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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 */
21static const char arch[] = "PowerPC";
22
23#define N_DESCR 6
24unsigned 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 */
34static 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
43unsigned 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
56unsigned char buf[1024];
57#define ELFDATA2LSB 1
58#define ELFDATA2MSB 2
59static int e_data = ELFDATA2MSB;
60#define ELFCLASS32 1
61#define ELFCLASS64 2
62static 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), (unsigned long long)(v) >> 32L), \
72 PUT_32BE((off) + 4, (unsigned long long)(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), (unsigned long long)(v)), \
82 PUT_32LE((off) + 4, (unsigned long long)(v) >> 32L))
83
84#define GET_16(off) (e_data == ELFDATA2MSB ? GET_16BE(off) : GET_16LE(off))
85#define GET_32(off) (e_data == ELFDATA2MSB ? GET_32BE(off) : GET_32LE(off))
86#define GET_64(off) (e_data == ELFDATA2MSB ? GET_64BE(off) : GET_64LE(off))
87#define PUT_16(off, v) (e_data == ELFDATA2MSB ? PUT_16BE(off, v) : \
88 PUT_16LE(off, v))
89#define PUT_32(off, v) (e_data == ELFDATA2MSB ? PUT_32BE(off, v) : \
90 PUT_32LE(off, v))
91#define PUT_64(off, v) (e_data == ELFDATA2MSB ? PUT_64BE(off, v) : \
92 PUT_64LE(off, v))
93
94/* Structure of an ELF file */
95#define E_IDENT 0 /* ELF header */
96#define E_PHOFF (e_class == ELFCLASS32 ? 28 : 32)
97#define E_PHENTSIZE (e_class == ELFCLASS32 ? 42 : 54)
98#define E_PHNUM (e_class == ELFCLASS32 ? 44 : 56)
99#define E_HSIZE (e_class == ELFCLASS32 ? 52 : 64)
100
101#define EI_MAGIC 0 /* offsets in E_IDENT area */
102#define EI_CLASS 4
103#define EI_DATA 5
104
105#define PH_TYPE 0 /* ELF program header */
106#define PH_OFFSET (e_class == ELFCLASS32 ? 4 : 8)
107#define PH_FILESZ (e_class == ELFCLASS32 ? 16 : 32)
108#define PH_HSIZE (e_class == ELFCLASS32 ? 32 : 56)
109
110#define PT_NOTE 4 /* Program header type = note */
111
112
113unsigned char elf_magic[4] = { 0x7f, 'E', 'L', 'F' };
114
115int
116main(int ac, char **av)
117{
118 int fd, n, i;
119 unsigned long ph, ps, np;
120 long nnote, nnote2, ns;
121
122 if (ac != 2) {
123 fprintf(stderr, "Usage: %s elf-file\n", av[0]);
124 exit(1);
125 }
126 fd = open(av[1], O_RDWR);
127 if (fd < 0) {
128 perror(av[1]);
129 exit(1);
130 }
131
132 nnote = 12 + ROUNDUP(strlen(arch) + 1) + sizeof(descr);
133 nnote2 = 12 + ROUNDUP(strlen(rpaname) + 1) + sizeof(rpanote);
134
135 n = read(fd, buf, sizeof(buf));
136 if (n < 0) {
137 perror("read");
138 exit(1);
139 }
140
141 if (memcmp(&buf[E_IDENT+EI_MAGIC], elf_magic, 4) != 0)
142 goto notelf;
143 e_class = buf[E_IDENT+EI_CLASS];
144 if (e_class != ELFCLASS32 && e_class != ELFCLASS64)
145 goto notelf;
146 e_data = buf[E_IDENT+EI_DATA];
147 if (e_data != ELFDATA2MSB && e_data != ELFDATA2LSB)
148 goto notelf;
149 if (n < E_HSIZE)
150 goto notelf;
151
152 ph = (e_class == ELFCLASS32 ? GET_32(E_PHOFF) : GET_64(E_PHOFF));
153 ps = GET_16(E_PHENTSIZE);
154 np = GET_16(E_PHNUM);
155 if (ph < E_HSIZE || ps < PH_HSIZE || np < 1)
156 goto notelf;
157 if (ph + (np + 2) * ps + nnote + nnote2 > n)
158 goto nospace;
159
160 for (i = 0; i < np; ++i) {
161 if (GET_32(ph + PH_TYPE) == PT_NOTE) {
162 fprintf(stderr, "%s already has a note entry\n",
163 av[1]);
164 exit(0);
165 }
166 ph += ps;
167 }
168
169 /* XXX check that the area we want to use is all zeroes */
170 for (i = 0; i < 2 * ps + nnote + nnote2; ++i)
171 if (buf[ph + i] != 0)
172 goto nospace;
173
174 /* fill in the program header entry */
175 ns = ph + 2 * ps;
176 PUT_32(ph + PH_TYPE, PT_NOTE);
177 if (e_class == ELFCLASS32)
178 PUT_32(ph + PH_OFFSET, ns);
179 else
180 PUT_64(ph + PH_OFFSET, ns);
181
182 if (e_class == ELFCLASS32)
183 PUT_32(ph + PH_FILESZ, nnote);
184 else
185 PUT_64(ph + PH_FILESZ, nnote);
186
187 /* fill in the note area we point to */
188 /* XXX we should probably make this a proper section */
189 PUT_32(ns, strlen(arch) + 1);
190 PUT_32(ns + 4, N_DESCR * 4);
191 PUT_32(ns + 8, 0x1275);
192 strcpy((char *) &buf[ns + 12], arch);
193 ns += 12 + strlen(arch) + 1;
194 for (i = 0; i < N_DESCR; ++i, ns += 4)
195 PUT_32BE(ns, descr[i]);
196
197 /* fill in the second program header entry and the RPA note area */
198 ph += ps;
199 PUT_32(ph + PH_TYPE, PT_NOTE);
200 if (e_class == ELFCLASS32)
201 PUT_32(ph + PH_OFFSET, ns);
202 else
203 PUT_64(ph + PH_OFFSET, ns);
204
205 if (e_class == ELFCLASS32)
206 PUT_32(ph + PH_FILESZ, nnote);
207 else
208 PUT_64(ph + PH_FILESZ, nnote2);
209
210 /* fill in the note area we point to */
211 PUT_32(ns, strlen(rpaname) + 1);
212 PUT_32(ns + 4, sizeof(rpanote));
213 PUT_32(ns + 8, 0x12759999);
214 strcpy((char *) &buf[ns + 12], rpaname);
215 ns += 12 + ROUNDUP(strlen(rpaname) + 1);
216 for (i = 0; i < N_RPA_DESCR; ++i, ns += 4)
217 PUT_32BE(ns, rpanote[i]);
218
219 /* Update the number of program headers */
220 PUT_16(E_PHNUM, np + 2);
221
222 /* write back */
223 i = lseek(fd, (long) 0, SEEK_SET);
224 if (i < 0) {
225 perror("lseek");
226 exit(1);
227 }
228 i = write(fd, buf, n);
229 if (i < 0) {
230 perror("write");
231 exit(1);
232 }
233 if (i < n) {
234 fprintf(stderr, "%s: write truncated\n", av[1]);
235 exit(1);
236 }
237
238 exit(0);
239
240 notelf:
241 fprintf(stderr, "%s does not appear to be an ELF file\n", av[1]);
242 exit(1);
243
244 nospace:
245 fprintf(stderr, "sorry, I can't find space in %s to put the note\n",
246 av[1]);
247 exit(1);
248}