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 
19 const 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  */
30 int 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