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2024-09-20 cf4ce59b3b70238352c7f1729f0f7223214828ad 
 kernel/tools/objtool/orc_gen.c
....@@ -1,242 +1,242 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /*
23  * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
3
- *
4
- * This program is free software; you can redistribute it and/or
5
- * modify it under the terms of the GNU General Public License
6
- * as published by the Free Software Foundation; either version 2
7
- * of the License, or (at your option) any later version.
8
- *
9
- * This program is distributed in the hope that it will be useful,
10
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
11
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12
- * GNU General Public License for more details.
13
- *
14
- * You should have received a copy of the GNU General Public License
15
- * along with this program; if not, see <http://www.gnu.org/licenses/>.
164  */
175 
186 #include <stdlib.h>
197 #include <string.h>
208 
21
-#include "orc.h"
9
+#include <linux/objtool.h>
10
+#include <asm/orc_types.h>
11
+
2212 #include "check.h"
2313 #include "warn.h"
2414 
25
-int create_orc(struct objtool_file *file)
15
+static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi,
16
+			  struct instruction *insn)
2617 {
27
-	struct instruction *insn;
18
+	struct cfi_reg *bp = &cfi->regs[CFI_BP];
2819 
29
-	for_each_insn(file, insn) {
30
-		struct orc_entry *orc = &insn->orc;
31
-		struct cfi_reg *cfa = &insn->state.cfa;
32
-		struct cfi_reg *bp = &insn->state.regs[CFI_BP];
20
+	memset(orc, 0, sizeof(*orc));
3321 
34
-		orc->end = insn->state.end;
35
-
36
-		if (cfa->base == CFI_UNDEFINED) {
37
-			orc->sp_reg = ORC_REG_UNDEFINED;
38
-			continue;
39
-		}
40
-
41
-		switch (cfa->base) {
42
-		case CFI_SP:
43
-			orc->sp_reg = ORC_REG_SP;
44
-			break;
45
-		case CFI_SP_INDIRECT:
46
-			orc->sp_reg = ORC_REG_SP_INDIRECT;
47
-			break;
48
-		case CFI_BP:
49
-			orc->sp_reg = ORC_REG_BP;
50
-			break;
51
-		case CFI_BP_INDIRECT:
52
-			orc->sp_reg = ORC_REG_BP_INDIRECT;
53
-			break;
54
-		case CFI_R10:
55
-			orc->sp_reg = ORC_REG_R10;
56
-			break;
57
-		case CFI_R13:
58
-			orc->sp_reg = ORC_REG_R13;
59
-			break;
60
-		case CFI_DI:
61
-			orc->sp_reg = ORC_REG_DI;
62
-			break;
63
-		case CFI_DX:
64
-			orc->sp_reg = ORC_REG_DX;
65
-			break;
66
-		default:
67
-			WARN_FUNC("unknown CFA base reg %d",
68
-				  insn->sec, insn->offset, cfa->base);
69
-			return -1;
70
-		}
71
-
72
-		switch(bp->base) {
73
-		case CFI_UNDEFINED:
74
-			orc->bp_reg = ORC_REG_UNDEFINED;
75
-			break;
76
-		case CFI_CFA:
77
-			orc->bp_reg = ORC_REG_PREV_SP;
78
-			break;
79
-		case CFI_BP:
80
-			orc->bp_reg = ORC_REG_BP;
81
-			break;
82
-		default:
83
-			WARN_FUNC("unknown BP base reg %d",
84
-				  insn->sec, insn->offset, bp->base);
85
-			return -1;
86
-		}
87
-
88
-		orc->sp_offset = cfa->offset;
89
-		orc->bp_offset = bp->offset;
90
-		orc->type = insn->state.type;
22
+	if (!cfi) {
23
+		orc->end = 0;
24
+		orc->sp_reg = ORC_REG_UNDEFINED;
25
+		return 0;
9126 	}
9227 
93
-	return 0;
94
-}
28
+	orc->end = cfi->end;
9529 
96
-static int create_orc_entry(struct section *u_sec, struct section *ip_relasec,
97
-				unsigned int idx, struct section *insn_sec,
98
-				unsigned long insn_off, struct orc_entry *o)
99
-{
100
-	struct orc_entry *orc;
101
-	struct rela *rela;
30
+	if (cfi->cfa.base == CFI_UNDEFINED) {
31
+		orc->sp_reg = ORC_REG_UNDEFINED;
32
+		return 0;
33
+	}
10234 
103
-	/* populate ORC data */
104
-	orc = (struct orc_entry *)u_sec->data->d_buf + idx;
105
-	memcpy(orc, o, sizeof(*orc));
106
-
107
-	/* populate rela for ip */
108
-	rela = malloc(sizeof(*rela));
109
-	if (!rela) {
110
-		perror("malloc");
35
+	switch (cfi->cfa.base) {
36
+	case CFI_SP:
37
+		orc->sp_reg = ORC_REG_SP;
38
+		break;
39
+	case CFI_SP_INDIRECT:
40
+		orc->sp_reg = ORC_REG_SP_INDIRECT;
41
+		break;
42
+	case CFI_BP:
43
+		orc->sp_reg = ORC_REG_BP;
44
+		break;
45
+	case CFI_BP_INDIRECT:
46
+		orc->sp_reg = ORC_REG_BP_INDIRECT;
47
+		break;
48
+	case CFI_R10:
49
+		orc->sp_reg = ORC_REG_R10;
50
+		break;
51
+	case CFI_R13:
52
+		orc->sp_reg = ORC_REG_R13;
53
+		break;
54
+	case CFI_DI:
55
+		orc->sp_reg = ORC_REG_DI;
56
+		break;
57
+	case CFI_DX:
58
+		orc->sp_reg = ORC_REG_DX;
59
+		break;
60
+	default:
61
+		WARN_FUNC("unknown CFA base reg %d",
62
+			  insn->sec, insn->offset, cfi->cfa.base);
11163 		return -1;
11264 	}
113
-	memset(rela, 0, sizeof(*rela));
11465 
115
-	if (insn_sec->sym) {
116
-		rela->sym = insn_sec->sym;
117
-		rela->addend = insn_off;
118
-	} else {
119
-		/*
120
-		 * The Clang assembler doesn't produce section symbols, so we
121
-		 * have to reference the function symbol instead:
122
-		 */
123
-		rela->sym = find_symbol_containing(insn_sec, insn_off);
124
-		if (!rela->sym) {
125
-			/*
126
-			 * Hack alert.  This happens when we need to reference
127
-			 * the NOP pad insn immediately after the function.
128
-			 */
129
-			rela->sym = find_symbol_containing(insn_sec,
130
-							   insn_off - 1);
131
-		}
132
-		if (!rela->sym) {
133
-			WARN("missing symbol for insn at offset 0x%lx\n",
134
-			     insn_off);
135
-			return -1;
136
-		}
137
-
138
-		rela->addend = insn_off - rela->sym->offset;
66
+	switch (bp->base) {
67
+	case CFI_UNDEFINED:
68
+		orc->bp_reg = ORC_REG_UNDEFINED;
69
+		break;
70
+	case CFI_CFA:
71
+		orc->bp_reg = ORC_REG_PREV_SP;
72
+		break;
73
+	case CFI_BP:
74
+		orc->bp_reg = ORC_REG_BP;
75
+		break;
76
+	default:
77
+		WARN_FUNC("unknown BP base reg %d",
78
+			  insn->sec, insn->offset, bp->base);
79
+		return -1;
13980 	}
14081 
141
-	rela->type = R_X86_64_PC32;
142
-	rela->offset = idx * sizeof(int);
143
-
144
-	list_add_tail(&rela->list, &ip_relasec->rela_list);
145
-	hash_add(ip_relasec->rela_hash, &rela->hash, rela->offset);
82
+	orc->sp_offset = cfi->cfa.offset;
83
+	orc->bp_offset = bp->offset;
84
+	orc->type = cfi->type;
14685 
14786 	return 0;
14887 }
14988 
150
-int create_orc_sections(struct objtool_file *file)
89
+static int write_orc_entry(struct elf *elf, struct section *orc_sec,
90
+			   struct section *ip_sec, unsigned int idx,
91
+			   struct section *insn_sec, unsigned long insn_off,
92
+			   struct orc_entry *o)
15193 {
152
-	struct instruction *insn, *prev_insn;
153
-	struct section *sec, *u_sec, *ip_relasec;
154
-	unsigned int idx;
94
+	struct orc_entry *orc;
15595 
156
-	struct orc_entry empty = {
157
-		.sp_reg = ORC_REG_UNDEFINED,
96
+	/* populate ORC data */
97
+	orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
98
+	memcpy(orc, o, sizeof(*orc));
99
+
100
+	/* populate reloc for ip */
101
+	if (elf_add_reloc_to_insn(elf, ip_sec, idx * sizeof(int), R_X86_64_PC32,
102
+				  insn_sec, insn_off))
103
+		return -1;
104
+
105
+	return 0;
106
+}
107
+
108
+struct orc_list_entry {
109
+	struct list_head list;
110
+	struct orc_entry orc;
111
+	struct section *insn_sec;
112
+	unsigned long insn_off;
113
+};
114
+
115
+static int orc_list_add(struct list_head *orc_list, struct orc_entry *orc,
116
+			struct section *sec, unsigned long offset)
117
+{
118
+	struct orc_list_entry *entry = malloc(sizeof(*entry));
119
+
120
+	if (!entry) {
121
+		WARN("malloc failed");
122
+		return -1;
123
+	}
124
+
125
+	entry->orc	= *orc;
126
+	entry->insn_sec = sec;
127
+	entry->insn_off = offset;
128
+
129
+	list_add_tail(&entry->list, orc_list);
130
+	return 0;
131
+}
132
+
133
+static unsigned long alt_group_len(struct alt_group *alt_group)
134
+{
135
+	return alt_group->last_insn->offset +
136
+	       alt_group->last_insn->len -
137
+	       alt_group->first_insn->offset;
138
+}
139
+
140
+int orc_create(struct objtool_file *file)
141
+{
142
+	struct section *sec, *orc_sec;
143
+	unsigned int nr = 0, idx = 0;
144
+	struct orc_list_entry *entry;
145
+	struct list_head orc_list;
146
+
147
+	struct orc_entry null = {
148
+		.sp_reg  = ORC_REG_UNDEFINED,
158149 		.bp_reg  = ORC_REG_UNDEFINED,
159
-		.type    = ORC_TYPE_CALL,
150
+		.type    = UNWIND_HINT_TYPE_CALL,
160151 	};
161152 
153
+	/* Build a deduplicated list of ORC entries: */
154
+	INIT_LIST_HEAD(&orc_list);
155
+	for_each_sec(file, sec) {
156
+		struct orc_entry orc, prev_orc = {0};
157
+		struct instruction *insn;
158
+		bool empty = true;
159
+
160
+		if (!sec->text)
161
+			continue;
162
+
163
+		sec_for_each_insn(file, sec, insn) {
164
+			struct alt_group *alt_group = insn->alt_group;
165
+			int i;
166
+
167
+			if (!alt_group) {
168
+				if (init_orc_entry(&orc, insn->cfi, insn))
169
+					return -1;
170
+				if (!memcmp(&prev_orc, &orc, sizeof(orc)))
171
+					continue;
172
+				if (orc_list_add(&orc_list, &orc, sec,
173
+						 insn->offset))
174
+					return -1;
175
+				nr++;
176
+				prev_orc = orc;
177
+				empty = false;
178
+				continue;
179
+			}
180
+
181
+			/*
182
+			 * Alternatives can have different stack layout
183
+			 * possibilities (but they shouldn't conflict).
184
+			 * Instead of traversing the instructions, use the
185
+			 * alt_group's flattened byte-offset-addressed CFI
186
+			 * array.
187
+			 */
188
+			for (i = 0; i < alt_group_len(alt_group); i++) {
189
+				struct cfi_state *cfi = alt_group->cfi[i];
190
+				if (!cfi)
191
+					continue;
192
+				/* errors are reported on the original insn */
193
+				if (init_orc_entry(&orc, cfi, insn))
194
+					return -1;
195
+				if (!memcmp(&prev_orc, &orc, sizeof(orc)))
196
+					continue;
197
+				if (orc_list_add(&orc_list, &orc, insn->sec,
198
+						 insn->offset + i))
199
+					return -1;
200
+				nr++;
201
+				prev_orc = orc;
202
+				empty = false;
203
+			}
204
+
205
+			/* Skip to the end of the alt_group */
206
+			insn = alt_group->last_insn;
207
+		}
208
+
209
+		/* Add a section terminator */
210
+		if (!empty) {
211
+			orc_list_add(&orc_list, &null, sec, sec->len);
212
+			nr++;
213
+		}
214
+	}
215
+	if (!nr)
216
+		return 0;
217
+
218
+	/* Create .orc_unwind, .orc_unwind_ip and .rela.orc_unwind_ip sections: */
162219 	sec = find_section_by_name(file->elf, ".orc_unwind");
163220 	if (sec) {
164221 		WARN("file already has .orc_unwind section, skipping");
165222 		return -1;
166223 	}
167
-
168
-	/* count the number of needed orcs */
169
-	idx = 0;
170
-	for_each_sec(file, sec) {
171
-		if (!sec->text)
172
-			continue;
173
-
174
-		prev_insn = NULL;
175
-		sec_for_each_insn(file, sec, insn) {
176
-			if (!prev_insn ||
177
-			    memcmp(&insn->orc, &prev_insn->orc,
178
-				   sizeof(struct orc_entry))) {
179
-				idx++;
180
-			}
181
-			prev_insn = insn;
182
-		}
183
-
184
-		/* section terminator */
185
-		if (prev_insn)
186
-			idx++;
187
-	}
188
-	if (!idx)
224
+	orc_sec = elf_create_section(file->elf, ".orc_unwind", 0,
225
+				     sizeof(struct orc_entry), nr);
226
+	if (!orc_sec)
189227 		return -1;
190228 
191
-
192
-	/* create .orc_unwind_ip and .rela.orc_unwind_ip sections */
193
-	sec = elf_create_section(file->elf, ".orc_unwind_ip", sizeof(int), idx);
229
+	sec = elf_create_section(file->elf, ".orc_unwind_ip", 0, sizeof(int), nr);
194230 	if (!sec)
195231 		return -1;
196232 
197
-	ip_relasec = elf_create_rela_section(file->elf, sec);
198
-	if (!ip_relasec)
199
-		return -1;
200
-
201
-	/* create .orc_unwind section */
202
-	u_sec = elf_create_section(file->elf, ".orc_unwind",
203
-				   sizeof(struct orc_entry), idx);
204
-
205
-	/* populate sections */
206
-	idx = 0;
207
-	for_each_sec(file, sec) {
208
-		if (!sec->text)
209
-			continue;
210
-
211
-		prev_insn = NULL;
212
-		sec_for_each_insn(file, sec, insn) {
213
-			if (!prev_insn || memcmp(&insn->orc, &prev_insn->orc,
214
-						 sizeof(struct orc_entry))) {
215
-
216
-				if (create_orc_entry(u_sec, ip_relasec, idx,
217
-						     insn->sec, insn->offset,
218
-						     &insn->orc))
219
-					return -1;
220
-
221
-				idx++;
222
-			}
223
-			prev_insn = insn;
224
-		}
225
-
226
-		/* section terminator */
227
-		if (prev_insn) {
228
-			if (create_orc_entry(u_sec, ip_relasec, idx,
229
-					     prev_insn->sec,
230
-					     prev_insn->offset + prev_insn->len,
231
-					     &empty))
232
-				return -1;
233
-
234
-			idx++;
235
-		}
233
+	/* Write ORC entries to sections: */
234
+	list_for_each_entry(entry, &orc_list, list) {
235
+		if (write_orc_entry(file->elf, orc_sec, sec, idx++,
236
+				    entry->insn_sec, entry->insn_off,
237
+				    &entry->orc))
238
+			return -1;
236239 	}
237
-
238
-	if (elf_rebuild_rela_section(ip_relasec))
239
-		return -1;
240240 
241241 	return 0;
242242 }