Re: [PATCH 13/13] tracing/uprobes: Add support for full argument access methods

[Namhyung Kim <namhyung@kernel.org>]

On Tue, 27 Aug 2013 20:54:45 +0900, Masami Hiramatsu wrote:
> (2013/08/27 17:48), Namhyung Kim wrote:
>> @@ -315,13 +316,18 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
>>  			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;
>> -			else
>> -				ret = -EINVAL;
>> +			if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR))
>> +				return -EINVAL;
>> +
>> +			if (is_kprobe)
>> +				f->fn = fetch_kernel_stack_address;
>> +			else {
>> +				f->fn = t->fetch[FETCH_MTD_stack];
>> +				f->data = (void *)0;
>> +			}
>
> No, the 'stack' means the address of the stack frame. Perhaps you might make a
> new function to retrieve it from pt_regs.

Hmm.. right.  How about this?


static __kprobes void fetch_user_stack_address(struct pt_regs *regs,
					  void *dummy, void *dest, void *priv)
{
	*(unsigned long *)dest = user_stack_pointer(regs);
}


...

			if (is_kprobe)
				f->fn = fetch_kernel_stack_address;
			else
				f->fn = fetch_user_stack_address;


Thanks,
Namhyung