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Commit 9ed7e1b8 authored by Chase Douglas's avatar Chase Douglas Committed by Arnaldo Carvalho de Melo
Browse files

perf probe: Add kernel source path option 



The probe plugin requires access to the source code for some operations.  The
source code must be in the exact same location as specified by the DWARF tags,
but sometimes the location is an absolute path that cannot be replicated by a
normal user. This change adds the -s|--source option to allow the user to
specify the root of the kernel source tree.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <1276543590-10486-1-git-send-email-chase.douglas@canonical.com>
Signed-off-by: default avatarChase Douglas <chase.douglas@canonical.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent cfc21cc6

tools/perf/Documentation/perf-probe.txt

+4 −0
Original line number Diff line number Diff line
@@ -31,6 +31,10 @@ OPTIONS 
--vmlinux=PATH::

	Specify vmlinux path which has debuginfo (Dwarf binary).



-s::

--source=PATH::

	Specify path to kernel source.



-v::

--verbose::

        Be more verbose (show parsed arguments, etc).

tools/perf/builtin-probe.c

+2 −0
Original line number Diff line number Diff line
@@ -182,6 +182,8 @@ static const struct option options[] = { 
		     "Show source code lines.", opt_show_lines),

	OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,

		   "file", "vmlinux pathname"),

	OPT_STRING('s', "source", &symbol_conf.source_prefix,

		   "directory", "path to kernel source"),

#endif

	OPT__DRY_RUN(&probe_event_dry_run),

	OPT_INTEGER('\0', "max-probes", &params.max_probe_points,

tools/perf/util/probe-finder.c

+55 −3
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
#include "event.h"

#include "debug.h"

#include "util.h"

#include "symbol.h"

#include "probe-finder.h"



/* Kprobe tracer basic type is up to u64 */
@@ -57,6 +58,55 @@ static int strtailcmp(const char *s1, const char *s2) 
	return 0;

}



/*

 * Find a src file from a DWARF tag path. Prepend optional source path prefix

 * and chop off leading directories that do not exist. Result is passed back as

 * a newly allocated path on success.

 * Return 0 if file was found and readable, -errno otherwise.

 */

static int get_real_path(const char *raw_path, char **new_path)

{

	if (!symbol_conf.source_prefix) {

		if (access(raw_path, R_OK) == 0) {

			*new_path = strdup(raw_path);

			return 0;

		} else

			return -errno;

	}



	*new_path = malloc((strlen(symbol_conf.source_prefix) +

			    strlen(raw_path) + 2));

	if (!*new_path)

		return -ENOMEM;



	for (;;) {

		sprintf(*new_path, "%s/%s", symbol_conf.source_prefix,

			raw_path);



		if (access(*new_path, R_OK) == 0)

			return 0;



		switch (errno) {

		case ENAMETOOLONG:

		case ENOENT:

		case EROFS:

		case EFAULT:

			raw_path = strchr(++raw_path, '/');

			if (!raw_path) {

				free(*new_path);

				*new_path = NULL;

				return -ENOENT;

			}

			continue;



		default:

			free(*new_path);

			*new_path = NULL;

			return -errno;

		}

	}

}



/* Line number list operations */



/* Add a line to line number list */
@@ -1096,11 +1146,13 @@ int find_perf_probe_point(int fd, unsigned long addr, 
static int line_range_add_line(const char *src, unsigned int lineno,

			       struct line_range *lr)

{

	int ret;



	/* Copy real path */

	if (!lr->path) {

		lr->path = strdup(src);

		if (lr->path == NULL)

			return -ENOMEM;

		ret = get_real_path(src, &lr->path);

		if (ret != 0)

			return ret;

	}

	return line_list__add_line(&lr->line_list, lineno);

}

tools/perf/util/symbol.h

+1 −0
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ struct symbol_conf { 
			full_paths,

			show_cpu_utilization;

	const char	*vmlinux_name,

			*source_prefix,

			*field_sep;

	const char	*default_guest_vmlinux_name,

			*default_guest_kallsyms,