FETCHARGS : Arguments. Each probe can have up to 128 args.
%REG : Fetch register REG
+ @ADDR : Fetch memory at ADDR (ADDR should be in userspace)
+ $stackN : Fetch Nth entry of stack (N >= 0)
+ $stack : Fetch stack address.
+ $retval : Fetch return value.(*)
+ +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
+ NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
+ FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
+ (u8/u16/u32/u64/s8/s16/s32/s64), "string" and bitfield
+ are supported.
+
+ (*) only for return probe.
+ (**) this is useful for fetching a field of data structures.
+
+Types
+-----
+Several types are supported for fetch-args. Uprobe tracer will access memory
+by given type. Prefix 's' and 'u' means those types are signed and unsigned
+respectively. Traced arguments are shown in decimal (signed) or hex (unsigned).
+String type is a special type, which fetches a "null-terminated" string from
+user space.
+Bitfield is another special type, which takes 3 parameters, bit-width, bit-
+offset, and container-size (usually 32). The syntax is;
+
+ b<bit-width>@<bit-offset>/<container-size>
+
Event Profiling
---------------
}
/* Special function : only accept unsigned long */
-static __kprobes void fetch_stack_address(struct pt_regs *regs,
- void *dummy, void *dest)
+static __kprobes void fetch_kernel_stack_address(struct pt_regs *regs,
+ void *dummy, void *dest)
{
*(unsigned long *)dest = kernel_stack_pointer(regs);
}
+static __kprobes void fetch_user_stack_address(struct pt_regs *regs,
+ void *dummy, void *dest)
+{
+ *(unsigned long *)dest = user_stack_pointer(regs);
+}
+
static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
fetch_func_t orig_fn,
const struct fetch_type *ftbl)
#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
static int parse_probe_vars(char *arg, const struct fetch_type *t,
- struct fetch_param *f, bool is_return)
+ struct fetch_param *f, bool is_return,
+ bool is_kprobe)
{
int ret = 0;
unsigned long param;
ret = -EINVAL;
} else if (strncmp(arg, "stack", 5) == 0) {
if (arg[5] == '\0') {
- if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
- f->fn = fetch_stack_address;
+ if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR))
+ return -EINVAL;
+
+ if (is_kprobe)
+ f->fn = fetch_kernel_stack_address;
else
- ret = -EINVAL;
+ f->fn = fetch_user_stack_address;
} else if (isdigit(arg[5])) {
ret = kstrtoul(arg + 5, 10, ¶m);
- if (ret || param > PARAM_MAX_STACK)
+ if (ret || (is_kprobe && param > PARAM_MAX_STACK))
ret = -EINVAL;
else {
f->fn = t->fetch[FETCH_MTD_stack];
ftbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table;
BUG_ON(ftbl == NULL);
- /* Until uprobe_events supports only reg arguments */
- if (!is_kprobe && arg[0] != '%')
- return -EINVAL;
-
switch (arg[0]) {
case '$':
- ret = parse_probe_vars(arg + 1, t, f, is_return);
+ ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe);
break;
case '%': /* named register */
f->fn = t->fetch[FETCH_MTD_memory];
f->data = (void *)param;
} else {
+ /* uprobes don't support symbols */
+ if (!is_kprobe)
+ return -EINVAL;
+
ret = traceprobe_split_symbol_offset(arg + 1, &offset);
if (ret)
break;