Commit | Line | Data |
---|---|---|
62607313 PA |
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> | |
273b281f | 19 | #include <generated/utsrelease.h> |
62607313 PA |
20 | #include <asm/boot.h> |
21 | #include <asm/e820.h> | |
0341c14d | 22 | #include <asm/page_types.h> |
62607313 PA |
23 | #include <asm/setup.h> |
24 | #include "boot.h" | |
77d1a499 PA |
25 | #include "voffset.h" |
26 | #include "zoffset.h" | |
62607313 | 27 | |
62607313 | 28 | BOOTSEG = 0x07C0 /* original address of boot-sector */ |
5e47c478 | 29 | SYSSEG = 0x1000 /* historical load address >> 4 */ |
62607313 PA |
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 | |
47 | bootsect_start: | |
291f3632 MF |
48 | #ifdef CONFIG_EFI_STUB |
49 | # "MZ", MS-DOS header | |
50 | .byte 0x4d | |
51 | .byte 0x5a | |
52 | #endif | |
62607313 PA |
53 | |
54 | # Normalize the start address | |
55 | ljmp $BOOTSEG, $start2 | |
56 | ||
57 | start2: | |
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 | ||
68 | msg_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 | ||
77 | bs_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 | ||
291f3632 MF |
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 | ||
62607313 PA |
95 | .section ".bsdata", "a" |
96 | bugger_off_msg: | |
97 | .ascii "Direct booting from floppy is no longer supported.\r\n" | |
98 | .ascii "Please 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 | ||
291f3632 MF |
103 | #ifdef CONFIG_EFI_STUB |
104 | pe_header: | |
105 | .ascii "PE" | |
106 | .word 0 | |
107 | ||
108 | coff_header: | |
109 | #ifdef CONFIG_X86_32 | |
110 | .word 0x14c # i386 | |
111 | #else | |
112 | .word 0x8664 # x86-64 | |
113 | #endif | |
114 | .word 2 # 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 | ||
132 | optional_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 | ||
e31be363 | 150 | .long 0x0200 # BaseOfCode |
291f3632 MF |
151 | #ifdef CONFIG_X86_32 |
152 | .long 0 # data | |
153 | #endif | |
154 | ||
155 | extra_header_fields: | |
156 | #ifdef CONFIG_X86_32 | |
157 | .long 0 # ImageBase | |
158 | #else | |
159 | .quad 0 # ImageBase | |
160 | #endif | |
161 | .long 0x1000 # SectionAlignment | |
162 | .long 0x200 # 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 0x1 # 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 | |
202 | section_table: | |
203 | .ascii ".text" | |
204 | .byte 0 | |
205 | .byte 0 | |
206 | .byte 0 | |
207 | .long 0 | |
208 | .long 0x0 # startup_{32,64} | |
209 | .long 0 # Size of initialized data | |
210 | # on disk | |
211 | .long 0x0 # startup_{32,64} | |
212 | .long 0 # PointerToRelocations | |
213 | .long 0 # PointerToLineNumbers | |
214 | .word 0 # NumberOfRelocations | |
215 | .word 0 # NumberOfLineNumbers | |
216 | .long 0x60500020 # Characteristics (section flags) | |
217 | ||
218 | # | |
219 | # The EFI application loader requires a relocation section | |
2e064b1e JJ |
220 | # because EFI applications must be relocatable. But since |
221 | # we don't need the loader to fixup any relocs for us, we | |
222 | # just create an empty (zero-length) .reloc section header. | |
291f3632 MF |
223 | # |
224 | .ascii ".reloc" | |
225 | .byte 0 | |
226 | .byte 0 | |
2e064b1e JJ |
227 | .long 0 |
228 | .long 0 | |
229 | .long 0 # SizeOfRawData | |
230 | .long 0 # PointerToRawData | |
291f3632 MF |
231 | .long 0 # PointerToRelocations |
232 | .long 0 # PointerToLineNumbers | |
233 | .word 0 # NumberOfRelocations | |
234 | .word 0 # NumberOfLineNumbers | |
235 | .long 0x42100040 # Characteristics (section flags) | |
236 | #endif /* CONFIG_EFI_STUB */ | |
62607313 PA |
237 | |
238 | # Kernel attributes; used by setup. This is part 1 of the | |
239 | # header, from the old boot sector. | |
240 | ||
241 | .section ".header", "a" | |
242 | .globl hdr | |
243 | hdr: | |
5e47c478 | 244 | setup_sects: .byte 0 /* Filled in by build.c */ |
62607313 | 245 | root_flags: .word ROOT_RDONLY |
5e47c478 PA |
246 | syssize: .long 0 /* Filled in by build.c */ |
247 | ram_size: .word 0 /* Obsolete */ | |
62607313 | 248 | vid_mode: .word SVGA_MODE |
5e47c478 | 249 | root_dev: .word 0 /* Filled in by build.c */ |
62607313 PA |
250 | boot_flag: .word 0xAA55 |
251 | ||
252 | # offset 512, entry point | |
253 | ||
254 | .globl _start | |
255 | _start: | |
256 | # Explicitly enter this as bytes, or the assembler | |
257 | # tries to generate a 3-byte jump here, which causes | |
258 | # everything else to push off to the wrong offset. | |
259 | .byte 0xeb # short (2-byte) jump | |
260 | .byte start_of_setup-1f | |
261 | 1: | |
262 | ||
263 | # Part 2 of the header, from the old setup.S | |
264 | ||
265 | .ascii "HdrS" # header signature | |
37ba7ab5 | 266 | .word 0x020a # header version number (>= 0x0105) |
62607313 PA |
267 | # or else old loadlin-1.5 will fail) |
268 | .globl realmode_swtch | |
269 | realmode_swtch: .word 0, 0 # default_switch, SETUPSEG | |
5e47c478 PA |
270 | start_sys_seg: .word SYSSEG # obsolete and meaningless, but just |
271 | # in case something decided to "use" it | |
62607313 PA |
272 | .word kernel_version-512 # pointing to kernel version string |
273 | # above section of header is compatible | |
274 | # with loadlin-1.5 (header v1.5). Don't | |
275 | # change it. | |
276 | ||
5e47c478 PA |
277 | type_of_loader: .byte 0 # 0 means ancient bootloader, newer |
278 | # bootloaders know to change this. | |
395cf969 | 279 | # See Documentation/x86/boot.txt for |
62607313 PA |
280 | # assigned ids |
281 | ||
282 | # flags, unused bits must be zero (RFU) bit within loadflags | |
283 | loadflags: | |
284 | LOADED_HIGH = 1 # If set, the kernel is loaded high | |
285 | CAN_USE_HEAP = 0x80 # If set, the loader also has set | |
286 | # heap_end_ptr to tell how much | |
287 | # space behind setup.S can be used for | |
288 | # heap purposes. | |
289 | # Only the loader knows what is free | |
62607313 | 290 | .byte LOADED_HIGH |
62607313 PA |
291 | |
292 | setup_move_size: .word 0x8000 # size to move, when setup is not | |
293 | # loaded at 0x90000. We will move setup | |
294 | # to 0x90000 then just before jumping | |
295 | # into the kernel. However, only the | |
296 | # loader knows how much data behind | |
297 | # us also needs to be loaded. | |
298 | ||
299 | code32_start: # here loaders can put a different | |
300 | # start address for 32-bit code. | |
62607313 | 301 | .long 0x100000 # 0x100000 = default for big kernel |
62607313 PA |
302 | |
303 | ramdisk_image: .long 0 # address of loaded ramdisk image | |
304 | # Here the loader puts the 32-bit | |
305 | # address where it loaded the image. | |
306 | # This only will be read by the kernel. | |
307 | ||
308 | ramdisk_size: .long 0 # its size in bytes | |
309 | ||
310 | bootsect_kludge: | |
311 | .long 0 # obsolete | |
312 | ||
6b6815c6 PA |
313 | heap_end_ptr: .word _end+STACK_SIZE-512 |
314 | # (Header version 0x0201 or later) | |
62607313 PA |
315 | # space from here (exclusive) down to |
316 | # end of setup code can be used by setup | |
317 | # for local heap purposes. | |
318 | ||
5031296c PA |
319 | ext_loader_ver: |
320 | .byte 0 # Extended boot loader version | |
321 | ext_loader_type: | |
322 | .byte 0 # Extended boot loader type | |
323 | ||
62607313 PA |
324 | cmd_line_ptr: .long 0 # (Header version 0x0202 or later) |
325 | # If nonzero, a 32-bit pointer | |
326 | # to the kernel command line. | |
327 | # The command line should be | |
328 | # located between the start of | |
329 | # setup and the end of low | |
330 | # memory (0xa0000), or it may | |
331 | # get overwritten before it | |
332 | # gets read. If this field is | |
333 | # used, there is no longer | |
334 | # anything magical about the | |
335 | # 0x90000 segment; the setup | |
336 | # can be located anywhere in | |
337 | # low memory 0x10000 or higher. | |
338 | ||
cf8fa920 | 339 | ramdisk_max: .long 0x7fffffff |
62607313 PA |
340 | # (Header version 0x0203 or later) |
341 | # The highest safe address for | |
342 | # the contents of an initrd | |
cf8fa920 PA |
343 | # The current kernel allows up to 4 GB, |
344 | # but leave it at 2 GB to avoid | |
345 | # possible bootloader bugs. | |
62607313 PA |
346 | |
347 | kernel_alignment: .long CONFIG_PHYSICAL_ALIGN #physical addr alignment | |
348 | #required for protected mode | |
349 | #kernel | |
350 | #ifdef CONFIG_RELOCATABLE | |
351 | relocatable_kernel: .byte 1 | |
352 | #else | |
353 | relocatable_kernel: .byte 0 | |
354 | #endif | |
37ba7ab5 | 355 | min_alignment: .byte MIN_KERNEL_ALIGN_LG2 # minimum alignment |
62607313 PA |
356 | pad3: .word 0 |
357 | ||
358 | cmdline_size: .long COMMAND_LINE_SIZE-1 #length of the command line, | |
359 | #added with boot protocol | |
360 | #version 2.06 | |
361 | ||
a24e7851 RR |
362 | hardware_subarch: .long 0 # subarchitecture, added with 2.07 |
363 | # default to 0 for normal x86 PC | |
364 | ||
365 | hardware_subarch_data: .quad 0 | |
366 | ||
77d1a499 PA |
367 | payload_offset: .long ZO_input_data |
368 | payload_length: .long ZO_z_input_len | |
099e1377 | 369 | |
8b664aa6 HY |
370 | setup_data: .quad 0 # 64-bit physical pointer to |
371 | # single linked list of | |
372 | # struct setup_data | |
373 | ||
37ba7ab5 PA |
374 | pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr |
375 | ||
c6ac4c18 | 376 | #define ZO_INIT_SIZE (ZO__end - ZO_startup_32 + ZO_z_extract_offset) |
37ba7ab5 PA |
377 | #define VO_INIT_SIZE (VO__end - VO__text) |
378 | #if ZO_INIT_SIZE > VO_INIT_SIZE | |
379 | #define INIT_SIZE ZO_INIT_SIZE | |
380 | #else | |
381 | #define INIT_SIZE VO_INIT_SIZE | |
382 | #endif | |
383 | init_size: .long INIT_SIZE # kernel initialization size | |
384 | ||
62607313 PA |
385 | # End of setup header ##################################################### |
386 | ||
7a734e7d | 387 | .section ".entrytext", "ax" |
62607313 PA |
388 | start_of_setup: |
389 | #ifdef SAFE_RESET_DISK_CONTROLLER | |
390 | # Reset the disk controller. | |
391 | movw $0x0000, %ax # Reset disk controller | |
392 | movb $0x80, %dl # All disks | |
393 | int $0x13 | |
394 | #endif | |
395 | ||
62607313 PA |
396 | # Force %es = %ds |
397 | movw %ds, %ax | |
398 | movw %ax, %es | |
399 | cld | |
400 | ||
16252da6 JR |
401 | # Apparently some ancient versions of LILO invoked the kernel with %ss != %ds, |
402 | # which happened to work by accident for the old code. Recalculate the stack | |
403 | # pointer if %ss is invalid. Otherwise leave it alone, LOADLIN sets up the | |
404 | # stack behind its own code, so we can't blindly put it directly past the heap. | |
6b6815c6 | 405 | |
6b6815c6 PA |
406 | movw %ss, %dx |
407 | cmpw %ax, %dx # %ds == %ss? | |
408 | movw %sp, %dx | |
16252da6 JR |
409 | je 2f # -> assume %sp is reasonably set |
410 | ||
411 | # Invalid %ss, make up a new stack | |
412 | movw $_end, %dx | |
413 | testb $CAN_USE_HEAP, loadflags | |
414 | jz 1f | |
415 | movw heap_end_ptr, %dx | |
416 | 1: addw $STACK_SIZE, %dx | |
417 | jnc 2f | |
418 | xorw %dx, %dx # Prevent wraparound | |
6b6815c6 | 419 | |
16252da6 | 420 | 2: # Now %dx should point to the end of our stack space |
6b6815c6 PA |
421 | andw $~3, %dx # dword align (might as well...) |
422 | jnz 3f | |
423 | movw $0xfffc, %dx # Make sure we're not zero | |
16252da6 | 424 | 3: movw %ax, %ss |
6b6815c6 PA |
425 | movzwl %dx, %esp # Clear upper half of %esp |
426 | sti # Now we should have a working stack | |
427 | ||
428 | # We will have entered with %cs = %ds+0x20, normalize %cs so | |
429 | # it is on par with the other segments. | |
430 | pushw %ds | |
431 | pushw $6f | |
432 | lretw | |
433 | 6: | |
62607313 PA |
434 | |
435 | # Check signature at end of setup | |
436 | cmpl $0x5a5aaa55, setup_sig | |
437 | jne setup_bad | |
438 | ||
439 | # Zero the bss | |
440 | movw $__bss_start, %di | |
441 | movw $_end+3, %cx | |
442 | xorl %eax, %eax | |
443 | subw %di, %cx | |
444 | shrw $2, %cx | |
445 | rep; stosl | |
446 | ||
447 | # Jump to C code (should not return) | |
448 | calll main | |
449 | ||
450 | # Setup corrupt somehow... | |
451 | setup_bad: | |
452 | movl $setup_corrupt, %eax | |
453 | calll puts | |
454 | # Fall through... | |
455 | ||
456 | .globl die | |
457 | .type die, @function | |
458 | die: | |
459 | hlt | |
460 | jmp die | |
461 | ||
bbc15f46 | 462 | .size die, .-die |
62607313 PA |
463 | |
464 | .section ".initdata", "a" | |
465 | setup_corrupt: | |
466 | .byte 7 | |
8b608d2f | 467 | .string "No setup signature found...\n" |
291f3632 MF |
468 | |
469 | .data | |
470 | dummy: .long 0 |