diff options
| -rw-r--r-- | kernel/trace/Kconfig | 12 | ||||
| -rw-r--r-- | kernel/trace/Makefile | 1 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 30 | ||||
| -rw-r--r-- | kernel/trace/trace_event_types.h | 18 | ||||
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 1202 |
5 files changed, 1263 insertions, 0 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 06be85a7ef8c..fb5fbf75f279 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -411,6 +411,18 @@ config BLK_DEV_IO_TRACE If unsure, say N. +config KPROBE_TRACER + depends on KPROBES + depends on X86 + bool "Trace kprobes" + select TRACING + select GENERIC_TRACER + help + This tracer probes everywhere where kprobes can probe it, and + records various registers and memories specified by user. + This also allows you to trace kprobe probe points as a dynamic + defined events. It provides per-probe event filtering interface. + config DYNAMIC_FTRACE bool "enable/disable ftrace tracepoints dynamically" depends on FUNCTION_TRACER diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 844164dca90a..7c00a1ec1496 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -54,5 +54,6 @@ obj-$(CONFIG_EVENT_TRACING) += trace_export.o obj-$(CONFIG_FTRACE_SYSCALLS) += trace_syscalls.o obj-$(CONFIG_EVENT_PROFILE) += trace_event_profile.o obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o +obj-$(CONFIG_KPROBE_TRACER) += trace_kprobe.o libftrace-y := ftrace.o diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 654fd657bd03..667f832d16b7 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -38,6 +38,8 @@ enum trace_type { TRACE_KMEM_FREE, TRACE_POWER, TRACE_BLK, + TRACE_KPROBE, + TRACE_KRETPROBE, __TRACE_LAST_TYPE, }; @@ -205,6 +207,30 @@ struct syscall_trace_exit { unsigned long ret; }; +struct kprobe_trace_entry { + struct trace_entry ent; + unsigned long ip; + int nargs; + unsigned long args[]; +}; + +#define SIZEOF_KPROBE_TRACE_ENTRY(n) \ + (offsetof(struct kprobe_trace_entry, args) + \ + (sizeof(unsigned long) * (n))) + +struct kretprobe_trace_entry { + struct trace_entry ent; + unsigned long func; + unsigned long ret_ip; + int nargs; + unsigned long args[]; +}; + +#define SIZEOF_KRETPROBE_TRACE_ENTRY(n) \ + (offsetof(struct kretprobe_trace_entry, args) + \ + (sizeof(unsigned long) * (n))) + + /* * trace_flag_type is an enumeration that holds different @@ -317,6 +343,10 @@ extern void __ftrace_bad_type(void); TRACE_KMEM_ALLOC); \ IF_ASSIGN(var, ent, struct kmemtrace_free_entry, \ TRACE_KMEM_FREE); \ + IF_ASSIGN(var, ent, struct kprobe_trace_entry, \ + TRACE_KPROBE); \ + IF_ASSIGN(var, ent, struct kretprobe_trace_entry, \ + TRACE_KRETPROBE); \ __ftrace_bad_type(); \ } while (0) diff --git a/kernel/trace/trace_event_types.h b/kernel/trace/trace_event_types.h index e74f0906ab1a..186b598a1f11 100644 --- a/kernel/trace/trace_event_types.h +++ b/kernel/trace/trace_event_types.h @@ -175,4 +175,22 @@ TRACE_EVENT_FORMAT(kmem_free, TRACE_KMEM_FREE, kmemtrace_free_entry, ignore, TP_RAW_FMT("type:%u call_site:%lx ptr:%p") ); +TRACE_EVENT_FORMAT(kprobe, TRACE_KPROBE, kprobe_trace_entry, ignore, + TRACE_STRUCT( + TRACE_FIELD(unsigned long, ip, ip) + TRACE_FIELD(int, nargs, nargs) + TRACE_FIELD_ZERO(unsigned long, args) + ), + TP_RAW_FMT("%08lx: args:0x%lx ...") +); + +TRACE_EVENT_FORMAT(kretprobe, TRACE_KRETPROBE, kretprobe_trace_entry, ignore, + TRACE_STRUCT( + TRACE_FIELD(unsigned long, func, func) + TRACE_FIELD(unsigned long, ret_ip, ret_ip) + TRACE_FIELD(int, nargs, nargs) + TRACE_FIELD_ZERO(unsigned long, args) + ), + TP_RAW_FMT("%08lx <- %08lx: args:0x%lx ...") +); #undef TRACE_SYSTEM diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c new file mode 100644 index 000000000000..0c4f00aafb92 --- /dev/null +++ b/kernel/trace/trace_kprobe.c @@ -0,0 +1,1202 @@ +/* + * kprobe based kernel tracer + * + * 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 <linux/kprobes.h> +#include <linux/seq_file.h> +#include <linux/slab.h> +#include <linux/smp.h> +#include <linux/debugfs.h> +#include <linux/types.h> +#include <linux/string.h> +#include <linux/ctype.h> +#include <linux/ptrace.h> + +#include "trace.h" +#include "trace_output.h" + +#define TRACE_KPROBE_ARGS 6 +#define MAX_ARGSTR_LEN 63 + +/* currently, trace_kprobe only supports X86. */ + +struct fetch_func { + unsigned long (*func)(struct pt_regs *, void *); + void *data; +}; + +static __kprobes unsigned long call_fetch(struct fetch_func *f, + struct pt_regs *regs) +{ + return f->func(regs, f->data); +} + +/* fetch handlers */ +static __kprobes unsigned long fetch_register(struct pt_regs *regs, + void *offset) +{ + return regs_get_register(regs, (unsigned int)((unsigned long)offset)); +} + +static __kprobes unsigned long fetch_stack(struct pt_regs *regs, + void *num) +{ + return regs_get_kernel_stack_nth(regs, + (unsigned int)((unsigned long)num)); +} + +static __kprobes unsigned long fetch_memory(struct pt_regs *regs, void *addr) +{ + unsigned long retval; + + if (probe_kernel_address(addr, retval)) + return 0; + return retval; +} + +static __kprobes unsigned long fetch_argument(struct pt_regs *regs, void *num) +{ + return regs_get_argument_nth(regs, (unsigned int)((unsigned long)num)); +} + +static __kprobes unsigned long fetch_retvalue(struct pt_regs *regs, + void *dummy) +{ + return regs_return_value(regs); +} + +static __kprobes unsigned long fetch_ip(struct pt_regs *regs, void *dummy) +{ + return instruction_pointer(regs); +} + +static __kprobes unsigned long fetch_stack_address(struct pt_regs *regs, + void *dummy) +{ + return kernel_stack_pointer(regs); +} + +/* Memory fetching by symbol */ +struct symbol_cache { + char *symbol; + long offset; + unsigned long addr; +}; + +static unsigned long update_symbol_cache(struct symbol_cache *sc) +{ + sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol); + if (sc->addr) + sc->addr += sc->offset; + return sc->addr; +} + +static void free_symbol_cache(struct symbol_cache *sc) +{ + kfree(sc->symbol); + kfree(sc); +} + +static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset) +{ + struct symbol_cache *sc; + + if (!sym || strlen(sym) == 0) + return NULL; + sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL); + if (!sc) + return NULL; + + sc->symbol = kstrdup(sym, GFP_KERNEL); + if (!sc->symbol) { + kfree(sc); + return NULL; + } + sc->offset = offset; + + update_symbol_cache(sc); + return sc; +} + +static __kprobes unsigned long fetch_symbol(struct pt_regs *regs, void *data) +{ + struct symbol_cache *sc = data; + + if (sc->addr) + return fetch_memory(regs, (void *)sc->addr); + else + return 0; +} + +/* Special indirect memory access interface */ +struct indirect_fetch_data { + struct fetch_func orig; + long offset; +}; + +static __kprobes unsigned long fetch_indirect(struct pt_regs *regs, void *data) +{ + struct indirect_fetch_data *ind = data; + unsigned long addr; + + addr = call_fetch(&ind->orig, regs); + if (addr) { + addr += ind->offset; + return fetch_memory(regs, (void *)addr); + } else + return 0; +} + +static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data) +{ + if (data->orig.func == fetch_indirect) + free_indirect_fetch_data(data->orig.data); + else if (data->orig.func == fetch_symbol) + free_symbol_cache(data->orig.data); + kfree(data); +} + +/** + * kprobe_trace_core + */ + +struct trace_probe { + struct list_head list; + union { + struct kprobe kp; + struct kretprobe rp; + }; + const char *symbol; /* symbol name */ + unsigned int nr_args; + struct fetch_func args[TRACE_KPROBE_ARGS]; + struct ftrace_event_call call; +}; + +static int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs); +static int kretprobe_trace_func(struct kretprobe_instance *ri, + struct pt_regs *regs); + +static __kprobes int probe_is_return(struct trace_probe *tp) +{ + return (tp->rp.handler == kretprobe_trace_func); +} + +static __kprobes const char *probe_symbol(struct trace_probe *tp) +{ + return tp->symbol ? tp->symbol : "unknown"; +} + +static __kprobes long probe_offset(struct trace_probe *tp) +{ + return (probe_is_return(tp)) ? tp->rp.kp.offset : tp->kp.offset; +} + +static __kprobes void *probe_address(struct trace_probe *tp) +{ + return (probe_is_return(tp)) ? tp->rp.kp.addr : tp->kp.addr; +} + +static int trace_arg_string(char *buf, size_t n, struct fetch_func *ff) +{ + int ret = -EINVAL; + + if (ff->func == fetch_argument) + ret = snprintf(buf, n, "a%lu", (unsigned long)ff->data); + else if (ff->func == fetch_register) { + const char *name; + name = regs_query_register_name((unsigned int)((long)ff->data)); + ret = snprintf(buf, n, "%%%s", name); + } else if (ff->func == fetch_stack) + ret = snprintf(buf, n, "s%lu", (unsigned long)ff->data); + else if (ff->func == fetch_memory) + ret = snprintf(buf, n, "@0x%p", ff->data); + else if (ff->func == fetch_symbol) { + struct symbol_cache *sc = ff->data; + ret = snprintf(buf, n, "@%s%+ld", sc->symbol, sc->offset); + } else if (ff->func == fetch_retvalue) + ret = snprintf(buf, n, "rv"); + else if (ff->func == fetch_ip) + ret = snprintf(buf, n, "ra"); + else if (ff->func == fetch_stack_address) + ret = snprintf(buf, n, "sa"); + else if (ff->func == fetch_indirect) { + struct indirect_fetch_data *id = ff->data; + size_t l = 0; + ret = snprintf(buf, n, "%+ld(", id->offset); + if (ret >= n) + goto end; + l += ret; + ret = trace_arg_string(buf + l, n - l, &id->orig); + if (ret < 0) + goto end; + l += ret; + ret = snprintf(buf + l, n - l, ")"); + ret += l; + } +end: + if (ret >= n) + return -ENOSPC; + return ret; +} + +static int register_probe_event(struct trace_probe *tp); +static void unregister_probe_event(struct trace_probe *tp); + +static DEFINE_MUTEX(probe_lock); +static LIST_HEAD(probe_list); + +static struct trace_probe *alloc_trace_probe(const char *symbol, + const char *event) +{ + struct trace_probe *tp; + + tp = kzalloc(sizeof(struct trace_probe), GFP_KERNEL); + if (!tp) + return ERR_PTR(-ENOMEM); + + if (symbol) { + tp->symbol = kstrdup(symbol, GFP_KERNEL); + if (!tp->symbol) + goto error; + } + if (event) { + tp->call.name = kstrdup(event, GFP_KERNEL); + if (!tp->call.name) + goto error; + } + + INIT_LIST_HEAD(&tp->list); + return tp; +error: + kfree(tp->symbol); + kfree(tp); + return ERR_PTR(-ENOMEM); +} + +static void free_trace_probe(struct trace_probe *tp) +{ + int i; + + for (i = 0; i < tp->nr_args; i++) + if (tp->args[i].func == fetch_symbol) + free_symbol_cache(tp->args[i].data); + else if (tp->args[i].func == fetch_indirect) + free_indirect_fetch_data(tp->args[i].data); + + kfree(tp->call.name); + kfree(tp->symbol); + kfree(tp); +} + +static struct trace_probe *find_probe_event(const char *event) +{ + struct trace_probe *tp; + + list_for_each_entry(tp, &probe_list, list) + if (tp->call.name && !strcmp(tp->call.name, event)) + return tp; + return NULL; +} + +static void __unregister_trace_probe(struct trace_probe *tp) +{ + if (probe_is_return(tp)) + unregister_kretprobe(&tp->rp); + else + unregister_kprobe(&tp->kp); +} + +/* Unregister a trace_probe and probe_event: call with locking probe_lock */ +static void unregister_trace_probe(struct trace_probe *tp) +{ + if (tp->call.name) + unregister_probe_event(tp); + __unregister_trace_probe(tp); + list_del(&tp->list); +} + +/* 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); + + if (probe_is_return(tp)) + ret = register_kretprobe(&tp->rp); + else + ret = register_kprobe(&tp->kp); + + if (ret) { + pr_warning("Could not insert probe(%d)\n", ret); + if (ret == -EILSEQ) { + pr_warning("Probing address(0x%p) is not an " + "instruction boundary.\n", + probe_address(tp)); + ret = -EINVAL; + } + goto end; + } + /* register as an event */ + if (tp->call.name) { + old_tp = find_probe_event(tp->call.name); + if (old_tp) { + /* delete old event */ + unregister_trace_probe(old_tp); + free_trace_probe(old_tp); + } + ret = register_probe_event(tp); + if (ret) { + pr_warning("Faild to register probe event(%d)\n", ret); + __unregister_trace_probe(tp); + } + } + list_add_tail(&tp->list, &probe_list); +end: + mutex_unlock(&probe_lock); + return ret; +} + +/* Split symbol and offset. */ +static int split_symbol_offset(char *symbol, long *offset) +{ + char *tmp; + int ret; + + if (!offset) + return -EINVAL; + + tmp = strchr(symbol, '+'); + if (!tmp) + tmp = strchr(symbol, '-'); + + if (tmp) { + /* skip sign because strict_strtol doesn't accept '+' */ + ret = strict_strtol(tmp + 1, 0, offset); + if (ret) + return ret; + if (*tmp == '-') + *offset = -(*offset); + *tmp = '\0'; + } else + *offset = 0; + return 0; +} + +#define PARAM_MAX_ARGS 16 +#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long)) + +static int parse_trace_arg(char *arg, struct fetch_func *ff, int is_return) +{ + int ret = 0; + unsigned long param; + long offset; + char *tmp; + + switch (arg[0]) { + case 'a': /* argument */ + ret = strict_strtoul(arg + 1, 10, ¶m); + if (ret || param > PARAM_MAX_ARGS) + ret = -EINVAL; + else { + ff->func = fetch_argument; + ff->data = (void *)param; + } + break; + case 'r': /* retval or retaddr */ + if (is_return && arg[1] == 'v') { + ff->func = fetch_retvalue; + ff->data = NULL; + } else if (is_return && arg[1] == 'a') { + ff->func = fetch_ip; + ff->data = NULL; + } else + ret = -EINVAL; + break; + case '%': /* named register */ + ret = regs_query_register_offset(arg + 1); + if (ret >= 0) { + ff->func = fetch_register; + ff->data = (void *)(unsigned long)ret; + ret = 0; + } + break; + case 's': /* stack */ + if (arg[1] == 'a') { + ff->func = fetch_stack_address; + ff->data = NULL; + } else { + ret = strict_strtoul(arg + 1, 10, ¶m); + if (ret || param > PARAM_MAX_STACK) + ret = -EINVAL; + else { + ff->func = fetch_stack; + ff->data = (void *)param; + } + } + break; + case '@': /* memory or symbol */ + if (isdigit(arg[1])) { + ret = strict_strtoul(arg + 1, 0, ¶m); + if (ret) + break; + ff->func = fetch_memory; + ff->data = (void *)param; + } else { + ret = split_symbol_offset(arg + 1, &offset); + if (ret) + break; + ff->data = alloc_symbol_cache(arg + 1, + offset); + if (ff->data) + ff->func = fetch_symbol; + else + ret = -EINVAL; + } + break; + case '+': /* indirect memory */ + case '-': + tmp = strchr(arg, '('); + if (!tmp) { + ret = -EINVAL; + break; + } + *tmp = '\0'; + ret = strict_strtol(arg + 1, 0, &offset); + if (ret) + break; + if (arg[0] == '-') + offset = -offset; + arg = tmp + 1; + tmp = strrchr(arg, ')'); + if (tmp) { + struct indirect_fetch_data *id; + *tmp = '\0'; + id = kzalloc(sizeof(struct indirect_fetch_data), + GFP_KERNEL); + if (!id) + return -ENOMEM; + id->offset = offset; + ret = parse_trace_arg(arg, &id->orig, is_return); + if (ret) + kfree(id); + else { + ff->func = fetch_indirect; + ff->data = (void *)id; + } + } else + ret = -EINVAL; + break; + default: + /* TODO: support custom handler */ + ret = -EINVAL; + } + return ret; +} + +static int create_trace_probe(int argc, char **argv) +{ + /* + * Argument syntax: + * - Add kprobe: p[:EVENT] SYMBOL[+OFFS|-OFFS]|ADDRESS [FETCHARGS] + * - Add kretprobe: r[:EVENT] SYMBOL[+0] [FETCHARGS] + * Fetch args: + * aN : fetch Nth of function argument. (N:0-) + * rv : fetch return value + * ra : fetch return address + * sa : fetch stack address + * sN : 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 + * Indirect memory fetch: + * +|-offs(ARG) : fetch memory at ARG +|- offs address. + */ + struct trace_probe *tp; + struct kprobe *kp; + int i, ret = 0; + int is_return = 0; + char *symbol = NULL, *event = NULL; + long offset = 0; + void *addr = NULL; + + if (argc < 2) + return -EINVAL; + + if (argv[0][0] == 'p') + is_return = 0; + else if (argv[0][0] == 'r') + is_return = 1; + else + return -EINVAL; + + if (argv[0][1] == ':') { + event = &argv[0][2]; + if (strlen(event) == 0) { + pr_info("Event name is not specifiled\n"); + return -EINVAL; + } + } + + if (isdigit(argv[1][0])) { + if (is_return) + return -EINVAL; + /* an address specified */ + ret = strict_strtoul(&argv[0][2], 0, (unsigned long *)&addr); + if (ret) + return ret; + } else { + /* a symbol specified */ + symbol = argv[1]; + /* TODO: support .init module functions */ + ret = split_symbol_offset(symbol, &offset); + if (ret) + return ret; + if (offset && is_return) + return -EINVAL; + } + + /* setup a probe */ + tp = alloc_trace_probe(symbol, event); + if (IS_ERR(tp)) + return PTR_ERR(tp); + + if (is_return) { + kp = &tp->rp.kp; + tp->rp.handler = kretprobe_trace_func; + } else { + kp = &tp->kp; + tp->kp.pre_handler = kprobe_trace_func; + } + + if (tp->symbol) { + kp->symbol_name = tp->symbol; + kp->offset = offset; + } else + kp->addr = addr; + + /* parse arguments */ + argc -= 2; argv += 2; ret = 0; + for (i = 0; i < argc && i < TRACE_KPROBE_ARGS; i++) { + if (strlen(argv[i]) > MAX_ARGSTR_LEN) { + pr_info("Argument%d(%s) is too long.\n", i, argv[i]); + ret = -ENOSPC; + goto error; + } + ret = parse_trace_arg(argv[i], &tp->args[i], is_return); + if (ret) + goto error; + } + tp->nr_args = i; + + ret = register_trace_probe(tp); + if (ret) + goto error; + return 0; + +error: + free_trace_probe(tp); + return ret; +} + +static void cleanup_all_probes(void) +{ + struct trace_probe *tp; + + mutex_lock(&probe_lock); + /* TODO: Use batch unregistration */ + while (!list_empty(&probe_list)) { + tp = list_entry(probe_list.next, struct trace_probe, list); + unregister_trace_probe(tp); + free_trace_probe(tp); + } + mutex_unlock(&probe_lock); +} + + +/* 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, ret; + char buf[MAX_ARGSTR_LEN + 1]; + + seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p'); + if (tp->call.name) + seq_printf(m, ":%s", tp->call.name); + + if (tp->symbol) + seq_printf(m, " %s%+ld", probe_symbol(tp), probe_offset(tp)); + else + seq_printf(m, " 0x%p", probe_address(tp)); + + for (i = 0; i < tp->nr_args; i++) { + ret = trace_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i]); + if (ret < 0) { + pr_warning("Argument%d decoding error(%d).\n", i, ret); + return ret; + } + seq_printf(m, " %s", buf); + } + seq_printf(m, "\n"); + return 0; +} + +static const struct seq_operations probes_seq_op = { + .start = probes_seq_start, + .next = probes_seq_next, + .stop = probes_seq_stop, + .show = probes_seq_show +}; + +static int probes_open(struct inode *inode, struct file *file) +{ + if ((file->f_mode & FMODE_WRITE) && + (file->f_flags & O_TRUNC)) + cleanup_all_probes(); + + return seq_open(file, &probes_seq_op); +} + +static int command_trace_probe(const char *buf) +{ + char **argv; + int argc = 0, ret = 0; + + argv = argv_split(GFP_KERNEL, buf, &argc); + if (!argv) + return -ENOMEM; + + if (argc) + ret = create_trace_probe(argc, argv); + + argv_free(argv); + return ret; +} + +#define WRITE_BUFSIZE 128 + +static ssize_t probes_write(struct file *file, const char __user *buffer, + size_t count, loff_t *ppos) +{ + char *kbuf, *tmp; + int ret; + size_t done; + size_t size; + + kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL); + if (!kbuf) + return -ENOMEM; + + ret = done = 0; + while (done < count) { + size = count - done; + if (size >= WRITE_BUFSIZE) + size = WRITE_BUFSIZE - 1; + if (copy_from_user(kbuf, buffer + done, size)) { + ret = -EFAULT; + goto out; + } + kbuf[size] = '\0'; + tmp = strchr(kbuf, '\n'); + if (tmp) { + *tmp = '\0'; + size = tmp - kbuf + 1; + } else if (done + size < count) { + pr_warning("Line length is too long: " + "Should be less than %d.", WRITE_BUFSIZE); + ret = -EINVAL; + goto out; + } + done += size; + /* Remove comments */ + tmp = strchr(kbuf, '#'); + if (tmp) + *tmp = '\0'; + + ret = command_trace_probe(kbuf); + if (ret) + goto out; + } + ret = done; +out: + kfree(kbuf); + return ret; +} + +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, +}; + +/* Kprobe handler */ +static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs) +{ + struct trace_probe *tp = container_of(kp, struct trace_probe, kp); + struct kprobe_trace_entry *entry; + struct ring_buffer_event *event; + int size, i, pc; + unsigned long irq_flags; + struct ftrace_event_call *call = &event_kprobe; + + if (&tp->call.name) + call = &tp->call; + + local_save_flags(irq_flags); + pc = preempt_count(); + + size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args); + + event = trace_current_buffer_lock_reserve(TRACE_KPROBE, size, + irq_flags, pc); + if (!event) + return 0; + + entry = ring_buffer_event_data(event); + entry->nargs = tp->nr_args; + entry->ip = (unsigned long)kp->addr; + for (i = 0; i < tp->nr_args; i++) + entry->args[i] = call_fetch(&tp->args[i], regs); + + if (!filter_current_check_discard(call, entry, event)) + trace_nowake_buffer_unlock_commit(event, irq_flags, pc); + return 0; +} + +/* Kretprobe handler */ +static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri, + struct pt_regs *regs) +{ + struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp); + struct kretprobe_trace_entry *entry; + struct ring_buffer_event *event; + int size, i, pc; + unsigned long irq_flags; + struct ftrace_event_call *call = &event_kretprobe; + + if (&tp->call.name) + call = &tp->call; + + local_save_flags(irq_flags); + pc = preempt_count(); + + size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args); + + event = trace_current_buffer_lock_reserve(TRACE_KRETPROBE, size, + irq_flags, pc); + if (!event) + return 0; + + entry = ring_buffer_event_data(event); + entry->nargs = tp->nr_args; + entry->func = (unsigned long)probe_address(tp); + entry->ret_ip = (unsigned long)ri->ret_addr; + for (i = 0; i < tp->nr_args; i++) + entry->args[i] = call_fetch(&tp->args[i], regs); + + if (!filter_current_check_discard(call, entry, event)) + trace_nowake_buffer_unlock_commit(event, irq_flags, pc); + + return 0; +} + +/* Event entry printers */ +enum print_line_t +print_kprobe_event(struct trace_iterator *iter, int flags) +{ + struct kprobe_trace_entry *field; + struct trace_seq *s = &iter->seq; + int i; + + trace_assign_type(field, iter->ent); + + if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) + goto partial; + + if (!trace_seq_puts(s, ":")) + goto partial; + + for (i = 0; i < field->nargs; i++) + if (!trace_seq_printf(s, " 0x%lx", field->args[i])) + goto partial; + + if (!trace_seq_puts(s, "\n")) + goto partial; + + return TRACE_TYPE_HANDLED; +partial: + return TRACE_TYPE_PARTIAL_LINE; +} + +enum print_line_t +print_kretprobe_event(struct trace_iterator *iter, int flags) +{ + struct kretprobe_trace_entry *field; + struct trace_seq *s = &iter->seq; + int i; + + trace_assign_type(field, iter->ent); + + 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; + + for (i = 0; i < field->nargs; i++) + if (!trace_seq_printf(s, " 0x%lx", field->args[i])) + goto partial; + + if (!trace_seq_puts(s, "\n")) + goto partial; + + return TRACE_TYPE_HANDLED; +partial: + return TRACE_TYPE_PARTIAL_LINE; +} + +static struct trace_event kprobe_trace_event = { + .type = TRACE_KPROBE, + .trace = print_kprobe_event, +}; + +static struct trace_event kretprobe_trace_event = { + .type = TRACE_KRETPROBE, + .trace = print_kretprobe_event, +}; + +static int probe_event_enable(struct ftrace_event_call *call) +{ + struct trace_probe *tp = (struct trace_probe *)call->data; + + if (probe_is_return(tp)) + return enable_kretprobe(&tp->rp); + else + return enable_kprobe(&tp->kp); +} + +static void probe_event_disable(struct ftrace_event_call *call) +{ + struct trace_probe *tp = (struct trace_probe *)call->data; + + if (probe_is_return(tp)) + disable_kretprobe(&tp->rp); + else + disable_kprobe(&tp->kp); +} + +static int probe_event_raw_init(struct ftrace_event_call *event_call) +{ + INIT_LIST_HEAD(&event_call->fields); + init_preds(event_call); + return 0; +} + +#undef DEFINE_FIELD +#define DEFINE_FIELD(type, item, name, is_signed) \ + do { \ + ret = trace_define_field(event_call, #type, name, \ + offsetof(typeof(field), item), \ + sizeof(field.item), is_signed, \ + FILTER_OTHER); \ + if (ret) \ + return ret; \ + } while (0) + +static int kprobe_event_define_fields(struct ftrace_event_call *event_call) +{ + int ret, i; + struct kprobe_trace_entry field; + char buf[MAX_ARGSTR_LEN + 1]; + struct trace_probe *tp = (struct trace_probe *)event_call->data; + + ret = trace_define_common_fields(event_call); + if (!ret) + return ret; + + DEFINE_FIELD(unsigned long, ip, "ip", 0); + DEFINE_FIELD(int, nargs, "nargs", 1); + for (i = 0; i < tp->nr_args; i++) { + /* Set argN as a field */ + sprintf(buf, "arg%d", i); + DEFINE_FIELD(unsigned long, args[i], buf, 0); + /* Set argument string as an alias field */ + ret = trace_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i]); + if (ret < 0) + return ret; + DEFINE_FIELD(unsigned long, args[i], buf, 0); + } + return 0; +} + +static int kretprobe_event_define_fields(struct ftrace_event_call *event_call) +{ + int ret, i; + struct kretprobe_trace_entry field; + char buf[MAX_ARGSTR_LEN + 1]; + struct trace_probe *tp = (struct trace_probe *)event_call->data; + + ret = trace_define_common_fields(event_call); + if (!ret) + return ret; + + DEFINE_FIELD(unsigned long, func, "func", 0); + DEFINE_FIELD(unsigned long, ret_ip, "ret_ip", 0); + DEFINE_FIELD(int, nargs, "nargs", 1); + for (i = 0; i < tp->nr_args; i++) { + /* Set argN as a field */ + sprintf(buf, "arg%d", i); + DEFINE_FIELD(unsigned long, args[i], buf, 0); + /* Set argument string as an alias field */ + ret = trace_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i]); + if (ret < 0) + return ret; + DEFINE_FIELD(unsigned long, args[i], buf, 0); + } + return 0; +} + +static int __probe_event_show_format(struct trace_seq *s, + struct trace_probe *tp, const char *fmt, + const char *arg) +{ + int i, ret; + char buf[MAX_ARGSTR_LEN + 1]; + + /* Show aliases */ + for (i = 0; i < tp->nr_args; i++) { + ret = trace_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i]); + if (ret < 0) + return ret; + if (!trace_seq_printf(s, "\talias: %s;\toriginal: arg%d;\n", + buf, i)) + return 0; + } + /* Show format */ + if (!trace_seq_printf(s, "\nprint fmt: \"%s", fmt)) + return 0; + + for (i = 0; i < tp->nr_args; i++) + if (!trace_seq_puts(s, " 0x%lx")) + return 0; + + if (!trace_seq_printf(s, "\", %s", arg)) + return 0; + + for (i = 0; i < tp->nr_args; i++) + if (!trace_seq_printf(s, ", arg%d", i)) + return 0; + + return trace_seq_puts(s, "\n"); +} + +#undef SHOW_FIELD +#define SHOW_FIELD(type, item, name) \ + do { \ + ret = trace_seq_printf(s, "\tfield: " #type " %s;\t" \ + "offset:%u;tsize:%u;\n", name, \ + (unsigned int)offsetof(typeof(field), item),\ + (unsigned int)sizeof(type)); \ + if (!ret) \ + return 0; \ + } while (0) + +static int kprobe_event_show_format(struct ftrace_event_call *call, + struct trace_seq *s) +{ + struct kprobe_trace_entry field __attribute__((unused)); + int ret, i; + char buf[8]; + struct trace_probe *tp = (struct trace_probe *)call->data; + + SHOW_FIELD(unsigned long, ip, "ip"); + SHOW_FIELD(int, nargs, "nargs"); + + /* Show fields */ + for (i = 0; i < tp->nr_args; i++) { + sprintf(buf, "arg%d", i); + SHOW_FIELD(unsigned long, args[i], buf); + } + trace_seq_puts(s, "\n"); + + return __probe_event_show_format(s, tp, "%lx:", "ip"); +} + +static int kretprobe_event_show_format(struct ftrace_event_call *call, + struct trace_seq *s) +{ + struct kretprobe_trace_entry field __attribute__((unused)); + int ret, i; + char buf[8]; + struct trace_probe *tp = (struct trace_probe *)call->data; + + SHOW_FIELD(unsigned long, func, "func"); + SHOW_FIELD(unsigned long, ret_ip, "ret_ip"); + SHOW_FIELD(int, nargs, "nargs"); + + /* Show fields */ + for (i = 0; i < tp->nr_args; i++) { + sprintf(buf, "arg%d", i); + SHOW_FIELD(unsigned long, args[i], buf); + } + trace_seq_puts(s, "\n"); + + return __probe_event_show_format(s, tp, "%lx <- %lx:", + "func, ret_ip"); +} + +static int register_probe_event(struct trace_probe *tp) +{ + struct ftrace_event_call *call = &tp->call; + int ret; + + /* Initialize ftrace_event_call */ + call->system = "kprobes"; + if (probe_is_return(tp)) { + call->event = &kretprobe_trace_event; + call->id = TRACE_KRETPROBE; + call->raw_init = probe_event_raw_init; + call->show_format = kretprobe_event_show_format; + call->define_fields = kretprobe_event_define_fields; + } else { + call->event = &kprobe_trace_event; + call->id = TRACE_KPROBE; + call->raw_init = probe_event_raw_init; + call->show_format = kprobe_event_show_format; + call->define_fields = kprobe_event_define_fields; + } + call->enabled = 1; + call->regfunc = probe_event_enable; + call->unregfunc = probe_event_disable; + call->data = tp; + ret = trace_add_event_call(call); + if (ret) + pr_info("Failed to register kprobe event: %s\n", call->name); + return ret; +} + +static void unregister_probe_event(struct trace_probe *tp) +{ + /* + * Prevent to unregister event itself because the event is shared + * among other probes. + */ + tp->call.event = NULL; + trace_remove_event_call(&tp->call); +} + +/* Make a debugfs interface for controling probe points */ +static __init int init_kprobe_trace(void) +{ + struct dentry *d_tracer; + struct dentry *entry; + int ret; + + ret = register_ftrace_event(&kprobe_trace_event); + if (!ret) { + pr_warning("Could not register kprobe_trace_event type.\n"); + return 0; + } + ret = register_ftrace_event(&kretprobe_trace_event); + if (!ret) { + pr_warning("Could not register kretprobe_trace_event type.\n"); + return 0; + } + + d_tracer = tracing_init_dentry(); + if (!d_tracer) + return 0; + + entry = debugfs_create_file("kprobe_events", 0644, d_tracer, + NULL, &kprobe_events_ops); + + if (!entry) + pr_warning("Could not create debugfs " + "'kprobe_events' entry\n"); + return 0; +} +fs_initcall(init_kprobe_trace); + + +#ifdef CONFIG_FTRACE_STARTUP_TEST + +static 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 __init int kprobe_trace_self_tests_init(void) +{ + int ret; + int (*target)(int, int, int, int, int, int); + + target = kprobe_trace_selftest_target; + + pr_info("Testing kprobe tracing: "); + + ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target " + "a1 a2 a3 a4 a5 a6"); + if (WARN_ON_ONCE(ret)) + pr_warning("error enabling function entry\n"); + + ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target " + "ra rv"); + if (WARN_ON_ONCE(ret)) + pr_warning("error enabling function return\n"); + + ret = target(1, 2, 3, 4, 5, 6); + + cleanup_all_probes(); + + pr_cont("OK\n"); + return 0; +} + +late_initcall(kprobe_trace_self_tests_init); + +#endif |
