Commit be88184b authored by Alexis Berlemont's avatar Alexis Berlemont Committed by Arnaldo Carvalho de Melo
Browse files

perf sdt: Add scanning of sdt probes arguments 



During a "perf buildid-cache --add" command, the section ".note.stapsdt"
of the "added" binary is scanned in order to list the available SDT
markers available in a binary. The parts containing the probes arguments
were left unscanned.

The whole section is now parsed; the probe arguments are extracted for
later use.

Signed-off-by: default avatarAlexis Berlemont <alexis.berlemont@gmail.com>
Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20161214000732.1710-2-alexis.berlemont@gmail.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 70946723

tools/perf/util/symbol-elf.c

+23 −2
Original line number Diff line number Diff line
@@ -1828,7 +1828,7 @@ void kcore_extract__delete(struct kcore_extract *kce) 
static int populate_sdt_note(Elf **elf, const char *data, size_t len,

			     struct list_head *sdt_notes)

{

	const char *provider, *name;

	const char *provider, *name, *args;

	struct sdt_note *tmp = NULL;

	GElf_Ehdr ehdr;

	GElf_Addr base_off = 0;
@@ -1887,6 +1887,25 @@ static int populate_sdt_note(Elf **elf, const char *data, size_t len, 
		goto out_free_prov;

	}



	args = memchr(name, '\0', data + len - name);



	/*

	 * There is no argument if:

	 * - We reached the end of the note;

	 * - There is not enough room to hold a potential string;

	 * - The argument string is empty or just contains ':'.

	 */

	if (args == NULL || data + len - args < 2 ||

		args[1] == ':' || args[1] == '\0')

		tmp->args = NULL;

	else {

		tmp->args = strdup(++args);

		if (!tmp->args) {

			ret = -ENOMEM;

			goto out_free_name;

		}

	}



	if (gelf_getclass(*elf) == ELFCLASS32) {

		memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));

		tmp->bit32 = true;
@@ -1898,7 +1917,7 @@ static int populate_sdt_note(Elf **elf, const char *data, size_t len, 
	if (!gelf_getehdr(*elf, &ehdr)) {

		pr_debug("%s : cannot get elf header.\n", __func__);

		ret = -EBADF;

		goto out_free_name;

		goto out_free_args;

	}



	/* Adjust the prelink effect :
@@ -1923,6 +1942,8 @@ static int populate_sdt_note(Elf **elf, const char *data, size_t len, 
	list_add_tail(&tmp->note_list, sdt_notes);

	return 0;



out_free_args:

	free(tmp->args);

out_free_name:

	free(tmp->name);

out_free_prov:

tools/perf/util/symbol.h

+1 −0
Original line number Diff line number Diff line
@@ -351,6 +351,7 @@ int arch__choose_best_symbol(struct symbol *syma, struct symbol *symb); 
struct sdt_note {

	char *name;			/* name of the note*/

	char *provider;			/* provider name */

	char *args;

	bool bit32;			/* whether the location is 32 bits? */

	union {				/* location, base and semaphore addrs */

		Elf64_Addr a64[3];

CRA Git | Maintained and supported by SUSTech CRA and CCSE