| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * uprobes-based tracing events |
| * |
| * Copyright (C) IBM Corporation, 2010-2012 |
| * Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com> |
| */ |
| #define pr_fmt(fmt) "trace_uprobe: " fmt |
| |
| #include <linux/ctype.h> |
| #include <linux/module.h> |
| #include <linux/uaccess.h> |
| #include <linux/uprobes.h> |
| #include <linux/namei.h> |
| #include <linux/string.h> |
| #include <linux/rculist.h> |
| |
| #include "trace_dynevent.h" |
| #include "trace_probe.h" |
| #include "trace_probe_tmpl.h" |
| |
| #define UPROBE_EVENT_SYSTEM "uprobes" |
| |
| struct uprobe_trace_entry_head { |
| struct trace_entry ent; |
| unsigned long vaddr[]; |
| }; |
| |
| #define SIZEOF_TRACE_ENTRY(is_return) \ |
| (sizeof(struct uprobe_trace_entry_head) + \ |
| sizeof(unsigned long) * (is_return ? 2 : 1)) |
| |
| #define DATAOF_TRACE_ENTRY(entry, is_return) \ |
| ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return)) |
| |
| struct trace_uprobe_filter { |
| rwlock_t rwlock; |
| int nr_systemwide; |
| struct list_head perf_events; |
| }; |
| |
| static int trace_uprobe_create(int argc, const char **argv); |
| static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev); |
| static int trace_uprobe_release(struct dyn_event *ev); |
| static bool trace_uprobe_is_busy(struct dyn_event *ev); |
| static bool trace_uprobe_match(const char *system, const char *event, |
| struct dyn_event *ev); |
| |
| static struct dyn_event_operations trace_uprobe_ops = { |
| .create = trace_uprobe_create, |
| .show = trace_uprobe_show, |
| .is_busy = trace_uprobe_is_busy, |
| .free = trace_uprobe_release, |
| .match = trace_uprobe_match, |
| }; |
| |
| /* |
| * uprobe event core functions |
| */ |
| struct trace_uprobe { |
| struct dyn_event devent; |
| struct trace_uprobe_filter filter; |
| struct uprobe_consumer consumer; |
| struct path path; |
| struct inode *inode; |
| char *filename; |
| unsigned long offset; |
| unsigned long ref_ctr_offset; |
| unsigned long nhit; |
| struct trace_probe tp; |
| }; |
| |
| static bool is_trace_uprobe(struct dyn_event *ev) |
| { |
| return ev->ops == &trace_uprobe_ops; |
| } |
| |
| static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev) |
| { |
| return container_of(ev, struct trace_uprobe, devent); |
| } |
| |
| /** |
| * for_each_trace_uprobe - iterate over the trace_uprobe list |
| * @pos: the struct trace_uprobe * for each entry |
| * @dpos: the struct dyn_event * to use as a loop cursor |
| */ |
| #define for_each_trace_uprobe(pos, dpos) \ |
| for_each_dyn_event(dpos) \ |
| if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos))) |
| |
| #define SIZEOF_TRACE_UPROBE(n) \ |
| (offsetof(struct trace_uprobe, tp.args) + \ |
| (sizeof(struct probe_arg) * (n))) |
| |
| static int register_uprobe_event(struct trace_uprobe *tu); |
| static int unregister_uprobe_event(struct trace_uprobe *tu); |
| |
| struct uprobe_dispatch_data { |
| struct trace_uprobe *tu; |
| unsigned long bp_addr; |
| }; |
| |
| static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); |
| static int uretprobe_dispatcher(struct uprobe_consumer *con, |
| unsigned long func, struct pt_regs *regs); |
| |
| #ifdef CONFIG_STACK_GROWSUP |
| static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) |
| { |
| return addr - (n * sizeof(long)); |
| } |
| #else |
| static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) |
| { |
| return addr + (n * sizeof(long)); |
| } |
| #endif |
| |
| static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n) |
| { |
| unsigned long ret; |
| unsigned long addr = user_stack_pointer(regs); |
| |
| addr = adjust_stack_addr(addr, n); |
| |
| if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret))) |
| return 0; |
| |
| return ret; |
| } |
| |
| /* |
| * Uprobes-specific fetch functions |
| */ |
| static nokprobe_inline int |
| probe_mem_read(void *dest, void *src, size_t size) |
| { |
| void __user *vaddr = (void __force __user *)src; |
| |
| return copy_from_user(dest, vaddr, size) ? -EFAULT : 0; |
| } |
| /* |
| * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max |
| * length and relative data location. |
| */ |
| static nokprobe_inline int |
| fetch_store_string(unsigned long addr, void *dest, void *base) |
| { |
| long ret; |
| u32 loc = *(u32 *)dest; |
| int maxlen = get_loc_len(loc); |
| u8 *dst = get_loc_data(dest, base); |
| void __user *src = (void __force __user *) addr; |
| |
| if (unlikely(!maxlen)) |
| return -ENOMEM; |
| |
| if (addr == FETCH_TOKEN_COMM) |
| ret = strlcpy(dst, current->comm, maxlen); |
| else |
| ret = strncpy_from_user(dst, src, maxlen); |
| if (ret >= 0) { |
| if (ret == maxlen) |
| dst[ret - 1] = '\0'; |
| else |
| /* |
| * Include the terminating null byte. In this case it |
| * was copied by strncpy_from_user but not accounted |
| * for in ret. |
| */ |
| ret++; |
| *(u32 *)dest = make_data_loc(ret, (void *)dst - base); |
| } |
| |
| return ret; |
| } |
| |
| /* Return the length of string -- including null terminal byte */ |
| static nokprobe_inline int |
| fetch_store_strlen(unsigned long addr) |
| { |
| int len; |
| void __user *vaddr = (void __force __user *) addr; |
| |
| if (addr == FETCH_TOKEN_COMM) |
| len = strlen(current->comm) + 1; |
| else |
| len = strnlen_user(vaddr, MAX_STRING_SIZE); |
| |
| return (len > MAX_STRING_SIZE) ? 0 : len; |
| } |
| |
| static unsigned long translate_user_vaddr(unsigned long file_offset) |
| { |
| unsigned long base_addr; |
| struct uprobe_dispatch_data *udd; |
| |
| udd = (void *) current->utask->vaddr; |
| |
| base_addr = udd->bp_addr - udd->tu->offset; |
| return base_addr + file_offset; |
| } |
| |
| /* Note that we don't verify it, since the code does not come from user space */ |
| static int |
| process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, |
| void *base) |
| { |
| unsigned long val; |
| |
| /* 1st stage: get value from context */ |
| switch (code->op) { |
| case FETCH_OP_REG: |
| val = regs_get_register(regs, code->param); |
| break; |
| case FETCH_OP_STACK: |
| val = get_user_stack_nth(regs, code->param); |
| break; |
| case FETCH_OP_STACKP: |
| val = user_stack_pointer(regs); |
| break; |
| case FETCH_OP_RETVAL: |
| val = regs_return_value(regs); |
| break; |
| case FETCH_OP_IMM: |
| val = code->immediate; |
| break; |
| case FETCH_OP_COMM: |
| val = FETCH_TOKEN_COMM; |
| break; |
| case FETCH_OP_FOFFS: |
| val = translate_user_vaddr(code->immediate); |
| break; |
| default: |
| return -EILSEQ; |
| } |
| code++; |
| |
| return process_fetch_insn_bottom(code, val, dest, base); |
| } |
| NOKPROBE_SYMBOL(process_fetch_insn) |
| |
| static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) |
| { |
| rwlock_init(&filter->rwlock); |
| filter->nr_systemwide = 0; |
| INIT_LIST_HEAD(&filter->perf_events); |
| } |
| |
| static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) |
| { |
| return !filter->nr_systemwide && list_empty(&filter->perf_events); |
| } |
| |
| static inline bool is_ret_probe(struct trace_uprobe *tu) |
| { |
| return tu->consumer.ret_handler != NULL; |
| } |
| |
| static bool trace_uprobe_is_busy(struct dyn_event *ev) |
| { |
| struct trace_uprobe *tu = to_trace_uprobe(ev); |
| |
| return trace_probe_is_enabled(&tu->tp); |
| } |
| |
| static bool trace_uprobe_match(const char *system, const char *event, |
| struct dyn_event *ev) |
| { |
| struct trace_uprobe *tu = to_trace_uprobe(ev); |
| |
| return strcmp(trace_event_name(&tu->tp.call), event) == 0 && |
| (!system || strcmp(tu->tp.call.class->system, system) == 0); |
| } |
| |
| /* |
| * Allocate new trace_uprobe and initialize it (including uprobes). |
| */ |
| static struct trace_uprobe * |
| alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) |
| { |
| struct trace_uprobe *tu; |
| |
| if (!event || !group) |
| return ERR_PTR(-EINVAL); |
| |
| tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); |
| if (!tu) |
| return ERR_PTR(-ENOMEM); |
| |
| tu->tp.call.class = &tu->tp.class; |
| tu->tp.call.name = kstrdup(event, GFP_KERNEL); |
| if (!tu->tp.call.name) |
| goto error; |
| |
| tu->tp.class.system = kstrdup(group, GFP_KERNEL); |
| if (!tu->tp.class.system) |
| goto error; |
| |
| dyn_event_init(&tu->devent, &trace_uprobe_ops); |
| INIT_LIST_HEAD(&tu->tp.files); |
| tu->consumer.handler = uprobe_dispatcher; |
| if (is_ret) |
| tu->consumer.ret_handler = uretprobe_dispatcher; |
| init_trace_uprobe_filter(&tu->filter); |
| return tu; |
| |
| error: |
| kfree(tu->tp.call.name); |
| kfree(tu); |
| |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| static void free_trace_uprobe(struct trace_uprobe *tu) |
| { |
| int i; |
| |
| if (!tu) |
| return; |
| |
| for (i = 0; i < tu->tp.nr_args; i++) |
| traceprobe_free_probe_arg(&tu->tp.args[i]); |
| |
| path_put(&tu->path); |
| kfree(tu->tp.call.class->system); |
| kfree(tu->tp.call.name); |
| kfree(tu->filename); |
| kfree(tu); |
| } |
| |
| static struct trace_uprobe *find_probe_event(const char *event, const char *group) |
| { |
| struct dyn_event *pos; |
| struct trace_uprobe *tu; |
| |
| for_each_trace_uprobe(tu, pos) |
| if (strcmp(trace_event_name(&tu->tp.call), event) == 0 && |
| strcmp(tu->tp.call.class->system, group) == 0) |
| return tu; |
| |
| return NULL; |
| } |
| |
| /* Unregister a trace_uprobe and probe_event */ |
| static int unregister_trace_uprobe(struct trace_uprobe *tu) |
| { |
| int ret; |
| |
| ret = unregister_uprobe_event(tu); |
| if (ret) |
| return ret; |
| |
| dyn_event_remove(&tu->devent); |
| free_trace_uprobe(tu); |
| return 0; |
| } |
| |
| /* |
| * Uprobe with multiple reference counter is not allowed. i.e. |
| * If inode and offset matches, reference counter offset *must* |
| * match as well. Though, there is one exception: If user is |
| * replacing old trace_uprobe with new one(same group/event), |
| * then we allow same uprobe with new reference counter as far |
| * as the new one does not conflict with any other existing |
| * ones. |
| */ |
| static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new) |
| { |
| struct dyn_event *pos; |
| struct trace_uprobe *tmp, *old = NULL; |
| struct inode *new_inode = d_real_inode(new->path.dentry); |
| |
| old = find_probe_event(trace_event_name(&new->tp.call), |
| new->tp.call.class->system); |
| |
| for_each_trace_uprobe(tmp, pos) { |
| if ((old ? old != tmp : true) && |
| new_inode == d_real_inode(tmp->path.dentry) && |
| new->offset == tmp->offset && |
| new->ref_ctr_offset != tmp->ref_ctr_offset) { |
| pr_warn("Reference counter offset mismatch."); |
| return ERR_PTR(-EINVAL); |
| } |
| } |
| return old; |
| } |
| |
| /* Register a trace_uprobe and probe_event */ |
| static int register_trace_uprobe(struct trace_uprobe *tu) |
| { |
| struct trace_uprobe *old_tu; |
| int ret; |
| |
| mutex_lock(&event_mutex); |
| |
| /* register as an event */ |
| old_tu = find_old_trace_uprobe(tu); |
| if (IS_ERR(old_tu)) { |
| ret = PTR_ERR(old_tu); |
| goto end; |
| } |
| |
| if (old_tu) { |
| /* delete old event */ |
| ret = unregister_trace_uprobe(old_tu); |
| if (ret) |
| goto end; |
| } |
| |
| ret = register_uprobe_event(tu); |
| if (ret) { |
| pr_warn("Failed to register probe event(%d)\n", ret); |
| goto end; |
| } |
| |
| dyn_event_add(&tu->devent); |
| |
| end: |
| mutex_unlock(&event_mutex); |
| |
| return ret; |
| } |
| |
| /* |
| * Argument syntax: |
| * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] |
| * |
| * - Remove uprobe: -:[GRP/]EVENT |
| */ |
| static int trace_uprobe_create(int argc, const char **argv) |
| { |
| struct trace_uprobe *tu; |
| const char *event = NULL, *group = UPROBE_EVENT_SYSTEM; |
| char *arg, *filename, *rctr, *rctr_end, *tmp; |
| char buf[MAX_EVENT_NAME_LEN]; |
| struct path path; |
| unsigned long offset, ref_ctr_offset; |
| bool is_return = false; |
| int i, ret; |
| |
| ret = 0; |
| ref_ctr_offset = 0; |
| |
| /* argc must be >= 1 */ |
| if (argv[0][0] == 'r') |
| is_return = true; |
| else if (argv[0][0] != 'p' || argc < 2) |
| return -ECANCELED; |
| |
| if (argv[0][1] == ':') |
| event = &argv[0][2]; |
| |
| if (!strchr(argv[1], '/')) |
| return -ECANCELED; |
| |
| filename = kstrdup(argv[1], GFP_KERNEL); |
| if (!filename) |
| return -ENOMEM; |
| |
| /* Find the last occurrence, in case the path contains ':' too. */ |
| arg = strrchr(filename, ':'); |
| if (!arg || !isdigit(arg[1])) { |
| kfree(filename); |
| return -ECANCELED; |
| } |
| |
| trace_probe_log_init("trace_uprobe", argc, argv); |
| trace_probe_log_set_index(1); /* filename is the 2nd argument */ |
| |
| *arg++ = '\0'; |
| ret = kern_path(filename, LOOKUP_FOLLOW, &path); |
| if (ret) { |
| trace_probe_log_err(0, FILE_NOT_FOUND); |
| kfree(filename); |
| trace_probe_log_clear(); |
| return ret; |
| } |
| if (!d_is_reg(path.dentry)) { |
| trace_probe_log_err(0, NO_REGULAR_FILE); |
| ret = -EINVAL; |
| goto fail_address_parse; |
| } |
| |
| /* Parse reference counter offset if specified. */ |
| rctr = strchr(arg, '('); |
| if (rctr) { |
| rctr_end = strchr(rctr, ')'); |
| if (!rctr_end) { |
| ret = -EINVAL; |
| rctr_end = rctr + strlen(rctr); |
| trace_probe_log_err(rctr_end - filename, |
| REFCNT_OPEN_BRACE); |
| goto fail_address_parse; |
| } else if (rctr_end[1] != '\0') { |
| ret = -EINVAL; |
| trace_probe_log_err(rctr_end + 1 - filename, |
| BAD_REFCNT_SUFFIX); |
| goto fail_address_parse; |
| } |
| |
| *rctr++ = '\0'; |
| *rctr_end = '\0'; |
| ret = kstrtoul(rctr, 0, &ref_ctr_offset); |
| if (ret) { |
| trace_probe_log_err(rctr - filename, BAD_REFCNT); |
| goto fail_address_parse; |
| } |
| } |
| |
| /* Parse uprobe offset. */ |
| ret = kstrtoul(arg, 0, &offset); |
| if (ret) { |
| trace_probe_log_err(arg - filename, BAD_UPROBE_OFFS); |
| goto fail_address_parse; |
| } |
| |
| /* setup a probe */ |
| trace_probe_log_set_index(0); |
| if (event) { |
| ret = traceprobe_parse_event_name(&event, &group, buf, |
| event - argv[0]); |
| if (ret) |
| goto fail_address_parse; |
| } else { |
| char *tail; |
| char *ptr; |
| |
| tail = kstrdup(kbasename(filename), GFP_KERNEL); |
| if (!tail) { |
| ret = -ENOMEM; |
| goto fail_address_parse; |
| } |
| |
| ptr = strpbrk(tail, ".-_"); |
| if (ptr) |
| *ptr = '\0'; |
| |
| snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); |
| event = buf; |
| kfree(tail); |
| } |
| |
| argc -= 2; |
| argv += 2; |
| |
| tu = alloc_trace_uprobe(group, event, argc, is_return); |
| if (IS_ERR(tu)) { |
| ret = PTR_ERR(tu); |
| /* This must return -ENOMEM otherwise there is a bug */ |
| WARN_ON_ONCE(ret != -ENOMEM); |
| goto fail_address_parse; |
| } |
| tu->offset = offset; |
| tu->ref_ctr_offset = ref_ctr_offset; |
| tu->path = path; |
| tu->filename = filename; |
| |
| /* parse arguments */ |
| for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { |
| tmp = kstrdup(argv[i], GFP_KERNEL); |
| if (!tmp) { |
| ret = -ENOMEM; |
| goto error; |
| } |
| |
| trace_probe_log_set_index(i + 2); |
| ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp, |
| is_return ? TPARG_FL_RETURN : 0); |
| kfree(tmp); |
| if (ret) |
| goto error; |
| } |
| |
| ret = register_trace_uprobe(tu); |
| if (!ret) |
| goto out; |
| |
| error: |
| free_trace_uprobe(tu); |
| out: |
| trace_probe_log_clear(); |
| return ret; |
| |
| fail_address_parse: |
| trace_probe_log_clear(); |
| path_put(&path); |
| kfree(filename); |
| |
| return ret; |
| } |
| |
| static int create_or_delete_trace_uprobe(int argc, char **argv) |
| { |
| int ret; |
| |
| if (argv[0][0] == '-') |
| return dyn_event_release(argc, argv, &trace_uprobe_ops); |
| |
| ret = trace_uprobe_create(argc, (const char **)argv); |
| return ret == -ECANCELED ? -EINVAL : ret; |
| } |
| |
| static int trace_uprobe_release(struct dyn_event *ev) |
| { |
| struct trace_uprobe *tu = to_trace_uprobe(ev); |
| |
| return unregister_trace_uprobe(tu); |
| } |
| |
| /* Probes listing interfaces */ |
| static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev) |
| { |
| struct trace_uprobe *tu = to_trace_uprobe(ev); |
| char c = is_ret_probe(tu) ? 'r' : 'p'; |
| int i; |
| |
| seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system, |
| trace_event_name(&tu->tp.call), tu->filename, |
| (int)(sizeof(void *) * 2), tu->offset); |
| |
| if (tu->ref_ctr_offset) |
| seq_printf(m, "(0x%lx)", tu->ref_ctr_offset); |
| |
| for (i = 0; i < tu->tp.nr_args; i++) |
| seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm); |
| |
| seq_putc(m, '\n'); |
| return 0; |
| } |
| |
| static int probes_seq_show(struct seq_file *m, void *v) |
| { |
| struct dyn_event *ev = v; |
| |
| if (!is_trace_uprobe(ev)) |
| return 0; |
| |
| return trace_uprobe_show(m, ev); |
| } |
| |
| static const struct seq_operations probes_seq_op = { |
| .start = dyn_event_seq_start, |
| .next = dyn_event_seq_next, |
| .stop = dyn_event_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 = dyn_events_release_all(&trace_uprobe_ops); |
| if (ret) |
| 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 trace_parse_run_command(file, buffer, count, ppos, |
| create_or_delete_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 dyn_event *ev = v; |
| struct trace_uprobe *tu; |
| |
| if (!is_trace_uprobe(ev)) |
| return 0; |
| |
| tu = to_trace_uprobe(ev); |
| seq_printf(m, " %s %-44s %15lu\n", tu->filename, |
| trace_event_name(&tu->tp.call), tu->nhit); |
| return 0; |
| } |
| |
| static const struct seq_operations profile_seq_op = { |
| .start = dyn_event_seq_start, |
| .next = dyn_event_seq_next, |
| .stop = dyn_event_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, |
| }; |
| |
| struct uprobe_cpu_buffer { |
| struct mutex mutex; |
| void *buf; |
| }; |
| static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer; |
| static int uprobe_buffer_refcnt; |
| |
| static int uprobe_buffer_init(void) |
| { |
| int cpu, err_cpu; |
| |
| uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer); |
| if (uprobe_cpu_buffer == NULL) |
| return -ENOMEM; |
| |
| for_each_possible_cpu(cpu) { |
| struct page *p = alloc_pages_node(cpu_to_node(cpu), |
| GFP_KERNEL, 0); |
| if (p == NULL) { |
| err_cpu = cpu; |
| goto err; |
| } |
| per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p); |
| mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex); |
| } |
| |
| return 0; |
| |
| err: |
| for_each_possible_cpu(cpu) { |
| if (cpu == err_cpu) |
| break; |
| free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); |
| } |
| |
| free_percpu(uprobe_cpu_buffer); |
| return -ENOMEM; |
| } |
| |
| static int uprobe_buffer_enable(void) |
| { |
| int ret = 0; |
| |
| BUG_ON(!mutex_is_locked(&event_mutex)); |
| |
| if (uprobe_buffer_refcnt++ == 0) { |
| ret = uprobe_buffer_init(); |
| if (ret < 0) |
| uprobe_buffer_refcnt--; |
| } |
| |
| return ret; |
| } |
| |
| static void uprobe_buffer_disable(void) |
| { |
| int cpu; |
| |
| BUG_ON(!mutex_is_locked(&event_mutex)); |
| |
| if (--uprobe_buffer_refcnt == 0) { |
| for_each_possible_cpu(cpu) |
| free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, |
| cpu)->buf); |
| |
| free_percpu(uprobe_cpu_buffer); |
| uprobe_cpu_buffer = NULL; |
| } |
| } |
| |
| static struct uprobe_cpu_buffer *uprobe_buffer_get(void) |
| { |
| struct uprobe_cpu_buffer *ucb; |
| int cpu; |
| |
| cpu = raw_smp_processor_id(); |
| ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu); |
| |
| /* |
| * Use per-cpu buffers for fastest access, but we might migrate |
| * so the mutex makes sure we have sole access to it. |
| */ |
| mutex_lock(&ucb->mutex); |
| |
| return ucb; |
| } |
| |
| static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) |
| { |
| mutex_unlock(&ucb->mutex); |
| } |
| |
| static void __uprobe_trace_func(struct trace_uprobe *tu, |
| unsigned long func, struct pt_regs *regs, |
| struct uprobe_cpu_buffer *ucb, int dsize, |
| struct trace_event_file *trace_file) |
| { |
| struct uprobe_trace_entry_head *entry; |
| struct ring_buffer_event *event; |
| struct ring_buffer *buffer; |
| void *data; |
| int size, esize; |
| struct trace_event_call *call = &tu->tp.call; |
| |
| WARN_ON(call != trace_file->event_call); |
| |
| if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) |
| return; |
| |
| if (trace_trigger_soft_disabled(trace_file)) |
| return; |
| |
| esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); |
| size = esize + tu->tp.size + dsize; |
| event = trace_event_buffer_lock_reserve(&buffer, trace_file, |
| call->event.type, size, 0, 0); |
| if (!event) |
| return; |
| |
| entry = ring_buffer_event_data(event); |
| if (is_ret_probe(tu)) { |
| entry->vaddr[0] = func; |
| entry->vaddr[1] = instruction_pointer(regs); |
| data = DATAOF_TRACE_ENTRY(entry, true); |
| } else { |
| entry->vaddr[0] = instruction_pointer(regs); |
| data = DATAOF_TRACE_ENTRY(entry, false); |
| } |
| |
| memcpy(data, ucb->buf, tu->tp.size + dsize); |
| |
| event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0); |
| } |
| |
| /* uprobe handler */ |
| static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, |
| struct uprobe_cpu_buffer *ucb, int dsize) |
| { |
| struct event_file_link *link; |
| |
| if (is_ret_probe(tu)) |
| return 0; |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(link, &tu->tp.files, list) |
| __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); |
| rcu_read_unlock(); |
| |
| return 0; |
| } |
| |
| static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, |
| struct pt_regs *regs, |
| struct uprobe_cpu_buffer *ucb, int dsize) |
| { |
| struct event_file_link *link; |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(link, &tu->tp.files, list) |
| __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); |
| rcu_read_unlock(); |
| } |
| |
| /* 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 *entry; |
| struct trace_seq *s = &iter->seq; |
| struct trace_uprobe *tu; |
| u8 *data; |
| |
| entry = (struct uprobe_trace_entry_head *)iter->ent; |
| tu = container_of(event, struct trace_uprobe, tp.call.event); |
| |
| if (is_ret_probe(tu)) { |
| trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", |
| trace_event_name(&tu->tp.call), |
| entry->vaddr[1], entry->vaddr[0]); |
| data = DATAOF_TRACE_ENTRY(entry, true); |
| } else { |
| trace_seq_printf(s, "%s: (0x%lx)", |
| trace_event_name(&tu->tp.call), |
| entry->vaddr[0]); |
| data = DATAOF_TRACE_ENTRY(entry, false); |
| } |
| |
| if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0) |
| goto out; |
| |
| trace_seq_putc(s, '\n'); |
| |
| out: |
| return trace_handle_return(s); |
| } |
| |
| typedef bool (*filter_func_t)(struct uprobe_consumer *self, |
| enum uprobe_filter_ctx ctx, |
| struct mm_struct *mm); |
| |
| static int |
| probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file, |
| filter_func_t filter) |
| { |
| bool enabled = trace_probe_is_enabled(&tu->tp); |
| struct event_file_link *link = NULL; |
| int ret; |
| |
| if (file) { |
| if (tu->tp.flags & TP_FLAG_PROFILE) |
| return -EINTR; |
| |
| link = kmalloc(sizeof(*link), GFP_KERNEL); |
| if (!link) |
| return -ENOMEM; |
| |
| link->file = file; |
| list_add_tail_rcu(&link->list, &tu->tp.files); |
| |
| tu->tp.flags |= TP_FLAG_TRACE; |
| } else { |
| if (tu->tp.flags & TP_FLAG_TRACE) |
| return -EINTR; |
| |
| tu->tp.flags |= TP_FLAG_PROFILE; |
| } |
| |
| WARN_ON(!uprobe_filter_is_empty(&tu->filter)); |
| |
| if (enabled) |
| return 0; |
| |
| ret = uprobe_buffer_enable(); |
| if (ret) |
| goto err_flags; |
| |
| tu->consumer.filter = filter; |
| tu->inode = d_real_inode(tu->path.dentry); |
| if (tu->ref_ctr_offset) { |
| ret = uprobe_register_refctr(tu->inode, tu->offset, |
| tu->ref_ctr_offset, &tu->consumer); |
| } else { |
| ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); |
| } |
| |
| if (ret) |
| goto err_buffer; |
| |
| return 0; |
| |
| err_buffer: |
| uprobe_buffer_disable(); |
| |
| err_flags: |
| if (file) { |
| list_del(&link->list); |
| kfree(link); |
| tu->tp.flags &= ~TP_FLAG_TRACE; |
| } else { |
| tu->tp.flags &= ~TP_FLAG_PROFILE; |
| } |
| return ret; |
| } |
| |
| static void |
| probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file) |
| { |
| if (!trace_probe_is_enabled(&tu->tp)) |
| return; |
| |
| if (file) { |
| struct event_file_link *link; |
| |
| link = find_event_file_link(&tu->tp, file); |
| if (!link) |
| return; |
| |
| list_del_rcu(&link->list); |
| /* synchronize with u{,ret}probe_trace_func */ |
| synchronize_rcu(); |
| kfree(link); |
| |
| if (!list_empty(&tu->tp.files)) |
| return; |
| } |
| |
| WARN_ON(!uprobe_filter_is_empty(&tu->filter)); |
| |
| uprobe_unregister(tu->inode, tu->offset, &tu->consumer); |
| tu->inode = NULL; |
| tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE; |
| |
| uprobe_buffer_disable(); |
| } |
| |
| static int uprobe_event_define_fields(struct trace_event_call *event_call) |
| { |
| int ret, size; |
| struct uprobe_trace_entry_head field; |
| struct trace_uprobe *tu = event_call->data; |
| |
| if (is_ret_probe(tu)) { |
| DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); |
| DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); |
| size = SIZEOF_TRACE_ENTRY(true); |
| } else { |
| DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); |
| size = SIZEOF_TRACE_ENTRY(false); |
| } |
| |
| return traceprobe_define_arg_fields(event_call, size, &tu->tp); |
| } |
| |
| #ifdef CONFIG_PERF_EVENTS |
| static bool |
| __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) |
| { |
| struct perf_event *event; |
| |
| if (filter->nr_systemwide) |
| return true; |
| |
| list_for_each_entry(event, &filter->perf_events, hw.tp_list) { |
| if (event->hw.target->mm == mm) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static inline bool |
| uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) |
| { |
| return __uprobe_perf_filter(&tu->filter, event->hw.target->mm); |
| } |
| |
| static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) |
| { |
| bool done; |
| |
| write_lock(&tu->filter.rwlock); |
| if (event->hw.target) { |
| list_del(&event->hw.tp_list); |
| done = tu->filter.nr_systemwide || |
| (event->hw.target->flags & PF_EXITING) || |
| uprobe_filter_event(tu, event); |
| } else { |
| tu->filter.nr_systemwide--; |
| done = tu->filter.nr_systemwide; |
| } |
| write_unlock(&tu->filter.rwlock); |
| |
| if (!done) |
| return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); |
| |
| return 0; |
| } |
| |
| static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) |
| { |
| bool done; |
| int err; |
| |
| write_lock(&tu->filter.rwlock); |
| if (event->hw.target) { |
| /* |
| * event->parent != NULL means copy_process(), we can avoid |
| * uprobe_apply(). current->mm must be probed and we can rely |
| * on dup_mmap() which preserves the already installed bp's. |
| * |
| * attr.enable_on_exec means that exec/mmap will install the |
| * breakpoints we need. |
| */ |
| done = tu->filter.nr_systemwide || |
| event->parent || event->attr.enable_on_exec || |
| uprobe_filter_event(tu, event); |
| list_add(&event->hw.tp_list, &tu->filter.perf_events); |
| } else { |
| done = tu->filter.nr_systemwide; |
| tu->filter.nr_systemwide++; |
| } |
| write_unlock(&tu->filter.rwlock); |
| |
| err = 0; |
| if (!done) { |
| err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); |
| if (err) |
| uprobe_perf_close(tu, event); |
| } |
| return err; |
| } |
| |
| static bool uprobe_perf_filter(struct uprobe_consumer *uc, |
| enum uprobe_filter_ctx ctx, struct mm_struct *mm) |
| { |
| struct trace_uprobe *tu; |
| int ret; |
| |
| tu = container_of(uc, struct trace_uprobe, consumer); |
| read_lock(&tu->filter.rwlock); |
| ret = __uprobe_perf_filter(&tu->filter, mm); |
| read_unlock(&tu->filter.rwlock); |
| |
| return ret; |
| } |
| |
| static void __uprobe_perf_func(struct trace_uprobe *tu, |
| unsigned long func, struct pt_regs *regs, |
| struct uprobe_cpu_buffer *ucb, int dsize) |
| { |
| struct trace_event_call *call = &tu->tp.call; |
| struct uprobe_trace_entry_head *entry; |
| struct hlist_head *head; |
| void *data; |
| int size, esize; |
| int rctx; |
| |
| if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) |
| return; |
| |
| esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); |
| |
| size = esize + tu->tp.size + dsize; |
| size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32); |
| if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) |
| return; |
| |
| preempt_disable(); |
| head = this_cpu_ptr(call->perf_events); |
| if (hlist_empty(head)) |
| goto out; |
| |
| entry = perf_trace_buf_alloc(size, NULL, &rctx); |
| if (!entry) |
| goto out; |
| |
| if (is_ret_probe(tu)) { |
| entry->vaddr[0] = func; |
| entry->vaddr[1] = instruction_pointer(regs); |
| data = DATAOF_TRACE_ENTRY(entry, true); |
| } else { |
| entry->vaddr[0] = instruction_pointer(regs); |
| data = DATAOF_TRACE_ENTRY(entry, false); |
| } |
| |
| memcpy(data, ucb->buf, tu->tp.size + dsize); |
| |
| if (size - esize > tu->tp.size + dsize) { |
| int len = tu->tp.size + dsize; |
| |
| memset(data + len, 0, size - esize - len); |
| } |
| |
| perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, |
| head, NULL); |
| out: |
| preempt_enable(); |
| } |
| |
| /* uprobe profile handler */ |
| static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs, |
| struct uprobe_cpu_buffer *ucb, int dsize) |
| { |
| if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) |
| return UPROBE_HANDLER_REMOVE; |
| |
| if (!is_ret_probe(tu)) |
| __uprobe_perf_func(tu, 0, regs, ucb, dsize); |
| return 0; |
| } |
| |
| static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, |
| struct pt_regs *regs, |
| struct uprobe_cpu_buffer *ucb, int dsize) |
| { |
| __uprobe_perf_func(tu, func, regs, ucb, dsize); |
| } |
| |
| int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type, |
| const char **filename, u64 *probe_offset, |
| bool perf_type_tracepoint) |
| { |
| const char *pevent = trace_event_name(event->tp_event); |
| const char *group = event->tp_event->class->system; |
| struct trace_uprobe *tu; |
| |
| if (perf_type_tracepoint) |
| tu = find_probe_event(pevent, group); |
| else |
| tu = event->tp_event->data; |
| if (!tu) |
| return -EINVAL; |
| |
| *fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE |
| : BPF_FD_TYPE_UPROBE; |
| *filename = tu->filename; |
| *probe_offset = tu->offset; |
| return 0; |
| } |
| #endif /* CONFIG_PERF_EVENTS */ |
| |
| static int |
| trace_uprobe_register(struct trace_event_call *event, enum trace_reg type, |
| void *data) |
| { |
| struct trace_uprobe *tu = event->data; |
| struct trace_event_file *file = data; |
| |
| switch (type) { |
| case TRACE_REG_REGISTER: |
| return probe_event_enable(tu, file, NULL); |
| |
| case TRACE_REG_UNREGISTER: |
| probe_event_disable(tu, file); |
| return 0; |
| |
| #ifdef CONFIG_PERF_EVENTS |
| case TRACE_REG_PERF_REGISTER: |
| return probe_event_enable(tu, NULL, uprobe_perf_filter); |
| |
| case TRACE_REG_PERF_UNREGISTER: |
| probe_event_disable(tu, NULL); |
| return 0; |
| |
| case TRACE_REG_PERF_OPEN: |
| return uprobe_perf_open(tu, data); |
| |
| case TRACE_REG_PERF_CLOSE: |
| return uprobe_perf_close(tu, data); |
| |
| #endif |
| default: |
| return 0; |
| } |
| return 0; |
| } |
| |
| static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) |
| { |
| struct trace_uprobe *tu; |
| struct uprobe_dispatch_data udd; |
| struct uprobe_cpu_buffer *ucb; |
| int dsize, esize; |
| int ret = 0; |
| |
| |
| tu = container_of(con, struct trace_uprobe, consumer); |
| tu->nhit++; |
| |
| udd.tu = tu; |
| udd.bp_addr = instruction_pointer(regs); |
| |
| current->utask->vaddr = (unsigned long) &udd; |
| |
| if (WARN_ON_ONCE(!uprobe_cpu_buffer)) |
| return 0; |
| |
| dsize = __get_data_size(&tu->tp, regs); |
| esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); |
| |
| ucb = uprobe_buffer_get(); |
| store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); |
| |
| if (tu->tp.flags & TP_FLAG_TRACE) |
| ret |= uprobe_trace_func(tu, regs, ucb, dsize); |
| |
| #ifdef CONFIG_PERF_EVENTS |
| if (tu->tp.flags & TP_FLAG_PROFILE) |
| ret |= uprobe_perf_func(tu, regs, ucb, dsize); |
| #endif |
| uprobe_buffer_put(ucb); |
| return ret; |
| } |
| |
| static int uretprobe_dispatcher(struct uprobe_consumer *con, |
| unsigned long func, struct pt_regs *regs) |
| { |
| struct trace_uprobe *tu; |
| struct uprobe_dispatch_data udd; |
| struct uprobe_cpu_buffer *ucb; |
| int dsize, esize; |
| |
| tu = container_of(con, struct trace_uprobe, consumer); |
| |
| udd.tu = tu; |
| udd.bp_addr = func; |
| |
| current->utask->vaddr = (unsigned long) &udd; |
| |
| if (WARN_ON_ONCE(!uprobe_cpu_buffer)) |
| return 0; |
| |
| dsize = __get_data_size(&tu->tp, regs); |
| esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); |
| |
| ucb = uprobe_buffer_get(); |
| store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); |
| |
| if (tu->tp.flags & TP_FLAG_TRACE) |
| uretprobe_trace_func(tu, func, regs, ucb, dsize); |
| |
| #ifdef CONFIG_PERF_EVENTS |
| if (tu->tp.flags & TP_FLAG_PROFILE) |
| uretprobe_perf_func(tu, func, regs, ucb, dsize); |
| #endif |
| uprobe_buffer_put(ucb); |
| return 0; |
| } |
| |
| static struct trace_event_functions uprobe_funcs = { |
| .trace = print_uprobe_event |
| }; |
| |
| static inline void init_trace_event_call(struct trace_uprobe *tu, |
| struct trace_event_call *call) |
| { |
| INIT_LIST_HEAD(&call->class->fields); |
| call->event.funcs = &uprobe_funcs; |
| call->class->define_fields = uprobe_event_define_fields; |
| |
| call->flags = TRACE_EVENT_FL_UPROBE; |
| call->class->reg = trace_uprobe_register; |
| call->data = tu; |
| } |
| |
| static int register_uprobe_event(struct trace_uprobe *tu) |
| { |
| struct trace_event_call *call = &tu->tp.call; |
| int ret = 0; |
| |
| init_trace_event_call(tu, call); |
| |
| if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) |
| return -ENOMEM; |
| |
| ret = register_trace_event(&call->event); |
| if (!ret) { |
| kfree(call->print_fmt); |
| return -ENODEV; |
| } |
| |
| ret = trace_add_event_call(call); |
| |
| if (ret) { |
| pr_info("Failed to register uprobe event: %s\n", |
| trace_event_name(call)); |
| kfree(call->print_fmt); |
| unregister_trace_event(&call->event); |
| } |
| |
| return ret; |
| } |
| |
| static int unregister_uprobe_event(struct trace_uprobe *tu) |
| { |
| int ret; |
| |
| /* tu->event is unregistered in trace_remove_event_call() */ |
| ret = trace_remove_event_call(&tu->tp.call); |
| if (ret) |
| return ret; |
| kfree(tu->tp.call.print_fmt); |
| tu->tp.call.print_fmt = NULL; |
| return 0; |
| } |
| |
| #ifdef CONFIG_PERF_EVENTS |
| struct trace_event_call * |
| create_local_trace_uprobe(char *name, unsigned long offs, |
| unsigned long ref_ctr_offset, bool is_return) |
| { |
| struct trace_uprobe *tu; |
| struct path path; |
| int ret; |
| |
| ret = kern_path(name, LOOKUP_FOLLOW, &path); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| if (!d_is_reg(path.dentry)) { |
| path_put(&path); |
| return ERR_PTR(-EINVAL); |
| } |
| |
| /* |
| * local trace_kprobes are not added to dyn_event, so they are never |
| * searched in find_trace_kprobe(). Therefore, there is no concern of |
| * duplicated name "DUMMY_EVENT" here. |
| */ |
| tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0, |
| is_return); |
| |
| if (IS_ERR(tu)) { |
| pr_info("Failed to allocate trace_uprobe.(%d)\n", |
| (int)PTR_ERR(tu)); |
| path_put(&path); |
| return ERR_CAST(tu); |
| } |
| |
| tu->offset = offs; |
| tu->path = path; |
| tu->ref_ctr_offset = ref_ctr_offset; |
| tu->filename = kstrdup(name, GFP_KERNEL); |
| init_trace_event_call(tu, &tu->tp.call); |
| |
| if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) { |
| ret = -ENOMEM; |
| goto error; |
| } |
| |
| return &tu->tp.call; |
| error: |
| free_trace_uprobe(tu); |
| return ERR_PTR(ret); |
| } |
| |
| void destroy_local_trace_uprobe(struct trace_event_call *event_call) |
| { |
| struct trace_uprobe *tu; |
| |
| tu = container_of(event_call, struct trace_uprobe, tp.call); |
| |
| kfree(tu->tp.call.print_fmt); |
| tu->tp.call.print_fmt = NULL; |
| |
| free_trace_uprobe(tu); |
| } |
| #endif /* CONFIG_PERF_EVENTS */ |
| |
| /* Make a trace interface for controling probe points */ |
| static __init int init_uprobe_trace(void) |
| { |
| struct dentry *d_tracer; |
| int ret; |
| |
| ret = dyn_event_register(&trace_uprobe_ops); |
| if (ret) |
| return ret; |
| |
| d_tracer = tracing_init_dentry(); |
| if (IS_ERR(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); |