aboutsummaryrefslogtreecommitdiffstats
path: root/com32/modules/mboot.c
blob: 2ebba06646c47b8622307f63d326d9e85e63acd3 (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
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
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
/*
 *  mboot.c
 *
 *  Loader for Multiboot-compliant kernels and modules.
 *
 *  Copyright (C) 2005 Tim Deegan <Tim.Deegan@cl.cam.ac.uk>
 *  Parts based on GNU GRUB, Copyright 2000  Free Software Foundation, Inc.
 *  Parts based on SYSLINUX, Copyright 1994-2008 H. Peter Anvin.
 *  Thanks to Ram Yalamanchili for the ELF section-header loading.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License as
 *  published by the Free Software Foundation; either version 2 of the
 *  License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 *  02111-1307, USA.
 *
 */


#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <console.h>
#include <zlib.h>
#include <com32.h>
#include <syslinux/pxe.h>

#include "i386-elf.h"
#include "mb_info.h"
#include "mb_header.h"

#include <klibc/compiler.h> /* For __constructor */

#define MIN(_x, _y) (((_x)<(_y))?(_x):(_y))
#define MAX(_x, _y) (((_x)>(_y))?(_x):(_y))

/* Define this for some more printout */
#undef DEBUG

/* Memory magic numbers */
#define STACK_SIZE      0x20000      /* XXX Could be much smaller */
#define MALLOC_SIZE     0x100000     /* XXX Could be much smaller */
#define MIN_RUN_ADDR    0x10000      /* Lowest address we'll consider using */
#define MEM_HOLE_START  0xa0000      /* Memory hole runs from 640k ... */
#define MEM_HOLE_END    0x100000     /* ... to 1MB */
#define X86_PAGE_SIZE   0x1000
#define DHCP_ACK_SIZE   2048         /* Maximum size of the DHCP ACK package.
                                        Probably too large since we're interested
                                        in the first bunch of bytes only. */

size_t __stack_size = STACK_SIZE;    /* How much stack we'll use */
extern void *__mem_end;              /* Start of malloc() heap */
extern char _end[];                  /* End of static data */

/* Pointer to free memory for loading into: load area is between here
 * and section_addr */
static char *next_load_addr;

/* Memory map for run-time */
typedef struct section section_t;
struct section {
    size_t dest;                     /* Start of run-time allocation */
    char *src;                       /* Current location of data for memmove(),
                                      * or NULL for bzero() */
    size_t size;                     /* Length of allocation */
};
static char *section_addr;
static int section_count;

static size_t max_run_addr;          /* Highest address we'll consider using */
static size_t next_mod_run_addr;     /* Where the next module will be put */

/* File loads are in units of this much */
#define LOAD_CHUNK 0x20000

/* Layout of the input to the 32-bit lidt instruction */
struct lidt_operand {
    unsigned int limit:16;
    unsigned int base:32;
} __attribute__((packed));

/* Magic strings */
static const char version_string[]   = "COM32 Multiboot loader v0.2";
static const char copyright_string[] = "Copyright (C) 2005-2006 Tim Deegan.";
static const char module_separator[] = "---";


/*
 *  Start of day magic, run from __start during library init.
 */

static void __constructor check_version(void)
    /* Check the SYSLINUX version.  Docs say we should be OK from v2.08,
     * but in fact we crash on anything below v2.12 (when libc came in). */
{
    com32sys_t regs_in, regs_out;
    const char *p, *too_old = "Fatal: SYSLINUX image is too old; "
                              "mboot.c32 needs at least version 2.12.\r\n";

    memset(&regs_in, 0, sizeof(regs_in));
    regs_in.eax.l = 0x0001;  /* "Get version" */
    __intcall(0x22, &regs_in, &regs_out);
    if (regs_out.ecx.w[0] >= 0x020c) return;

    /* Pointless: on older versions this print fails too. :( */
    for (p = too_old ; *p ; p++) {
        memset(&regs_in, 0, sizeof(regs_in));
        regs_in.eax.b[1] = 0x02;      /* "Write character" */
        regs_in.edx.b[0] = *p;
        __intcall(0x21, &regs_in, &regs_out);
    }

    __intcall(0x20, &regs_in, &regs_out);  /* "Terminate program" */
}


static void __constructor grab_memory(void)
    /* Runs before init_memory_arena() (com32/lib/malloc.c) to let
     * the malloc() code know how much space it's allowed to use.
     * We don't use malloc() directly, but some of the library code
     * does (zlib, for example). */
{
    /* Find the stack pointer */
    register char * sp;
    asm volatile("movl %%esp, %0" : "=r" (sp));

    /* Initialize the allocation of *run-time* memory: don't let ourselves
     * overwrite the stack during the relocation later. */
    max_run_addr = (size_t) sp - (MALLOC_SIZE + STACK_SIZE);

    /* Move the end-of-memory marker: malloc() will use only memory
     * above __mem_end and below the stack.  We will load files starting
     * at the old __mem_end and working towards the new one, and allocate
     * section descriptors at the top of that area, working down. */
    next_load_addr = __mem_end;
    section_addr = sp - (MALLOC_SIZE + STACK_SIZE);
    section_count = 0;

    /* But be careful not to move it the wrong direction if memory is
     * tight.  Instead we'll fail more gracefully later, when we try to
     * load a file and find that next_load_addr > section_addr. */
    __mem_end = MAX(section_addr, next_load_addr);
}




/*
 *  Run-time memory map functions: allocating and recording allocations.
 */

static int cmp_sections(const void *a, const void *b)
    /* For sorting section descriptors by destination address */
{
    const section_t *sa = a;
    const section_t *sb = b;
    if (sa->dest < sb->dest) return -1;
    if (sa->dest > sb->dest) return 1;
    return 0;
}


static void add_section(size_t dest, char *src, size_t size)
    /* Adds something to the list of sections to relocate. */
{
    section_t *sec;

#ifdef DEBUG
    printf("SECTION: %#8.8x --> %#8.8x (%#x)\n", (size_t) src, dest, size);
#endif

    section_addr -= sizeof (section_t);
    if (section_addr < next_load_addr) {
        printf("Fatal: out of memory allocating section descriptor.\n");
        exit(1);
    }
    sec = (section_t *) section_addr;
    section_count++;

    sec->src = src;
    sec->dest = dest;
    sec->size = size;

    /* Keep the list sorted */
    qsort(sec, section_count, sizeof (section_t), cmp_sections);
}


static size_t place_low_section(size_t size, size_t align)
    /* Find a space in the run-time memory map, below 640K */
{
    int i;
    size_t start;
    section_t *sections = (section_t *) section_addr;

    start = MIN_RUN_ADDR;
    start = (start + (align-1)) & ~(align-1);

    /* Section list is sorted by destination, so can do this in one pass */
    for (i = 0; i < section_count; i++) {
        if (sections[i].dest < start + size) {
            /* Hit the bottom of this section */
            start = sections[i].dest + sections[i].size;
            start = (start + (align-1)) & ~(align-1);
        }
    }
    if (start + size < MEM_HOLE_START) return start;
    else return 0;
}


static size_t place_module_section(size_t size, size_t align)
    /* Find a space in the run-time memory map for this module. */
{
    /* Ideally we'd run through the sections looking for a free space
     * like place_low_section() does, but some OSes (Xen, at least)
     * assume that the bootloader has loaded all the modules
     * consecutively, above the kernel.  So, what we actually do is
     * keep a pointer to the highest address allocated so far, and
     * always allocate modules there. */

    size_t start = next_mod_run_addr;
    start = (start + (align-1)) & ~(align-1);

    if (start + size > max_run_addr) return 0;

    next_mod_run_addr = start + size;
    return start;
}


static void place_kernel_section(size_t start, size_t size)
    /* Allocate run-time space for part of the kernel, checking for
     * sanity.  We assume the kernel isn't broken enough to have
     * overlapping segments. */
{
    /* We always place modules above the kernel */
    next_mod_run_addr = MAX(next_mod_run_addr, start + size);

    if (start > max_run_addr || start + size > max_run_addr) {
        /* Overruns the end of memory */
        printf("Fatal: kernel loads too high (%#8.8x+%#x > %#8.8x).\n",
               start, size, max_run_addr);
        exit(1);
    }
    if (start >= MEM_HOLE_END) {
        /* Above the memory hole: easy */
#ifdef DEBUG
        printf("Placed kernel section (%#8.8x+%#x)\n", start, size);
#endif
        return;
    }
    if (start >= MEM_HOLE_START) {
        /* In the memory hole.  Not so good */
        printf("Fatal: kernel load address (%#8.8x) is in the memory hole.\n",
               start);
        exit(1);
    }
    if (start + size > MEM_HOLE_START) {
        /* Too big for low memory */
        printf("Fatal: kernel (%#8.8x+%#x) runs into the memory hole.\n",
               start, size);
        exit(1);
    }
    if (start < MIN_RUN_ADDR) {
        /* Loads too low */
        printf("Fatal: kernel load address (%#8.8x) is too low (<%#8.8x).\n",
               start, MIN_RUN_ADDR);
        exit(1);
    }
    /* Kernel loads below the memory hole: OK */
#ifdef DEBUG
    printf("Placed kernel section (%#8.8x+%#x)\n", start, size);
#endif
}


static void reorder_sections(void)
    /* Reorders sections into a safe order, where no relocation
     * overwrites the source of a later one.  */
{
    section_t *secs = (section_t *) section_addr;
    section_t tmp;
    int i, j, tries;

#ifdef DEBUG
    printf("Relocations:\n");
    for (i = 0; i < section_count ; i++) {
        printf("    %#8.8x --> %#8.8x (%#x)\n",
               (size_t)secs[i].src, secs[i].dest, secs[i].size);
    }
#endif

    for (i = 0; i < section_count; i++) {
        tries = 0;
    scan_again:
        for (j = i + 1 ; j < section_count; j++) {
            if (secs[j].src != NULL
                && secs[i].dest + secs[i].size > (size_t) secs[j].src
                && secs[i].dest < (size_t) secs[j].src + secs[j].size) {
                /* Would overwrite the source of the later move */
                if (++tries > section_count) {
                    /* Deadlock! */
                    /* XXX Try to break deadlocks? */
                    printf("Fatal: circular dependence in relocations.\n");
                    exit(1);
                }
                /* Swap these sections (using struct copies) */
                tmp = secs[i]; secs[i] = secs[j]; secs[j] = tmp;
                /* Start scanning again from the new secs[i]... */
                goto scan_again;
            }
        }
    }

#ifdef DEBUG
    printf("Relocations:\n");
    for (i = 0; i < section_count ; i++) {
        printf("    %#8.8x --> %#8.8x (%#x)\n",
               (size_t)secs[i].src, secs[i].dest, secs[i].size);
    }
#endif
}


static void init_mmap(struct multiboot_info *mbi)
    /* Get a full memory map from the BIOS to pass to the kernel. */
{
    com32sys_t regs_in, regs_out;
    struct AddrRangeDesc *e820;
    int e820_slots;
    size_t mem_lower, mem_upper, run_addr, mmap_size;
    register size_t sp;

    /* Default values for mem_lower and mem_upper in case the BIOS won't
     * tell us: 640K, and all memory up to the stack. */
    asm volatile("movl %%esp, %0" : "=r" (sp));
    mem_upper = (sp - MEM_HOLE_END) / 1024;
    mem_lower = (MEM_HOLE_START) / 1024;

#ifdef DEBUG
    printf("Requesting memory map from BIOS:\n");
#endif

    /* Ask the BIOS for the full memory map of the machine.  We'll
     * build it in Multiboot format (i.e. with size fields) in the
     * bounce buffer, and then allocate some high memory to keep it in
     * until boot time. */
    e820 = __com32.cs_bounce;
    e820_slots = 0;
    regs_out.ebx.l = 0;

    while(((void *)(e820 + 1)) < __com32.cs_bounce + __com32.cs_bounce_size)
    {
        memset(e820, 0, sizeof (*e820));
        memset(&regs_in, 0, sizeof regs_in);
        e820->size = sizeof(*e820) - sizeof(e820->size);

        /* Ask the BIOS to fill in this descriptor */
        regs_in.eax.l = 0xe820;         /* "Get system memory map" */
        regs_in.ebx.l = regs_out.ebx.l; /* Continuation value from last call */
        regs_in.ecx.l = 20;             /* Size of buffer to write into */
        regs_in.edx.l = 0x534d4150;     /* "SMAP" */
        regs_in.es = SEG(&e820->BaseAddr);
        regs_in.edi.w[0] = OFFS(&e820->BaseAddr);
        __intcall(0x15, &regs_in, &regs_out);

        if ((regs_out.eflags.l & EFLAGS_CF) != 0 && regs_out.ebx.l != 0)
            break;  /* End of map */

        if (((regs_out.eflags.l & EFLAGS_CF) != 0 && regs_out.ebx.l == 0)
            || (regs_out.eax.l != 0x534d4150))
        {
            /* Error */
            printf("Error %x reading E820 memory map: %s.\n",
                   (int) regs_out.eax.b[0],
                   (regs_out.eax.b[0] == 0x80) ? "invalid command" :
                   (regs_out.eax.b[0] == 0x86) ? "not supported" :
                   "unknown error");
            break;
        }

        /* Success */
#ifdef DEBUG
        printf("    %#16.16Lx -- %#16.16Lx : ",
               e820->BaseAddr, e820->BaseAddr + e820->Length);
        switch (e820->Type) {
        case 1: printf("Available\n"); break;
        case 2: printf("Reserved\n"); break;
        case 3: printf("ACPI Reclaim\n"); break;
        case 4: printf("ACPI NVS\n"); break;
        default: printf("? (Reserved)\n"); break;
        }
#endif

        if (e820->Type == 1) {
            if (e820->BaseAddr == 0) {
                mem_lower = MIN(MEM_HOLE_START, e820->Length) / 1024;
            } else if (e820->BaseAddr == MEM_HOLE_END) {
                mem_upper = MIN(0xfff00000, e820->Length) / 1024;
            }
        }

        /* Move to next slot */
        e820++;
        e820_slots++;

        /* Done? */
        if (regs_out.ebx.l == 0)
            break;
    }

    /* Record the simple information in the MBI */
    mbi->flags |= MB_INFO_MEMORY;
    mbi->mem_lower = mem_lower;
    mbi->mem_upper = mem_upper;

    /* Record the full memory map in the MBI */
    if (e820_slots != 0) {
        mmap_size = e820_slots * sizeof(*e820);
        /* Where will it live at run time? */
        run_addr = place_low_section(mmap_size, 1);
        if (run_addr == 0) {
            printf("Fatal: can't find space for the e820 mmap.\n");
            exit(1);
        }
        /* Where will it live now? */
        e820 = (struct AddrRangeDesc *) next_load_addr;
        if (next_load_addr + mmap_size > section_addr) {
            printf("Fatal: out of memory storing the e820 mmap.\n");
            exit(1);
        }
        next_load_addr += mmap_size;
        /* Copy it out of the bounce buffer */
        memcpy(e820, __com32.cs_bounce, mmap_size);
        /* Remember to copy it again at run time */
        add_section(run_addr, (char *) e820, mmap_size);
        /* Record it in the MBI */
        mbi->flags |= MB_INFO_MEM_MAP;
        mbi->mmap_length = mmap_size;
        mbi->mmap_addr = run_addr;
    }
}




/*
 *  Code for loading and parsing files.
 */

static void load_file(char *filename, char **startp, size_t *sizep)
    /* Load a file into memory.  Returns where it is and how big via
     * startp and sizep */
{
    gzFile fp;
    char *start;
    int bsize;

    printf("Loading %s.", filename);

    start = next_load_addr;
    startp[0] = start;
    sizep[0] = 0;

    /* Open the file */
    if ((fp = gzopen(filename, "r")) == NULL) {
        printf("\nFatal: cannot open %s\n", filename);
        exit(1);
    }

    while (next_load_addr + LOAD_CHUNK <= section_addr) {
        bsize = gzread(fp, next_load_addr, LOAD_CHUNK);
        printf("%s",".");

        if (bsize < 0) {
            printf("\nFatal: read error in %s\n", filename);
            gzclose(fp);
            exit(1);
        }

        next_load_addr += bsize;
        sizep[0] += bsize;

        if (bsize < LOAD_CHUNK) {
            printf("%s","\n");
            gzclose(fp);
            return;
        }
    }

    /* Running out of memory.  Try and use up the last bit */
    if (section_addr > next_load_addr) {
        bsize = gzread(fp, next_load_addr, section_addr - next_load_addr);
        printf("%s",".");
    } else {
        bsize = 0;
    }

    if (bsize < 0) {
        gzclose(fp);
        printf("\nFatal: read error in %s\n", filename);
        exit(1);
    }

    next_load_addr += bsize;
    sizep[0] += bsize;

    if (!gzeof(fp)) {
        gzclose(fp);
        printf("\nFatal: out of memory reading %s\n", filename);
        exit(1);
    }

    printf("%s","\n");
    gzclose(fp);
    return;
}


static size_t load_kernel(struct multiboot_info *mbi, char *cmdline)
    /* Load a multiboot/elf32 kernel and allocate run-time memory for it.
     * Returns the kernel's entry address.  */
{
    unsigned int i;
    char *load_addr;                  /* Where the image was loaded */
    size_t load_size;                              /* How big it is */
    char *seg_addr;                   /* Where a segment was loaded */
    size_t seg_size, bss_size;                     /* How big it is */
    size_t run_addr, run_size;            /* Where it should be put */
    size_t shdr_run_addr;
    char *p;
    Elf32_Ehdr *ehdr;
    Elf32_Phdr *phdr;
    Elf32_Shdr *shdr;
    struct multiboot_header *mbh;

    printf("Kernel: %s\n", cmdline);

    load_addr = 0;
    load_size = 0;
    p = strchr(cmdline, ' ');
    if (p != NULL) *p = 0;
    load_file(cmdline, &load_addr, &load_size);
    if (load_size < 12) {
        printf("Fatal: %s is too short to be a multiboot kernel.",
               cmdline);
        exit(1);
    }
    if (p != NULL) *p = ' ';


    /* Look for a multiboot header in the first 8k of the file */
    for (i = 0; i <= MIN(load_size - 12, MULTIBOOT_SEARCH - 12); i += 4)
    {
        mbh = (struct multiboot_header *)(load_addr + i);
        if (mbh->magic != MULTIBOOT_MAGIC
            || ((mbh->magic+mbh->flags+mbh->checksum) & 0xffffffff))
        {
            /* Not a multiboot header */
            continue;
        }
        if (mbh->flags & (MULTIBOOT_UNSUPPORTED | MULTIBOOT_VIDEO_MODE)) {
            /* Requires options we don't support */
            printf("Fatal: Kernel requires multiboot options "
                   "that I don't support: %#x.\n",
                   mbh->flags & (MULTIBOOT_UNSUPPORTED|MULTIBOOT_VIDEO_MODE));
            exit(1);
        }

        /* This kernel will do: figure out where all the pieces will live */

        if (mbh->flags & MULTIBOOT_AOUT_KLUDGE) {

            /* Use the offsets in the multiboot header */
#ifdef DEBUG
            printf("Using multiboot header.\n");
#endif

            /* Where is the code in the loaded file? */
            seg_addr = ((char *)mbh) - (mbh->header_addr - mbh->load_addr);

            /* How much code is there? */
            run_addr = mbh->load_addr;
            if (mbh->load_end_addr != 0)
                seg_size = mbh->load_end_addr - mbh->load_addr;
            else
                seg_size = load_size - (seg_addr - load_addr);

            /* How much memory will it take up? */
            if (mbh->bss_end_addr != 0)
                run_size = mbh->bss_end_addr - mbh->load_addr;
            else
                run_size = seg_size;

            if (seg_size > run_size) {
                printf("Fatal: can't put %i bytes of kernel into %i bytes "
                       "of memory.\n", seg_size, run_size);
                exit(1);
            }
            if (seg_addr + seg_size > load_addr + load_size) {
                printf("Fatal: multiboot load segment runs off the "
                       "end of the file.\n");
                exit(1);
            }

            /* Does it fit where it wants to be? */
            place_kernel_section(run_addr, run_size);

            /* Put it on the relocation list */
            if (seg_size < run_size) {
                /* Set up the kernel BSS too */
                if (seg_size > 0)
                    add_section(run_addr, seg_addr, seg_size);
                bss_size = run_size - seg_size;
                add_section(run_addr + seg_size, NULL, bss_size);
            } else {
                /* No BSS */
                add_section(run_addr, seg_addr, run_size);
            }

            /* Done. */
            return mbh->entry_addr;

        } else {

            /* Now look for an ELF32 header */
            ehdr = (Elf32_Ehdr *)load_addr;
            if (*(unsigned long *)ehdr != 0x464c457f
                || ehdr->e_ident[EI_DATA] != ELFDATA2LSB
                || ehdr->e_ident[EI_CLASS] != ELFCLASS32
                || ehdr->e_machine != EM_386)
            {
                printf("Fatal: kernel has neither ELF32/x86 nor multiboot load"
                       " headers.\n");
                exit(1);
            }
            if (ehdr->e_phoff + ehdr->e_phnum*sizeof (*phdr) > load_size) {
                printf("Fatal: malformed ELF header overruns EOF.\n");
                exit(1);
            }
            if (ehdr->e_phnum <= 0) {
                printf("Fatal: ELF kernel has no program headers.\n");
                exit(1);
            }

#ifdef DEBUG
            printf("Using ELF header.\n");
#endif

            if (ehdr->e_type != ET_EXEC
                || ehdr->e_version != EV_CURRENT
                || ehdr->e_phentsize != sizeof (Elf32_Phdr)) {
                printf("Warning: funny-looking ELF header.\n");
            }
            phdr = (Elf32_Phdr *)(load_addr + ehdr->e_phoff);

            /* Obey the program headers to load the kernel */
            for(i = 0; i < ehdr->e_phnum; i++) {

                /* How much is in this segment? */
                run_size = phdr[i].p_memsz;
                if (phdr[i].p_type != PT_LOAD)
                    seg_size = 0;
                else
                    seg_size = (size_t)phdr[i].p_filesz;

                /* Where is it in the loaded file? */
                seg_addr = load_addr + phdr[i].p_offset;
                if (seg_addr + seg_size > load_addr + load_size) {
                    printf("Fatal: ELF load segment runs off the "
                           "end of the file.\n");
                    exit(1);
                }

                /* Skip segments that don't take up any memory */
                if (run_size == 0) continue;

                /* Place the segment where it wants to be */
                run_addr = phdr[i].p_paddr;
                place_kernel_section(run_addr, run_size);

                /* Put it on the relocation list */
                if (seg_size < run_size) {
                    /* Set up the kernel BSS too */
                    if (seg_size > 0)
                        add_section(run_addr, seg_addr, seg_size);
                    bss_size = run_size - seg_size;
                    add_section(run_addr + seg_size, NULL, bss_size);
                } else {
                    /* No BSS */
                    add_section(run_addr, seg_addr, run_size);
                }
            }

            if (ehdr->e_shoff != 0) {
#ifdef DEBUG
                printf("Loading ELF section table.\n");
#endif
                /* Section Header */
                shdr = (Elf32_Shdr *)(load_addr + ehdr->e_shoff);

                /* Section Header Table size */
                run_size = ehdr->e_shentsize * ehdr->e_shnum;
                shdr_run_addr = place_module_section(run_size, 0x1000);
                if (shdr_run_addr == 0) {
                    printf("Warning: Not enough memory to load the "
                           "section table.\n");
                    return ehdr->e_entry;
                }
                add_section(shdr_run_addr, (void*) shdr, run_size);

                /* Load section tables not loaded thru program segments */
                for (i = 0; i < ehdr->e_shnum; i++) {
                   /* This case is when this section is already included in
                    * program header or it's 0 size, so no need to load */
                   if (shdr[i].sh_addr != 0 || !shdr[i].sh_size)
                       continue;

                   if (shdr[i].sh_addralign == 0)
                       shdr[i].sh_addralign = 1;

                   run_addr = place_module_section(shdr[i].sh_size,
                                                   shdr[i].sh_addralign);
                   if (run_addr == 0) {
                       printf("Warning: Not enough memory to load "
                              "section %d.\n", i);
                       return ehdr->e_entry;
                   }
                   shdr[i].sh_addr = run_addr;
                   add_section(run_addr,
                               (void*) (shdr[i].sh_offset + load_addr),
                               shdr[i].sh_size);
                }

                mbi->flags |= MB_INFO_ELF_SHDR;
                mbi->syms.e.num = ehdr->e_shnum;
                mbi->syms.e.size = ehdr->e_shentsize;
                mbi->syms.e.shndx = ehdr->e_shstrndx;
                mbi->syms.e.addr = shdr_run_addr;
#ifdef DEBUG
                printf("Section information: shnum: %lu, entSize: %lu, "
                       "shstrndx: %lu, addr: 0x%lx\n",
                       mbi->syms.e.num, mbi->syms.e.size,
                       mbi->syms.e.shndx, mbi->syms.e.addr);
#endif
            }

            /* Done! */
            return ehdr->e_entry;
        }
    }

    /* This is not a multiboot kernel */
    printf("Fatal: not a multiboot kernel.\n");
    exit(1);
}



static void load_module(struct mod_list *mod, char *cmdline)
    /* Load a multiboot module and allocate a memory area for it */
{
    char *load_addr, *p;
    size_t load_size, run_addr;

    printf("Module: %s\n", cmdline);

    load_addr = 0;
    load_size = 0;
    p = strchr(cmdline, ' ');
    if (p != NULL) *p = 0;
    load_file(cmdline, &load_addr, &load_size);
    if (p != NULL) *p = ' ';

    /* Decide where it's going to live */
    run_addr = place_module_section(load_size, X86_PAGE_SIZE);
    if (run_addr == 0) {
        printf("Fatal: can't find space for this module.\n");
        exit(1);
    }
    add_section(run_addr, load_addr, load_size);

    /* Remember where we put it */
    mod->mod_start = run_addr;
    mod->mod_end = run_addr + load_size;
    mod->pad = 0;

#ifdef DEBUG
    printf("Placed module (%#8.8x+%#x)\n", run_addr, load_size);
#endif
}




/*
 *  Code for shuffling sections into place and booting the new kernel
 */

static void trampoline_start(section_t *secs, int sec_count,
                             size_t mbi_run_addr, size_t entry)
    /* Final shuffle-and-boot code.  Running on the stack; no external code
     * or data can be relied on. */
{
    int i;
    struct lidt_operand idt;

    /* SYSLINUX has set up SS, DS and ES as 32-bit 0--4G data segments,
     * but doesn't specify FS and GS.  Multiboot wants them all to be
     * the same, so we'd better do that before we overwrite the GDT. */
    asm volatile("movl %ds, %ecx; movl %ecx, %fs; movl %ecx, %gs");

    /* Turn off interrupts */
    asm volatile("cli");

    /* SYSLINUX has set up an IDT at 0x100000 that does all the
     * comboot calls, and we're about to overwrite it.  The Multiboot
     * spec says that the kernel must set up its own IDT before turning
     * on interrupts, but it's still entitled to use BIOS calls, so we'll
     * put the IDT back to the BIOS one at the base of memory. */
    idt.base = 0;
    idt.limit = 0x800;
    asm volatile("lidt %0" : : "m" (idt));

    /* Now, shuffle the sections */
    for (i = 0; i < sec_count; i++) {
        if (secs[i].src == NULL) {
            /* asm bzero() code from com32/lib/memset.c */
            char *q = (char *) secs[i].dest;
            size_t nl = secs[i].size >> 2;
            asm volatile("rep ; stosl ; movl %3,%0 ; rep ; stosb"
                         : "+c" (nl), "+D" (q)
                         : "a" (0x0U), "r" (secs[i].size & 3));
        } else {
            /* asm memmove() code from com32/lib/memmove.c */
            const char *p = secs[i].src;
            char *q = (char *) secs[i].dest;
            size_t n = secs[i].size;
            if ( q < p ) {
                asm volatile("rep ; movsb"
                             : "+c" (n), "+S" (p), "+D" (q));
            } else {
                p += (n-1);
                q += (n-1);
                asm volatile("std ; rep ; movsb ; cld"
                             : "+c" (n), "+S" (p), "+D" (q));
            }
        }
    }

    /* Now set up the last tiny bit of Multiboot environment.
     * A20 is already enabled.
     * CR0 already has PG cleared and PE set.
     * EFLAGS already has VM and IF cleared.
     * ESP is the kernels' problem.
     * GDTR is the kernel's problem.
     * CS is already a 32-bit, 0--4G code segments.
     * DS, ES, FS and GS are already 32-bit, 0--4G data segments.
     *
     * EAX must be 0x2badb002 and EBX must point to the MBI when we jump. */

    asm volatile ("jmp %*%2"
                  : : "a" (0x2badb002), "b" (mbi_run_addr), "cdSDm" (entry));
}
static void trampoline_end(void) {}


static void boot(size_t mbi_run_addr, size_t entry)
    /* Tidy up SYSLINUX, shuffle memory and boot the kernel */
{
    com32sys_t regs;
    section_t *tr_sections;
    void (*trampoline)(section_t *, int, size_t, size_t);
    size_t trampoline_size;

    /* Make sure the relocations are safe. */
    reorder_sections();

    /* Copy the shuffle-and-boot code and the array of relocations
     * onto the memory we previously used for malloc() heap.  This is
     * safe because it's not the source or the destination of any
     * copies, and there'll be no more library calls after the copy. */

    tr_sections = ((section_t *) section_addr) + section_count;
    trampoline = (void *) (tr_sections + section_count);
    trampoline_size = (void *)&trampoline_end - (void *)&trampoline_start;

#ifdef DEBUG
    printf("tr_sections:     %p\n"
           "trampoline:      %p\n"
           "trampoline_size: %#8.8x\n"
           "max_run_addr:    %#8.8x\n",
           tr_sections, trampoline, trampoline_size, max_run_addr);
#endif

    printf("Booting: MBI=%#8.8x, entry=%#8.8x\n", mbi_run_addr, entry);

    memmove(tr_sections, section_addr, section_count * sizeof (section_t));
    memmove(trampoline, trampoline_start, trampoline_size);

    /* Tell SYSLINUX to clean up */
    memset(&regs, 0, sizeof regs);
    regs.eax.l = 0x000c; /* "Perform final cleanup" */
    regs.edx.l = 0;      /* "Normal cleanup" */
    __intcall(0x22, &regs, NULL);

    /* Into the unknown */
    trampoline(tr_sections, section_count, mbi_run_addr, entry);
}


int main(int argc, char **argv)
    /* Parse the command-line and invoke loaders */
{
    struct multiboot_info *mbi;
    struct mod_list *modp;
    int modules, num_append_args;
    int mbi_reloc_offset;
    char *p;
    size_t mbi_run_addr, mbi_size, entry;
    int i;
    bool opt_solaris = false;
    void *dhcpdata;
    size_t dhcplen;

    /* Say hello */
    openconsole(&dev_null_r, &dev_stdcon_w);

    printf("%s.  %s\n", version_string, copyright_string);

    /* This is way too ugly. */
    if (!strcmp("-solaris", argv[1])) {
        opt_solaris = true;
        argv[1] = argv[0];
        argv = &argv[1];
        argc -= 1;
    }

    if (argc < 2 || !strcmp(argv[1], module_separator)) {
        printf("Fatal: No kernel filename!\n");
        exit(1);
    }

#ifdef DEBUG
    printf("_end:           %p\n"
           "argv[1]:        %p\n"
           "next_load_addr: %p\n"
           "section_addr    %p\n"
           "__mem_end:      %p\n"
           "argv[0]:        %p\n",
           &_end, argv[1], next_load_addr, section_addr, __mem_end, argv[0]);
#endif

    /* How much space will the MBI need? */
    modules = 0;
    mbi_size = sizeof(struct multiboot_info) + strlen(version_string) + 5;
    for (i = 1 ; i < argc ; i++) {
        if (!strcmp(argv[i], module_separator)) {
            modules++;
            mbi_size += sizeof(struct mod_list) + 1;
        } else {
            mbi_size += strlen(argv[i]) + 1;
        }
    }
    if (opt_solaris)
        mbi_size += DHCP_ACK_SIZE;

    /* Allocate space in the load buffer for the MBI, all the command
     * lines, and all the module details. */
    mbi = (struct multiboot_info *)next_load_addr;
    next_load_addr += mbi_size;
    if (next_load_addr > section_addr) {
        printf("Fatal: out of memory allocating for boot metadata.\n");
        exit(1);
    }
    memset(mbi, 0, sizeof (struct multiboot_info));
    p = (char *)(mbi + 1);
    mbi->flags = MB_INFO_CMDLINE | MB_INFO_BOOT_LOADER_NAME;

    /* Figure out the memory map.
     * N.B. Must happen before place_section() is called */
    init_mmap(mbi);

    mbi_run_addr = place_low_section(mbi_size, 4);
    if (mbi_run_addr == 0) {
        printf("Fatal: can't find space for the MBI!\n");
        exit(1);
    }
    mbi_reloc_offset = (size_t)mbi - mbi_run_addr;
    add_section(mbi_run_addr, (void *)mbi, mbi_size);

    /* Module info structs */
    modp = (struct mod_list *) (((size_t)p + 3) & ~3);
    if (modules > 0) mbi->flags |= MB_INFO_MODS;
    mbi->mods_count = modules;
    mbi->mods_addr = ((size_t)modp) - mbi_reloc_offset;
    p = (char *)(modp + modules);

    /* Append cmdline args show up in the beginning, append these
     * to kernel cmdline later on */
    for (i = 1; i < argc; i++) {
        if (strchr(argv[i], '=') != NULL) {
            continue;
        }
        break;
    }

    /* Command lines: first kernel, then modules */
    mbi->cmdline = ((size_t)p) - mbi_reloc_offset;
    modules = 0;
    num_append_args = i-1;

    for (; i < argc ; i++) {
        if (!strcmp(argv[i], module_separator)) {
            /* Add append args to kernel cmdline */
            if (modules == 0 && num_append_args) {
                int j;
                for (j = 1; j < num_append_args+1; j++) {
                    strcpy(p, argv[j]);
                    p += strlen(argv[j]);
                    *p++ = ' ';
                }
            }
            *p++ = '\0';
            modp[modules++].cmdline = ((size_t)p) - mbi_reloc_offset;
        } else {
            strcpy(p, argv[i]);
            p += strlen(argv[i]);
            *p++ = ' ';
        }
    }
    *p++ = '\0';

    /* Bootloader ID */
    strcpy(p, version_string);
    mbi->boot_loader_name = ((size_t)p) - mbi_reloc_offset;
    p += strlen(version_string) + 1;

    if (opt_solaris) {
        printf("Solaris DHCP passing enabled... ");
        /* Try to get the DHCP ACK packet from PXE */
        if (!pxe_get_cached_info(PXENV_PACKET_TYPE_DHCP_ACK,
				 &dhcpdata, &dhcplen)) {
            /* Solaris expects the DHCP ACK packet to be passed in the drives_*
               structure. However, the flags field must indicate that the
               drives_structure is not being used.
               Furthermore, the boot_device must be set to 0x20ffffff
            */
            dhcplen = MIN(dhcplen, DHCP_ACK_SIZE);
            memcpy(p, dhcpdata, dhcplen);
            mbi->drives_addr = ((size_t)p) - mbi_reloc_offset;
            mbi->drives_length = dhcplen;
            mbi->flags &= ~MB_INFO_DRIVE_INFO;
            p += dhcplen;

            mbi->boot_device = 0x20ffffff;
            mbi->flags |= MB_INFO_BOOTDEV;
	    printf("ok\n");
        } else {
	    printf("not found.\n");
        }
    }

    /* Now, do all the loading, and boot it */
    entry = load_kernel(mbi, (char *)(mbi->cmdline + mbi_reloc_offset));
    for (i=0; i<modules; i++) {
        load_module(&(modp[i]), (char *)(modp[i].cmdline + mbi_reloc_offset));
    }
    boot(mbi_run_addr, entry);

    return 1;
}

/*
 *  EOF
 */