aboutsummaryrefslogtreecommitdiffstats
path: root/arch/ppc64/boot/addRamDisk.c
blob: d99c04a38e4673764b384cc3fa31726367150965 (plain) (blame)
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
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
#include <stdio.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <elf.h>

#define ElfHeaderSize  (64 * 1024)
#define ElfPages  (ElfHeaderSize / 4096)
#define KERNELBASE (0xc000000000000000)
#define _ALIGN_UP(addr,size)	(((addr)+((size)-1))&(~((size)-1)))

struct addr_range {
	unsigned long long addr;
	unsigned long memsize;
	unsigned long offset;
};

static int check_elf64(void *p, int size, struct addr_range *r)
{
	Elf64_Ehdr *elf64 = p;
	Elf64_Phdr *elf64ph;

	if (elf64->e_ident[EI_MAG0] != ELFMAG0 ||
	    elf64->e_ident[EI_MAG1] != ELFMAG1 ||
	    elf64->e_ident[EI_MAG2] != ELFMAG2 ||
	    elf64->e_ident[EI_MAG3] != ELFMAG3 ||
	    elf64->e_ident[EI_CLASS] != ELFCLASS64 ||
	    elf64->e_ident[EI_DATA] != ELFDATA2MSB ||
	    elf64->e_type != ET_EXEC || elf64->e_machine != EM_PPC64)
		return 0;

	if ((elf64->e_phoff + sizeof(Elf64_Phdr)) > size)
		return 0;

	elf64ph = (Elf64_Phdr *) ((unsigned long)elf64 +
				  (unsigned long)elf64->e_phoff);

	r->memsize = (unsigned long)elf64ph->p_memsz;
	r->offset = (unsigned long)elf64ph->p_offset;
	r->addr = (unsigned long long)elf64ph->p_vaddr;

#ifdef DEBUG
	printf("PPC64 ELF file, ph:\n");
	printf("p_type   0x%08x\n", elf64ph->p_type);
	printf("p_flags  0x%08x\n", elf64ph->p_flags);
	printf("p_offset 0x%016llx\n", elf64ph->p_offset);
	printf("p_vaddr  0x%016llx\n", elf64ph->p_vaddr);
	printf("p_paddr  0x%016llx\n", elf64ph->p_paddr);
	printf("p_filesz 0x%016llx\n", elf64ph->p_filesz);
	printf("p_memsz  0x%016llx\n", elf64ph->p_memsz);
	printf("p_align  0x%016llx\n", elf64ph->p_align);
	printf("... skipping 0x%08lx bytes of ELF header\n",
	       (unsigned long)elf64ph->p_offset);
#endif

	return 64;
}
void get4k(FILE *file, char *buf )
{
	unsigned j;
	unsigned num = fread(buf, 1, 4096, file);
	for ( j=num; j<4096; ++j )
		buf[j] = 0;
}

void put4k(FILE *file, char *buf )
{
	fwrite(buf, 1, 4096, file);
}

void death(const char *msg, FILE *fdesc, const char *fname) 
{
	fprintf(stderr, msg);
	fclose(fdesc);
	unlink(fname);
	exit(1);
}

int main(int argc, char **argv)
{
	char inbuf[4096];
	struct addr_range vmlinux;
	FILE *ramDisk;
	FILE *inputVmlinux;
	FILE *outputVmlinux;

	char *rd_name, *lx_name, *out_name;

	size_t i;
	unsigned long ramFileLen;
	unsigned long ramLen;
	unsigned long roundR;
	unsigned long offset_end;

	unsigned long kernelLen;
	unsigned long actualKernelLen;
	unsigned long round;
	unsigned long roundedKernelLen;
	unsigned long ramStartOffs;
	unsigned long ramPages;
	unsigned long roundedKernelPages;
	unsigned long hvReleaseData;
	u_int32_t eyeCatcher = 0xc8a5d9c4;
	unsigned long naca;
	unsigned long xRamDisk;
	unsigned long xRamDiskSize;
	long padPages;
  
  
	if (argc < 2) {
		fprintf(stderr, "Name of RAM disk file missing.\n");
		exit(1);
	}
	rd_name = argv[1];

	if (argc < 3) {
		fprintf(stderr, "Name of vmlinux file missing.\n");
		exit(1);
	}
	lx_name = argv[2];

	if (argc < 4) {
		fprintf(stderr, "Name of vmlinux output file missing.\n");
		exit(1);
	}
	out_name = argv[3];


	ramDisk = fopen(rd_name, "r");
	if ( ! ramDisk ) {
		fprintf(stderr, "RAM disk file \"%s\" failed to open.\n", rd_name);
		exit(1);
	}

	inputVmlinux = fopen(lx_name, "r");
	if ( ! inputVmlinux ) {
		fprintf(stderr, "vmlinux file \"%s\" failed to open.\n", lx_name);
		exit(1);
	}
  
	outputVmlinux = fopen(out_name, "w+");
	if ( ! outputVmlinux ) {
		fprintf(stderr, "output vmlinux file \"%s\" failed to open.\n", out_name);
		exit(1);
	}

	i = fread(inbuf, 1, sizeof(inbuf), inputVmlinux);
	if (i != sizeof(inbuf)) {
		fprintf(stderr, "can not read vmlinux file %s: %u\n", lx_name, i);
		exit(1);
	}

	i = check_elf64(inbuf, sizeof(inbuf), &vmlinux);
	if (i == 0) {
		fprintf(stderr, "You must have a linux kernel specified as argv[2]\n");
		exit(1);
	}

	/* Input Vmlinux file */
	fseek(inputVmlinux, 0, SEEK_END);
	kernelLen = ftell(inputVmlinux);
	fseek(inputVmlinux, 0, SEEK_SET);
	printf("kernel file size = %d\n", kernelLen);

	actualKernelLen = kernelLen - ElfHeaderSize;

	printf("actual kernel length (minus ELF header) = %d\n", actualKernelLen);

	round = actualKernelLen % 4096;
	roundedKernelLen = actualKernelLen;
	if ( round )
		roundedKernelLen += (4096 - round);
	printf("Vmlinux length rounded up to a 4k multiple = %ld/0x%lx \n", roundedKernelLen, roundedKernelLen);
	roundedKernelPages = roundedKernelLen / 4096;
	printf("Vmlinux pages to copy = %ld/0x%lx \n", roundedKernelPages, roundedKernelPages);

	offset_end = _ALIGN_UP(vmlinux.memsize, 4096);
	/* calc how many pages we need to insert between the vmlinux and the start of the ram disk */
	padPages = offset_end/4096 - roundedKernelPages;

	/* Check and see if the vmlinux is already larger than _end in System.map */
	if (padPages < 0) {
		/* vmlinux is larger than _end - adjust the offset to the start of the embedded ram disk */ 
		offset_end = roundedKernelLen;
		printf("vmlinux is larger than _end indicates it needs to be - offset_end = %lx \n", offset_end);
		padPages = 0;
		printf("will insert %lx pages between the vmlinux and the start of the ram disk \n", padPages);
	}
	else {
		/* _end is larger than vmlinux - use the offset to _end that we calculated from the system map */
		printf("vmlinux is smaller than _end indicates is needed - offset_end = %lx \n", offset_end);
		printf("will insert %lx pages between the vmlinux and the start of the ram disk \n", padPages);
	}



	/* Input Ram Disk file */
	// Set the offset that the ram disk will be started at.
	ramStartOffs = offset_end;  /* determined from the input vmlinux file and the system map */
	printf("Ram Disk will start at offset = 0x%lx \n", ramStartOffs);
  
	fseek(ramDisk, 0, SEEK_END);
	ramFileLen = ftell(ramDisk);
	fseek(ramDisk, 0, SEEK_SET);
	printf("%s file size = %ld/0x%lx \n", rd_name, ramFileLen, ramFileLen);

	ramLen = ramFileLen;

	roundR = 4096 - (ramLen % 4096);
	if ( roundR ) {
		printf("Rounding RAM disk file up to a multiple of 4096, adding %ld/0x%lx \n", roundR, roundR);
		ramLen += roundR;
	}

	printf("Rounded RAM disk size is %ld/0x%lx \n", ramLen, ramLen);
	ramPages = ramLen / 4096;
	printf("RAM disk pages to copy = %ld/0x%lx\n", ramPages, ramPages);



  // Copy 64K ELF header
	for (i=0; i<(ElfPages); ++i) {
		get4k( inputVmlinux, inbuf );
		put4k( outputVmlinux, inbuf );
	}

	/* Copy the vmlinux (as full pages). */
	fseek(inputVmlinux, ElfHeaderSize, SEEK_SET);
	for ( i=0; i<roundedKernelPages; ++i ) {
		get4k( inputVmlinux, inbuf );
		put4k( outputVmlinux, inbuf );
	}
  
	/* Insert pad pages (if appropriate) that are needed between */
	/* | the end of the vmlinux and the ram disk. */
	for (i=0; i<padPages; ++i) {
		memset(inbuf, 0, 4096);
		put4k(outputVmlinux, inbuf);
	}

	/* Copy the ram disk (as full pages). */
	for ( i=0; i<ramPages; ++i ) {
		get4k( ramDisk, inbuf );
		put4k( outputVmlinux, inbuf );
	}

	/* Close the input files */
	fclose(ramDisk);
	fclose(inputVmlinux);
	/* And flush the written output file */
	fflush(outputVmlinux);



	/* Fixup the new vmlinux to contain the ram disk starting offset (xRamDisk) and the ram disk size (xRamDiskSize) */
	/* fseek to the hvReleaseData pointer */
	fseek(outputVmlinux, ElfHeaderSize + 0x24, SEEK_SET);
	if (fread(&hvReleaseData, 4, 1, outputVmlinux) != 1) {
		death("Could not read hvReleaseData pointer\n", outputVmlinux, out_name);
	}
	hvReleaseData = ntohl(hvReleaseData); /* Convert to native int */
	printf("hvReleaseData is at %08x\n", hvReleaseData);

	/* fseek to the hvReleaseData */
	fseek(outputVmlinux, ElfHeaderSize + hvReleaseData, SEEK_SET);
	if (fread(inbuf, 0x40, 1, outputVmlinux) != 1) {
		death("Could not read hvReleaseData\n", outputVmlinux, out_name);
	}
	/* Check hvReleaseData sanity */
	if (memcmp(inbuf, &eyeCatcher, 4) != 0) {
		death("hvReleaseData is invalid\n", outputVmlinux, out_name);
	}
	/* Get the naca pointer */
	naca = ntohl(*((u_int32_t*) &inbuf[0x0C])) - KERNELBASE;
	printf("Naca is at offset 0x%lx \n", naca);

	/* fseek to the naca */
	fseek(outputVmlinux, ElfHeaderSize + naca, SEEK_SET);
	if (fread(inbuf, 0x18, 1, outputVmlinux) != 1) {
		death("Could not read naca\n", outputVmlinux, out_name);
	}
	xRamDisk = ntohl(*((u_int32_t *) &inbuf[0x0c]));
	xRamDiskSize = ntohl(*((u_int32_t *) &inbuf[0x14]));
	/* Make sure a RAM disk isn't already present */
	if ((xRamDisk != 0) || (xRamDiskSize != 0)) {
		death("RAM disk is already attached to this kernel\n", outputVmlinux, out_name);
	}
	/* Fill in the values */
	*((u_int32_t *) &inbuf[0x0c]) = htonl(ramStartOffs);
	*((u_int32_t *) &inbuf[0x14]) = htonl(ramPages);

	/* Write out the new naca */
	fflush(outputVmlinux);
	fseek(outputVmlinux, ElfHeaderSize + naca, SEEK_SET);
	if (fwrite(inbuf, 0x18, 1, outputVmlinux) != 1) {
		death("Could not write naca\n", outputVmlinux, out_name);
	}
	printf("Ram Disk of 0x%lx pages is attached to the kernel at offset 0x%08x\n",
	       ramPages, ramStartOffs);

	/* Done */
	fclose(outputVmlinux);
	/* Set permission to executable */
	chmod(out_name, S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);

	return 0;
}