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): Heiko Carstens <heiko.carstens@de.ibm.com>,
7 *	      Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
8 *
9 */
10
11#include <errno.h>
12#include <stddef.h>
13#include <stdlib.h>
14#include <linux/kernel.h>
15#include <asm/ptrace.h>
16#include <string.h>
17#include <dwarf-regs.h>
18#include "dwarf-regs-table.h"
19
20const char *get_arch_regstr(unsigned int n)
21{
22	return (n >= ARRAY_SIZE(s390_dwarf_regs)) ? NULL : s390_dwarf_regs[n];
23}
24
25/*
26 * Convert the register name into an offset to struct pt_regs (kernel).
27 * This is required by the BPF prologue generator.  The BPF
28 * program is called in the BPF overflow handler in the perf
29 * core.
30 */
31int regs_query_register_offset(const char *name)
32{
33	unsigned long gpr;
34
35	if (!name || strncmp(name, "%r", 2))
36		return -EINVAL;
37
38	errno = 0;
39	gpr = strtoul(name + 2, NULL, 10);
40	if (errno || gpr >= 16)
41		return -EINVAL;
42
43	return offsetof(user_pt_regs, gprs) + 8 * gpr;
44}
45