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
|
; -----------------------------------------------------------------------
;
; Copyright 1994-2009 H. Peter Anvin - All Rights Reserved
; Copyright 2009 Intel Corporation; author: H. Peter Anvin
;
; 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, Inc., 53 Temple Place Ste 330,
; Bostom MA 02111-1307, USA; either version 2 of the License, or
; (at your option) any later version; incorporated herein by reference.
;
; -----------------------------------------------------------------------
;
; layout.inc
;
; Memory layout of segments
;
; Default to 16-bit code
bits 16
; Memory below 0800h is reserved for the BIOS and the MBR.
BSS_START equ 0800h
; Text starts at the load address of 07C00h.
TEXT_START equ 7C00h
; The secondary BSS section, above the text; we really wish we could
; just make it follow .bcopy32 or hang off the end,
; but it doesn't seem to work that way.
LATEBSS_START equ 0B800h
;
; The various sections and their relationship
;
; Use .earlybss for things that MUST be in low memory.
section .earlybss nobits
section .config write progbits align=4
section .replacestub exec write progbits align=16
; Use .bss16 for things that doesn't have to be in low memory;
; .earlybss should be used for things that absolutely have
; to be below 0x7c00.
section .bss16 write nobits align=16
%if 0 ; IS_PXELINUX
; Warning here: RBFG build 22 randomly overwrites
; memory location [0x5680,0x576c), possibly more. It
; seems that it gets confused and screws up the
; pointer to its own internal packet buffer and starts
; writing a received ARP packet into low memory.
section .rbfg write nobits
RBFG_brainfuck: resb 2048 ; Bigger than an Ethernet packet...
%endif
section .init exec write progbits align=1
section .text16 exec write progbits align=1
section .textnr exec nowrite progbits align=1
section .bcopyxx exec write progbits align=16
section .data16 write progbits align=16
section .adv write nobits align=512
; .uibss contains bss data which is guaranteed to be
; safe to clobber during the loading of the image. This
; is because while loading the primary image we will clobber
; the spillover from the last fractional sector load.
section .uibss write nobits align=16
; Symbols from linker script
%macro SECINFO 1
extern __%1_start, __%1_lma, __%1_end
extern __%1_len, __%1_dwords
%endmacro
SECINFO bss16
SECINFO uibss
SECINFO config
SECINFO replacestub
SECINFO pm_code
SECINFO high_clear
SECINFO bss
extern free_high_memory
global _start
section .text16
;
; Segment assignments in the bottom 640K
; Keep the low-memory footprint as small as possible... overrun is a hard
; failure!
;
; 0000h - main code/data segment (and BIOS segment)
;
; This stuff really should come from the linker...
;
global xfer_buf_seg, core_xfer_buf
xfer_buf_seg equ 3000h
core_xfer_buf equ xfer_buf_seg << 4
serial_buf_size equ 4096 ; Should be a power of 2
;
; Contents of aux_seg
;
extern aux_seg ; Actual segment assigned by linker
struc aux
.fontbuf resb 8192
.serial resb serial_buf_size
alignb 4096 ; Align the next segment to 4K
endstruc
section .auxseg write nobits align=16
auxseg resb aux_size
;
; Bounce buffer for I/O to high mem
; Note: we keep all the segments page-aligned, even if that probably
; is somewhat excessive. Sector alignment is obligatory, however.
;
global cache_seg, core_cache_buf
cache_seg equ 4000h ; 64K area for metadata cache
core_cache_buf equ cache_seg << 4
real_mode_seg equ 5000h
pktbuf_seg equ cache_seg ; PXELINUX packet buffers
comboot_seg equ real_mode_seg ; COMBOOT image loading zone
|
