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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * This file is included twice from vdso2c.c. It generates code for 32-bit
4 * and 64-bit vDSOs. We need both for 64-bit builds, since 32-bit vDSOs
5 * are built for 32-bit userspace.
6 */
7
8static void BITSFUNC(copy)(FILE *outfile, const unsigned char *data, size_t len)
9{
10 size_t i;
11
12 for (i = 0; i < len; i++) {
13 if (i % 10 == 0)
14 fprintf(outfile, "\n\t");
15 fprintf(outfile, "0x%02X, ", (int)(data)[i]);
16 }
17}
18
19
20/*
21 * Extract a section from the input data into a standalone blob. Used to
22 * capture kernel-only data that needs to persist indefinitely, e.g. the
23 * exception fixup tables, but only in the kernel, i.e. the section can
24 * be stripped from the final vDSO image.
25 */
26static void BITSFUNC(extract)(const unsigned char *data, size_t data_len,
27 FILE *outfile, ELF(Shdr) *sec, const char *name)
28{
29 unsigned long offset;
30 size_t len;
31
32 offset = (unsigned long)GET_LE(&sec->sh_offset);
33 len = (size_t)GET_LE(&sec->sh_size);
34
35 if (offset + len > data_len)
36 fail("section to extract overruns input data");
37
38 fprintf(outfile, "static const unsigned char %s[%zu] = {", name, len);
39 BITSFUNC(copy)(outfile, data + offset, len);
40 fprintf(outfile, "\n};\n\n");
41}
42
43static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
44 void *stripped_addr, size_t stripped_len,
45 FILE *outfile, const char *image_name)
46{
47 int found_load = 0;
48 unsigned long load_size = -1; /* Work around bogus warning */
49 unsigned long mapping_size;
50 ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr;
51 unsigned long i, syms_nr;
52 ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr, *secstrings_hdr,
53 *alt_sec = NULL, *extable_sec = NULL;
54 ELF(Dyn) *dyn = 0, *dyn_end = 0;
55 const char *secstrings;
56 INT_BITS syms[NSYMS] = {};
57
58 ELF(Phdr) *pt = (ELF(Phdr) *)(raw_addr + GET_LE(&hdr->e_phoff));
59
60 if (GET_LE(&hdr->e_type) != ET_DYN)
61 fail("input is not a shared object\n");
62
63 /* Walk the segment table. */
64 for (i = 0; i < GET_LE(&hdr->e_phnum); i++) {
65 if (GET_LE(&pt[i].p_type) == PT_LOAD) {
66 if (found_load)
67 fail("multiple PT_LOAD segs\n");
68
69 if (GET_LE(&pt[i].p_offset) != 0 ||
70 GET_LE(&pt[i].p_vaddr) != 0)
71 fail("PT_LOAD in wrong place\n");
72
73 if (GET_LE(&pt[i].p_memsz) != GET_LE(&pt[i].p_filesz))
74 fail("cannot handle memsz != filesz\n");
75
76 load_size = GET_LE(&pt[i].p_memsz);
77 found_load = 1;
78 } else if (GET_LE(&pt[i].p_type) == PT_DYNAMIC) {
79 dyn = raw_addr + GET_LE(&pt[i].p_offset);
80 dyn_end = raw_addr + GET_LE(&pt[i].p_offset) +
81 GET_LE(&pt[i].p_memsz);
82 }
83 }
84 if (!found_load)
85 fail("no PT_LOAD seg\n");
86
87 if (stripped_len < load_size)
88 fail("stripped input is too short\n");
89
90 if (!dyn)
91 fail("input has no PT_DYNAMIC section -- your toolchain is buggy\n");
92
93 /* Walk the dynamic table */
94 for (i = 0; dyn + i < dyn_end &&
95 GET_LE(&dyn[i].d_tag) != DT_NULL; i++) {
96 typeof(dyn[i].d_tag) tag = GET_LE(&dyn[i].d_tag);
97 if (tag == DT_REL || tag == DT_RELSZ || tag == DT_RELA ||
98 tag == DT_RELENT || tag == DT_TEXTREL)
99 fail("vdso image contains dynamic relocations\n");
100 }
101
102 /* Walk the section table */
103 secstrings_hdr = raw_addr + GET_LE(&hdr->e_shoff) +
104 GET_LE(&hdr->e_shentsize)*GET_LE(&hdr->e_shstrndx);
105 secstrings = raw_addr + GET_LE(&secstrings_hdr->sh_offset);
106 for (i = 0; i < GET_LE(&hdr->e_shnum); i++) {
107 ELF(Shdr) *sh = raw_addr + GET_LE(&hdr->e_shoff) +
108 GET_LE(&hdr->e_shentsize) * i;
109 if (GET_LE(&sh->sh_type) == SHT_SYMTAB)
110 symtab_hdr = sh;
111
112 if (!strcmp(secstrings + GET_LE(&sh->sh_name),
113 ".altinstructions"))
114 alt_sec = sh;
115 if (!strcmp(secstrings + GET_LE(&sh->sh_name), "__ex_table"))
116 extable_sec = sh;
117 }
118
119 if (!symtab_hdr)
120 fail("no symbol table\n");
121
122 strtab_hdr = raw_addr + GET_LE(&hdr->e_shoff) +
123 GET_LE(&hdr->e_shentsize) * GET_LE(&symtab_hdr->sh_link);
124
125 syms_nr = GET_LE(&symtab_hdr->sh_size) / GET_LE(&symtab_hdr->sh_entsize);
126 /* Walk the symbol table */
127 for (i = 0; i < syms_nr; i++) {
128 unsigned int k;
129 ELF(Sym) *sym = raw_addr + GET_LE(&symtab_hdr->sh_offset) +
130 GET_LE(&symtab_hdr->sh_entsize) * i;
131 const char *sym_name = raw_addr +
132 GET_LE(&strtab_hdr->sh_offset) +
133 GET_LE(&sym->st_name);
134
135 for (k = 0; k < NSYMS; k++) {
136 if (!strcmp(sym_name, required_syms[k].name)) {
137 if (syms[k]) {
138 fail("duplicate symbol %s\n",
139 required_syms[k].name);
140 }
141
142 /*
143 * Careful: we use negative addresses, but
144 * st_value is unsigned, so we rely
145 * on syms[k] being a signed type of the
146 * correct width.
147 */
148 syms[k] = GET_LE(&sym->st_value);
149 }
150 }
151 }
152
153 /* Validate mapping addresses. */
154 for (i = 0; i < sizeof(special_pages) / sizeof(special_pages[0]); i++) {
155 INT_BITS symval = syms[special_pages[i]];
156
157 if (!symval)
158 continue; /* The mapping isn't used; ignore it. */
159
160 if (symval % 4096)
161 fail("%s must be a multiple of 4096\n",
162 required_syms[i].name);
163 if (symval + 4096 < syms[sym_vvar_start])
164 fail("%s underruns vvar_start\n",
165 required_syms[i].name);
166 if (symval + 4096 > 0)
167 fail("%s is on the wrong side of the vdso text\n",
168 required_syms[i].name);
169 }
170 if (syms[sym_vvar_start] % 4096)
171 fail("vvar_begin must be a multiple of 4096\n");
172
173 if (!image_name) {
174 fwrite(stripped_addr, stripped_len, 1, outfile);
175 return;
176 }
177
178 mapping_size = (stripped_len + 4095) / 4096 * 4096;
179
180 fprintf(outfile, "/* AUTOMATICALLY GENERATED -- DO NOT EDIT */\n\n");
181 fprintf(outfile, "#include <linux/linkage.h>\n");
182 fprintf(outfile, "#include <asm/page_types.h>\n");
183 fprintf(outfile, "#include <asm/vdso.h>\n");
184 fprintf(outfile, "\n");
185 fprintf(outfile,
186 "static unsigned char raw_data[%lu] __ro_after_init __aligned(PAGE_SIZE) = {",
187 mapping_size);
188 for (i = 0; i < stripped_len; i++) {
189 if (i % 10 == 0)
190 fprintf(outfile, "\n\t");
191 fprintf(outfile, "0x%02X, ",
192 (int)((unsigned char *)stripped_addr)[i]);
193 }
194 fprintf(outfile, "\n};\n\n");
195 if (extable_sec)
196 BITSFUNC(extract)(raw_addr, raw_len, outfile,
197 extable_sec, "extable");
198
199 fprintf(outfile, "const struct vdso_image %s = {\n", image_name);
200 fprintf(outfile, "\t.data = raw_data,\n");
201 fprintf(outfile, "\t.size = %lu,\n", mapping_size);
202 if (alt_sec) {
203 fprintf(outfile, "\t.alt = %lu,\n",
204 (unsigned long)GET_LE(&alt_sec->sh_offset));
205 fprintf(outfile, "\t.alt_len = %lu,\n",
206 (unsigned long)GET_LE(&alt_sec->sh_size));
207 }
208 if (extable_sec) {
209 fprintf(outfile, "\t.extable_base = %lu,\n",
210 (unsigned long)GET_LE(&extable_sec->sh_offset));
211 fprintf(outfile, "\t.extable_len = %lu,\n",
212 (unsigned long)GET_LE(&extable_sec->sh_size));
213 fprintf(outfile, "\t.extable = extable,\n");
214 }
215
216 for (i = 0; i < NSYMS; i++) {
217 if (required_syms[i].export && syms[i])
218 fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n",
219 required_syms[i].name, (int64_t)syms[i]);
220 }
221 fprintf(outfile, "};\n");
222}
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * This file is included twice from vdso2c.c. It generates code for 32-bit
4 * and 64-bit vDSOs. We need both for 64-bit builds, since 32-bit vDSOs
5 * are built for 32-bit userspace.
6 */
7
8static void BITSFUNC(copy)(FILE *outfile, const unsigned char *data, size_t len)
9{
10 size_t i;
11
12 for (i = 0; i < len; i++) {
13 if (i % 10 == 0)
14 fprintf(outfile, "\n\t");
15 fprintf(outfile, "0x%02X, ", (int)(data)[i]);
16 }
17}
18
19
20/*
21 * Extract a section from the input data into a standalone blob. Used to
22 * capture kernel-only data that needs to persist indefinitely, e.g. the
23 * exception fixup tables, but only in the kernel, i.e. the section can
24 * be stripped from the final vDSO image.
25 */
26static void BITSFUNC(extract)(const unsigned char *data, size_t data_len,
27 FILE *outfile, ELF(Shdr) *sec, const char *name)
28{
29 unsigned long offset;
30 size_t len;
31
32 offset = (unsigned long)GET_LE(&sec->sh_offset);
33 len = (size_t)GET_LE(&sec->sh_size);
34
35 if (offset + len > data_len)
36 fail("section to extract overruns input data");
37
38 fprintf(outfile, "static const unsigned char %s[%zu] = {", name, len);
39 BITSFUNC(copy)(outfile, data + offset, len);
40 fprintf(outfile, "\n};\n\n");
41}
42
43static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
44 void *stripped_addr, size_t stripped_len,
45 FILE *outfile, const char *image_name)
46{
47 int found_load = 0;
48 unsigned long load_size = -1; /* Work around bogus warning */
49 unsigned long mapping_size;
50 ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr;
51 unsigned long i, syms_nr;
52 ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr, *secstrings_hdr,
53 *alt_sec = NULL, *extable_sec = NULL;
54 ELF(Dyn) *dyn = 0, *dyn_end = 0;
55 const char *secstrings;
56 INT_BITS syms[NSYMS] = {};
57
58 ELF(Phdr) *pt = (ELF(Phdr) *)(raw_addr + GET_LE(&hdr->e_phoff));
59
60 if (GET_LE(&hdr->e_type) != ET_DYN)
61 fail("input is not a shared object\n");
62
63 /* Walk the segment table. */
64 for (i = 0; i < GET_LE(&hdr->e_phnum); i++) {
65 if (GET_LE(&pt[i].p_type) == PT_LOAD) {
66 if (found_load)
67 fail("multiple PT_LOAD segs\n");
68
69 if (GET_LE(&pt[i].p_offset) != 0 ||
70 GET_LE(&pt[i].p_vaddr) != 0)
71 fail("PT_LOAD in wrong place\n");
72
73 if (GET_LE(&pt[i].p_memsz) != GET_LE(&pt[i].p_filesz))
74 fail("cannot handle memsz != filesz\n");
75
76 load_size = GET_LE(&pt[i].p_memsz);
77 found_load = 1;
78 } else if (GET_LE(&pt[i].p_type) == PT_DYNAMIC) {
79 dyn = raw_addr + GET_LE(&pt[i].p_offset);
80 dyn_end = raw_addr + GET_LE(&pt[i].p_offset) +
81 GET_LE(&pt[i].p_memsz);
82 }
83 }
84 if (!found_load)
85 fail("no PT_LOAD seg\n");
86
87 if (stripped_len < load_size)
88 fail("stripped input is too short\n");
89
90 if (!dyn)
91 fail("input has no PT_DYNAMIC section -- your toolchain is buggy\n");
92
93 /* Walk the dynamic table */
94 for (i = 0; dyn + i < dyn_end &&
95 GET_LE(&dyn[i].d_tag) != DT_NULL; i++) {
96 typeof(dyn[i].d_tag) tag = GET_LE(&dyn[i].d_tag);
97 if (tag == DT_REL || tag == DT_RELSZ || tag == DT_RELA ||
98 tag == DT_RELENT || tag == DT_TEXTREL)
99 fail("vdso image contains dynamic relocations\n");
100 }
101
102 /* Walk the section table */
103 secstrings_hdr = raw_addr + GET_LE(&hdr->e_shoff) +
104 GET_LE(&hdr->e_shentsize)*GET_LE(&hdr->e_shstrndx);
105 secstrings = raw_addr + GET_LE(&secstrings_hdr->sh_offset);
106 for (i = 0; i < GET_LE(&hdr->e_shnum); i++) {
107 ELF(Shdr) *sh = raw_addr + GET_LE(&hdr->e_shoff) +
108 GET_LE(&hdr->e_shentsize) * i;
109 if (GET_LE(&sh->sh_type) == SHT_SYMTAB)
110 symtab_hdr = sh;
111
112 if (!strcmp(secstrings + GET_LE(&sh->sh_name),
113 ".altinstructions"))
114 alt_sec = sh;
115 if (!strcmp(secstrings + GET_LE(&sh->sh_name), "__ex_table"))
116 extable_sec = sh;
117 }
118
119 if (!symtab_hdr)
120 fail("no symbol table\n");
121
122 strtab_hdr = raw_addr + GET_LE(&hdr->e_shoff) +
123 GET_LE(&hdr->e_shentsize) * GET_LE(&symtab_hdr->sh_link);
124
125 syms_nr = GET_LE(&symtab_hdr->sh_size) / GET_LE(&symtab_hdr->sh_entsize);
126 /* Walk the symbol table */
127 for (i = 0; i < syms_nr; i++) {
128 unsigned int k;
129 ELF(Sym) *sym = raw_addr + GET_LE(&symtab_hdr->sh_offset) +
130 GET_LE(&symtab_hdr->sh_entsize) * i;
131 const char *sym_name = raw_addr +
132 GET_LE(&strtab_hdr->sh_offset) +
133 GET_LE(&sym->st_name);
134
135 for (k = 0; k < NSYMS; k++) {
136 if (!strcmp(sym_name, required_syms[k].name)) {
137 if (syms[k]) {
138 fail("duplicate symbol %s\n",
139 required_syms[k].name);
140 }
141
142 /*
143 * Careful: we use negative addresses, but
144 * st_value is unsigned, so we rely
145 * on syms[k] being a signed type of the
146 * correct width.
147 */
148 syms[k] = GET_LE(&sym->st_value);
149 }
150 }
151 }
152
153 /* Validate mapping addresses. */
154 for (i = 0; i < sizeof(special_pages) / sizeof(special_pages[0]); i++) {
155 INT_BITS symval = syms[special_pages[i]];
156
157 if (!symval)
158 continue; /* The mapping isn't used; ignore it. */
159
160 if (symval % 4096)
161 fail("%s must be a multiple of 4096\n",
162 required_syms[i].name);
163 if (symval + 4096 < syms[sym_vvar_start])
164 fail("%s underruns vvar_start\n",
165 required_syms[i].name);
166 if (symval + 4096 > 0)
167 fail("%s is on the wrong side of the vdso text\n",
168 required_syms[i].name);
169 }
170 if (syms[sym_vvar_start] % 4096)
171 fail("vvar_begin must be a multiple of 4096\n");
172
173 if (!image_name) {
174 fwrite(stripped_addr, stripped_len, 1, outfile);
175 return;
176 }
177
178 mapping_size = (stripped_len + 4095) / 4096 * 4096;
179
180 fprintf(outfile, "/* AUTOMATICALLY GENERATED -- DO NOT EDIT */\n\n");
181 fprintf(outfile, "#include <linux/linkage.h>\n");
182 fprintf(outfile, "#include <linux/init.h>\n");
183 fprintf(outfile, "#include <asm/page_types.h>\n");
184 fprintf(outfile, "#include <asm/vdso.h>\n");
185 fprintf(outfile, "\n");
186 fprintf(outfile,
187 "static unsigned char raw_data[%lu] __ro_after_init __aligned(PAGE_SIZE) = {",
188 mapping_size);
189 for (i = 0; i < stripped_len; i++) {
190 if (i % 10 == 0)
191 fprintf(outfile, "\n\t");
192 fprintf(outfile, "0x%02X, ",
193 (int)((unsigned char *)stripped_addr)[i]);
194 }
195 fprintf(outfile, "\n};\n\n");
196 if (extable_sec)
197 BITSFUNC(extract)(raw_addr, raw_len, outfile,
198 extable_sec, "extable");
199
200 fprintf(outfile, "const struct vdso_image %s = {\n", image_name);
201 fprintf(outfile, "\t.data = raw_data,\n");
202 fprintf(outfile, "\t.size = %lu,\n", mapping_size);
203 if (alt_sec) {
204 fprintf(outfile, "\t.alt = %lu,\n",
205 (unsigned long)GET_LE(&alt_sec->sh_offset));
206 fprintf(outfile, "\t.alt_len = %lu,\n",
207 (unsigned long)GET_LE(&alt_sec->sh_size));
208 }
209 if (extable_sec) {
210 fprintf(outfile, "\t.extable_base = %lu,\n",
211 (unsigned long)GET_LE(&extable_sec->sh_offset));
212 fprintf(outfile, "\t.extable_len = %lu,\n",
213 (unsigned long)GET_LE(&extable_sec->sh_size));
214 fprintf(outfile, "\t.extable = extable,\n");
215 }
216
217 for (i = 0; i < NSYMS; i++) {
218 if (required_syms[i].export && syms[i])
219 fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n",
220 required_syms[i].name, (int64_t)syms[i]);
221 }
222 fprintf(outfile, "};\n\n");
223 fprintf(outfile, "static __init int init_%s(void) {\n", image_name);
224 fprintf(outfile, "\treturn init_vdso_image(&%s);\n", image_name);
225 fprintf(outfile, "};\n");
226 fprintf(outfile, "subsys_initcall(init_%s);\n", image_name);
227
228}