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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * dwarf-regs.c : Mapping of DWARF debug register numbers into register names.
4 * Extracted from probe-finder.c
5 *
6 * Written by Masami Hiramatsu <mhiramat@redhat.com>
7 */
8
9#include <stddef.h>
10#include <errno.h> /* for EINVAL */
11#include <string.h> /* for strcmp */
12#include <linux/ptrace.h> /* for struct pt_regs */
13#include <linux/kernel.h> /* for offsetof */
14#include <dwarf-regs.h>
15
16/*
17 * See arch/x86/kernel/ptrace.c.
18 * Different from it:
19 *
20 * - Since struct pt_regs is defined differently for user and kernel,
21 * but we want to use 'ax, bx' instead of 'rax, rbx' (which is struct
22 * field name of user's pt_regs), we make REG_OFFSET_NAME to accept
23 * both string name and reg field name.
24 *
25 * - Since accessing x86_32's pt_regs from x86_64 building is difficult
26 * and vise versa, we simply fill offset with -1, so
27 * get_arch_regstr() still works but regs_query_register_offset()
28 * returns error.
29 * The only inconvenience caused by it now is that we are not allowed
30 * to generate BPF prologue for a x86_64 kernel if perf is built for
31 * x86_32. This is really a rare usecase.
32 *
33 * - Order is different from kernel's ptrace.c for get_arch_regstr(). Use
34 * the order defined by dwarf.
35 */
36
37struct pt_regs_offset {
38 const char *name;
39 int offset;
40};
41
42#define REG_OFFSET_END {.name = NULL, .offset = 0}
43
44#ifdef __x86_64__
45# define REG_OFFSET_NAME_64(n, r) {.name = n, .offset = offsetof(struct pt_regs, r)}
46# define REG_OFFSET_NAME_32(n, r) {.name = n, .offset = -1}
47#else
48# define REG_OFFSET_NAME_64(n, r) {.name = n, .offset = -1}
49# define REG_OFFSET_NAME_32(n, r) {.name = n, .offset = offsetof(struct pt_regs, r)}
50#endif
51
52/* TODO: switching by dwarf address size */
53#ifndef __x86_64__
54static const struct pt_regs_offset x86_32_regoffset_table[] = {
55 REG_OFFSET_NAME_32("%ax", eax),
56 REG_OFFSET_NAME_32("%cx", ecx),
57 REG_OFFSET_NAME_32("%dx", edx),
58 REG_OFFSET_NAME_32("%bx", ebx),
59 REG_OFFSET_NAME_32("$stack", esp), /* Stack address instead of %sp */
60 REG_OFFSET_NAME_32("%bp", ebp),
61 REG_OFFSET_NAME_32("%si", esi),
62 REG_OFFSET_NAME_32("%di", edi),
63 REG_OFFSET_END,
64};
65
66#define regoffset_table x86_32_regoffset_table
67#else
68static const struct pt_regs_offset x86_64_regoffset_table[] = {
69 REG_OFFSET_NAME_64("%ax", rax),
70 REG_OFFSET_NAME_64("%dx", rdx),
71 REG_OFFSET_NAME_64("%cx", rcx),
72 REG_OFFSET_NAME_64("%bx", rbx),
73 REG_OFFSET_NAME_64("%si", rsi),
74 REG_OFFSET_NAME_64("%di", rdi),
75 REG_OFFSET_NAME_64("%bp", rbp),
76 REG_OFFSET_NAME_64("%sp", rsp),
77 REG_OFFSET_NAME_64("%r8", r8),
78 REG_OFFSET_NAME_64("%r9", r9),
79 REG_OFFSET_NAME_64("%r10", r10),
80 REG_OFFSET_NAME_64("%r11", r11),
81 REG_OFFSET_NAME_64("%r12", r12),
82 REG_OFFSET_NAME_64("%r13", r13),
83 REG_OFFSET_NAME_64("%r14", r14),
84 REG_OFFSET_NAME_64("%r15", r15),
85 REG_OFFSET_END,
86};
87
88#define regoffset_table x86_64_regoffset_table
89#endif
90
91/* Minus 1 for the ending REG_OFFSET_END */
92#define ARCH_MAX_REGS ((sizeof(regoffset_table) / sizeof(regoffset_table[0])) - 1)
93
94/* Return architecture dependent register string (for kprobe-tracer) */
95const char *get_arch_regstr(unsigned int n)
96{
97 return (n < ARCH_MAX_REGS) ? regoffset_table[n].name : NULL;
98}
99
100/* Reuse code from arch/x86/kernel/ptrace.c */
101/**
102 * regs_query_register_offset() - query register offset from its name
103 * @name: the name of a register
104 *
105 * regs_query_register_offset() returns the offset of a register in struct
106 * pt_regs from its name. If the name is invalid, this returns -EINVAL;
107 */
108int regs_query_register_offset(const char *name)
109{
110 const struct pt_regs_offset *roff;
111 for (roff = regoffset_table; roff->name != NULL; roff++)
112 if (!strcmp(roff->name, name))
113 return roff->offset;
114 return -EINVAL;
115}
116
117struct dwarf_regs_idx {
118 const char *name;
119 int idx;
120};
121
122static const struct dwarf_regs_idx x86_regidx_table[] = {
123 { "rax", 0 }, { "eax", 0 }, { "ax", 0 }, { "al", 0 },
124 { "rdx", 1 }, { "edx", 1 }, { "dx", 1 }, { "dl", 1 },
125 { "rcx", 2 }, { "ecx", 2 }, { "cx", 2 }, { "cl", 2 },
126 { "rbx", 3 }, { "edx", 3 }, { "bx", 3 }, { "bl", 3 },
127 { "rsi", 4 }, { "esi", 4 }, { "si", 4 }, { "sil", 4 },
128 { "rdi", 5 }, { "edi", 5 }, { "di", 5 }, { "dil", 5 },
129 { "rbp", 6 }, { "ebp", 6 }, { "bp", 6 }, { "bpl", 6 },
130 { "rsp", 7 }, { "esp", 7 }, { "sp", 7 }, { "spl", 7 },
131 { "r8", 8 }, { "r8d", 8 }, { "r8w", 8 }, { "r8b", 8 },
132 { "r9", 9 }, { "r9d", 9 }, { "r9w", 9 }, { "r9b", 9 },
133 { "r10", 10 }, { "r10d", 10 }, { "r10w", 10 }, { "r10b", 10 },
134 { "r11", 11 }, { "r11d", 11 }, { "r11w", 11 }, { "r11b", 11 },
135 { "r12", 12 }, { "r12d", 12 }, { "r12w", 12 }, { "r12b", 12 },
136 { "r13", 13 }, { "r13d", 13 }, { "r13w", 13 }, { "r13b", 13 },
137 { "r14", 14 }, { "r14d", 14 }, { "r14w", 14 }, { "r14b", 14 },
138 { "r15", 15 }, { "r15d", 15 }, { "r15w", 15 }, { "r15b", 15 },
139 { "rip", DWARF_REG_PC },
140};
141
142int get_arch_regnum(const char *name)
143{
144 unsigned int i;
145
146 if (*name != '%')
147 return -EINVAL;
148
149 for (i = 0; i < ARRAY_SIZE(x86_regidx_table); i++)
150 if (!strcmp(x86_regidx_table[i].name, name + 1))
151 return x86_regidx_table[i].idx;
152 return -ENOENT;
153}
1/*
2 * dwarf-regs.c : Mapping of DWARF debug register numbers into register names.
3 * Extracted from probe-finder.c
4 *
5 * Written by Masami Hiramatsu <mhiramat@redhat.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20 *
21 */
22
23#include <stddef.h>
24#include <errno.h> /* for EINVAL */
25#include <string.h> /* for strcmp */
26#include <linux/ptrace.h> /* for struct pt_regs */
27#include <linux/kernel.h> /* for offsetof */
28#include <dwarf-regs.h>
29
30/*
31 * See arch/x86/kernel/ptrace.c.
32 * Different from it:
33 *
34 * - Since struct pt_regs is defined differently for user and kernel,
35 * but we want to use 'ax, bx' instead of 'rax, rbx' (which is struct
36 * field name of user's pt_regs), we make REG_OFFSET_NAME to accept
37 * both string name and reg field name.
38 *
39 * - Since accessing x86_32's pt_regs from x86_64 building is difficult
40 * and vise versa, we simply fill offset with -1, so
41 * get_arch_regstr() still works but regs_query_register_offset()
42 * returns error.
43 * The only inconvenience caused by it now is that we are not allowed
44 * to generate BPF prologue for a x86_64 kernel if perf is built for
45 * x86_32. This is really a rare usecase.
46 *
47 * - Order is different from kernel's ptrace.c for get_arch_regstr(). Use
48 * the order defined by dwarf.
49 */
50
51struct pt_regs_offset {
52 const char *name;
53 int offset;
54};
55
56#define REG_OFFSET_END {.name = NULL, .offset = 0}
57
58#ifdef __x86_64__
59# define REG_OFFSET_NAME_64(n, r) {.name = n, .offset = offsetof(struct pt_regs, r)}
60# define REG_OFFSET_NAME_32(n, r) {.name = n, .offset = -1}
61#else
62# define REG_OFFSET_NAME_64(n, r) {.name = n, .offset = -1}
63# define REG_OFFSET_NAME_32(n, r) {.name = n, .offset = offsetof(struct pt_regs, r)}
64#endif
65
66/* TODO: switching by dwarf address size */
67#ifndef __x86_64__
68static const struct pt_regs_offset x86_32_regoffset_table[] = {
69 REG_OFFSET_NAME_32("%ax", eax),
70 REG_OFFSET_NAME_32("%cx", ecx),
71 REG_OFFSET_NAME_32("%dx", edx),
72 REG_OFFSET_NAME_32("%bx", ebx),
73 REG_OFFSET_NAME_32("$stack", esp), /* Stack address instead of %sp */
74 REG_OFFSET_NAME_32("%bp", ebp),
75 REG_OFFSET_NAME_32("%si", esi),
76 REG_OFFSET_NAME_32("%di", edi),
77 REG_OFFSET_END,
78};
79
80#define regoffset_table x86_32_regoffset_table
81#else
82static const struct pt_regs_offset x86_64_regoffset_table[] = {
83 REG_OFFSET_NAME_64("%ax", rax),
84 REG_OFFSET_NAME_64("%dx", rdx),
85 REG_OFFSET_NAME_64("%cx", rcx),
86 REG_OFFSET_NAME_64("%bx", rbx),
87 REG_OFFSET_NAME_64("%si", rsi),
88 REG_OFFSET_NAME_64("%di", rdi),
89 REG_OFFSET_NAME_64("%bp", rbp),
90 REG_OFFSET_NAME_64("%sp", rsp),
91 REG_OFFSET_NAME_64("%r8", r8),
92 REG_OFFSET_NAME_64("%r9", r9),
93 REG_OFFSET_NAME_64("%r10", r10),
94 REG_OFFSET_NAME_64("%r11", r11),
95 REG_OFFSET_NAME_64("%r12", r12),
96 REG_OFFSET_NAME_64("%r13", r13),
97 REG_OFFSET_NAME_64("%r14", r14),
98 REG_OFFSET_NAME_64("%r15", r15),
99 REG_OFFSET_END,
100};
101
102#define regoffset_table x86_64_regoffset_table
103#endif
104
105/* Minus 1 for the ending REG_OFFSET_END */
106#define ARCH_MAX_REGS ((sizeof(regoffset_table) / sizeof(regoffset_table[0])) - 1)
107
108/* Return architecture dependent register string (for kprobe-tracer) */
109const char *get_arch_regstr(unsigned int n)
110{
111 return (n < ARCH_MAX_REGS) ? regoffset_table[n].name : NULL;
112}
113
114/* Reuse code from arch/x86/kernel/ptrace.c */
115/**
116 * regs_query_register_offset() - query register offset from its name
117 * @name: the name of a register
118 *
119 * regs_query_register_offset() returns the offset of a register in struct
120 * pt_regs from its name. If the name is invalid, this returns -EINVAL;
121 */
122int regs_query_register_offset(const char *name)
123{
124 const struct pt_regs_offset *roff;
125 for (roff = regoffset_table; roff->name != NULL; roff++)
126 if (!strcmp(roff->name, name))
127 return roff->offset;
128 return -EINVAL;
129}