perf sdt powerpc: Add argument support

#include <string.h>

#include <regex.h>

#include "../../perf.h"

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

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

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

const struct sample_reg sample_reg_masks[] = {

	SMPL_REG(r0, PERF_REG_POWERPC_R0),

	SMPL_REG(dsisr, PERF_REG_POWERPC_DSISR),

	SMPL_REG_END

};

/* REG or %rREG */

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

/* -NUM(REG) or NUM(REG) or -NUM(%rREG) or NUM(%rREG) */

#define SDT_OP_REGEX2  "^(\\-)?([0-9]+)\\((%r)?([1-2]?[0-9]|3[0-1])\\)$"

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;

}

/*

 * Parse OP and convert it into uprobe format, which is, +/-NUM(%gprREG).

 * Possible variants of OP are:

 *	Format		Example

 *	-------------------------

 *	NUM(REG)	48(18)

 *	-NUM(REG)	-48(18)

 *	NUM(%rREG)	48(%r18)

 *	-NUM(%rREG)	-48(%r18)

 *	REG		18

 *	%rREG		%r18

 *	iNUM		i0

 *	i-NUM		i-1

 *

 * SDT marker arguments on Powerpc uses %rREG form with -mregnames flag

 * and REG form with -mno-regnames. Here REG is general purpose register,

 * which is in 0 to 31 range.

 */

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

{

	int ret, new_len;

	regmatch_t rm[5];

	char prefix;

	/* Constant argument. Uprobe does not support it */

	if (old_op[0] == 'i') {

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

		return SDT_ARG_SKIP;

	}

	ret = sdt_init_op_regex();

	if (ret < 0)

		return ret;

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

		/* REG or %rREG --> %gprREG */

		new_len = 5;	/* % g p r NULL */

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

		*new_op = zalloc(new_len);

		if (!*new_op)

			return -ENOMEM;

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

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

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

		/*

		 * -NUM(REG) or NUM(REG) or -NUM(%rREG) or NUM(%rREG) -->

		 *	+/-NUM(%gprREG)

		 */

		prefix = (rm[1].rm_so == -1) ? '+' : '-';

		new_len = 8;	/* +/- ( % g p r ) NULL */

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

		new_len += (int)(rm[4].rm_eo - rm[4].rm_so);

		*new_op = zalloc(new_len);

		if (!*new_op)

			return -ENOMEM;

		scnprintf(*new_op, new_len, "%c%.*s(%%gpr%.*s)", prefix,

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

			(int)(rm[4].rm_eo - rm[4].rm_so), old_op + rm[4].rm_so);

	} else {

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

		return SDT_ARG_SKIP;

	}

	return SDT_ARG_VALID;

}