aboutsummaryrefslogtreecommitdiff
path: root/arch/ppc/boot/utils/addRamDisk.c
blob: 93400dfcce7f7fb38741c65c2400295f54c1da14 (plain)
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
#include <stdio.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>

#define ElfHeaderSize  (64 * 1024)
#define ElfPages  (ElfHeaderSize / 4096)
#define KERNELBASE (0xc0000000)

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)
{
    printf(msg);
    fclose(fdesc);
    unlink(fname);
    exit(1);
}

int main(int argc, char **argv)
{
    char inbuf[4096];
    FILE *ramDisk = NULL;
    FILE *inputVmlinux = NULL;
    FILE *outputVmlinux = NULL;
    unsigned i = 0;
    u_int32_t ramFileLen = 0;
    u_int32_t ramLen = 0;
    u_int32_t roundR = 0;
    u_int32_t kernelLen = 0;
    u_int32_t actualKernelLen = 0;
    u_int32_t round = 0;
    u_int32_t roundedKernelLen = 0;
    u_int32_t ramStartOffs = 0;
    u_int32_t ramPages = 0;
    u_int32_t roundedKernelPages = 0;
    u_int32_t hvReleaseData = 0;
    u_int32_t eyeCatcher = 0xc8a5d9c4;
    u_int32_t naca = 0;
    u_int32_t xRamDisk = 0;
    u_int32_t xRamDiskSize = 0;
    if ( argc < 2 ) {
	printf("Name of RAM disk file missing.\n");
	exit(1);
    }

    if ( argc < 3 ) {
	printf("Name of vmlinux file missing.\n");
	exit(1);
    }

    if ( argc < 4 ) {
	printf("Name of vmlinux output file missing.\n");
	exit(1);
    }

    ramDisk = fopen(argv[1], "r");
    if ( ! ramDisk ) {
	printf("RAM disk file \"%s\" failed to open.\n", argv[1]);
	exit(1);
    }
    inputVmlinux = fopen(argv[2], "r");
    if ( ! inputVmlinux ) {
	printf("vmlinux file \"%s\" failed to open.\n", argv[2]);
	exit(1);
    }
    outputVmlinux = fopen(argv[3], "w+");
    if ( ! outputVmlinux ) {
	printf("output vmlinux file \"%s\" failed to open.\n", argv[3]);
	exit(1);
    }
    fseek(ramDisk, 0, SEEK_END);
    ramFileLen = ftell(ramDisk);
    fseek(ramDisk, 0, SEEK_SET);
    printf("%s file size = %d\n", argv[1], ramFileLen);

    ramLen = ramFileLen;

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

    printf("Rounded RAM disk size is %d\n", ramLen);
    fseek(inputVmlinux, 0, SEEK_END);
    kernelLen = ftell(inputVmlinux);
    fseek(inputVmlinux, 0, SEEK_SET);
    printf("kernel file size = %d\n", kernelLen);
    if ( kernelLen == 0 ) {
	printf("You must have a linux kernel specified as argv[2]\n");
	exit(1);
    }

    actualKernelLen = kernelLen - ElfHeaderSize;

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

    round = actualKernelLen % 4096;
    roundedKernelLen = actualKernelLen;
    if ( round )
	roundedKernelLen += (4096 - round);

    printf("actual kernel length rounded up to a 4k multiple = %d\n", roundedKernelLen);

    ramStartOffs = roundedKernelLen;
    ramPages = ramLen / 4096;

    printf("RAM disk pages to copy = %d\n", ramPages);

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

    roundedKernelPages = roundedKernelLen / 4096;

    fseek(inputVmlinux, ElfHeaderSize, SEEK_SET);

    for ( i=0; i<roundedKernelPages; ++i ) {
	get4k( inputVmlinux, inbuf );
	put4k( outputVmlinux, inbuf );
    }

    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);

    /* 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, argv[3]);
    }
    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, argv[3]);
    }
    /* Check hvReleaseData sanity */
    if (memcmp(inbuf, &eyeCatcher, 4) != 0) {
        death("hvReleaseData is invalid\n", outputVmlinux, argv[3]);
    }
    /* Get the naca pointer */
    naca = ntohl(*((u_int32_t *) &inbuf[0x0c])) - KERNELBASE;
    printf("naca is at %08x\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, argv[3]);
    }
    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, argv[3]);
    }
    /* 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, argv[3]);
    }
    printf("RAM Disk of 0x%x pages size is attached to the kernel at offset 0x%08x\n",
            ramPages, ramStartOffs);

    /* Done */
    fclose(outputVmlinux);
    /* Set permission to executable */
    chmod(argv[3], S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);

    return 0;
}