Commit feab999e authored by Leo Yan's avatar Leo Yan Committed by Arnaldo Carvalho de Melo
Browse files

perf arm64: Add argument support for SDT 



Now the two OP formats are used for SDT marker argument in Arm64 ELF,
one format is general register xNUM (e.g. x1, x2, etc), another is for
using stack pointer to access local variables (e.g. [sp], [sp, 8]).

This patch adds support SDT marker argument for Arm64, it parses OP and
converts to uprobe compatible format.

Signed-off-by: default avatarLeo Yan <leo.yan@linaro.org>
Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Truong <alexandre.truong@arm.com>
Cc: Alexis Berlemont <alexis.berlemont@gmail.com>
Cc: He Zhe <zhe.he@windriver.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lore.kernel.org/lkml/20201225052751.24513-4-leo.yan@linaro.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent f19b5872

tools/perf/arch/arm64/util/perf_regs.c

+94 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <errno.h>

#include <regex.h>

#include <string.h>

#include <linux/kernel.h>

#include <linux/zalloc.h>



#include "../../../util/debug.h"

#include "../../../util/event.h"

#include "../../../util/perf_regs.h"



const struct sample_reg sample_reg_masks[] = {
@@ -37,3 +45,89 @@ const struct sample_reg sample_reg_masks[] = { 
	SMPL_REG(pc, PERF_REG_ARM64_PC),

	SMPL_REG_END

};



/* %xNUM */

#define SDT_OP_REGEX1  "^(x[1-2]?[0-9]|3[0-1])$"



/* [sp], [sp, NUM] */

#define SDT_OP_REGEX2  "^\\[sp(, )?([0-9]+)?\\]$"



static regex_t sdt_op_regex1, sdt_op_regex2;



static int sdt_init_op_regex(void)

{

	static int initialized;

	int ret = 0;



	if (initialized)

		return 0;



	ret = regcomp(&sdt_op_regex1, SDT_OP_REGEX1, REG_EXTENDED);

	if (ret)

		goto error;



	ret = regcomp(&sdt_op_regex2, SDT_OP_REGEX2, REG_EXTENDED);

	if (ret)

		goto free_regex1;



	initialized = 1;

	return 0;



free_regex1:

	regfree(&sdt_op_regex1);

error:

	pr_debug4("Regex compilation error.\n");

	return ret;

}



/*

 * SDT marker arguments on Arm64 uses %xREG or [sp, NUM], currently

 * support these two formats.

 */

int arch_sdt_arg_parse_op(char *old_op, char **new_op)

{

	int ret, new_len;

	regmatch_t rm[5];



	ret = sdt_init_op_regex();

	if (ret < 0)

		return ret;



	if (!regexec(&sdt_op_regex1, old_op, 3, rm, 0)) {

		/* Extract xNUM */

		new_len = 2;	/* % NULL */

		new_len += (int)(rm[1].rm_eo - rm[1].rm_so);



		*new_op = zalloc(new_len);

		if (!*new_op)

			return -ENOMEM;



		scnprintf(*new_op, new_len, "%%%.*s",

			(int)(rm[1].rm_eo - rm[1].rm_so), old_op + rm[1].rm_so);

	} else if (!regexec(&sdt_op_regex2, old_op, 5, rm, 0)) {

		/* [sp], [sp, NUM] or [sp,NUM] */

		new_len = 7;	/* + ( % s p ) NULL */



		/* If the arugment is [sp], need to fill offset '0' */

		if (rm[2].rm_so == -1)

			new_len += 1;

		else

			new_len += (int)(rm[2].rm_eo - rm[2].rm_so);



		*new_op = zalloc(new_len);

		if (!*new_op)

			return -ENOMEM;



		if (rm[2].rm_so == -1)

			scnprintf(*new_op, new_len, "+0(%%sp)");

		else

			scnprintf(*new_op, new_len, "+%.*s(%%sp)",

				  (int)(rm[2].rm_eo - rm[2].rm_so),

				  old_op + rm[2].rm_so);

	} else {

		pr_debug4("Skipping unsupported SDT argument: %s\n", old_op);

		return SDT_ARG_SKIP;

	}



	return SDT_ARG_VALID;

}