1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
|
/*
* Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved.
*/
/*
* This file is included up to twice from vdso2c.c. It generates code for
* 32-bit and 64-bit vDSOs. We will eventually need both for 64-bit builds,
* since 32-bit vDSOs will then be built for 32-bit userspace.
*/
static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
void *stripped_addr, size_t stripped_len,
FILE *outfile, const char *name)
{
int found_load = 0;
unsigned long load_size = -1; /* Work around bogus warning */
unsigned long mapping_size;
int i;
unsigned long j;
ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr;
ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr;
ELF(Dyn) *dyn = 0, *dyn_end = 0;
INT_BITS syms[NSYMS] = {};
ELF(Phdr) *pt = (ELF(Phdr) *)(raw_addr + GET_BE(&hdr->e_phoff));
/* Walk the segment table. */
for (i = 0; i < GET_BE(&hdr->e_phnum); i++) {
if (GET_BE(&pt[i].p_type) == PT_LOAD) {
if (found_load)
fail("multiple PT_LOAD segs\n");
if (GET_BE(&pt[i].p_offset) != 0 ||
GET_BE(&pt[i].p_vaddr) != 0)
fail("PT_LOAD in wrong place\n");
if (GET_BE(&pt[i].p_memsz) != GET_BE(&pt[i].p_filesz))
fail("cannot handle memsz != filesz\n");
load_size = GET_BE(&pt[i].p_memsz);
found_load = 1;
} else if (GET_BE(&pt[i].p_type) == PT_DYNAMIC) {
dyn = raw_addr + GET_BE(&pt[i].p_offset);
dyn_end = raw_addr + GET_BE(&pt[i].p_offset) +
GET_BE(&pt[i].p_memsz);
}
}
if (!found_load)
fail("no PT_LOAD seg\n");
if (stripped_len < load_size)
fail("stripped input is too short\n");
/* Walk the dynamic table */
for (i = 0; dyn + i < dyn_end &&
GET_BE(&dyn[i].d_tag) != DT_NULL; i++) {
typeof(dyn[i].d_tag) tag = GET_BE(&dyn[i].d_tag);
typeof(dyn[i].d_un.d_val) val = GET_BE(&dyn[i].d_un.d_val);
if ((tag == DT_RELSZ || tag == DT_RELASZ) && (val != 0))
fail("vdso image contains dynamic relocations\n");
}
/* Walk the section table */
for (i = 0; i < GET_BE(&hdr->e_shnum); i++) {
ELF(Shdr) *sh = raw_addr + GET_BE(&hdr->e_shoff) +
GET_BE(&hdr->e_shentsize) * i;
if (GET_BE(&sh->sh_type) == SHT_SYMTAB)
symtab_hdr = sh;
}
if (!symtab_hdr)
fail("no symbol table\n");
strtab_hdr = raw_addr + GET_BE(&hdr->e_shoff) +
GET_BE(&hdr->e_shentsize) * GET_BE(&symtab_hdr->sh_link);
/* Walk the symbol table */
for (i = 0;
i < GET_BE(&symtab_hdr->sh_size) / GET_BE(&symtab_hdr->sh_entsize);
i++) {
int k;
ELF(Sym) *sym = raw_addr + GET_BE(&symtab_hdr->sh_offset) +
GET_BE(&symtab_hdr->sh_entsize) * i;
const char *name = raw_addr + GET_BE(&strtab_hdr->sh_offset) +
GET_BE(&sym->st_name);
for (k = 0; k < NSYMS; k++) {
if (!strcmp(name, required_syms[k].name)) {
if (syms[k]) {
fail("duplicate symbol %s\n",
required_syms[k].name);
}
/*
* Careful: we use negative addresses, but
* st_value is unsigned, so we rely
* on syms[k] being a signed type of the
* correct width.
*/
syms[k] = GET_BE(&sym->st_value);
}
}
}
/* Validate mapping addresses. */
if (syms[sym_vvar_start] % 8192)
fail("vvar_begin must be a multiple of 8192\n");
if (!name) {
fwrite(stripped_addr, stripped_len, 1, outfile);
return;
}
mapping_size = (stripped_len + 8191) / 8192 * 8192;
fprintf(outfile, "/* AUTOMATICALLY GENERATED -- DO NOT EDIT */\n\n");
fprintf(outfile, "#include <linux/cache.h>\n");
fprintf(outfile, "#include <asm/vdso.h>\n");
fprintf(outfile, "\n");
fprintf(outfile,
"static unsigned char raw_data[%lu] __ro_after_init __aligned(8192)= {",
mapping_size);
for (j = 0; j < stripped_len; j++) {
if (j % 10 == 0)
fprintf(outfile, "\n\t");
fprintf(outfile, "0x%02X, ",
(int)((unsigned char *)stripped_addr)[j]);
}
fprintf(outfile, "\n};\n\n");
fprintf(outfile, "const struct vdso_image %s_builtin = {\n", name);
fprintf(outfile, "\t.data = raw_data,\n");
fprintf(outfile, "\t.size = %lu,\n", mapping_size);
for (i = 0; i < NSYMS; i++) {
if (required_syms[i].export && syms[i])
fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n",
required_syms[i].name, (int64_t)syms[i]);
}
fprintf(outfile, "};\n");
}
|
