + + if (!group || !is_good_name(group)) { + ret = -EINVAL; + goto error; + } + + tp->class.system = kstrdup(group, GFP_KERNEL); + if (!tp->class.system) + goto error; + + INIT_LIST_HEAD(&tp->list); + return tp; +error: + kfree(tp->call.name); + kfree(tp->symbol); + kfree(tp); + return ERR_PTR(ret); +} + +static void free_trace_probe(struct trace_probe *tp) +{ + int i; + + for (i = 0; i < tp->nr_args; i++) + traceprobe_free_probe_arg(&tp->args[i]); + + kfree(tp->call.class->system); + kfree(tp->call.name); + kfree(tp->symbol); + kfree(tp); +} + +static struct trace_probe *find_trace_probe(const char *event, + const char *group) +{ + struct trace_probe *tp; + + list_for_each_entry(tp, &probe_list, list) + if (strcmp(tp->call.name, event) == 0 && + strcmp(tp->call.class->system, group) == 0) + return tp; + return NULL; +} + +static int trace_probe_nr_files(struct trace_probe *tp) +{ + struct ftrace_event_file **file; + int ret = 0; + + /* + * Since all tp->files updater is protected by probe_enable_lock, + * we don't need to lock an rcu_read_lock. + */ + file = rcu_dereference_raw(tp->files); + if (file) + while (*(file++)) + ret++; + + return ret; +} + +static DEFINE_MUTEX(probe_enable_lock); + +/* + * Enable trace_probe + * if the file is NULL, enable "perf" handler, or enable "trace" handler. + */ +static int +enable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file) +{ + int ret = 0; + + mutex_lock(&probe_enable_lock); + + if (file) { + struct ftrace_event_file **new, **old; + int n = trace_probe_nr_files(tp); + + old = rcu_dereference_raw(tp->files); + /* 1 is for new one and 1 is for stopper */ + new = kzalloc((n + 2) * sizeof(struct ftrace_event_file *), + GFP_KERNEL); + if (!new) { + ret = -ENOMEM; + goto out_unlock; + } + memcpy(new, old, n * sizeof(struct ftrace_event_file *)); + new[n] = file; + /* The last one keeps a NULL */ + + rcu_assign_pointer(tp->files, new); + tp->flags |= TP_FLAG_TRACE; + + if (old) { + /* Make sure the probe is done with old files */ + synchronize_sched(); + kfree(old); + } + } else + tp->flags |= TP_FLAG_PROFILE; + + if (trace_probe_is_enabled(tp) && trace_probe_is_registered(tp) && + !trace_probe_has_gone(tp)) { + if (trace_probe_is_return(tp)) + ret = enable_kretprobe(&tp->rp); + else + ret = enable_kprobe(&tp->rp.kp); + } + + out_unlock: + mutex_unlock(&probe_enable_lock); + + return ret; +} + +static int +trace_probe_file_index(struct trace_probe *tp, struct ftrace_event_file *file) +{ + struct ftrace_event_file **files; + int i; + + /* + * Since all tp->files updater is protected by probe_enable_lock, + * we don't need to lock an rcu_read_lock. + */ + files = rcu_dereference_raw(tp->files); + if (files) { + for (i = 0; files[i]; i++) + if (files[i] == file) + return i; + } + + return -1; +} + +/* + * Disable trace_probe + * if the file is NULL, disable "perf" handler, or disable "trace" handler. + */ +static int +disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file) +{ + struct ftrace_event_file **old = NULL; + int wait = 0; + int ret = 0; + + mutex_lock(&probe_enable_lock); + + if (file) { + struct ftrace_event_file **new, **old; + int n = trace_probe_nr_files(tp); + int i, j; + + old = rcu_dereference_raw(tp->files); + if (n == 0 || trace_probe_file_index(tp, file) < 0) { + ret = -EINVAL; + goto out_unlock; + } + + if (n == 1) { /* Remove the last file */ + tp->flags &= ~TP_FLAG_TRACE; + new = NULL; + } else { + new = kzalloc(n * sizeof(struct ftrace_event_file *), + GFP_KERNEL); + if (!new) { + ret = -ENOMEM; + goto out_unlock; + } + + /* This copy & check loop copies the NULL stopper too */ + for (i = 0, j = 0; j < n && i < n + 1; i++) + if (old[i] != file) + new[j++] = old[i]; + } + + rcu_assign_pointer(tp->files, new); + wait = 1; + } else + tp->flags &= ~TP_FLAG_PROFILE; + + if (!trace_probe_is_enabled(tp) && trace_probe_is_registered(tp)) { + if (trace_probe_is_return(tp)) + disable_kretprobe(&tp->rp); + else + disable_kprobe(&tp->rp.kp); + wait = 1; + } + + out_unlock: + mutex_unlock(&probe_enable_lock); + + if (wait) { + /* + * Synchronize with kprobe_trace_func/kretprobe_trace_func + * to ensure disabled (all running handlers are finished). + * This is not only for kfree(), but also the caller, + * trace_remove_event_call() supposes it for releasing + * event_call related objects, which will be accessed in + * the kprobe_trace_func/kretprobe_trace_func. + */ + synchronize_sched(); + kfree(old); /* Ignored if link == NULL */ + } + + return ret; +} + +/* Internal register function - just handle k*probes and flags */ +static int __register_trace_probe(struct trace_probe *tp) +{ + int i, ret; + + if (trace_probe_is_registered(tp)) + return -EINVAL; + + for (i = 0; i < tp->nr_args; i++) + traceprobe_update_arg(&tp->args[i]); + + /* Set/clear disabled flag according to tp->flag */ + if (trace_probe_is_enabled(tp)) + tp->rp.kp.flags &= ~KPROBE_FLAG_DISABLED; + else + tp->rp.kp.flags |= KPROBE_FLAG_DISABLED; + + if (trace_probe_is_return(tp)) + ret = register_kretprobe(&tp->rp); + else + ret = register_kprobe(&tp->rp.kp); + + if (ret == 0) + tp->flags |= TP_FLAG_REGISTERED; + else { + pr_warning("Could not insert probe at %s+%lu: %d\n", + trace_probe_symbol(tp), trace_probe_offset(tp), ret); + if (ret == -ENOENT && trace_probe_is_on_module(tp)) { + pr_warning("This probe might be able to register after" + "target module is loaded. Continue.\n"); + ret = 0; + } else if (ret == -EILSEQ) { + pr_warning("Probing address(0x%p) is not an " + "instruction boundary.\n", + tp->rp.kp.addr); + ret = -EINVAL; + } + } + + return ret; +} + +/* Internal unregister function - just handle k*probes and flags */ +static void __unregister_trace_probe(struct trace_probe *tp) +{ + if (trace_probe_is_registered(tp)) { + if (trace_probe_is_return(tp)) + unregister_kretprobe(&tp->rp); + else + unregister_kprobe(&tp->rp.kp); + tp->flags &= ~TP_FLAG_REGISTERED; + /* Cleanup kprobe for reuse */ + if (tp->rp.kp.symbol_name) + tp->rp.kp.addr = NULL; + } +} + +/* Unregister a trace_probe and probe_event: call with locking probe_lock */ +static int unregister_trace_probe(struct trace_probe *tp) +{ + /* Enabled event can not be unregistered */ + if (trace_probe_is_enabled(tp)) + return -EBUSY; + + /* Will fail if probe is being used by ftrace or perf */ + if (unregister_probe_event(tp)) + return -EBUSY; + + __unregister_trace_probe(tp); + list_del(&tp->list); + + return 0; +} + +/* Register a trace_probe and probe_event */ +static int register_trace_probe(struct trace_probe *tp) +{ + struct trace_probe *old_tp; + int ret; + + mutex_lock(&probe_lock); + + /* Delete old (same name) event if exist */ + old_tp = find_trace_probe(tp->call.name, tp->call.class->system); + if (old_tp) { + ret = unregister_trace_probe(old_tp); + if (ret < 0) + goto end; + free_trace_probe(old_tp); + } + + /* Register new event */ + ret = register_probe_event(tp); + if (ret) { + pr_warning("Failed to register probe event(%d)\n", ret); + goto end; + } + + /* Register k*probe */ + ret = __register_trace_probe(tp); + if (ret < 0) + unregister_probe_event(tp); + else + list_add_tail(&tp->list, &probe_list); + +end: + mutex_unlock(&probe_lock); + return ret; +} + +/* Module notifier call back, checking event on the module */ +static int trace_probe_module_callback(struct notifier_block *nb, + unsigned long val, void *data) +{ + struct module *mod = data; + struct trace_probe *tp; + int ret; + + if (val != MODULE_STATE_COMING) + return NOTIFY_DONE; + + /* Update probes on coming module */ + mutex_lock(&probe_lock); + list_for_each_entry(tp, &probe_list, list) { + if (trace_probe_within_module(tp, mod)) { + /* Don't need to check busy - this should have gone. */ + __unregister_trace_probe(tp); + ret = __register_trace_probe(tp); + if (ret) + pr_warning("Failed to re-register probe %s on" + "%s: %d\n", + tp->call.name, mod->name, ret); + } + } + mutex_unlock(&probe_lock); + + return NOTIFY_DONE; +} + +static struct notifier_block trace_probe_module_nb = { + .notifier_call = trace_probe_module_callback, + .priority = 1 /* Invoked after kprobe module callback */ +}; + +static int create_trace_probe(int argc, char **argv) +{ + /* + * Argument syntax: + * - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] + * - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS] + * Fetch args: + * $retval : fetch return value + * $stack : fetch stack address + * $stackN : fetch Nth of stack (N:0-) + * @ADDR : fetch memory at ADDR (ADDR should be in kernel) + * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) + * %REG : fetch register REG + * Dereferencing memory fetch: + * +|-offs(ARG) : fetch memory at ARG +|- offs address. + * Alias name of args: + * NAME=FETCHARG : set NAME as alias of FETCHARG. + * Type of args: + * FETCHARG:TYPE : use TYPE instead of unsigned long. + */ + struct trace_probe *tp; + int i, ret = 0; + bool is_return = false, is_delete = false; + char *symbol = NULL, *event = NULL, *group = NULL; + char *arg; + unsigned long offset = 0; + void *addr = NULL; + char buf[MAX_EVENT_NAME_LEN]; + + /* argc must be >= 1 */ + if (argv[0][0] == 'p') + is_return = false; + else if (argv[0][0] == 'r') + is_return = true; + else if (argv[0][0] == '-') + is_delete = true; + else { + 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 = KPROBE_EVENT_SYSTEM; + + if (is_delete) { + if (!event) { + pr_info("Delete command needs an event name.\n"); + return -EINVAL; + } + mutex_lock(&probe_lock); + tp = find_trace_probe(event, group); + if (!tp) { + mutex_unlock(&probe_lock); + pr_info("Event %s/%s doesn't exist.\n", group, event); + return -ENOENT; + } + /* delete an event */ + ret = unregister_trace_probe(tp); + if (ret == 0) + free_trace_probe(tp); + mutex_unlock(&probe_lock); + return ret; + } + + if (argc < 2) { + pr_info("Probe point is not specified.\n"); + return -EINVAL; + } + if (isdigit(argv[1][0])) { + if (is_return) { + pr_info("Return probe point must be a symbol.\n"); + return -EINVAL; + } + /* an address specified */ + ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr); + if (ret) { + pr_info("Failed to parse address.\n"); + return ret; + } + } else { + /* a symbol specified */ + symbol = argv[1]; + /* TODO: support .init module functions */ + ret = traceprobe_split_symbol_offset(symbol, &offset); + if (ret) { + pr_info("Failed to parse symbol.\n"); + return ret; + } + if (offset && is_return) { + pr_info("Return probe must be used without offset.\n"); + return -EINVAL; + } + } + argc -= 2; argv += 2; + + /* setup a probe */ + if (!event) { + /* Make a new event name */ + if (symbol) + snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld", + is_return ? 'r' : 'p', symbol, offset); + else + snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p", + is_return ? 'r' : 'p', addr); + event = buf; + } + tp = alloc_trace_probe(group, event, addr, symbol, offset, argc, + is_return); + if (IS_ERR(tp)) { + pr_info("Failed to allocate trace_probe.(%d)\n", + (int)PTR_ERR(tp)); + return PTR_ERR(tp); + } + + /* parse arguments */ + ret = 0; + for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { + /* Increment count for freeing args in error case */ + tp->nr_args++; + + /* Parse argument name */ + arg = strchr(argv[i], '='); + if (arg) { + *arg++ = '\0'; + tp->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); + tp->args[i].name = kstrdup(buf, GFP_KERNEL); + } + + if (!tp->args[i].name) { + pr_info("Failed to allocate argument[%d] name.\n", i); + ret = -ENOMEM; + goto error; + } + + if (!is_good_name(tp->args[i].name)) { + pr_info("Invalid argument[%d] name: %s\n", + i, tp->args[i].name); + ret = -EINVAL; + goto error; + } + + if (traceprobe_conflict_field_name(tp->args[i].name, + tp->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, &tp->size, &tp->args[i], + is_return, true); + if (ret) { + pr_info("Parse error at argument[%d]. (%d)\n", i, ret); + goto error; + } + } + + ret = register_trace_probe(tp); + if (ret) + goto error; + return 0; + +error: + free_trace_probe(tp); + return ret; +} + +static int release_all_trace_probes(void) +{ + struct trace_probe *tp; + int ret = 0; + + mutex_lock(&probe_lock); + /* Ensure no probe is in use. */ + list_for_each_entry(tp, &probe_list, list) + if (trace_probe_is_enabled(tp)) { + ret = -EBUSY; + goto end; + } + /* TODO: Use batch unregistration */ + while (!list_empty(&probe_list)) { + tp = list_entry(probe_list.next, struct trace_probe, list); + ret = unregister_trace_probe(tp); + if (ret) + goto end; + free_trace_probe(tp); + } + +end: + mutex_unlock(&probe_lock); + + return ret; +} + +/* Probes listing interfaces */ +static void *probes_seq_start(struct seq_file *m, loff_t *pos) +{ + mutex_lock(&probe_lock); + return seq_list_start(&probe_list, *pos); +} + +static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) +{ + return seq_list_next(v, &probe_list, pos); +} + +static void probes_seq_stop(struct seq_file *m, void *v) +{ + mutex_unlock(&probe_lock); +} + +static int probes_seq_show(struct seq_file *m, void *v) +{ + struct trace_probe *tp = v; + int i; + + seq_printf(m, "%c", trace_probe_is_return(tp) ? 'r' : 'p'); + seq_printf(m, ":%s/%s", tp->call.class->system, tp->call.name); + + if (!tp->symbol) + seq_printf(m, " 0x%p", tp->rp.kp.addr); + else if (tp->rp.kp.offset) + seq_printf(m, " %s+%u", trace_probe_symbol(tp), + tp->rp.kp.offset); + else + seq_printf(m, " %s", trace_probe_symbol(tp)); + + for (i = 0; i < tp->nr_args; i++) + seq_printf(m, " %s=%s", tp->args[i].name, tp->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) +{ + int ret; + + if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { + ret = release_all_trace_probes(); + if (ret < 0) + return ret; + } + + 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_probe); +} + +static const struct file_operations kprobe_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_probe *tp = v; + + seq_printf(m, " %-44s %15lu %15lu\n", tp->call.name, tp->nhit, + tp->rp.kp.nmissed); + + 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 kprobe_profile_ops = { + .owner = THIS_MODULE, + .open = profile_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +/* Sum up total data length for dynamic arraies (strings) */ +static __kprobes int __get_data_size(struct trace_probe *tp, + struct pt_regs *regs) +{ + int i, ret = 0; + u32 len; + + for (i = 0; i < tp->nr_args; i++) + if (unlikely(tp->args[i].fetch_size.fn)) { + call_fetch(&tp->args[i].fetch_size, regs, &len); + ret += len; + } + + return ret; +} + +/* Store the value of each argument */ +static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp, + struct pt_regs *regs, + u8 *data, int maxlen) +{ + int i; + u32 end = tp->size; + u32 *dl; /* Data (relative) location */ + + for (i = 0; i < tp->nr_args; i++) { + if (unlikely(tp->args[i].fetch_size.fn)) { + /* + * First, we set the relative location and + * maximum data length to *dl + */ + dl = (u32 *)(data + tp->args[i].offset); + *dl = make_data_rloc(maxlen, end - tp->args[i].offset); + /* Then try to fetch string or dynamic array data */ + call_fetch(&tp->args[i].fetch, regs, dl); + /* Reduce maximum length */ + end += get_rloc_len(*dl); + maxlen -= get_rloc_len(*dl); + /* Trick here, convert data_rloc to data_loc */ + *dl = convert_rloc_to_loc(*dl, + ent_size + tp->args[i].offset); + } else + /* Just fetching data normally */ + call_fetch(&tp->args[i].fetch, regs, + data + tp->args[i].offset); + } +} + +/* Kprobe handler */ +static __kprobes void +__kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs, + struct ftrace_event_file *ftrace_file) +{ + struct kprobe_trace_entry_head *entry; + struct ring_buffer_event *event; + struct ring_buffer *buffer; + int size, dsize, pc; + unsigned long irq_flags; + struct ftrace_event_call *call = &tp->call; + + WARN_ON(call != ftrace_file->event_call); + + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) + return; + + local_save_flags(irq_flags); + pc = preempt_count(); + + dsize = __get_data_size(tp, regs); + size = sizeof(*entry) + tp->size + dsize; + + event = trace_event_buffer_lock_reserve(&buffer, ftrace_file, + call->event.type, + size, irq_flags, pc); + if (!event) + return; + + entry = ring_buffer_event_data(event); + entry->ip = (unsigned long)tp->rp.kp.addr; + store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize); + + if (!filter_current_check_discard(buffer, call, entry, event)) + trace_buffer_unlock_commit_regs(buffer, event, + irq_flags, pc, regs); +} + +static __kprobes void +kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs) +{ + /* + * Note: preempt is already disabled around the kprobe handler. + * However, we still need an smp_read_barrier_depends() corresponding + * to smp_wmb() in rcu_assign_pointer() to access the pointer. + */ + struct ftrace_event_file **file = rcu_dereference_raw(tp->files); + + if (unlikely(!file)) + return; + + while (*file) { + __kprobe_trace_func(tp, regs, *file); + file++; + } +} + +/* Kretprobe handler */ +static __kprobes void +__kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri, + struct pt_regs *regs, + struct ftrace_event_file *ftrace_file) +{ + struct kretprobe_trace_entry_head *entry; + struct ring_buffer_event *event; + struct ring_buffer *buffer; + int size, pc, dsize; + unsigned long irq_flags; + struct ftrace_event_call *call = &tp->call; + + WARN_ON(call != ftrace_file->event_call); + + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) + return; + + local_save_flags(irq_flags); + pc = preempt_count(); + + dsize = __get_data_size(tp, regs); + size = sizeof(*entry) + tp->size + dsize; + + event = trace_event_buffer_lock_reserve(&buffer, ftrace_file, + call->event.type, + size, irq_flags, pc); + if (!event) + return; + + entry = ring_buffer_event_data(event); + entry->func = (unsigned long)tp->rp.kp.addr; + entry->ret_ip = (unsigned long)ri->ret_addr; + store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize); + + if (!filter_current_check_discard(buffer, call, entry, event)) + trace_buffer_unlock_commit_regs(buffer, event, + irq_flags, pc, regs); +} + +static __kprobes void +kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri, + struct pt_regs *regs) +{ + /* + * Note: preempt is already disabled around the kprobe handler. + * However, we still need an smp_read_barrier_depends() corresponding + * to smp_wmb() in rcu_assign_pointer() to access the pointer. + */ + struct ftrace_event_file **file = rcu_dereference_raw(tp->files); + + if (unlikely(!file)) + return; + + while (*file) { + __kretprobe_trace_func(tp, ri, regs, *file); + file++; + } +} + +/* Event entry printers */ +static enum print_line_t +print_kprobe_event(struct trace_iterator *iter, int flags, + struct trace_event *event) +{ + struct kprobe_trace_entry_head *field; + struct trace_seq *s = &iter->seq; + struct trace_probe *tp; + u8 *data; + int i; + + field = (struct kprobe_trace_entry_head *)iter->ent; + tp = container_of(event, struct trace_probe, call.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; + + data = (u8 *)&field[1]; + for (i = 0; i < tp->nr_args; i++) + if (!tp->args[i].type->print(s, tp->args[i].name, + data + tp->args[i].offset, field)) + goto partial; + + if (!trace_seq_puts(s, "\n")) + goto partial; + + return TRACE_TYPE_HANDLED; +partial: + return TRACE_TYPE_PARTIAL_LINE; +} + +static enum print_line_t +print_kretprobe_event(struct trace_iterator *iter, int flags, + struct trace_event *event) +{ + struct kretprobe_trace_entry_head *field; + struct trace_seq *s = &iter->seq; + struct trace_probe *tp; + u8 *data; + int i; + + field = (struct kretprobe_trace_entry_head *)iter->ent; + tp = container_of(event, struct trace_probe, call.event); + + if (!trace_seq_printf(s, "%s: (", tp->call.name)) + goto partial; + + if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET)) + goto partial; + + if (!trace_seq_puts(s, " <- ")) + goto partial; + + if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET)) + goto partial; + + if (!trace_seq_puts(s, ")")) + goto partial; + + data = (u8 *)&field[1]; + for (i = 0; i < tp->nr_args; i++) + if (!tp->args[i].type->print(s, tp->args[i].name, + data + tp->args[i].offset, field)) + goto partial; + + if (!trace_seq_puts(s, "\n")) + goto partial; + + return TRACE_TYPE_HANDLED; +partial: + return TRACE_TYPE_PARTIAL_LINE; +} + + +static int kprobe_event_define_fields(struct ftrace_event_call *event_call) +{ + int ret, i; + struct kprobe_trace_entry_head field; + struct trace_probe *tp = (struct trace_probe *)event_call->data; + + DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); + /* Set argument names as fields */ + for (i = 0; i < tp->nr_args; i++) { + ret = trace_define_field(event_call, tp->args[i].type->fmttype, + tp->args[i].name, + sizeof(field) + tp->args[i].offset, + tp->args[i].type->size, + tp->args[i].type->is_signed, + FILTER_OTHER); + if (ret) + return ret; + } + return 0; +} + +static int kretprobe_event_define_fields(struct ftrace_event_call *event_call) +{ + int ret, i; + struct kretprobe_trace_entry_head field; + struct trace_probe *tp = (struct trace_probe *)event_call->data; + + DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0); + DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0); + /* Set argument names as fields */ + for (i = 0; i < tp->nr_args; i++) { + ret = trace_define_field(event_call, tp->args[i].type->fmttype, + tp->args[i].name, + sizeof(field) + tp->args[i].offset, + tp->args[i].type->size, + tp->args[i].type->is_signed, + FILTER_OTHER); + if (ret) + return ret; + } + return 0; +} + +static int __set_print_fmt(struct trace_probe *tp, char *buf, int len) +{ + int i; + int pos = 0; + + const char *fmt, *arg; + + if (!trace_probe_is_return(tp)) { + fmt = "(%lx)"; + arg = "REC->" FIELD_STRING_IP; + } else { + fmt = "(%lx <- %lx)"; + arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP; + } + + /* 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=%s", + tp->args[i].name, tp->args[i].type->fmt); + } + + pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg); + + for (i = 0; i < tp->nr_args; i++) { + if (strcmp(tp->args[i].type->name, "string") == 0) + pos += snprintf(buf + pos, LEN_OR_ZERO, + ", __get_str(%s)", + tp->args[i].name); + else + 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_probe *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; +} + +#ifdef CONFIG_PERF_EVENTS + +/* Kprobe profile handler */ +static __kprobes void +kprobe_perf_func(struct trace_probe *tp, struct pt_regs *regs) +{ + struct ftrace_event_call *call = &tp->call; + struct kprobe_trace_entry_head *entry; + struct hlist_head *head; + int size, __size, dsize; + int rctx; + + dsize = __get_data_size(tp, regs); + __size = sizeof(*entry) + tp->size + dsize; + 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->event.type, regs, &rctx); + if (!entry) + return; + + entry->ip = (unsigned long)tp->rp.kp.addr; + memset(&entry[1], 0, dsize); + store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize); + + head = this_cpu_ptr(call->perf_events); + perf_trace_buf_submit(entry, size, rctx, + entry->ip, 1, regs, head, NULL); +} + +/* Kretprobe profile handler */ +static __kprobes void +kretprobe_perf_func(struct trace_probe *tp, struct kretprobe_instance *ri, + struct pt_regs *regs) +{ + struct ftrace_event_call *call = &tp->call; + struct kretprobe_trace_entry_head *entry; + struct hlist_head *head; + int size, __size, dsize; + int rctx; + + dsize = __get_data_size(tp, regs); + __size = sizeof(*entry) + tp->size + dsize; + 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->event.type, regs, &rctx); + if (!entry) + return; + + entry->func = (unsigned long)tp->rp.kp.addr; + entry->ret_ip = (unsigned long)ri->ret_addr; + store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize); + + head = this_cpu_ptr(call->perf_events); + perf_trace_buf_submit(entry, size, rctx, + entry->ret_ip, 1, regs, head, NULL); +} +#endif /* CONFIG_PERF_EVENTS */ + +static __kprobes +int kprobe_register(struct ftrace_event_call *event, + enum trace_reg type, void *data) +{ + struct trace_probe *tp = (struct trace_probe *)event->data; + struct ftrace_event_file *file = data; + + switch (type) { + case TRACE_REG_REGISTER: + return enable_trace_probe(tp, file); + case TRACE_REG_UNREGISTER: + return disable_trace_probe(tp, file); + +#ifdef CONFIG_PERF_EVENTS + case TRACE_REG_PERF_REGISTER: + return enable_trace_probe(tp, NULL); + case TRACE_REG_PERF_UNREGISTER: + return disable_trace_probe(tp, NULL); + case TRACE_REG_PERF_OPEN: + case TRACE_REG_PERF_CLOSE: + case TRACE_REG_PERF_ADD: + case TRACE_REG_PERF_DEL: + return 0; +#endif + } + return 0; +} + +static __kprobes +int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) +{ + struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp); + + tp->nhit++; + + if (tp->flags & TP_FLAG_TRACE) + kprobe_trace_func(tp, regs); +#ifdef CONFIG_PERF_EVENTS + if (tp->flags & TP_FLAG_PROFILE) + kprobe_perf_func(tp, regs); +#endif + return 0; /* We don't tweek kernel, so just return 0 */ +} + +static __kprobes +int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) +{ + struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp); + + tp->nhit++; + + if (tp->flags & TP_FLAG_TRACE) + kretprobe_trace_func(tp, ri, regs); +#ifdef CONFIG_PERF_EVENTS + if (tp->flags & TP_FLAG_PROFILE) + kretprobe_perf_func(tp, ri, regs); +#endif + return 0; /* We don't tweek kernel, so just return 0 */ +} + +static struct trace_event_functions kretprobe_funcs = { + .trace = print_kretprobe_event +}; + +static struct trace_event_functions kprobe_funcs = { + .trace = print_kprobe_event +}; + +static int register_probe_event(struct trace_probe *tp) +{ + struct ftrace_event_call *call = &tp->call; + int ret; + + /* Initialize ftrace_event_call */ + INIT_LIST_HEAD(&call->class->fields); + if (trace_probe_is_return(tp)) { + call->event.funcs = &kretprobe_funcs; + call->class->define_fields = kretprobe_event_define_fields; + } else { + call->event.funcs = &kprobe_funcs; + call->class->define_fields = kprobe_event_define_fields; + } + if (set_print_fmt(tp) < 0) + return -ENOMEM; + ret = register_ftrace_event(&call->event); + if (!ret) { + kfree(call->print_fmt); + return -ENODEV; + } + call->flags = 0; + call->class->reg = kprobe_register; + call->data = tp; + ret = trace_add_event_call(call); + if (ret) { + pr_info("Failed to register kprobe event: %s\n", call->name); + kfree(call->print_fmt); + unregister_ftrace_event(&call->event); + } + return ret; +} + +static int unregister_probe_event(struct trace_probe *tp) +{ + int ret; + + /* tp->event is unregistered in trace_remove_event_call() */ + ret = trace_remove_event_call(&tp->call); + if (!ret) + kfree(tp->call.print_fmt); + return ret; +} + +/* Make a debugfs interface for controlling probe points */ +static __init int init_kprobe_trace(void) +{ + struct dentry *d_tracer; + struct dentry *entry; + + if (register_module_notifier(&trace_probe_module_nb)) + return -EINVAL; + + d_tracer = tracing_init_dentry(); + if (!d_tracer) + return 0; + + entry = debugfs_create_file("kprobe_events", 0644, d_tracer, + NULL, &kprobe_events_ops); + + /* Event list interface */ + if (!entry) + pr_warning("Could not create debugfs " + "'kprobe_events' entry\n"); + + /* Profile interface */ + entry = debugfs_create_file("kprobe_profile", 0444, d_tracer, + NULL, &kprobe_profile_ops); + + if (!entry) + pr_warning("Could not create debugfs " + "'kprobe_profile' entry\n"); + return 0; +} +fs_initcall(init_kprobe_trace); + + +#ifdef CONFIG_FTRACE_STARTUP_TEST + +/* + * The "__used" keeps gcc from removing the function symbol + * from the kallsyms table. + */ +static __used int kprobe_trace_selftest_target(int a1, int a2, int a3, + int a4, int a5, int a6) +{ + return a1 + a2 + a3 + a4 + a5 + a6; +} + +static struct ftrace_event_file * +find_trace_probe_file(struct trace_probe *tp, struct trace_array *tr) +{ + struct ftrace_event_file *file; + + list_for_each_entry(file, &tr->events, list) + if (file->event_call == &tp->call) + return file; + + return NULL; +} + +static __init int kprobe_trace_self_tests_init(void) +{ + int ret, warn = 0; + int (*target)(int, int, int, int, int, int); + struct trace_probe *tp; + struct ftrace_event_file *file; + + target = kprobe_trace_selftest_target; + + pr_info("Testing kprobe tracing: "); + + ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target " + "$stack $stack0 +0($stack)", + create_trace_probe); + if (WARN_ON_ONCE(ret)) { + pr_warn("error on probing function entry.\n"); + warn++; + } else { + /* Enable trace point */ + tp = find_trace_probe("testprobe", KPROBE_EVENT_SYSTEM); + if (WARN_ON_ONCE(tp == NULL)) { + pr_warn("error on getting new probe.\n"); + warn++; + } else { + file = find_trace_probe_file(tp, top_trace_array()); + if (WARN_ON_ONCE(file == NULL)) { + pr_warn("error on getting probe file.\n"); + warn++; + } else + enable_trace_probe(tp, file); + } + } + + ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target " + "$retval", create_trace_probe); + if (WARN_ON_ONCE(ret)) { + pr_warn("error on probing function return.\n"); + warn++; + } else { + /* Enable trace point */ + tp = find_trace_probe("testprobe2", KPROBE_EVENT_SYSTEM); + if (WARN_ON_ONCE(tp == NULL)) { + pr_warn("error on getting 2nd new probe.\n"); + warn++; + } else { + file = find_trace_probe_file(tp, top_trace_array()); + if (WARN_ON_ONCE(file == NULL)) { + pr_warn("error on getting probe file.\n"); + warn++; + } else + enable_trace_probe(tp, file); + } + } + + if (warn) + goto end; + + ret = target(1, 2, 3, 4, 5, 6); + + /* Disable trace points before removing it */ + tp = find_trace_probe("testprobe", KPROBE_EVENT_SYSTEM); + if (WARN_ON_ONCE(tp == NULL)) { + pr_warn("error on getting test probe.\n"); + warn++; + } else { + file = find_trace_probe_file(tp, top_trace_array()); + if (WARN_ON_ONCE(file == NULL)) { + pr_warn("error on getting probe file.\n"); + warn++; + } else + disable_trace_probe(tp, file); + } + + tp = find_trace_probe("testprobe2", KPROBE_EVENT_SYSTEM); + if (WARN_ON_ONCE(tp == NULL)) { + pr_warn("error on getting 2nd test probe.\n"); + warn++; + } else { + file = find_trace_probe_file(tp, top_trace_array()); + if (WARN_ON_ONCE(file == NULL)) { + pr_warn("error on getting probe file.\n"); + warn++; + } else + disable_trace_probe(tp, file); + } + + ret = traceprobe_command("-:testprobe", create_trace_probe); + if (WARN_ON_ONCE(ret)) { + pr_warn("error on deleting a probe.\n"); + warn++; + } + + ret = traceprobe_command("-:testprobe2", create_trace_probe); + if (WARN_ON_ONCE(ret)) { + pr_warn("error on deleting a probe.\n"); + warn++; + } + +end: + release_all_trace_probes(); + if (warn) + pr_cont("NG: Some tests are failed. Please check them.\n"); + else + pr_cont("OK\n"); + return 0; +} + +late_initcall(kprobe_trace_self_tests_init); + +#endif |