1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Program to hack in a PT_NOTE program header entry in an ELF file.
4 * This is needed for OF on RS/6000s to load an image correctly.
5 * Note that OF needs a program header entry for the note, not an
6 * ELF section.
7 *
8 * Copyright 2000 Paul Mackerras.
9 *
10 * Adapted for 64 bit little endian images by Andrew Tauferner.
11 *
12 * Usage: addnote zImage
13 */
14 #include <stdio.h>
15 #include <stdlib.h>
16 #include <fcntl.h>
17 #include <unistd.h>
18 #include <string.h>
19
20 /* CHRP note section */
21 static const char arch[] = "PowerPC";
22
23 #define N_DESCR 6
24 unsigned int descr[N_DESCR] = {
25 0xffffffff, /* real-mode = true */
26 0x02000000, /* real-base, i.e. where we expect OF to be */
27 0xffffffff, /* real-size */
28 0xffffffff, /* virt-base */
29 0xffffffff, /* virt-size */
30 0x4000, /* load-base */
31 };
32
33 /* RPA note section */
34 static const char rpaname[] = "IBM,RPA-Client-Config";
35
36 /*
37 * Note: setting ignore_my_client_config *should* mean that OF ignores
38 * all the other fields, but there is a firmware bug which means that
39 * it looks at the splpar field at least. So these values need to be
40 * reasonable.
41 */
42 #define N_RPA_DESCR 8
43 unsigned int rpanote[N_RPA_DESCR] = {
44 0, /* lparaffinity */
45 64, /* min_rmo_size */
46 0, /* min_rmo_percent */
47 40, /* max_pft_size */
48 1, /* splpar */
49 -1, /* min_load */
50 0, /* new_mem_def */
51 1, /* ignore_my_client_config */
52 };
53
54 #define ROUNDUP(len) (((len) + 3) & ~3)
55
56 unsigned char buf[1024];
57 #define ELFDATA2LSB 1
58 #define ELFDATA2MSB 2
59 static int e_data = ELFDATA2MSB;
60 #define ELFCLASS32 1
61 #define ELFCLASS64 2
62 static int e_class = ELFCLASS32;
63
64 #define GET_16BE(off) ((buf[off] << 8) + (buf[(off)+1]))
65 #define GET_32BE(off) ((GET_16BE(off) << 16U) + GET_16BE((off)+2U))
66 #define GET_64BE(off) ((((unsigned long long)GET_32BE(off)) << 32ULL) + \
67 ((unsigned long long)GET_32BE((off)+4ULL)))
68 #define PUT_16BE(off, v)(buf[off] = ((v) >> 8) & 0xff, \
69 buf[(off) + 1] = (v) & 0xff)
70 #define PUT_32BE(off, v)(PUT_16BE((off), (v) >> 16L), PUT_16BE((off) + 2, (v)))
71 #define PUT_64BE(off, v)((PUT_32BE((off), (v) >> 32L), \
72 PUT_32BE((off) + 4, (v))))
73
74 #define GET_16LE(off) ((buf[off]) + (buf[(off)+1] << 8))
75 #define GET_32LE(off) (GET_16LE(off) + (GET_16LE((off)+2U) << 16U))
76 #define GET_64LE(off) ((unsigned long long)GET_32LE(off) + \
77 (((unsigned long long)GET_32LE((off)+4ULL)) << 32ULL))
78 #define PUT_16LE(off, v) (buf[off] = (v) & 0xff, \
79 buf[(off) + 1] = ((v) >> 8) & 0xff)
80 #define PUT_32LE(off, v) (PUT_16LE((off), (v)), PUT_16LE((off) + 2, (v) >> 16L))
81 #define PUT_64LE(off, v) (PUT_32LE((off), (v)), PUT_32LE((off) + 4, (v) >> 32L))
82
83 #define GET_16(off) (e_data == ELFDATA2MSB ? GET_16BE(off) : GET_16LE(off))
84 #define GET_32(off) (e_data == ELFDATA2MSB ? GET_32BE(off) : GET_32LE(off))
85 #define GET_64(off) (e_data == ELFDATA2MSB ? GET_64BE(off) : GET_64LE(off))
86 #define PUT_16(off, v) (e_data == ELFDATA2MSB ? PUT_16BE(off, v) : \
87 PUT_16LE(off, v))
88 #define PUT_32(off, v) (e_data == ELFDATA2MSB ? PUT_32BE(off, v) : \
89 PUT_32LE(off, v))
90 #define PUT_64(off, v) (e_data == ELFDATA2MSB ? PUT_64BE(off, v) : \
91 PUT_64LE(off, v))
92
93 /* Structure of an ELF file */
94 #define E_IDENT 0 /* ELF header */
95 #define E_PHOFF (e_class == ELFCLASS32 ? 28 : 32)
96 #define E_PHENTSIZE (e_class == ELFCLASS32 ? 42 : 54)
97 #define E_PHNUM (e_class == ELFCLASS32 ? 44 : 56)
98 #define E_HSIZE (e_class == ELFCLASS32 ? 52 : 64)
99
100 #define EI_MAGIC 0 /* offsets in E_IDENT area */
101 #define EI_CLASS 4
102 #define EI_DATA 5
103
104 #define PH_TYPE 0 /* ELF program header */
105 #define PH_OFFSET (e_class == ELFCLASS32 ? 4 : 8)
106 #define PH_FILESZ (e_class == ELFCLASS32 ? 16 : 32)
107 #define PH_HSIZE (e_class == ELFCLASS32 ? 32 : 56)
108
109 #define PT_NOTE 4 /* Program header type = note */
110
111
112 unsigned char elf_magic[4] = { 0x7f, 'E', 'L', 'F' };
113
114 int
main(int ac,char ** av)115 main(int ac, char **av)
116 {
117 int fd, n, i;
118 unsigned long ph, ps, np;
119 long nnote, nnote2, ns;
120
121 if (ac != 2) {
122 fprintf(stderr, "Usage: %s elf-file\n", av[0]);
123 exit(1);
124 }
125 fd = open(av[1], O_RDWR);
126 if (fd < 0) {
127 perror(av[1]);
128 exit(1);
129 }
130
131 nnote = 12 + ROUNDUP(strlen(arch) + 1) + sizeof(descr);
132 nnote2 = 12 + ROUNDUP(strlen(rpaname) + 1) + sizeof(rpanote);
133
134 n = read(fd, buf, sizeof(buf));
135 if (n < 0) {
136 perror("read");
137 exit(1);
138 }
139
140 if (memcmp(&buf[E_IDENT+EI_MAGIC], elf_magic, 4) != 0)
141 goto notelf;
142 e_class = buf[E_IDENT+EI_CLASS];
143 if (e_class != ELFCLASS32 && e_class != ELFCLASS64)
144 goto notelf;
145 e_data = buf[E_IDENT+EI_DATA];
146 if (e_data != ELFDATA2MSB && e_data != ELFDATA2LSB)
147 goto notelf;
148 if (n < E_HSIZE)
149 goto notelf;
150
151 ph = (e_class == ELFCLASS32 ? GET_32(E_PHOFF) : GET_64(E_PHOFF));
152 ps = GET_16(E_PHENTSIZE);
153 np = GET_16(E_PHNUM);
154 if (ph < E_HSIZE || ps < PH_HSIZE || np < 1)
155 goto notelf;
156 if (ph + (np + 2) * ps + nnote + nnote2 > n)
157 goto nospace;
158
159 for (i = 0; i < np; ++i) {
160 if (GET_32(ph + PH_TYPE) == PT_NOTE) {
161 fprintf(stderr, "%s already has a note entry\n",
162 av[1]);
163 exit(0);
164 }
165 ph += ps;
166 }
167
168 /* XXX check that the area we want to use is all zeroes */
169 for (i = 0; i < 2 * ps + nnote + nnote2; ++i)
170 if (buf[ph + i] != 0)
171 goto nospace;
172
173 /* fill in the program header entry */
174 ns = ph + 2 * ps;
175 PUT_32(ph + PH_TYPE, PT_NOTE);
176 if (e_class == ELFCLASS32)
177 PUT_32(ph + PH_OFFSET, ns);
178 else
179 PUT_64(ph + PH_OFFSET, ns);
180
181 if (e_class == ELFCLASS32)
182 PUT_32(ph + PH_FILESZ, nnote);
183 else
184 PUT_64(ph + PH_FILESZ, nnote);
185
186 /* fill in the note area we point to */
187 /* XXX we should probably make this a proper section */
188 PUT_32(ns, strlen(arch) + 1);
189 PUT_32(ns + 4, N_DESCR * 4);
190 PUT_32(ns + 8, 0x1275);
191 strcpy((char *) &buf[ns + 12], arch);
192 ns += 12 + strlen(arch) + 1;
193 for (i = 0; i < N_DESCR; ++i, ns += 4)
194 PUT_32BE(ns, descr[i]);
195
196 /* fill in the second program header entry and the RPA note area */
197 ph += ps;
198 PUT_32(ph + PH_TYPE, PT_NOTE);
199 if (e_class == ELFCLASS32)
200 PUT_32(ph + PH_OFFSET, ns);
201 else
202 PUT_64(ph + PH_OFFSET, ns);
203
204 if (e_class == ELFCLASS32)
205 PUT_32(ph + PH_FILESZ, nnote);
206 else
207 PUT_64(ph + PH_FILESZ, nnote2);
208
209 /* fill in the note area we point to */
210 PUT_32(ns, strlen(rpaname) + 1);
211 PUT_32(ns + 4, sizeof(rpanote));
212 PUT_32(ns + 8, 0x12759999);
213 strcpy((char *) &buf[ns + 12], rpaname);
214 ns += 12 + ROUNDUP(strlen(rpaname) + 1);
215 for (i = 0; i < N_RPA_DESCR; ++i, ns += 4)
216 PUT_32BE(ns, rpanote[i]);
217
218 /* Update the number of program headers */
219 PUT_16(E_PHNUM, np + 2);
220
221 /* write back */
222 i = lseek(fd, (long) 0, SEEK_SET);
223 if (i < 0) {
224 perror("lseek");
225 exit(1);
226 }
227 i = write(fd, buf, n);
228 if (i < 0) {
229 perror("write");
230 exit(1);
231 }
232 if (i < n) {
233 fprintf(stderr, "%s: write truncated\n", av[1]);
234 exit(1);
235 }
236
237 exit(0);
238
239 notelf:
240 fprintf(stderr, "%s does not appear to be an ELF file\n", av[1]);
241 exit(1);
242
243 nospace:
244 fprintf(stderr, "sorry, I can't find space in %s to put the note\n",
245 av[1]);
246 exit(1);
247 }
248
