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Commit f9f83b33 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo
Browse files

perf trace beauty: Allow accessing syscall args values in a syscall arg formatter 

For instance, fcntl's upcoming 'arg' formatter needs to look at the
'cmd' value to decide how to format its value, sometimes it is a file
flags, sometimes an fd, a pointer to a structure, etc.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-2tw2jfaqm48dtw8a4addghze@git.kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 9cb7cf86

tools/perf/builtin-trace.c

+16 −7
Original line number Diff line number Diff line
@@ -1369,19 +1369,32 @@ static int trace__validate_ev_qualifier(struct trace *trace) 
 * variable to read it. Most notably this avoids extended load instructions

 * on unaligned addresses

 */

static unsigned long __syscall_arg__val(unsigned char *args, u8 idx)

{

	unsigned long val;

	unsigned char *p = args + sizeof(unsigned long) * idx;



	memcpy(&val, p, sizeof(val));

	return val;

}



unsigned long syscall_arg__val(struct syscall_arg *arg, u8 idx)

{

	return __syscall_arg__val(arg->args, idx);

}



static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,

				      unsigned char *args, struct trace *trace,

				      struct thread *thread)

{

	size_t printed = 0;

	unsigned char *p;

	unsigned long val;



	if (sc->args != NULL) {

		struct format_field *field;

		u8 bit = 1;

		struct syscall_arg arg = {

			.args	= args,

			.idx	= 0,

			.mask	= 0,

			.trace  = trace,
@@ -1393,9 +1406,7 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size, 
			if (arg.mask & bit)

				continue;



			/* special care for unaligned accesses */

			p = args + sizeof(unsigned long) * arg.idx;

			memcpy(&val, p, sizeof(val));

			val = syscall_arg__val(&arg, arg.idx);



			/*

 			 * Suppress this argument if its value is zero and
@@ -1431,9 +1442,7 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size, 
		int i = 0;



		while (i < 6) {

			/* special care for unaligned accesses */

			p = args + sizeof(unsigned long) * i;

			memcpy(&val, p, sizeof(val));

			val = __syscall_arg__val(args, i);

			printed += scnprintf(bf + printed, size - printed,

					     "%sarg%d: %ld",

					     printed ? ", " : "", i, val);

tools/perf/trace/beauty/beauty.h

+13 −0
Original line number Diff line number Diff line
@@ -6,8 +6,19 @@ 
struct trace;

struct thread;



/**

 * @val: value of syscall argument being formatted

 * @args: All the args, use syscall_args__val(arg, nth) to access one

 * @thread: tid state (maps, pid, tid, etc)

 * @trace: 'perf trace' internals: all threads, etc

 * @parm: private area, may be an strarray, for instance

 * @idx: syscall arg idx (is this the first?)

 * @mask: a syscall arg may mask another arg, see syscall_arg__scnprintf_futex_op

 */



struct syscall_arg {

	unsigned long val;

	unsigned char *args;

	struct thread *thread;

	struct trace  *trace;

	void	      *parm;
@@ -15,6 +26,8 @@ struct syscall_arg { 
	u8	      mask;

};



unsigned long syscall_arg__val(struct syscall_arg *arg, u8 idx);



size_t syscall_arg__scnprintf_strarrays(char *bf, size_t size, struct syscall_arg *arg);

#define SCA_STRARRAYS syscall_arg__scnprintf_strarrays