dwarf-regs.c

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// SPDX-License-Identifier: GPL-2.0
/*
 * Mapping of DWARF debug register numbers into register names.
 *
 * Copyright IBM Corp. 2010, 2017
 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
 *        Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
 *
 */

#include <errno.h>
#include <stddef.h>
#include <stdlib.h>
#include <linux/kernel.h>
#include <asm/ptrace.h>
#include <string.h>
#include <dwarf-regs.h>
#include "dwarf-regs-table.h"

const char *get_arch_regstr(unsigned int n)
{
    return (n >= ARRAY_SIZE(s390_dwarf_regs)) ? NULL : s390_dwarf_regs[n];
}

/*
 * Convert the register name into an offset to struct pt_regs (kernel).
 * This is required by the BPF prologue generator.  The BPF
 * program is called in the BPF overflow handler in the perf
 * core.
 */
int regs_query_register_offset(const char *name)
{
    unsigned long gpr;

    if (!name || strncmp(name, "%r", 2))
        return -EINVAL;

    errno = 0;
    gpr = strtoul(name + 2, NULL, 10);
    if (errno || gpr >= 16)
        return -EINVAL;

    return offsetof(user_pt_regs, gprs) + 8 * gpr;
}