1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
4 */
5
6#include <unistd.h>
7#include <linux/objtool.h>
8#include <asm/orc_types.h>
9#include "objtool.h"
10#include "warn.h"
11
12static const char *reg_name(unsigned int reg)
13{
14	switch (reg) {
15	case ORC_REG_PREV_SP:
16		return "prevsp";
17	case ORC_REG_DX:
18		return "dx";
19	case ORC_REG_DI:
20		return "di";
21	case ORC_REG_BP:
22		return "bp";
23	case ORC_REG_SP:
24		return "sp";
25	case ORC_REG_R10:
26		return "r10";
27	case ORC_REG_R13:
28		return "r13";
29	case ORC_REG_BP_INDIRECT:
30		return "bp(ind)";
31	case ORC_REG_SP_INDIRECT:
32		return "sp(ind)";
33	default:
34		return "?";
35	}
36}
37
38static const char *orc_type_name(unsigned int type)
39{
40	switch (type) {
41	case UNWIND_HINT_TYPE_CALL:
42		return "call";
43	case UNWIND_HINT_TYPE_REGS:
44		return "regs";
45	case UNWIND_HINT_TYPE_REGS_PARTIAL:
46		return "regs (partial)";
47	default:
48		return "?";
49	}
50}
51
52static void print_reg(unsigned int reg, int offset)
53{
54	if (reg == ORC_REG_BP_INDIRECT)
55		printf("(bp%+d)", offset);
56	else if (reg == ORC_REG_SP_INDIRECT)
57		printf("(sp%+d)", offset);
58	else if (reg == ORC_REG_UNDEFINED)
59		printf("(und)");
60	else
61		printf("%s%+d", reg_name(reg), offset);
62}
63
64int orc_dump(const char *_objname)
65{
66	int fd, nr_entries, i, *orc_ip = NULL, orc_size = 0;
67	struct orc_entry *orc = NULL;
68	char *name;
69	size_t nr_sections;
70	Elf64_Addr orc_ip_addr = 0;
71	size_t shstrtab_idx, strtab_idx = 0;
72	Elf *elf;
73	Elf_Scn *scn;
74	GElf_Shdr sh;
75	GElf_Rela rela;
76	GElf_Sym sym;
77	Elf_Data *data, *symtab = NULL, *rela_orc_ip = NULL;
78
79
80	objname = _objname;
81
82	elf_version(EV_CURRENT);
83
84	fd = open(objname, O_RDONLY);
85	if (fd == -1) {
86		perror("open");
87		return -1;
88	}
89
90	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
91	if (!elf) {
92		WARN_ELF("elf_begin");
93		return -1;
94	}
95
96	if (elf_getshdrnum(elf, &nr_sections)) {
97		WARN_ELF("elf_getshdrnum");
98		return -1;
99	}
100
101	if (elf_getshdrstrndx(elf, &shstrtab_idx)) {
102		WARN_ELF("elf_getshdrstrndx");
103		return -1;
104	}
105
106	for (i = 0; i < nr_sections; i++) {
107		scn = elf_getscn(elf, i);
108		if (!scn) {
109			WARN_ELF("elf_getscn");
110			return -1;
111		}
112
113		if (!gelf_getshdr(scn, &sh)) {
114			WARN_ELF("gelf_getshdr");
115			return -1;
116		}
117
118		name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
119		if (!name) {
120			WARN_ELF("elf_strptr");
121			return -1;
122		}
123
124		data = elf_getdata(scn, NULL);
125		if (!data) {
126			WARN_ELF("elf_getdata");
127			return -1;
128		}
129
130		if (!strcmp(name, ".symtab")) {
131			symtab = data;
132		} else if (!strcmp(name, ".strtab")) {
133			strtab_idx = i;
134		} else if (!strcmp(name, ".orc_unwind")) {
135			orc = data->d_buf;
136			orc_size = sh.sh_size;
137		} else if (!strcmp(name, ".orc_unwind_ip")) {
138			orc_ip = data->d_buf;
139			orc_ip_addr = sh.sh_addr;
140		} else if (!strcmp(name, ".rela.orc_unwind_ip")) {
141			rela_orc_ip = data;
142		}
143	}
144
145	if (!symtab || !strtab_idx || !orc || !orc_ip)
146		return 0;
147
148	if (orc_size % sizeof(*orc) != 0) {
149		WARN("bad .orc_unwind section size");
150		return -1;
151	}
152
153	nr_entries = orc_size / sizeof(*orc);
154	for (i = 0; i < nr_entries; i++) {
155		if (rela_orc_ip) {
156			if (!gelf_getrela(rela_orc_ip, i, &rela)) {
157				WARN_ELF("gelf_getrela");
158				return -1;
159			}
160
161			if (!gelf_getsym(symtab, GELF_R_SYM(rela.r_info), &sym)) {
162				WARN_ELF("gelf_getsym");
163				return -1;
164			}
165
166			if (GELF_ST_TYPE(sym.st_info) == STT_SECTION) {
167				scn = elf_getscn(elf, sym.st_shndx);
168				if (!scn) {
169					WARN_ELF("elf_getscn");
170					return -1;
171				}
172
173				if (!gelf_getshdr(scn, &sh)) {
174					WARN_ELF("gelf_getshdr");
175					return -1;
176				}
177
178				name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
179				if (!name) {
180					WARN_ELF("elf_strptr");
181					return -1;
182				}
183			} else {
184				name = elf_strptr(elf, strtab_idx, sym.st_name);
185				if (!name) {
186					WARN_ELF("elf_strptr");
187					return -1;
188				}
189			}
190
191			printf("%s+%llx:", name, (unsigned long long)rela.r_addend);
192
193		} else {
194			printf("%llx:", (unsigned long long)(orc_ip_addr + (i * sizeof(int)) + orc_ip[i]));
195		}
196
197
198		printf(" sp:");
199
200		print_reg(orc[i].sp_reg, orc[i].sp_offset);
201
202		printf(" bp:");
203
204		print_reg(orc[i].bp_reg, orc[i].bp_offset);
205
206		printf(" type:%s end:%d\n",
207		       orc_type_name(orc[i].type), orc[i].end);
208	}
209
210	elf_end(elf);
211	close(fd);
212
213	return 0;
214}
215