tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#include <stdio.h>
2#include <stdlib.h>
3#include <netinet/in.h>
4#include <unistd.h>
5#include <sys/types.h>
6#include <sys/stat.h>
7#include <string.h>
8#include <elf.h>
9
10#define ElfHeaderSize (64 * 1024)
11#define ElfPages (ElfHeaderSize / 4096)
12#define KERNELBASE (0xc000000000000000)
13#define _ALIGN_UP(addr,size) (((addr)+((size)-1))&(~((size)-1)))
14
15struct addr_range {
16 unsigned long long addr;
17 unsigned long memsize;
18 unsigned long offset;
19};
20
21static int check_elf64(void *p, int size, struct addr_range *r)
22{
23 Elf64_Ehdr *elf64 = p;
24 Elf64_Phdr *elf64ph;
25
26 if (elf64->e_ident[EI_MAG0] != ELFMAG0 ||
27 elf64->e_ident[EI_MAG1] != ELFMAG1 ||
28 elf64->e_ident[EI_MAG2] != ELFMAG2 ||
29 elf64->e_ident[EI_MAG3] != ELFMAG3 ||
30 elf64->e_ident[EI_CLASS] != ELFCLASS64 ||
31 elf64->e_ident[EI_DATA] != ELFDATA2MSB ||
32 elf64->e_type != ET_EXEC || elf64->e_machine != EM_PPC64)
33 return 0;
34
35 if ((elf64->e_phoff + sizeof(Elf64_Phdr)) > size)
36 return 0;
37
38 elf64ph = (Elf64_Phdr *) ((unsigned long)elf64 +
39 (unsigned long)elf64->e_phoff);
40
41 r->memsize = (unsigned long)elf64ph->p_memsz;
42 r->offset = (unsigned long)elf64ph->p_offset;
43 r->addr = (unsigned long long)elf64ph->p_vaddr;
44
45#ifdef DEBUG
46 printf("PPC64 ELF file, ph:\n");
47 printf("p_type 0x%08x\n", elf64ph->p_type);
48 printf("p_flags 0x%08x\n", elf64ph->p_flags);
49 printf("p_offset 0x%016llx\n", elf64ph->p_offset);
50 printf("p_vaddr 0x%016llx\n", elf64ph->p_vaddr);
51 printf("p_paddr 0x%016llx\n", elf64ph->p_paddr);
52 printf("p_filesz 0x%016llx\n", elf64ph->p_filesz);
53 printf("p_memsz 0x%016llx\n", elf64ph->p_memsz);
54 printf("p_align 0x%016llx\n", elf64ph->p_align);
55 printf("... skipping 0x%08lx bytes of ELF header\n",
56 (unsigned long)elf64ph->p_offset);
57#endif
58
59 return 64;
60}
61static void get4k(FILE *file, char *buf )
62{
63 unsigned j;
64 unsigned num = fread(buf, 1, 4096, file);
65 for ( j=num; j<4096; ++j )
66 buf[j] = 0;
67}
68
69static void put4k(FILE *file, char *buf )
70{
71 fwrite(buf, 1, 4096, file);
72}
73
74static void death(const char *msg, FILE *fdesc, const char *fname)
75{
76 fprintf(stderr, msg);
77 fclose(fdesc);
78 unlink(fname);
79 exit(1);
80}
81
82int main(int argc, char **argv)
83{
84 char inbuf[4096];
85 struct addr_range vmlinux;
86 FILE *ramDisk;
87 FILE *inputVmlinux;
88 FILE *outputVmlinux;
89
90 char *rd_name, *lx_name, *out_name;
91
92 size_t i;
93 unsigned long ramFileLen;
94 unsigned long ramLen;
95 unsigned long roundR;
96 unsigned long offset_end;
97
98 unsigned long kernelLen;
99 unsigned long actualKernelLen;
100 unsigned long round;
101 unsigned long roundedKernelLen;
102 unsigned long ramStartOffs;
103 unsigned long ramPages;
104 unsigned long roundedKernelPages;
105 unsigned long hvReleaseData;
106 u_int32_t eyeCatcher = 0xc8a5d9c4;
107 unsigned long naca;
108 unsigned long xRamDisk;
109 unsigned long xRamDiskSize;
110 long padPages;
111
112
113 if (argc < 2) {
114 fprintf(stderr, "Name of RAM disk file missing.\n");
115 exit(1);
116 }
117 rd_name = argv[1];
118
119 if (argc < 3) {
120 fprintf(stderr, "Name of vmlinux file missing.\n");
121 exit(1);
122 }
123 lx_name = argv[2];
124
125 if (argc < 4) {
126 fprintf(stderr, "Name of vmlinux output file missing.\n");
127 exit(1);
128 }
129 out_name = argv[3];
130
131
132 ramDisk = fopen(rd_name, "r");
133 if ( ! ramDisk ) {
134 fprintf(stderr, "RAM disk file \"%s\" failed to open.\n", rd_name);
135 exit(1);
136 }
137
138 inputVmlinux = fopen(lx_name, "r");
139 if ( ! inputVmlinux ) {
140 fprintf(stderr, "vmlinux file \"%s\" failed to open.\n", lx_name);
141 exit(1);
142 }
143
144 outputVmlinux = fopen(out_name, "w+");
145 if ( ! outputVmlinux ) {
146 fprintf(stderr, "output vmlinux file \"%s\" failed to open.\n", out_name);
147 exit(1);
148 }
149
150 i = fread(inbuf, 1, sizeof(inbuf), inputVmlinux);
151 if (i != sizeof(inbuf)) {
152 fprintf(stderr, "can not read vmlinux file %s: %u\n", lx_name, i);
153 exit(1);
154 }
155
156 i = check_elf64(inbuf, sizeof(inbuf), &vmlinux);
157 if (i == 0) {
158 fprintf(stderr, "You must have a linux kernel specified as argv[2]\n");
159 exit(1);
160 }
161
162 /* Input Vmlinux file */
163 fseek(inputVmlinux, 0, SEEK_END);
164 kernelLen = ftell(inputVmlinux);
165 fseek(inputVmlinux, 0, SEEK_SET);
166 printf("kernel file size = %lu\n", kernelLen);
167
168 actualKernelLen = kernelLen - ElfHeaderSize;
169
170 printf("actual kernel length (minus ELF header) = %lu\n", actualKernelLen);
171
172 round = actualKernelLen % 4096;
173 roundedKernelLen = actualKernelLen;
174 if ( round )
175 roundedKernelLen += (4096 - round);
176 printf("Vmlinux length rounded up to a 4k multiple = %ld/0x%lx \n", roundedKernelLen, roundedKernelLen);
177 roundedKernelPages = roundedKernelLen / 4096;
178 printf("Vmlinux pages to copy = %ld/0x%lx \n", roundedKernelPages, roundedKernelPages);
179
180 offset_end = _ALIGN_UP(vmlinux.memsize, 4096);
181 /* calc how many pages we need to insert between the vmlinux and the start of the ram disk */
182 padPages = offset_end/4096 - roundedKernelPages;
183
184 /* Check and see if the vmlinux is already larger than _end in System.map */
185 if (padPages < 0) {
186 /* vmlinux is larger than _end - adjust the offset to the start of the embedded ram disk */
187 offset_end = roundedKernelLen;
188 printf("vmlinux is larger than _end indicates it needs to be - offset_end = %lx \n", offset_end);
189 padPages = 0;
190 printf("will insert %lx pages between the vmlinux and the start of the ram disk \n", padPages);
191 }
192 else {
193 /* _end is larger than vmlinux - use the offset to _end that we calculated from the system map */
194 printf("vmlinux is smaller than _end indicates is needed - offset_end = %lx \n", offset_end);
195 printf("will insert %lx pages between the vmlinux and the start of the ram disk \n", padPages);
196 }
197
198
199
200 /* Input Ram Disk file */
201 // Set the offset that the ram disk will be started at.
202 ramStartOffs = offset_end; /* determined from the input vmlinux file and the system map */
203 printf("Ram Disk will start at offset = 0x%lx \n", ramStartOffs);
204
205 fseek(ramDisk, 0, SEEK_END);
206 ramFileLen = ftell(ramDisk);
207 fseek(ramDisk, 0, SEEK_SET);
208 printf("%s file size = %ld/0x%lx \n", rd_name, ramFileLen, ramFileLen);
209
210 ramLen = ramFileLen;
211
212 roundR = 4096 - (ramLen % 4096);
213 if ( roundR ) {
214 printf("Rounding RAM disk file up to a multiple of 4096, adding %ld/0x%lx \n", roundR, roundR);
215 ramLen += roundR;
216 }
217
218 printf("Rounded RAM disk size is %ld/0x%lx \n", ramLen, ramLen);
219 ramPages = ramLen / 4096;
220 printf("RAM disk pages to copy = %ld/0x%lx\n", ramPages, ramPages);
221
222
223
224 // Copy 64K ELF header
225 for (i=0; i<(ElfPages); ++i) {
226 get4k( inputVmlinux, inbuf );
227 put4k( outputVmlinux, inbuf );
228 }
229
230 /* Copy the vmlinux (as full pages). */
231 fseek(inputVmlinux, ElfHeaderSize, SEEK_SET);
232 for ( i=0; i<roundedKernelPages; ++i ) {
233 get4k( inputVmlinux, inbuf );
234 put4k( outputVmlinux, inbuf );
235 }
236
237 /* Insert pad pages (if appropriate) that are needed between */
238 /* | the end of the vmlinux and the ram disk. */
239 for (i=0; i<padPages; ++i) {
240 memset(inbuf, 0, 4096);
241 put4k(outputVmlinux, inbuf);
242 }
243
244 /* Copy the ram disk (as full pages). */
245 for ( i=0; i<ramPages; ++i ) {
246 get4k( ramDisk, inbuf );
247 put4k( outputVmlinux, inbuf );
248 }
249
250 /* Close the input files */
251 fclose(ramDisk);
252 fclose(inputVmlinux);
253 /* And flush the written output file */
254 fflush(outputVmlinux);
255
256
257
258 /* Fixup the new vmlinux to contain the ram disk starting offset (xRamDisk) and the ram disk size (xRamDiskSize) */
259 /* fseek to the hvReleaseData pointer */
260 fseek(outputVmlinux, ElfHeaderSize + 0x24, SEEK_SET);
261 if (fread(&hvReleaseData, 4, 1, outputVmlinux) != 1) {
262 death("Could not read hvReleaseData pointer\n", outputVmlinux, out_name);
263 }
264 hvReleaseData = ntohl(hvReleaseData); /* Convert to native int */
265 printf("hvReleaseData is at %08lx\n", hvReleaseData);
266
267 /* fseek to the hvReleaseData */
268 fseek(outputVmlinux, ElfHeaderSize + hvReleaseData, SEEK_SET);
269 if (fread(inbuf, 0x40, 1, outputVmlinux) != 1) {
270 death("Could not read hvReleaseData\n", outputVmlinux, out_name);
271 }
272 /* Check hvReleaseData sanity */
273 if (memcmp(inbuf, &eyeCatcher, 4) != 0) {
274 death("hvReleaseData is invalid\n", outputVmlinux, out_name);
275 }
276 /* Get the naca pointer */
277 naca = ntohl(*((u_int32_t*) &inbuf[0x0C])) - KERNELBASE;
278 printf("Naca is at offset 0x%lx \n", naca);
279
280 /* fseek to the naca */
281 fseek(outputVmlinux, ElfHeaderSize + naca, SEEK_SET);
282 if (fread(inbuf, 0x18, 1, outputVmlinux) != 1) {
283 death("Could not read naca\n", outputVmlinux, out_name);
284 }
285 xRamDisk = ntohl(*((u_int32_t *) &inbuf[0x0c]));
286 xRamDiskSize = ntohl(*((u_int32_t *) &inbuf[0x14]));
287 /* Make sure a RAM disk isn't already present */
288 if ((xRamDisk != 0) || (xRamDiskSize != 0)) {
289 death("RAM disk is already attached to this kernel\n", outputVmlinux, out_name);
290 }
291 /* Fill in the values */
292 *((u_int32_t *) &inbuf[0x0c]) = htonl(ramStartOffs);
293 *((u_int32_t *) &inbuf[0x14]) = htonl(ramPages);
294
295 /* Write out the new naca */
296 fflush(outputVmlinux);
297 fseek(outputVmlinux, ElfHeaderSize + naca, SEEK_SET);
298 if (fwrite(inbuf, 0x18, 1, outputVmlinux) != 1) {
299 death("Could not write naca\n", outputVmlinux, out_name);
300 }
301 printf("Ram Disk of 0x%lx pages is attached to the kernel at offset 0x%08lx\n",
302 ramPages, ramStartOffs);
303
304 /* Done */
305 fclose(outputVmlinux);
306 /* Set permission to executable */
307 chmod(out_name, S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);
308
309 return 0;
310}
311