wok annotate syslinux/stuff/iso2exe/bootlinux.c @ rev 14268

syslinux/iso2exe: do not overload (setup) version in bootlinux.c
author Pascal Bellard <pascal.bellard@slitaz.org>
date Thu Apr 04 11:19:19 2013 +0200 (2013-04-04)
parents bf8be127c60b
children df021be024df
rev   line source
pascal@13691 1 #include <stdio.h>
pascal@13691 2 #include "iso9660.h"
pascal@13691 3
pascal@13691 4 static unsigned version;
pascal@13691 5 #define SETUPSECTORS 0x1F1
pascal@13691 6 #define ROFLAG 0x1F2
pascal@13691 7 #define SYSSIZE 0x1F4
pascal@13691 8 #define VIDEOMODE 0x1FA
pascal@13691 9 #define BOOTFLAG 0x1FE
pascal@13691 10 #define HEADER 0x202
pascal@13691 11 #define VERSION 0x206
pascal@13691 12 #define RMSWOFS 0x208
pascal@13691 13 #define RMSWSEG 0x20A
pascal@13691 14 #define LOADERTYPE 0x210
pascal@13691 15 #define LOADFLAGS 0x211
pascal@13691 16 #define SYSTEMCODE 0x214
pascal@13691 17 #define INITRDCODE 0x218
pascal@13691 18 #define INITRDSIZE 0x21C
pascal@13691 19 #define HEAPPTR 0x224
pascal@13691 20 #define CMDLINE 0x228
pascal@13691 21
pascal@13691 22 #define SETUP_SEGMENT 0x9000
pascal@13691 23 #define CMDLINE_OFFSET 0x9E00
pascal@13691 24
pascal@13733 25 #define PAGE_BITS 12
pascal@13733 26 #define PAGE_SIZE 4096
pascal@13733 27 #define BUFFERSZ PAGE_SIZE
pascal@13691 28 static char buffer[BUFFERSZ];
pascal@13691 29 static unsigned long initrd_addr, initrd_size;
pascal@13691 30
pascal@13691 31 static int may_exit_dos = 1;
pascal@13691 32 static void die(char *msg)
pascal@13691 33 {
pascal@13691 34 printf("%s.\n", msg);
pascal@13691 35 if (may_exit_dos)
pascal@13691 36 exit(1);
pascal@13691 37 while (1);
pascal@13691 38 }
pascal@13691 39
pascal@13691 40 static int vm86(void)
pascal@13691 41 {
pascal@13691 42 #asm
pascal@13691 43 smsw ax
pascal@13691 44 and ax, #1 // 0:realmode 1:vm86
pascal@13691 45 #endasm
pascal@13691 46 }
pascal@13691 47
pascal@13691 48 static struct mem {
pascal@13691 49 unsigned long base;
pascal@13691 50 int align;
pascal@13691 51 } kernelmem = { 0x100000, 0 };
pascal@13691 52
pascal@13691 53 #define initrdmem kernelmem
pascal@13691 54
pascal@13691 55 static void movehi(void)
pascal@13691 56 {
pascal@13691 57 #asm
pascal@13691 58 pusha
pascal@13691 59 xor di, di // 30
pascal@13691 60 mov cx, #9 // 2E..1E
pascal@13691 61 zero1:
pascal@13691 62 push di
pascal@13691 63 loop zero1
pascal@13691 64 push dword [_kernelmem] // 1A p->base
pascal@13691 65 push #-1 // 18
pascal@13691 66 push di // 16
pascal@13691 67 xor eax, eax
pascal@13691 68 cdq
pascal@13691 69 mov dx, ds
pascal@13691 70 shl edx, #4
pascal@13691 71 mov ax, #_buffer
pascal@13691 72 add edx, eax
pascal@13691 73 push edx // 12 linear_address(buffer)
pascal@13691 74 push #-1 // 10
pascal@13691 75 mov cl, #8 // 0E..00
pascal@13691 76 zero2:
pascal@13691 77 push di
pascal@13691 78 loop zero2
pascal@13691 79 mov ch, #BUFFERSZ/512
pascal@13691 80 push ss
pascal@13691 81 pop es
pascal@13691 82 mov si, sp
pascal@13691 83 mov ax, #0x8793
pascal@13691 84 mov [si+0x15], al
pascal@13691 85 xchg [si+0x1D], al
pascal@13691 86 mov [si+0x1F], al // bits 24..31, doesn't work for me :(
pascal@13691 87 int 0x15
pascal@13691 88 add sp, #0x30
pascal@13691 89 popa
pascal@13691 90 #endasm
pascal@13691 91 }
pascal@13691 92
pascal@13733 93 #undef ZIMAGE_SUPPORT /* Does not work... */
pascal@13733 94
pascal@13699 95 static int versiondos;
pascal@13699 96 static int dosversion(void)
pascal@13699 97 {
pascal@13699 98 #asm
pascal@13699 99 mov ah, #0x30
pascal@13699 100 int 0x21
pascal@13699 101 cbw
pascal@13699 102 mov _versiondos, ax
pascal@13699 103 #endasm
pascal@13699 104 }
pascal@13699 105
pascal@13691 106 static void load(struct mem *p, unsigned long size)
pascal@13691 107 {
pascal@13691 108 if (vm86())
pascal@13691 109 die("Need real mode");
pascal@13691 110 switch (p->align) {
pascal@13691 111 case 0: // kernel
pascal@13699 112 switch (dosversion()) {
pascal@13699 113 case 3: case 4: case 6: break;
pascal@13699 114 default:
pascal@13699 115 printf("DOS %d not supported.\nTrying anyway...\n",
pascal@13699 116 versiondos);
pascal@13699 117 }
pascal@13733 118 p->align = PAGE_SIZE;
pascal@13691 119 break;
pascal@13691 120 case 4096: // first initrd
pascal@13691 121 initrd_addr = p->base;
pascal@13691 122 p->align = 4;
pascal@13691 123 }
pascal@13691 124 while (size) {
pascal@13691 125 int n, s = sizeof(buffer);
pascal@13691 126 for (n = 0; n < s; n++) buffer[n] = 0;
pascal@13691 127 if (s > size) s = size;
pascal@13691 128 n = isoread(buffer, s);
pascal@13691 129 movehi();
pascal@13691 130 if (n != -1) {
pascal@13691 131 p->base += n;
pascal@13691 132 size -= n;
pascal@13691 133 }
pascal@13691 134 if (s != n) break;
pascal@13691 135 }
pascal@13691 136 initrd_size = p->base - initrd_addr;
pascal@13691 137 p->base += p->align - 1;
pascal@13691 138 p->base &= - p->align;
pascal@13691 139 }
pascal@13691 140
pascal@13691 141 static unsigned setupofs = 0;
pascal@13691 142
pascal@13691 143 void movesetup(void)
pascal@13691 144 {
pascal@13691 145 #asm
pascal@13691 146 pusha
pascal@13691 147 push #SETUP_SEGMENT
pascal@13691 148 pop es
pascal@13691 149 mov si, #_buffer
pascal@13691 150 mov di, _setupofs
pascal@13691 151 mov cx, #BUFFERSZ/2
pascal@13691 152 rep
pascal@13691 153 movsw
pascal@13691 154 mov _setupofs, di
pascal@13691 155 popa
pascal@13691 156 #endasm
pascal@13691 157 }
pascal@13691 158
pascal@14257 159 static unsigned getcs(void)
pascal@14257 160 {
pascal@14257 161 #asm
pascal@14257 162 mov ax, cs
pascal@14257 163 #endasm
pascal@14257 164 }
pascal@14257 165
pascal@14257 166 unsigned long loadkernel(void)
pascal@13691 167 {
pascal@13691 168 unsigned setup, n = BUFFERSZ;
pascal@14268 169 unsigned long syssize = 0, kernel_version = 0;
pascal@13691 170
pascal@13691 171 do {
pascal@13691 172 isoread(buffer, n);
pascal@13691 173 if (setupofs == 0) {
pascal@13691 174 if (* (unsigned short *) (buffer + BOOTFLAG) != 0xAA55)
pascal@13691 175 die("The kernel is not bootable");
pascal@13691 176 setup = (1 + buffer[SETUPSECTORS]) << 9;
pascal@13691 177 if (setup == 512) setup = 5 << 9;
pascal@13691 178 syssize = * (unsigned long *) (buffer + SYSSIZE) << 4;
pascal@13691 179 version = * (unsigned short *) (buffer + VERSION);
pascal@13691 180 #define HDRS 0x53726448
pascal@13691 181 if (* (unsigned long *) (buffer + HEADER) != HDRS)
pascal@13691 182 version = 0;
pascal@13733 183 if (version < 0x204)
pascal@13733 184 syssize &= 0x000FFFFFUL;
pascal@13733 185 if (version) {
pascal@13733 186 #ifdef REALMODE_SWITCH
pascal@13733 187 extern int far_realmode_switch();
pascal@13733 188 #asm
pascal@13733 189 jmp end_realmode_switch
pascal@13733 190 _far_realmode_switch:
pascal@14257 191 call REALMODE_SWITCH
pascal@13733 192 cli
pascal@13733 193 mov al, #0x80 // Disable NMI
pascal@13733 194 out 0x70, al
pascal@13733 195 retf
pascal@13733 196 end_realmode_switch:
pascal@13733 197 #endasm
pascal@13733 198 * (unsigned short *) (buffer + RMSWOFS) =
pascal@13733 199 far_realmode_switch;
pascal@13733 200 * (unsigned short *) (buffer + RMSWSEG) =
pascal@13733 201 getcs();
pascal@13733 202 #endif
pascal@13733 203 kernelmem.base =
pascal@13733 204 * (unsigned long *) (buffer + SYSTEMCODE);
pascal@13733 205 * (unsigned short *) (buffer + HEAPPTR) =
pascal@13733 206 0x9B00;
pascal@13733 207 // buffer[LOADFLAGS] |= 0x80;
pascal@13733 208 * (unsigned short *) (buffer + LOADERTYPE) |=
pascal@13733 209 0x80FF;
pascal@13733 210 }
pascal@13691 211 if (!version || !(buffer[LOADFLAGS] & 1)) {
pascal@13691 212 #ifdef ZIMAGE_SUPPORT
pascal@13691 213 #asm
pascal@13691 214 pusha
pascal@13691 215 mov cx, #0x8000
pascal@13691 216 mov es, cx
pascal@13691 217 xor si, si
pascal@13691 218 xor di, di
pascal@13691 219 rep
pascal@13697 220 movsw // move 64K data
pascal@13691 221 push es
pascal@13691 222 pop ds
pascal@13691 223 push es
pascal@13691 224 pop ss
pascal@13697 225 mov ch, #0x70
pascal@13697 226 mov es, cx
pascal@13697 227 mov ch, #0x80
pascal@13697 228 rep
pascal@13697 229 seg cs
pascal@13697 230 movsw // move 64K code
pascal@13691 231 popa
pascal@13697 232 jmpi relocated, #0x7000
pascal@13691 233 relocated:
pascal@13691 234 #endasm
pascal@13691 235 kernelmem.base = 0x10000;
pascal@13697 236 if (syssize > 0x60000) /* 384K max */
pascal@13691 237 #endif
pascal@13691 238 die("Not a bzImage format");
pascal@13691 239 }
pascal@13691 240 }
pascal@13691 241 movesetup();
pascal@13691 242 setup -= n;
pascal@13691 243 n = (setup > BUFFERSZ) ? BUFFERSZ : setup;
pascal@13691 244 } while (setup > 0);
pascal@13691 245
pascal@14257 246 #asm
pascal@14257 247 push ds
pascal@14257 248 push #SETUP_SEGMENT
pascal@14257 249 pop ds
pascal@14257 250 mov si, #0x200
pascal@14257 251 mov eax, #0x53726448 // HdrS
pascal@14257 252 cdq // clear edx
pascal@14257 253 cmp [si+2], eax
pascal@14257 254 jne noversion
pascal@14257 255 add si, [si+14]
pascal@14257 256 mov cx, #3
pascal@14257 257 xor ax, ax
pascal@14257 258 nextdigit:
pascal@14264 259 shl al, #4
pascal@14264 260 shl ax, #4
pascal@14257 261 next:
pascal@14257 262 lodsb
pascal@14257 263 sub al, #0x30
pascal@14257 264 cmp al, #9
pascal@14257 265 jbe nextdigit
pascal@14264 266 shl eax, #16
pascal@14264 267 shld edx, eax, #8
pascal@14257 268 loop next
pascal@14257 269 pop ds
pascal@14268 270 mov .loadkernel.kernel_version[bp], edx
pascal@14257 271 noversion:
pascal@14257 272 #endasm
pascal@13691 273 load(&kernelmem, syssize);
pascal@14268 274 return kernel_version;
pascal@13691 275 }
pascal@13691 276
pascal@13691 277 void loadinitrd(void)
pascal@13691 278 {
pascal@13691 279 if (version)
pascal@13691 280 load(&initrdmem, isofilesize);
pascal@13691 281 }
pascal@13691 282
pascal@13691 283 void bootlinux(char *cmdline)
pascal@13691 284 {
pascal@13691 285 #asm
pascal@13691 286 push #SETUP_SEGMENT
pascal@13691 287 pop es
pascal@13691 288 mov eax, _initrd_addr
pascal@13691 289 or eax, eax
pascal@13691 290 jz no_initrd
pascal@13691 291 mov di, #0x218
pascal@13691 292 stosd
pascal@13691 293 mov eax, _initrd_size
pascal@13691 294 stosd
pascal@13691 295 no_initrd:
pascal@13691 296 #endasm
pascal@13691 297 if (cmdline) {
pascal@13691 298 if (version <= 0x201) {
pascal@13691 299 #asm
pascal@13691 300 mov di, #0x0020
pascal@13691 301 mov ax, #0xA33F
pascal@13691 302 stosw
pascal@13691 303 mov ax, #CMDLINE_OFFSET
pascal@13691 304 stosw
pascal@13691 305 #endasm
pascal@13691 306 }
pascal@13691 307 else {
pascal@13691 308 #asm
pascal@13691 309 mov di, #0x0228
pascal@13691 310 mov eax, #SETUP_SEGMENT*16+CMDLINE_OFFSET
pascal@13691 311 stosd
pascal@13691 312 #endasm
pascal@13691 313 }
pascal@13691 314 #asm
pascal@13691 315 xchg ax, di
pascal@13691 316 mov si, .bootlinux.cmdline[bp]
pascal@13691 317 copy:
pascal@13691 318 lodsb
pascal@13691 319 stosb
pascal@13691 320 or al,al
pascal@13691 321 jne copy
pascal@13691 322 #endasm
pascal@13691 323 }
pascal@13691 324 #asm
pascal@13691 325 push es
pascal@13691 326 pop ds
pascal@13691 327 push ds
pascal@13691 328 pop ss
pascal@13691 329 mov sp, #CMDLINE_OFFSET
pascal@13691 330 jmpi 0, #0x9020
pascal@13691 331 #endasm
pascal@13691 332 }