xref: /linux/tools/objtool/arch/x86/orc.c (revision f4566a1e73957800df75a3dd2dccee8a4697f327)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 #include <linux/objtool_types.h>
3 #include <asm/orc_types.h>
4 
5 #include <objtool/check.h>
6 #include <objtool/orc.h>
7 #include <objtool/warn.h>
8 #include <objtool/endianness.h>
9 
10 int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn)
11 {
12 	struct cfi_reg *bp = &cfi->regs[CFI_BP];
13 
14 	memset(orc, 0, sizeof(*orc));
15 
16 	if (!cfi) {
17 		/*
18 		 * This is usually either unreachable nops/traps (which don't
19 		 * trigger unreachable instruction warnings), or
20 		 * STACK_FRAME_NON_STANDARD functions.
21 		 */
22 		orc->type = ORC_TYPE_UNDEFINED;
23 		return 0;
24 	}
25 
26 	switch (cfi->type) {
27 	case UNWIND_HINT_TYPE_UNDEFINED:
28 		orc->type = ORC_TYPE_UNDEFINED;
29 		return 0;
30 	case UNWIND_HINT_TYPE_END_OF_STACK:
31 		orc->type = ORC_TYPE_END_OF_STACK;
32 		return 0;
33 	case UNWIND_HINT_TYPE_CALL:
34 		orc->type = ORC_TYPE_CALL;
35 		break;
36 	case UNWIND_HINT_TYPE_REGS:
37 		orc->type = ORC_TYPE_REGS;
38 		break;
39 	case UNWIND_HINT_TYPE_REGS_PARTIAL:
40 		orc->type = ORC_TYPE_REGS_PARTIAL;
41 		break;
42 	default:
43 		WARN_INSN(insn, "unknown unwind hint type %d", cfi->type);
44 		return -1;
45 	}
46 
47 	orc->signal = cfi->signal;
48 
49 	switch (cfi->cfa.base) {
50 	case CFI_SP:
51 		orc->sp_reg = ORC_REG_SP;
52 		break;
53 	case CFI_SP_INDIRECT:
54 		orc->sp_reg = ORC_REG_SP_INDIRECT;
55 		break;
56 	case CFI_BP:
57 		orc->sp_reg = ORC_REG_BP;
58 		break;
59 	case CFI_BP_INDIRECT:
60 		orc->sp_reg = ORC_REG_BP_INDIRECT;
61 		break;
62 	case CFI_R10:
63 		orc->sp_reg = ORC_REG_R10;
64 		break;
65 	case CFI_R13:
66 		orc->sp_reg = ORC_REG_R13;
67 		break;
68 	case CFI_DI:
69 		orc->sp_reg = ORC_REG_DI;
70 		break;
71 	case CFI_DX:
72 		orc->sp_reg = ORC_REG_DX;
73 		break;
74 	default:
75 		WARN_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base);
76 		return -1;
77 	}
78 
79 	switch (bp->base) {
80 	case CFI_UNDEFINED:
81 		orc->bp_reg = ORC_REG_UNDEFINED;
82 		break;
83 	case CFI_CFA:
84 		orc->bp_reg = ORC_REG_PREV_SP;
85 		break;
86 	case CFI_BP:
87 		orc->bp_reg = ORC_REG_BP;
88 		break;
89 	default:
90 		WARN_INSN(insn, "unknown BP base reg %d", bp->base);
91 		return -1;
92 	}
93 
94 	orc->sp_offset = cfi->cfa.offset;
95 	orc->bp_offset = bp->offset;
96 
97 	return 0;
98 }
99 
100 int write_orc_entry(struct elf *elf, struct section *orc_sec,
101 		    struct section *ip_sec, unsigned int idx,
102 		    struct section *insn_sec, unsigned long insn_off,
103 		    struct orc_entry *o)
104 {
105 	struct orc_entry *orc;
106 
107 	/* populate ORC data */
108 	orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
109 	memcpy(orc, o, sizeof(*orc));
110 	orc->sp_offset = bswap_if_needed(elf, orc->sp_offset);
111 	orc->bp_offset = bswap_if_needed(elf, orc->bp_offset);
112 
113 	/* populate reloc for ip */
114 	if (!elf_init_reloc_text_sym(elf, ip_sec, idx * sizeof(int), idx,
115 				     insn_sec, insn_off))
116 		return -1;
117 
118 	return 0;
119 }
120 
121 static const char *reg_name(unsigned int reg)
122 {
123 	switch (reg) {
124 	case ORC_REG_PREV_SP:
125 		return "prevsp";
126 	case ORC_REG_DX:
127 		return "dx";
128 	case ORC_REG_DI:
129 		return "di";
130 	case ORC_REG_BP:
131 		return "bp";
132 	case ORC_REG_SP:
133 		return "sp";
134 	case ORC_REG_R10:
135 		return "r10";
136 	case ORC_REG_R13:
137 		return "r13";
138 	case ORC_REG_BP_INDIRECT:
139 		return "bp(ind)";
140 	case ORC_REG_SP_INDIRECT:
141 		return "sp(ind)";
142 	default:
143 		return "?";
144 	}
145 }
146 
147 static const char *orc_type_name(unsigned int type)
148 {
149 	switch (type) {
150 	case ORC_TYPE_UNDEFINED:
151 		return "(und)";
152 	case ORC_TYPE_END_OF_STACK:
153 		return "end";
154 	case ORC_TYPE_CALL:
155 		return "call";
156 	case ORC_TYPE_REGS:
157 		return "regs";
158 	case ORC_TYPE_REGS_PARTIAL:
159 		return "regs (partial)";
160 	default:
161 		return "?";
162 	}
163 }
164 
165 static void print_reg(unsigned int reg, int offset)
166 {
167 	if (reg == ORC_REG_BP_INDIRECT)
168 		printf("(bp%+d)", offset);
169 	else if (reg == ORC_REG_SP_INDIRECT)
170 		printf("(sp)%+d", offset);
171 	else if (reg == ORC_REG_UNDEFINED)
172 		printf("(und)");
173 	else
174 		printf("%s%+d", reg_name(reg), offset);
175 }
176 
177 void orc_print_dump(struct elf *dummy_elf, struct orc_entry *orc, int i)
178 {
179 	printf("type:%s", orc_type_name(orc[i].type));
180 
181 	printf(" sp:");
182 	print_reg(orc[i].sp_reg, bswap_if_needed(dummy_elf, orc[i].sp_offset));
183 
184 	printf(" bp:");
185 	print_reg(orc[i].bp_reg, bswap_if_needed(dummy_elf, orc[i].bp_offset));
186 
187 	printf(" signal:%d\n", orc[i].signal);
188 }
189