Loading...
1/*
2 * header.S
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * Based on bootsect.S and setup.S
7 * modified by more people than can be counted
8 *
9 * Rewritten as a common file by H. Peter Anvin (Apr 2007)
10 *
11 * BIG FAT NOTE: We're in real mode using 64k segments. Therefore segment
12 * addresses must be multiplied by 16 to obtain their respective linear
13 * addresses. To avoid confusion, linear addresses are written using leading
14 * hex while segment addresses are written as segment:offset.
15 *
16 */
17
18#include <asm/segment.h>
19#include <generated/utsrelease.h>
20#include <asm/boot.h>
21#include <asm/e820.h>
22#include <asm/page_types.h>
23#include <asm/setup.h>
24#include "boot.h"
25#include "voffset.h"
26#include "zoffset.h"
27
28BOOTSEG = 0x07C0 /* original address of boot-sector */
29SYSSEG = 0x1000 /* historical load address >> 4 */
30
31#ifndef SVGA_MODE
32#define SVGA_MODE ASK_VGA
33#endif
34
35#ifndef RAMDISK
36#define RAMDISK 0
37#endif
38
39#ifndef ROOT_RDONLY
40#define ROOT_RDONLY 1
41#endif
42
43 .code16
44 .section ".bstext", "ax"
45
46 .global bootsect_start
47bootsect_start:
48#ifdef CONFIG_EFI_STUB
49 # "MZ", MS-DOS header
50 .byte 0x4d
51 .byte 0x5a
52#endif
53
54 # Normalize the start address
55 ljmp $BOOTSEG, $start2
56
57start2:
58 movw %cs, %ax
59 movw %ax, %ds
60 movw %ax, %es
61 movw %ax, %ss
62 xorw %sp, %sp
63 sti
64 cld
65
66 movw $bugger_off_msg, %si
67
68msg_loop:
69 lodsb
70 andb %al, %al
71 jz bs_die
72 movb $0xe, %ah
73 movw $7, %bx
74 int $0x10
75 jmp msg_loop
76
77bs_die:
78 # Allow the user to press a key, then reboot
79 xorw %ax, %ax
80 int $0x16
81 int $0x19
82
83 # int 0x19 should never return. In case it does anyway,
84 # invoke the BIOS reset code...
85 ljmp $0xf000,$0xfff0
86
87#ifdef CONFIG_EFI_STUB
88 .org 0x3c
89 #
90 # Offset to the PE header.
91 #
92 .long pe_header
93#endif /* CONFIG_EFI_STUB */
94
95 .section ".bsdata", "a"
96bugger_off_msg:
97 .ascii "Direct floppy boot is not supported. "
98 .ascii "Use a boot loader program instead.\r\n"
99 .ascii "\n"
100 .ascii "Remove disk and press any key to reboot ...\r\n"
101 .byte 0
102
103#ifdef CONFIG_EFI_STUB
104pe_header:
105 .ascii "PE"
106 .word 0
107
108coff_header:
109#ifdef CONFIG_X86_32
110 .word 0x14c # i386
111#else
112 .word 0x8664 # x86-64
113#endif
114 .word 3 # nr_sections
115 .long 0 # TimeDateStamp
116 .long 0 # PointerToSymbolTable
117 .long 1 # NumberOfSymbols
118 .word section_table - optional_header # SizeOfOptionalHeader
119#ifdef CONFIG_X86_32
120 .word 0x306 # Characteristics.
121 # IMAGE_FILE_32BIT_MACHINE |
122 # IMAGE_FILE_DEBUG_STRIPPED |
123 # IMAGE_FILE_EXECUTABLE_IMAGE |
124 # IMAGE_FILE_LINE_NUMS_STRIPPED
125#else
126 .word 0x206 # Characteristics
127 # IMAGE_FILE_DEBUG_STRIPPED |
128 # IMAGE_FILE_EXECUTABLE_IMAGE |
129 # IMAGE_FILE_LINE_NUMS_STRIPPED
130#endif
131
132optional_header:
133#ifdef CONFIG_X86_32
134 .word 0x10b # PE32 format
135#else
136 .word 0x20b # PE32+ format
137#endif
138 .byte 0x02 # MajorLinkerVersion
139 .byte 0x14 # MinorLinkerVersion
140
141 # Filled in by build.c
142 .long 0 # SizeOfCode
143
144 .long 0 # SizeOfInitializedData
145 .long 0 # SizeOfUninitializedData
146
147 # Filled in by build.c
148 .long 0x0000 # AddressOfEntryPoint
149
150 .long 0x0200 # BaseOfCode
151#ifdef CONFIG_X86_32
152 .long 0 # data
153#endif
154
155extra_header_fields:
156#ifdef CONFIG_X86_32
157 .long 0 # ImageBase
158#else
159 .quad 0 # ImageBase
160#endif
161 .long 0x20 # SectionAlignment
162 .long 0x20 # FileAlignment
163 .word 0 # MajorOperatingSystemVersion
164 .word 0 # MinorOperatingSystemVersion
165 .word 0 # MajorImageVersion
166 .word 0 # MinorImageVersion
167 .word 0 # MajorSubsystemVersion
168 .word 0 # MinorSubsystemVersion
169 .long 0 # Win32VersionValue
170
171 #
172 # The size of the bzImage is written in tools/build.c
173 #
174 .long 0 # SizeOfImage
175
176 .long 0x200 # SizeOfHeaders
177 .long 0 # CheckSum
178 .word 0xa # Subsystem (EFI application)
179 .word 0 # DllCharacteristics
180#ifdef CONFIG_X86_32
181 .long 0 # SizeOfStackReserve
182 .long 0 # SizeOfStackCommit
183 .long 0 # SizeOfHeapReserve
184 .long 0 # SizeOfHeapCommit
185#else
186 .quad 0 # SizeOfStackReserve
187 .quad 0 # SizeOfStackCommit
188 .quad 0 # SizeOfHeapReserve
189 .quad 0 # SizeOfHeapCommit
190#endif
191 .long 0 # LoaderFlags
192 .long 0x6 # NumberOfRvaAndSizes
193
194 .quad 0 # ExportTable
195 .quad 0 # ImportTable
196 .quad 0 # ResourceTable
197 .quad 0 # ExceptionTable
198 .quad 0 # CertificationTable
199 .quad 0 # BaseRelocationTable
200
201 # Section table
202section_table:
203 #
204 # The offset & size fields are filled in by build.c.
205 #
206 .ascii ".setup"
207 .byte 0
208 .byte 0
209 .long 0
210 .long 0x0 # startup_{32,64}
211 .long 0 # Size of initialized data
212 # on disk
213 .long 0x0 # startup_{32,64}
214 .long 0 # PointerToRelocations
215 .long 0 # PointerToLineNumbers
216 .word 0 # NumberOfRelocations
217 .word 0 # NumberOfLineNumbers
218 .long 0x60500020 # Characteristics (section flags)
219
220 #
221 # The EFI application loader requires a relocation section
222 # because EFI applications must be relocatable. The .reloc
223 # offset & size fields are filled in by build.c.
224 #
225 .ascii ".reloc"
226 .byte 0
227 .byte 0
228 .long 0
229 .long 0
230 .long 0 # SizeOfRawData
231 .long 0 # PointerToRawData
232 .long 0 # PointerToRelocations
233 .long 0 # PointerToLineNumbers
234 .word 0 # NumberOfRelocations
235 .word 0 # NumberOfLineNumbers
236 .long 0x42100040 # Characteristics (section flags)
237
238 #
239 # The offset & size fields are filled in by build.c.
240 #
241 .ascii ".text"
242 .byte 0
243 .byte 0
244 .byte 0
245 .long 0
246 .long 0x0 # startup_{32,64}
247 .long 0 # Size of initialized data
248 # on disk
249 .long 0x0 # startup_{32,64}
250 .long 0 # PointerToRelocations
251 .long 0 # PointerToLineNumbers
252 .word 0 # NumberOfRelocations
253 .word 0 # NumberOfLineNumbers
254 .long 0x60500020 # Characteristics (section flags)
255
256#endif /* CONFIG_EFI_STUB */
257
258 # Kernel attributes; used by setup. This is part 1 of the
259 # header, from the old boot sector.
260
261 .section ".header", "a"
262 .globl hdr
263hdr:
264setup_sects: .byte 0 /* Filled in by build.c */
265root_flags: .word ROOT_RDONLY
266syssize: .long 0 /* Filled in by build.c */
267ram_size: .word 0 /* Obsolete */
268vid_mode: .word SVGA_MODE
269root_dev: .word 0 /* Filled in by build.c */
270boot_flag: .word 0xAA55
271
272 # offset 512, entry point
273
274 .globl _start
275_start:
276 # Explicitly enter this as bytes, or the assembler
277 # tries to generate a 3-byte jump here, which causes
278 # everything else to push off to the wrong offset.
279 .byte 0xeb # short (2-byte) jump
280 .byte start_of_setup-1f
2811:
282
283 # Part 2 of the header, from the old setup.S
284
285 .ascii "HdrS" # header signature
286 .word 0x020a # header version number (>= 0x0105)
287 # or else old loadlin-1.5 will fail)
288 .globl realmode_swtch
289realmode_swtch: .word 0, 0 # default_switch, SETUPSEG
290start_sys_seg: .word SYSSEG # obsolete and meaningless, but just
291 # in case something decided to "use" it
292 .word kernel_version-512 # pointing to kernel version string
293 # above section of header is compatible
294 # with loadlin-1.5 (header v1.5). Don't
295 # change it.
296
297type_of_loader: .byte 0 # 0 means ancient bootloader, newer
298 # bootloaders know to change this.
299 # See Documentation/x86/boot.txt for
300 # assigned ids
301
302# flags, unused bits must be zero (RFU) bit within loadflags
303loadflags:
304LOADED_HIGH = 1 # If set, the kernel is loaded high
305CAN_USE_HEAP = 0x80 # If set, the loader also has set
306 # heap_end_ptr to tell how much
307 # space behind setup.S can be used for
308 # heap purposes.
309 # Only the loader knows what is free
310 .byte LOADED_HIGH
311
312setup_move_size: .word 0x8000 # size to move, when setup is not
313 # loaded at 0x90000. We will move setup
314 # to 0x90000 then just before jumping
315 # into the kernel. However, only the
316 # loader knows how much data behind
317 # us also needs to be loaded.
318
319code32_start: # here loaders can put a different
320 # start address for 32-bit code.
321 .long 0x100000 # 0x100000 = default for big kernel
322
323ramdisk_image: .long 0 # address of loaded ramdisk image
324 # Here the loader puts the 32-bit
325 # address where it loaded the image.
326 # This only will be read by the kernel.
327
328ramdisk_size: .long 0 # its size in bytes
329
330bootsect_kludge:
331 .long 0 # obsolete
332
333heap_end_ptr: .word _end+STACK_SIZE-512
334 # (Header version 0x0201 or later)
335 # space from here (exclusive) down to
336 # end of setup code can be used by setup
337 # for local heap purposes.
338
339ext_loader_ver:
340 .byte 0 # Extended boot loader version
341ext_loader_type:
342 .byte 0 # Extended boot loader type
343
344cmd_line_ptr: .long 0 # (Header version 0x0202 or later)
345 # If nonzero, a 32-bit pointer
346 # to the kernel command line.
347 # The command line should be
348 # located between the start of
349 # setup and the end of low
350 # memory (0xa0000), or it may
351 # get overwritten before it
352 # gets read. If this field is
353 # used, there is no longer
354 # anything magical about the
355 # 0x90000 segment; the setup
356 # can be located anywhere in
357 # low memory 0x10000 or higher.
358
359ramdisk_max: .long 0x7fffffff
360 # (Header version 0x0203 or later)
361 # The highest safe address for
362 # the contents of an initrd
363 # The current kernel allows up to 4 GB,
364 # but leave it at 2 GB to avoid
365 # possible bootloader bugs.
366
367kernel_alignment: .long CONFIG_PHYSICAL_ALIGN #physical addr alignment
368 #required for protected mode
369 #kernel
370#ifdef CONFIG_RELOCATABLE
371relocatable_kernel: .byte 1
372#else
373relocatable_kernel: .byte 0
374#endif
375min_alignment: .byte MIN_KERNEL_ALIGN_LG2 # minimum alignment
376pad3: .word 0
377
378cmdline_size: .long COMMAND_LINE_SIZE-1 #length of the command line,
379 #added with boot protocol
380 #version 2.06
381
382hardware_subarch: .long 0 # subarchitecture, added with 2.07
383 # default to 0 for normal x86 PC
384
385hardware_subarch_data: .quad 0
386
387payload_offset: .long ZO_input_data
388payload_length: .long ZO_z_input_len
389
390setup_data: .quad 0 # 64-bit physical pointer to
391 # single linked list of
392 # struct setup_data
393
394pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr
395
396#define ZO_INIT_SIZE (ZO__end - ZO_startup_32 + ZO_z_extract_offset)
397#define VO_INIT_SIZE (VO__end - VO__text)
398#if ZO_INIT_SIZE > VO_INIT_SIZE
399#define INIT_SIZE ZO_INIT_SIZE
400#else
401#define INIT_SIZE VO_INIT_SIZE
402#endif
403init_size: .long INIT_SIZE # kernel initialization size
404
405# End of setup header #####################################################
406
407 .section ".entrytext", "ax"
408start_of_setup:
409#ifdef SAFE_RESET_DISK_CONTROLLER
410# Reset the disk controller.
411 movw $0x0000, %ax # Reset disk controller
412 movb $0x80, %dl # All disks
413 int $0x13
414#endif
415
416# Force %es = %ds
417 movw %ds, %ax
418 movw %ax, %es
419 cld
420
421# Apparently some ancient versions of LILO invoked the kernel with %ss != %ds,
422# which happened to work by accident for the old code. Recalculate the stack
423# pointer if %ss is invalid. Otherwise leave it alone, LOADLIN sets up the
424# stack behind its own code, so we can't blindly put it directly past the heap.
425
426 movw %ss, %dx
427 cmpw %ax, %dx # %ds == %ss?
428 movw %sp, %dx
429 je 2f # -> assume %sp is reasonably set
430
431 # Invalid %ss, make up a new stack
432 movw $_end, %dx
433 testb $CAN_USE_HEAP, loadflags
434 jz 1f
435 movw heap_end_ptr, %dx
4361: addw $STACK_SIZE, %dx
437 jnc 2f
438 xorw %dx, %dx # Prevent wraparound
439
4402: # Now %dx should point to the end of our stack space
441 andw $~3, %dx # dword align (might as well...)
442 jnz 3f
443 movw $0xfffc, %dx # Make sure we're not zero
4443: movw %ax, %ss
445 movzwl %dx, %esp # Clear upper half of %esp
446 sti # Now we should have a working stack
447
448# We will have entered with %cs = %ds+0x20, normalize %cs so
449# it is on par with the other segments.
450 pushw %ds
451 pushw $6f
452 lretw
4536:
454
455# Check signature at end of setup
456 cmpl $0x5a5aaa55, setup_sig
457 jne setup_bad
458
459# Zero the bss
460 movw $__bss_start, %di
461 movw $_end+3, %cx
462 xorl %eax, %eax
463 subw %di, %cx
464 shrw $2, %cx
465 rep; stosl
466
467# Jump to C code (should not return)
468 calll main
469
470# Setup corrupt somehow...
471setup_bad:
472 movl $setup_corrupt, %eax
473 calll puts
474 # Fall through...
475
476 .globl die
477 .type die, @function
478die:
479 hlt
480 jmp die
481
482 .size die, .-die
483
484 .section ".initdata", "a"
485setup_corrupt:
486 .byte 7
487 .string "No setup signature found...\n"
488
489 .data
490dummy: .long 0
1/*
2 * header.S
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * Based on bootsect.S and setup.S
7 * modified by more people than can be counted
8 *
9 * Rewritten as a common file by H. Peter Anvin (Apr 2007)
10 *
11 * BIG FAT NOTE: We're in real mode using 64k segments. Therefore segment
12 * addresses must be multiplied by 16 to obtain their respective linear
13 * addresses. To avoid confusion, linear addresses are written using leading
14 * hex while segment addresses are written as segment:offset.
15 *
16 */
17
18#include <asm/segment.h>
19#include <generated/utsrelease.h>
20#include <asm/boot.h>
21#include <asm/e820.h>
22#include <asm/page_types.h>
23#include <asm/setup.h>
24#include <asm/bootparam.h>
25#include "boot.h"
26#include "voffset.h"
27#include "zoffset.h"
28
29BOOTSEG = 0x07C0 /* original address of boot-sector */
30SYSSEG = 0x1000 /* historical load address >> 4 */
31
32#ifndef SVGA_MODE
33#define SVGA_MODE ASK_VGA
34#endif
35
36#ifndef ROOT_RDONLY
37#define ROOT_RDONLY 1
38#endif
39
40 .code16
41 .section ".bstext", "ax"
42
43 .global bootsect_start
44bootsect_start:
45#ifdef CONFIG_EFI_STUB
46 # "MZ", MS-DOS header
47 .byte 0x4d
48 .byte 0x5a
49#endif
50
51 # Normalize the start address
52 ljmp $BOOTSEG, $start2
53
54start2:
55 movw %cs, %ax
56 movw %ax, %ds
57 movw %ax, %es
58 movw %ax, %ss
59 xorw %sp, %sp
60 sti
61 cld
62
63 movw $bugger_off_msg, %si
64
65msg_loop:
66 lodsb
67 andb %al, %al
68 jz bs_die
69 movb $0xe, %ah
70 movw $7, %bx
71 int $0x10
72 jmp msg_loop
73
74bs_die:
75 # Allow the user to press a key, then reboot
76 xorw %ax, %ax
77 int $0x16
78 int $0x19
79
80 # int 0x19 should never return. In case it does anyway,
81 # invoke the BIOS reset code...
82 ljmp $0xf000,$0xfff0
83
84#ifdef CONFIG_EFI_STUB
85 .org 0x3c
86 #
87 # Offset to the PE header.
88 #
89 .long pe_header
90#endif /* CONFIG_EFI_STUB */
91
92 .section ".bsdata", "a"
93bugger_off_msg:
94 .ascii "Use a boot loader.\r\n"
95 .ascii "\n"
96 .ascii "Remove disk and press any key to reboot...\r\n"
97 .byte 0
98
99#ifdef CONFIG_EFI_STUB
100pe_header:
101 .ascii "PE"
102 .word 0
103
104coff_header:
105#ifdef CONFIG_X86_32
106 .word 0x14c # i386
107#else
108 .word 0x8664 # x86-64
109#endif
110 .word 4 # nr_sections
111 .long 0 # TimeDateStamp
112 .long 0 # PointerToSymbolTable
113 .long 1 # NumberOfSymbols
114 .word section_table - optional_header # SizeOfOptionalHeader
115#ifdef CONFIG_X86_32
116 .word 0x306 # Characteristics.
117 # IMAGE_FILE_32BIT_MACHINE |
118 # IMAGE_FILE_DEBUG_STRIPPED |
119 # IMAGE_FILE_EXECUTABLE_IMAGE |
120 # IMAGE_FILE_LINE_NUMS_STRIPPED
121#else
122 .word 0x206 # Characteristics
123 # IMAGE_FILE_DEBUG_STRIPPED |
124 # IMAGE_FILE_EXECUTABLE_IMAGE |
125 # IMAGE_FILE_LINE_NUMS_STRIPPED
126#endif
127
128optional_header:
129#ifdef CONFIG_X86_32
130 .word 0x10b # PE32 format
131#else
132 .word 0x20b # PE32+ format
133#endif
134 .byte 0x02 # MajorLinkerVersion
135 .byte 0x14 # MinorLinkerVersion
136
137 # Filled in by build.c
138 .long 0 # SizeOfCode
139
140 .long 0 # SizeOfInitializedData
141 .long 0 # SizeOfUninitializedData
142
143 # Filled in by build.c
144 .long 0x0000 # AddressOfEntryPoint
145
146 .long 0x0200 # BaseOfCode
147#ifdef CONFIG_X86_32
148 .long 0 # data
149#endif
150
151extra_header_fields:
152#ifdef CONFIG_X86_32
153 .long 0 # ImageBase
154#else
155 .quad 0 # ImageBase
156#endif
157 .long 0x20 # SectionAlignment
158 .long 0x20 # FileAlignment
159 .word 0 # MajorOperatingSystemVersion
160 .word 0 # MinorOperatingSystemVersion
161 .word 0 # MajorImageVersion
162 .word 0 # MinorImageVersion
163 .word 0 # MajorSubsystemVersion
164 .word 0 # MinorSubsystemVersion
165 .long 0 # Win32VersionValue
166
167 #
168 # The size of the bzImage is written in tools/build.c
169 #
170 .long 0 # SizeOfImage
171
172 .long 0x200 # SizeOfHeaders
173 .long 0 # CheckSum
174 .word 0xa # Subsystem (EFI application)
175 .word 0 # DllCharacteristics
176#ifdef CONFIG_X86_32
177 .long 0 # SizeOfStackReserve
178 .long 0 # SizeOfStackCommit
179 .long 0 # SizeOfHeapReserve
180 .long 0 # SizeOfHeapCommit
181#else
182 .quad 0 # SizeOfStackReserve
183 .quad 0 # SizeOfStackCommit
184 .quad 0 # SizeOfHeapReserve
185 .quad 0 # SizeOfHeapCommit
186#endif
187 .long 0 # LoaderFlags
188 .long 0x6 # NumberOfRvaAndSizes
189
190 .quad 0 # ExportTable
191 .quad 0 # ImportTable
192 .quad 0 # ResourceTable
193 .quad 0 # ExceptionTable
194 .quad 0 # CertificationTable
195 .quad 0 # BaseRelocationTable
196
197 # Section table
198section_table:
199 #
200 # The offset & size fields are filled in by build.c.
201 #
202 .ascii ".setup"
203 .byte 0
204 .byte 0
205 .long 0
206 .long 0x0 # startup_{32,64}
207 .long 0 # Size of initialized data
208 # on disk
209 .long 0x0 # startup_{32,64}
210 .long 0 # PointerToRelocations
211 .long 0 # PointerToLineNumbers
212 .word 0 # NumberOfRelocations
213 .word 0 # NumberOfLineNumbers
214 .long 0x60500020 # Characteristics (section flags)
215
216 #
217 # The EFI application loader requires a relocation section
218 # because EFI applications must be relocatable. The .reloc
219 # offset & size fields are filled in by build.c.
220 #
221 .ascii ".reloc"
222 .byte 0
223 .byte 0
224 .long 0
225 .long 0
226 .long 0 # SizeOfRawData
227 .long 0 # PointerToRawData
228 .long 0 # PointerToRelocations
229 .long 0 # PointerToLineNumbers
230 .word 0 # NumberOfRelocations
231 .word 0 # NumberOfLineNumbers
232 .long 0x42100040 # Characteristics (section flags)
233
234 #
235 # The offset & size fields are filled in by build.c.
236 #
237 .ascii ".text"
238 .byte 0
239 .byte 0
240 .byte 0
241 .long 0
242 .long 0x0 # startup_{32,64}
243 .long 0 # Size of initialized data
244 # on disk
245 .long 0x0 # startup_{32,64}
246 .long 0 # PointerToRelocations
247 .long 0 # PointerToLineNumbers
248 .word 0 # NumberOfRelocations
249 .word 0 # NumberOfLineNumbers
250 .long 0x60500020 # Characteristics (section flags)
251
252 #
253 # The offset & size fields are filled in by build.c.
254 #
255 .ascii ".bss"
256 .byte 0
257 .byte 0
258 .byte 0
259 .byte 0
260 .long 0
261 .long 0x0
262 .long 0 # Size of initialized data
263 # on disk
264 .long 0x0
265 .long 0 # PointerToRelocations
266 .long 0 # PointerToLineNumbers
267 .word 0 # NumberOfRelocations
268 .word 0 # NumberOfLineNumbers
269 .long 0xc8000080 # Characteristics (section flags)
270
271#endif /* CONFIG_EFI_STUB */
272
273 # Kernel attributes; used by setup. This is part 1 of the
274 # header, from the old boot sector.
275
276 .section ".header", "a"
277 .globl sentinel
278sentinel: .byte 0xff, 0xff /* Used to detect broken loaders */
279
280 .globl hdr
281hdr:
282setup_sects: .byte 0 /* Filled in by build.c */
283root_flags: .word ROOT_RDONLY
284syssize: .long 0 /* Filled in by build.c */
285ram_size: .word 0 /* Obsolete */
286vid_mode: .word SVGA_MODE
287root_dev: .word 0 /* Filled in by build.c */
288boot_flag: .word 0xAA55
289
290 # offset 512, entry point
291
292 .globl _start
293_start:
294 # Explicitly enter this as bytes, or the assembler
295 # tries to generate a 3-byte jump here, which causes
296 # everything else to push off to the wrong offset.
297 .byte 0xeb # short (2-byte) jump
298 .byte start_of_setup-1f
2991:
300
301 # Part 2 of the header, from the old setup.S
302
303 .ascii "HdrS" # header signature
304 .word 0x020d # header version number (>= 0x0105)
305 # or else old loadlin-1.5 will fail)
306 .globl realmode_swtch
307realmode_swtch: .word 0, 0 # default_switch, SETUPSEG
308start_sys_seg: .word SYSSEG # obsolete and meaningless, but just
309 # in case something decided to "use" it
310 .word kernel_version-512 # pointing to kernel version string
311 # above section of header is compatible
312 # with loadlin-1.5 (header v1.5). Don't
313 # change it.
314
315type_of_loader: .byte 0 # 0 means ancient bootloader, newer
316 # bootloaders know to change this.
317 # See Documentation/x86/boot.txt for
318 # assigned ids
319
320# flags, unused bits must be zero (RFU) bit within loadflags
321loadflags:
322 .byte LOADED_HIGH # The kernel is to be loaded high
323
324setup_move_size: .word 0x8000 # size to move, when setup is not
325 # loaded at 0x90000. We will move setup
326 # to 0x90000 then just before jumping
327 # into the kernel. However, only the
328 # loader knows how much data behind
329 # us also needs to be loaded.
330
331code32_start: # here loaders can put a different
332 # start address for 32-bit code.
333 .long 0x100000 # 0x100000 = default for big kernel
334
335ramdisk_image: .long 0 # address of loaded ramdisk image
336 # Here the loader puts the 32-bit
337 # address where it loaded the image.
338 # This only will be read by the kernel.
339
340ramdisk_size: .long 0 # its size in bytes
341
342bootsect_kludge:
343 .long 0 # obsolete
344
345heap_end_ptr: .word _end+STACK_SIZE-512
346 # (Header version 0x0201 or later)
347 # space from here (exclusive) down to
348 # end of setup code can be used by setup
349 # for local heap purposes.
350
351ext_loader_ver:
352 .byte 0 # Extended boot loader version
353ext_loader_type:
354 .byte 0 # Extended boot loader type
355
356cmd_line_ptr: .long 0 # (Header version 0x0202 or later)
357 # If nonzero, a 32-bit pointer
358 # to the kernel command line.
359 # The command line should be
360 # located between the start of
361 # setup and the end of low
362 # memory (0xa0000), or it may
363 # get overwritten before it
364 # gets read. If this field is
365 # used, there is no longer
366 # anything magical about the
367 # 0x90000 segment; the setup
368 # can be located anywhere in
369 # low memory 0x10000 or higher.
370
371initrd_addr_max: .long 0x7fffffff
372 # (Header version 0x0203 or later)
373 # The highest safe address for
374 # the contents of an initrd
375 # The current kernel allows up to 4 GB,
376 # but leave it at 2 GB to avoid
377 # possible bootloader bugs.
378
379kernel_alignment: .long CONFIG_PHYSICAL_ALIGN #physical addr alignment
380 #required for protected mode
381 #kernel
382#ifdef CONFIG_RELOCATABLE
383relocatable_kernel: .byte 1
384#else
385relocatable_kernel: .byte 0
386#endif
387min_alignment: .byte MIN_KERNEL_ALIGN_LG2 # minimum alignment
388
389xloadflags:
390#ifdef CONFIG_X86_64
391# define XLF0 XLF_KERNEL_64 /* 64-bit kernel */
392#else
393# define XLF0 0
394#endif
395
396#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_X86_64)
397 /* kernel/boot_param/ramdisk could be loaded above 4g */
398# define XLF1 XLF_CAN_BE_LOADED_ABOVE_4G
399#else
400# define XLF1 0
401#endif
402
403#ifdef CONFIG_EFI_STUB
404# ifdef CONFIG_EFI_MIXED
405# define XLF23 (XLF_EFI_HANDOVER_32|XLF_EFI_HANDOVER_64)
406# else
407# ifdef CONFIG_X86_64
408# define XLF23 XLF_EFI_HANDOVER_64 /* 64-bit EFI handover ok */
409# else
410# define XLF23 XLF_EFI_HANDOVER_32 /* 32-bit EFI handover ok */
411# endif
412# endif
413#else
414# define XLF23 0
415#endif
416
417#if defined(CONFIG_X86_64) && defined(CONFIG_EFI) && defined(CONFIG_KEXEC_CORE)
418# define XLF4 XLF_EFI_KEXEC
419#else
420# define XLF4 0
421#endif
422
423 .word XLF0 | XLF1 | XLF23 | XLF4
424
425cmdline_size: .long COMMAND_LINE_SIZE-1 #length of the command line,
426 #added with boot protocol
427 #version 2.06
428
429hardware_subarch: .long 0 # subarchitecture, added with 2.07
430 # default to 0 for normal x86 PC
431
432hardware_subarch_data: .quad 0
433
434payload_offset: .long ZO_input_data
435payload_length: .long ZO_z_input_len
436
437setup_data: .quad 0 # 64-bit physical pointer to
438 # single linked list of
439 # struct setup_data
440
441pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr
442
443#define ZO_INIT_SIZE (ZO__end - ZO_startup_32 + ZO_z_extract_offset)
444#define VO_INIT_SIZE (VO__end - VO__text)
445#if ZO_INIT_SIZE > VO_INIT_SIZE
446#define INIT_SIZE ZO_INIT_SIZE
447#else
448#define INIT_SIZE VO_INIT_SIZE
449#endif
450init_size: .long INIT_SIZE # kernel initialization size
451handover_offset: .long 0 # Filled in by build.c
452
453# End of setup header #####################################################
454
455 .section ".entrytext", "ax"
456start_of_setup:
457# Force %es = %ds
458 movw %ds, %ax
459 movw %ax, %es
460 cld
461
462# Apparently some ancient versions of LILO invoked the kernel with %ss != %ds,
463# which happened to work by accident for the old code. Recalculate the stack
464# pointer if %ss is invalid. Otherwise leave it alone, LOADLIN sets up the
465# stack behind its own code, so we can't blindly put it directly past the heap.
466
467 movw %ss, %dx
468 cmpw %ax, %dx # %ds == %ss?
469 movw %sp, %dx
470 je 2f # -> assume %sp is reasonably set
471
472 # Invalid %ss, make up a new stack
473 movw $_end, %dx
474 testb $CAN_USE_HEAP, loadflags
475 jz 1f
476 movw heap_end_ptr, %dx
4771: addw $STACK_SIZE, %dx
478 jnc 2f
479 xorw %dx, %dx # Prevent wraparound
480
4812: # Now %dx should point to the end of our stack space
482 andw $~3, %dx # dword align (might as well...)
483 jnz 3f
484 movw $0xfffc, %dx # Make sure we're not zero
4853: movw %ax, %ss
486 movzwl %dx, %esp # Clear upper half of %esp
487 sti # Now we should have a working stack
488
489# We will have entered with %cs = %ds+0x20, normalize %cs so
490# it is on par with the other segments.
491 pushw %ds
492 pushw $6f
493 lretw
4946:
495
496# Check signature at end of setup
497 cmpl $0x5a5aaa55, setup_sig
498 jne setup_bad
499
500# Zero the bss
501 movw $__bss_start, %di
502 movw $_end+3, %cx
503 xorl %eax, %eax
504 subw %di, %cx
505 shrw $2, %cx
506 rep; stosl
507
508# Jump to C code (should not return)
509 calll main
510
511# Setup corrupt somehow...
512setup_bad:
513 movl $setup_corrupt, %eax
514 calll puts
515 # Fall through...
516
517 .globl die
518 .type die, @function
519die:
520 hlt
521 jmp die
522
523 .size die, .-die
524
525 .section ".initdata", "a"
526setup_corrupt:
527 .byte 7
528 .string "No setup signature found...\n"