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 
20 const 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  */
31 int 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