1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Mapping of DWARF debug register numbers into register names.
4 *
5 * Copyright IBM Corp. 2010, 2017
6 * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
7 *
8 */
9
10#include <errno.h>
11#include <stddef.h>
12#include <stdlib.h>
13#include <linux/kernel.h>
14#include <asm/ptrace.h>
15#include <string.h>
16#include <dwarf-regs.h>
17#include "dwarf-regs-table.h"
18
19const char *get_arch_regstr(unsigned int n)
20{
21	return (n >= ARRAY_SIZE(s390_dwarf_regs)) ? NULL : s390_dwarf_regs[n];
22}
23
24/*
25 * Convert the register name into an offset to struct pt_regs (kernel).
26 * This is required by the BPF prologue generator.  The BPF
27 * program is called in the BPF overflow handler in the perf
28 * core.
29 */
30int regs_query_register_offset(const char *name)
31{
32	unsigned long gpr;
33
34	if (!name || strncmp(name, "%r", 2))
35		return -EINVAL;
36
37	errno = 0;
38	gpr = strtoul(name + 2, NULL, 10);
39	if (errno || gpr >= 16)
40		return -EINVAL;
41
42	return offsetof(user_pt_regs, gprs) + 8 * gpr;
43}
44