new file mode 100644
@@ -0,0 +1,138 @@
+ Kprobe-based Event Tracer
+ =========================
+
+ Documentation is written by Masami Hiramatsu
+
+
+Overview
+--------
+This tracer is similar to the events tracer which is based on Tracepoint
+infrastructure. Instead of Tracepoint, this tracer is based on kprobes(kprobe
+and kretprobe). It probes anywhere where kprobes can probe(this means, all
+functions body except for __kprobes functions).
+
+Unlike the function tracer, this tracer can probe instructions inside of
+kernel functions. It allows you to check which instruction has been executed.
+
+Unlike the Tracepoint based events tracer, this tracer can add and remove
+probe points on the fly.
+
+Similar to the events tracer, this tracer doesn't need to be activated via
+current_tracer, instead of that, just set probe points via
+/sys/kernel/debug/tracing/kprobe_events. And you can set filters on each
+probe events via /sys/kernel/debug/tracing/events/kprobes/<EVENT>/filter.
+
+
+Synopsis of kprobe_events
+-------------------------
+ p[:EVENT] SYMBOL[+offs|-offs]|MEMADDR [FETCHARGS] : Set a probe
+ r[:EVENT] SYMBOL[+0] [FETCHARGS] : Set a return probe
+
+ EVENT : Event name.
+ SYMBOL[+offs|-offs] : Symbol+offset where the probe is inserted.
+ MEMADDR : Address where the probe is inserted.
+
+ FETCHARGS : Arguments.
+ %REG : Fetch register REG
+ sN : Fetch Nth entry of stack (N >= 0)
+ @ADDR : Fetch memory at ADDR (ADDR should be in kernel)
+ @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)
+ aN : Fetch function argument. (N >= 0)(*)
+ rv : Fetch return value.(**)
+ ra : Fetch return address.(**)
+ +|-offs(FETCHARG) : fetch memory at FETCHARG +|- offs address.(***)
+
+ (*) aN may not correct on asmlinkaged functions and at the middle of
+ function body.
+ (**) only for return probe.
+ (***) this is useful for fetching a field of data structures.
+
+
+Per-Probe Event Filtering
+-------------------------
+ Per-probe event filtering feature allows you to set different filter on each
+probe and gives you what arguments will be shown in trace buffer. If an event
+name is specified right after 'p:' or 'r:' in kprobe_events, the tracer adds
+an event under tracing/events/kprobes/<EVENT>, at the directory you can see
+'id', 'enabled', 'format' and 'filter'.
+
+enabled:
+ You can enable/disable the probe by writing 1 or 0 on it.
+
+format:
+ It shows the format of this probe event. It also shows aliases of arguments
+ which you specified to kprobe_events.
+
+filter:
+ You can write filtering rules of this event. And you can use both of aliase
+ names and field names for describing filters.
+
+
+Usage examples
+--------------
+To add a probe as a new event, write a new definition to kprobe_events
+as below.
+
+ echo p:myprobe do_sys_open a0 a1 a2 a3 > /sys/kernel/debug/tracing/kprobe_events
+
+ This sets a kprobe on the top of do_sys_open() function with recording
+1st to 4th arguments as "myprobe" event.
+
+ echo r:myretprobe do_sys_open rv ra >> /sys/kernel/debug/tracing/kprobe_events
+
+ This sets a kretprobe on the return point of do_sys_open() function with
+recording return value and return address as "myretprobe" event.
+ You can see the format of these events via
+/sys/kernel/debug/tracing/events/kprobes/<EVENT>/format.
+
+ cat /sys/kernel/debug/tracing/events/kprobes/myprobe/format
+name: myprobe
+ID: 23
+format:
+ field:unsigned short common_type; offset:0; size:2;
+ field:unsigned char common_flags; offset:2; size:1;
+ field:unsigned char common_preempt_count; offset:3; size:1;
+ field:int common_pid; offset:4; size:4;
+ field:int common_tgid; offset:8; size:4;
+
+ field: unsigned long ip; offset:16;tsize:8;
+ field: int nargs; offset:24;tsize:4;
+ field: unsigned long arg0; offset:32;tsize:8;
+ field: unsigned long arg1; offset:40;tsize:8;
+ field: unsigned long arg2; offset:48;tsize:8;
+ field: unsigned long arg3; offset:56;tsize:8;
+
+ alias: a0; original: arg0;
+ alias: a1; original: arg1;
+ alias: a2; original: arg2;
+ alias: a3; original: arg3;
+
+print fmt: "%lx: 0x%lx 0x%lx 0x%lx 0x%lx", ip, arg0, arg1, arg2, arg3
+
+
+ You can see that the event has 4 arguments and alias expressions
+corresponding to it.
+
+ echo > /sys/kernel/debug/tracing/kprobe_events
+
+ This clears all probe points. and you can see the traced information via
+/sys/kernel/debug/tracing/trace.
+
+ cat /sys/kernel/debug/tracing/trace
+# tracer: nop
+#
+# TASK-PID CPU# TIMESTAMP FUNCTION
+# | | | | |
+ <...>-1447 [001] 1038282.286875: do_sys_open+0x0/0xd6: 0x3 0x7fffd1ec4440 0x8000 0x0
+ <...>-1447 [001] 1038282.286878: sys_openat+0xc/0xe <- do_sys_open: 0xfffffffffffffffe 0xffffffff81367a3a
+ <...>-1447 [001] 1038282.286885: do_sys_open+0x0/0xd6: 0xffffff9c 0x40413c 0x8000 0x1b6
+ <...>-1447 [001] 1038282.286915: sys_open+0x1b/0x1d <- do_sys_open: 0x3 0xffffffff81367a3a
+ <...>-1447 [001] 1038282.286969: do_sys_open+0x0/0xd6: 0xffffff9c 0x4041c6 0x98800 0x10
+ <...>-1447 [001] 1038282.286976: sys_open+0x1b/0x1d <- do_sys_open: 0x3 0xffffffff81367a3a
+
+
+ Each line shows when the kernel hits a probe, and <- SYMBOL means kernel
+returns from SYMBOL(e.g. "sys_open+0x1b/0x1d <- do_sys_open" means kernel
+returns from do_sys_open to sys_open+0x1b).
+
+
@@ -445,6 +445,18 @@ 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
@@ -55,5 +55,6 @@ 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_KSYM_TRACER) += trace_ksym.o
+obj-$(CONFIG_KPROBE_TRACER) += trace_kprobe.o
libftrace-y := ftrace.o
@@ -45,6 +45,8 @@ enum trace_type {
TRACE_POWER,
TRACE_BLK,
TRACE_KSYM,
+ TRACE_KPROBE,
+ TRACE_KRETPROBE,
__TRACE_LAST_TYPE,
};
@@ -223,6 +225,29 @@ struct ksym_trace_entry {
char cmd[TASK_COMM_LEN];
};
+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
* states when a trace occurs. These are:
@@ -339,6 +364,10 @@ extern void __ftrace_bad_type(void);
IF_ASSIGN(var, ent, struct syscall_trace_exit, \
TRACE_SYSCALL_EXIT); \
IF_ASSIGN(var, ent, struct ksym_trace_entry, TRACE_KSYM);\
+ 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)
@@ -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
new file mode 100644
@@ -0,0 +1,1193 @@
+/*
+ * 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);
+}
+
+/* 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_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 */
+ 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
+ * 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 = container_of(call, struct trace_probe, call);
+
+ 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 = container_of(call, struct trace_probe, call);
+
+ 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);\
+ 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 = container_of(event_call,
+ struct trace_probe, call);
+
+ __common_field(int, type, 1);
+ __common_field(unsigned char, flags, 0);
+ __common_field(unsigned char, preempt_count, 0);
+ __common_field(int, pid, 1);
+ __common_field(int, tgid, 1);
+
+ 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 = container_of(event_call,
+ struct trace_probe, call);
+
+ __common_field(int, type, 1);
+ __common_field(unsigned char, flags, 0);
+ __common_field(unsigned char, preempt_count, 0);
+ __common_field(int, pid, 1);
+ __common_field(int, tgid, 1);
+
+ 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 ftrace_event_call *call,
+ struct trace_seq *s, const char *fmt,
+ const char *arg)
+{
+ int i, ret;
+ char buf[MAX_ARGSTR_LEN + 1];
+ struct trace_probe *tp = container_of(call, struct trace_probe, call);
+
+ /* 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 = container_of(call, struct trace_probe, call);
+
+ 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(call, s, "%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 = container_of(call, struct trace_probe, call);
+
+ 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(call, s, "%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;
+ 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