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1.1 root 1: /*
2: * Linux/i386 loader
3: * Supports bzImage, zImage and Image format.
4: *
5: * Based on work by Steve Gehlbach.
6: * Portions are taken from mkelfImage.
7: *
8: * 2003-09 by SONE Takeshi
9: */
10:
11: #include "config.h"
12: #include "kernel/kernel.h"
13: #include "libopenbios/bindings.h"
14: #include "libopenbios/sys_info.h"
15: #include "context.h"
16: #include "segment.h"
17: #include "loadfs.h"
18:
19: #define printf printk
20: #define debug printk
21: #define strtoull_with_suffix strtol
22:
23: #define LINUX_PARAM_LOC 0x90000
24: #define COMMAND_LINE_LOC 0x91000
25: #define GDT_LOC 0x92000
26: #define STACK_LOC 0x93000
27:
28: #define E820MAX 32 /* number of entries in E820MAP */
29: struct e820entry {
30: unsigned long long addr; /* start of memory segment */
31: unsigned long long size; /* size of memory segment */
32: unsigned long type; /* type of memory segment */
33: #define E820_RAM 1
34: #define E820_RESERVED 2
35: #define E820_ACPI 3 /* usable as RAM once ACPI tables have been read */
36: #define E820_NVS 4
37: };
38:
39: /* The header of Linux/i386 kernel */
40: struct linux_header {
41: uint8_t reserved1[0x1f1]; /* 0x000 */
42: uint8_t setup_sects; /* 0x1f1 */
43: uint16_t root_flags; /* 0x1f2 */
44: uint8_t reserved2[6]; /* 0x1f4 */
45: uint16_t vid_mode; /* 0x1fa */
46: uint16_t root_dev; /* 0x1fc */
47: uint16_t boot_sector_magic; /* 0x1fe */
48: /* 2.00+ */
49: uint8_t reserved3[2]; /* 0x200 */
50: uint8_t header_magic[4]; /* 0x202 */
51: uint16_t protocol_version; /* 0x206 */
52: uint32_t realmode_swtch; /* 0x208 */
53: uint16_t start_sys; /* 0x20c */
54: uint16_t kver_addr; /* 0x20e */
55: uint8_t type_of_loader; /* 0x210 */
56: uint8_t loadflags; /* 0x211 */
57: uint16_t setup_move_size; /* 0x212 */
58: uint32_t code32_start; /* 0x214 */
59: uint32_t ramdisk_image; /* 0x218 */
60: uint32_t ramdisk_size; /* 0x21c */
61: uint8_t reserved4[4]; /* 0x220 */
62: /* 2.01+ */
63: uint16_t heap_end_ptr; /* 0x224 */
64: uint8_t reserved5[2]; /* 0x226 */
65: /* 2.02+ */
66: uint32_t cmd_line_ptr; /* 0x228 */
67: /* 2.03+ */
68: uint32_t initrd_addr_max; /* 0x22c */
69: } __attribute__ ((packed));
70:
71:
72: /* Paramters passed to 32-bit part of Linux
73: * This is another view of the structure above.. */
74: struct linux_params {
75: uint8_t orig_x; /* 0x00 */
76: uint8_t orig_y; /* 0x01 */
77: uint16_t ext_mem_k; /* 0x02 -- EXT_MEM_K sits here */
78: uint16_t orig_video_page; /* 0x04 */
79: uint8_t orig_video_mode; /* 0x06 */
80: uint8_t orig_video_cols; /* 0x07 */
81: uint16_t unused2; /* 0x08 */
82: uint16_t orig_video_ega_bx; /* 0x0a */
83: uint16_t unused3; /* 0x0c */
84: uint8_t orig_video_lines; /* 0x0e */
85: uint8_t orig_video_isVGA; /* 0x0f */
86: uint16_t orig_video_points; /* 0x10 */
87:
88: /* VESA graphic mode -- linear frame buffer */
89: uint16_t lfb_width; /* 0x12 */
90: uint16_t lfb_height; /* 0x14 */
91: uint16_t lfb_depth; /* 0x16 */
92: uint32_t lfb_base; /* 0x18 */
93: uint32_t lfb_size; /* 0x1c */
94: uint16_t cl_magic; /* 0x20 */
95: #define CL_MAGIC_VALUE 0xA33F
96: uint16_t cl_offset; /* 0x22 */
97: uint16_t lfb_linelength; /* 0x24 */
98: uint8_t red_size; /* 0x26 */
99: uint8_t red_pos; /* 0x27 */
100: uint8_t green_size; /* 0x28 */
101: uint8_t green_pos; /* 0x29 */
102: uint8_t blue_size; /* 0x2a */
103: uint8_t blue_pos; /* 0x2b */
104: uint8_t rsvd_size; /* 0x2c */
105: uint8_t rsvd_pos; /* 0x2d */
106: uint16_t vesapm_seg; /* 0x2e */
107: uint16_t vesapm_off; /* 0x30 */
108: uint16_t pages; /* 0x32 */
109: uint8_t reserved4[12]; /* 0x34 -- 0x3f reserved for future expansion */
110:
111: //struct apm_bios_info apm_bios_info; /* 0x40 */
112: uint8_t apm_bios_info[0x40];
113: //struct drive_info_struct drive_info; /* 0x80 */
114: uint8_t drive_info[0x20];
115: //struct sys_desc_table sys_desc_table; /* 0xa0 */
116: uint8_t sys_desc_table[0x140];
117: uint32_t alt_mem_k; /* 0x1e0 */
118: uint8_t reserved5[4]; /* 0x1e4 */
119: uint8_t e820_map_nr; /* 0x1e8 */
120: uint8_t reserved6[9]; /* 0x1e9 */
121: uint16_t mount_root_rdonly; /* 0x1f2 */
122: uint8_t reserved7[4]; /* 0x1f4 */
123: uint16_t ramdisk_flags; /* 0x1f8 */
124: #define RAMDISK_IMAGE_START_MASK 0x07FF
125: #define RAMDISK_PROMPT_FLAG 0x8000
126: #define RAMDISK_LOAD_FLAG 0x4000
127: uint8_t reserved8[2]; /* 0x1fa */
128: uint16_t orig_root_dev; /* 0x1fc */
129: uint8_t reserved9[1]; /* 0x1fe */
130: uint8_t aux_device_info; /* 0x1ff */
131: uint8_t reserved10[2]; /* 0x200 */
132: uint8_t param_block_signature[4]; /* 0x202 */
133: uint16_t param_block_version; /* 0x206 */
134: uint8_t reserved11[8]; /* 0x208 */
135: uint8_t loader_type; /* 0x210 */
136: #define LOADER_TYPE_LOADLIN 1
137: #define LOADER_TYPE_BOOTSECT_LOADER 2
138: #define LOADER_TYPE_SYSLINUX 3
139: #define LOADER_TYPE_ETHERBOOT 4
140: #define LOADER_TYPE_KERNEL 5
141: uint8_t loader_flags; /* 0x211 */
142: uint8_t reserved12[2]; /* 0x212 */
143: uint32_t kernel_start; /* 0x214 */
144: uint32_t initrd_start; /* 0x218 */
145: uint32_t initrd_size; /* 0x21c */
146: uint8_t reserved12_5[8]; /* 0x220 */
147: uint32_t cmd_line_ptr; /* 0x228 */
148: uint8_t reserved13[164]; /* 0x22c */
149: struct e820entry e820_map[E820MAX]; /* 0x2d0 */
150: uint8_t reserved16[688]; /* 0x550 */
151: #define COMMAND_LINE_SIZE 256
152: /* Command line is copied here by 32-bit i386/kernel/head.S.
153: * So I will follow the boot protocol, rather than putting it
154: * directly here. --ts1 */
155: uint8_t command_line[COMMAND_LINE_SIZE]; /* 0x800 */
156: uint8_t reserved17[1792]; /* 0x900 - 0x1000 */
157: };
158:
159: uint64_t forced_memsize;
160:
161: /* Load the first part the file and check if it's Linux */
162: static uint32_t load_linux_header(struct linux_header *hdr)
163: {
164: int load_high;
165: uint32_t kern_addr;
166:
167: if (lfile_read(hdr, sizeof *hdr) != sizeof *hdr) {
168: debug("Can't read Linux header\n");
169: return 0;
170: }
171: if (hdr->boot_sector_magic != 0xaa55) {
172: debug("Not a Linux kernel image\n");
173: return 0;
174: }
175:
176: /* Linux is found. Print some information */
177: if (memcmp(hdr->header_magic, "HdrS", 4) != 0) {
178: /* This may be floppy disk image or something.
179: * Perform a simple (incomplete) sanity check. */
180: if (hdr->setup_sects >= 16
181: || file_size() - (hdr->setup_sects<<9) >= 512<<10) {
182: debug("This looks like a bootdisk image but not like Linux...\n");
183: return 0;
184: }
185:
186: printf("Possible very old Linux");
187: /* This kernel does not even have a protocol version.
188: * Force the value. */
189: hdr->protocol_version = 0; /* pre-2.00 */
190: } else
191: printf("Found Linux");
192: if (hdr->protocol_version >= 0x200 && hdr->kver_addr) {
193: char kver[256];
194: file_seek(hdr->kver_addr + 0x200);
195: if (lfile_read(kver, sizeof kver) != 0) {
196: kver[255] = 0;
197: printf(" version %s", kver);
198: }
199: }
200: debug(" (protocol %#x)", hdr->protocol_version);
201: load_high = 0;
202: if (hdr->protocol_version >= 0x200) {
203: debug(" (loadflags %#x)", hdr->loadflags);
204: load_high = hdr->loadflags & 1;
205: }
206: if (load_high) {
207: printf(" bzImage");
208: kern_addr = 0x100000;
209: } else {
210: printf(" zImage or Image");
211: kern_addr = 0x1000;
212: }
213: printf(".\n");
214:
215: return kern_addr;
216: }
217:
218: /* Set up parameters for 32-bit kernel */
219: static void
220: init_linux_params(struct linux_params *params, struct linux_header *hdr)
221: {
222: debug("Setting up paramters at %#lx\n", virt_to_phys(params));
223: memset(params, 0, sizeof *params);
224:
225: /* Copy some useful values from header */
226: params->mount_root_rdonly = hdr->root_flags;
227: params->orig_root_dev = hdr->root_dev;
228:
229: /* Video parameters.
230: * This assumes we have VGA in standard 80x25 text mode,
231: * just like our vga.c does.
232: * Cursor position is filled later to allow some more printf's. */
233: params->orig_video_mode = 3;
234: params->orig_video_cols = 80;
235: params->orig_video_lines = 25;
236: params->orig_video_isVGA = 1;
237: params->orig_video_points = 16;
238:
239: params->loader_type = 0xff; /* Unregistered Linux loader */
240: }
241:
242: /* Memory map */
243: static void
244: set_memory_size(struct linux_params *params, struct sys_info *info)
245: {
246: int i;
247: uint64_t end;
248: uint32_t ramtop = 0;
249: struct e820entry *linux_map;
250: struct memrange *filo_map;
251:
252: linux_map = params->e820_map;
253: filo_map = info->memrange;
254: for (i = 0; i < info->n_memranges; i++, linux_map++, filo_map++) {
255: if (i < E820MAX) {
256: /* Convert to BIOS e820 style */
257: linux_map->addr = filo_map->base;
258: linux_map->size = filo_map->size;
259: linux_map->type = E820_RAM;
260: debug("%016Lx - %016Lx\n", linux_map->addr,
261: linux_map->addr + linux_map->size);
262: params->e820_map_nr = i+1;
263: }
264:
265: /* Find out top of RAM. XXX This ignores hole above 1MB */
266: end = filo_map->base + filo_map->size;
267: if (end < (1ULL << 32)) { /* don't count memory above 4GB */
268: if (end > ramtop)
269: ramtop = (uint32_t) end;
270: }
271: }
272: debug("ramtop=%#x\n", ramtop);
273: /* Size of memory above 1MB in KB */
274: params->alt_mem_k = (ramtop - (1<<20)) >> 10;
275: /* old style, 64MB max */
276: if (ramtop >= (64<<20))
277: params->ext_mem_k = (63<<10);
278: else
279: params->ext_mem_k = params->alt_mem_k;
280: debug("ext_mem_k=%d, alt_mem_k=%d\n", params->ext_mem_k, params->alt_mem_k);
281: }
282:
283: /*
284: * Parse command line
285: * Some parameters, like initrd=<file>, are not passed to kernel,
286: * we are responsible to process them.
287: * Parameters for kernel are copied to kern_cmdline. Returns name of initrd.
288: */
289: static char *parse_command_line(const char *orig_cmdline, char *kern_cmdline)
290: {
291: const char *start, *sep, *end, *val;
292: char name[64];
293: int len;
294: int k_len;
295: int to_kern;
296: char *initrd = 0;
297: int toolong = 0;
298:
299: forced_memsize = 0;
300:
301: if (!orig_cmdline) {
302: *kern_cmdline = 0;
303: return 0;
304: }
305:
306: k_len = 0;
307: debug("original command line: \"%s\"\n", orig_cmdline);
308: debug("kernel command line at %#lx\n", virt_to_phys(kern_cmdline));
309:
310: start = orig_cmdline;
311: while (*start == ' ')
312: start++;
313: while (*start) {
314: end = strchr(start, ' ');
315: if (!end)
316: end = start + strlen(start);
317: sep = strchr(start, '=');
318: if (!sep || sep > end)
319: sep = end;
320: len = sep - start;
321: if (len >= sizeof(name))
322: len = sizeof(name) - 1;
323: memcpy(name, start, len);
324: name[len] = 0;
325:
326: if (*sep == '=') {
327: val = sep + 1;
328: len = end - val;
329: } else {
330: val = 0;
331: len = 0;
332: }
333:
334: /* Only initrd= and mem= are handled here. vga= is not,
335: * which I believe is a paramter to the realmode part of Linux,
336: * which we don't execute. */
337: if (strcmp(name, "initrd") == 0) {
338: if (!val)
339: printf("Missing filename to initrd parameter\n");
340: else {
341: initrd = malloc(len + 1);
342: memcpy(initrd, val, len);
343: initrd[len] = 0;
344: debug("initrd=%s\n", initrd);
345: }
346: /* Don't pass this to kernel */
347: to_kern = 0;
348: } else if (strcmp(name, "mem") == 0) {
349: if (!val)
350: printf("Missing value for mem parameter\n");
351: else {
352: forced_memsize = strtoull_with_suffix(val, (char**)&val, 0);
353: if (forced_memsize == 0)
354: printf("Invalid mem option, ignored\n");
355: if (val != end) {
356: printf("Garbage after mem=<size>, ignored\n");
357: forced_memsize = 0;
358: }
359: debug("mem=%Lu\n", forced_memsize);
360: }
361: /* mem= is for both loader and kernel */
362: to_kern = 1;
363: } else
364: to_kern = 1;
365:
366: if (to_kern) {
367: /* Copy to kernel command line buffer */
368: if (k_len != 0)
369: kern_cmdline[k_len++] = ' '; /* put separator */
370: len = end - start;
371: if (k_len + len >= COMMAND_LINE_SIZE) {
372: len = COMMAND_LINE_SIZE - k_len - 1;
373: if (!toolong) {
374: printf("Kernel command line is too long; truncated to "
375: "%d bytes\n", COMMAND_LINE_SIZE-1);
376: toolong = 1;
377: }
378: }
379: memcpy(kern_cmdline + k_len, start, len);
380: k_len += len;
381: }
382:
383: start = end;
384: while (*start == ' ')
385: start++;
386: }
387: kern_cmdline[k_len] = 0;
388: debug("kernel command line (%d bytes): \"%s\"\n", k_len, kern_cmdline);
389:
390: return initrd;
391: }
392:
393: /* Set command line location */
394: static void set_command_line_loc(struct linux_params *params,
395: struct linux_header *hdr)
396: {
397: if (hdr->protocol_version >= 0x202) {
398: /* new style */
399: params->cmd_line_ptr = COMMAND_LINE_LOC;
400: } else {
401: /* old style */
402: params->cl_magic = CL_MAGIC_VALUE;
403: params->cl_offset = COMMAND_LINE_LOC - LINUX_PARAM_LOC;
404: }
405: }
406:
407: /* Load 32-bit part of kernel */
408: static int load_linux_kernel(struct linux_header *hdr, uint32_t kern_addr)
409: {
410: uint32_t kern_offset, kern_size;
411:
412: if (hdr->setup_sects == 0)
413: hdr->setup_sects = 4;
414: kern_offset = (hdr->setup_sects + 1) * 512;
415: file_seek(kern_offset);
416: kern_size = file_size() - kern_offset;
417: debug("offset=%#x addr=%#x size=%#x\n", kern_offset, kern_addr, kern_size);
418:
419: #if 0
420: if (using_devsize) {
421: printf("Attempt to load up to end of device as kernel; "
422: "specify the image size\n");
423: return 0;
424: }
425: #endif
426:
427: printf("Loading kernel... ");
428: if (lfile_read(phys_to_virt(kern_addr), kern_size) != kern_size) {
429: printf("Can't read kernel\n");
430: return 0;
431: }
432: printf("ok\n");
433:
434: return kern_size;
435: }
436:
437: static int load_initrd(struct linux_header *hdr, struct sys_info *info,
438: uint32_t kern_end, struct linux_params *params, const char *initrd_file)
439: {
440: uint32_t max;
441: uint32_t start, end, size;
442: uint64_t forced;
443: extern char _start[], _end[];
444:
445: if (!file_open(initrd_file)) {
446: printf("Can't open initrd: %s\n", initrd_file);
447: return -1;
448: }
449:
450: #if 0
451: if (using_devsize) {
452: printf("Attempt to load up to end of device as initrd; "
453: "specify the image size\n");
454: return -1;
455: }
456: #endif
457:
458: size = file_size();
459:
460:
461: /* Find out the kernel's restriction on how high the initrd can be
462: * placed */
463: if (hdr->protocol_version >= 0x203)
464: max = hdr->initrd_addr_max;
465: else
466: max = 0x38000000; /* Hardcoded value for older kernels */
467:
468: /* FILO itself is at the top of RAM. (relocated)
469: * So, try putting initrd just below us. */
470: end = virt_to_phys(_start);
471: if (end > max)
472: end = max;
473:
474: /* If "mem=" option is given, we have to put the initrd within
475: * the specified range. */
476: if (forced_memsize) {
477: forced = forced_memsize;
478: if (forced > max)
479: forced = max;
480: /* If the "mem=" is lower, it's easy */
481: if (forced <= end)
482: end = forced;
483: else {
484: /* Otherwise, see if we can put it above us */
485: if (virt_to_phys(_end) + size <= forced)
486: end = forced; /* Ok */
487: }
488: }
489:
490: start = end - size;
491: start &= ~0xfff; /* page align */
492: end = start + size;
493:
494: debug("start=%#x end=%#x\n", start, end);
495:
496: if (start < kern_end) {
497: printf("Initrd is too big to fit in memory\n");
498: return -1;
499: }
500:
501: printf("Loading initrd... ");
502: if (lfile_read(phys_to_virt(start), size) != size) {
503: printf("Can't read initrd\n");
504: return -1;
505: }
506: printf("ok\n");
507:
508: params->initrd_start = start;
509: params->initrd_size = size;
510:
511: return 0;
512: }
513:
514: static void hardware_setup(void)
515: {
516: /* Disable nmi */
517: outb(0x80, 0x70);
518:
519: /* Make sure any coprocessor is properly reset.. */
520: outb(0, 0xf0);
521: outb(0, 0xf1);
522:
523: /* we're getting screwed again and again by this problem of the 8259.
524: * so we're going to leave this lying around for inclusion into
525: * crt0.S on an as-needed basis.
526: *
527: * well, that went ok, I hope. Now we have to reprogram the interrupts :-(
528: * we put them right after the intel-reserved hardware interrupts, at
529: * int 0x20-0x2F. There they won't mess up anything. Sadly IBM really
530: * messed this up with the original PC, and they haven't been able to
531: * rectify it afterwards. Thus the bios puts interrupts at 0x08-0x0f,
532: * which is used for the internal hardware interrupts as well. We just
533: * have to reprogram the 8259's, and it isn't fun.
534: */
535:
536: outb(0x11, 0x20); /* initialization sequence to 8259A-1 */
537: outb(0x11, 0xA0); /* and to 8259A-2 */
538:
539: outb(0x20, 0x21); /* start of hardware int's (0x20) */
540: outb(0x28, 0xA1); /* start of hardware int's 2 (0x28) */
541:
542: outb(0x04, 0x21); /* 8259-1 is master */
543: outb(0x02, 0xA1); /* 8259-2 is slave */
544:
545: outb(0x01, 0x21); /* 8086 mode for both */
546: outb(0x01, 0xA1);
547:
548: outb(0xFF, 0xA1); /* mask off all interrupts for now */
549: outb(0xFB, 0x21); /* mask all irq's but irq2 which is cascaded */
550: }
551:
552: /* Start Linux */
553: static int start_linux(uint32_t kern_addr, struct linux_params *params)
554: {
555: struct segment_desc *linux_gdt;
556: struct context *ctx;
557: //extern int cursor_x, cursor_y;
558:
559: ctx = init_context(phys_to_virt(STACK_LOC), 4096, 0);
560:
561: /* Linux expects GDT being in low memory */
562: linux_gdt = phys_to_virt(GDT_LOC);
563: memset(linux_gdt, 0, 13*sizeof(struct segment_desc));
564: /* Normal kernel code/data segments */
565: linux_gdt[2] = gdt[FLAT_CODE];
566: linux_gdt[3] = gdt[FLAT_DATA];
567: /* 2.6 kernel uses 12 and 13, but head.S uses backward-compatible
568: * segments (2 and 3), so it SHOULD not be a problem.
569: * However, some distro kernels (eg. RH9) with backported threading
570: * patch use 12 and 13 also when booting... */
571: linux_gdt[12] = gdt[FLAT_CODE];
572: linux_gdt[13] = gdt[FLAT_DATA];
573: ctx->gdt_base = GDT_LOC;
574: ctx->gdt_limit = 14*8-1;
575: ctx->cs = 0x10;
576: ctx->ds = 0x18;
577: ctx->es = 0x18;
578: ctx->fs = 0x18;
579: ctx->gs = 0x18;
580: ctx->ss = 0x18;
581:
582: /* Parameter location */
583: ctx->esi = virt_to_phys(params);
584:
585: /* Entry point */
586: ctx->eip = kern_addr;
587:
588: debug("eip=%#x\n", kern_addr);
589: printf("Jumping to entry point...\n");
590:
591: #ifdef VGA_CONSOLE
592: /* Update VGA cursor position.
593: * This must be here because the printf changes the value! */
594: params->orig_x = cursor_x;
595: params->orig_y = cursor_y;
596: #endif
597:
598: /* Go... */
599: ctx = switch_to(ctx);
600:
601: /* It's impossible but... */
602: printf("Returned with eax=%#x\n", ctx->eax);
603:
604: return ctx->eax;
605: }
606:
607: int linux_load(struct sys_info *info, const char *file, const char *cmdline)
608: {
609: struct linux_header hdr;
610: struct linux_params *params;
611: uint32_t kern_addr, kern_size;
612: char *initrd_file = 0;
613:
614: if (!file_open(file))
615: return -1;
616:
617: kern_addr = load_linux_header(&hdr);
618: if (kern_addr == 0)
619: return LOADER_NOT_SUPPORT;
620:
621: params = phys_to_virt(LINUX_PARAM_LOC);
622: init_linux_params(params, &hdr);
623: set_memory_size(params, info);
624: initrd_file = parse_command_line(cmdline, phys_to_virt(COMMAND_LINE_LOC));
625: set_command_line_loc(params, &hdr);
626:
627: kern_size = load_linux_kernel(&hdr, kern_addr);
628: if (kern_size == 0) {
629: if (initrd_file)
630: free(initrd_file);
631: return -1;
632: }
633:
634: if (initrd_file) {
635: if (load_initrd(&hdr, info, kern_addr+kern_size, params, initrd_file)
636: != 0) {
637: free(initrd_file);
638: return -1;
639: }
640: free(initrd_file);
641: }
642:
643: hardware_setup();
644:
645: start_linux(kern_addr, params);
646: return 0;
647: }
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