perf_regs.c

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// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#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(r1, PERF_REG_POWERPC_R1),
    SMPL_REG(r2, PERF_REG_POWERPC_R2),
    SMPL_REG(r3, PERF_REG_POWERPC_R3),
    SMPL_REG(r4, PERF_REG_POWERPC_R4),
    SMPL_REG(r5, PERF_REG_POWERPC_R5),
    SMPL_REG(r6, PERF_REG_POWERPC_R6),
    SMPL_REG(r7, PERF_REG_POWERPC_R7),
    SMPL_REG(r8, PERF_REG_POWERPC_R8),
    SMPL_REG(r9, PERF_REG_POWERPC_R9),
    SMPL_REG(r10, PERF_REG_POWERPC_R10),
    SMPL_REG(r11, PERF_REG_POWERPC_R11),
    SMPL_REG(r12, PERF_REG_POWERPC_R12),
    SMPL_REG(r13, PERF_REG_POWERPC_R13),
    SMPL_REG(r14, PERF_REG_POWERPC_R14),
    SMPL_REG(r15, PERF_REG_POWERPC_R15),
    SMPL_REG(r16, PERF_REG_POWERPC_R16),
    SMPL_REG(r17, PERF_REG_POWERPC_R17),
    SMPL_REG(r18, PERF_REG_POWERPC_R18),
    SMPL_REG(r19, PERF_REG_POWERPC_R19),
    SMPL_REG(r20, PERF_REG_POWERPC_R20),
    SMPL_REG(r21, PERF_REG_POWERPC_R21),
    SMPL_REG(r22, PERF_REG_POWERPC_R22),
    SMPL_REG(r23, PERF_REG_POWERPC_R23),
    SMPL_REG(r24, PERF_REG_POWERPC_R24),
    SMPL_REG(r25, PERF_REG_POWERPC_R25),
    SMPL_REG(r26, PERF_REG_POWERPC_R26),
    SMPL_REG(r27, PERF_REG_POWERPC_R27),
    SMPL_REG(r28, PERF_REG_POWERPC_R28),
    SMPL_REG(r29, PERF_REG_POWERPC_R29),
    SMPL_REG(r30, PERF_REG_POWERPC_R30),
    SMPL_REG(r31, PERF_REG_POWERPC_R31),
    SMPL_REG(nip, PERF_REG_POWERPC_NIP),
    SMPL_REG(msr, PERF_REG_POWERPC_MSR),
    SMPL_REG(orig_r3, PERF_REG_POWERPC_ORIG_R3),
    SMPL_REG(ctr, PERF_REG_POWERPC_CTR),
    SMPL_REG(link, PERF_REG_POWERPC_LINK),
    SMPL_REG(xer, PERF_REG_POWERPC_XER),
    SMPL_REG(ccr, PERF_REG_POWERPC_CCR),
    SMPL_REG(softe, PERF_REG_POWERPC_SOFTE),
    SMPL_REG(trap, PERF_REG_POWERPC_TRAP),
    SMPL_REG(dar, PERF_REG_POWERPC_DAR),
    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;
}