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Commit | Line | Data |
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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | /* |
3 | * linux/boot/head.S | |
4 | * | |
5 | * Copyright (C) 1991, 1992, 1993 Linus Torvalds | |
1da177e4 LT |
6 | */ |
7 | ||
8 | /* | |
9 | * head.S contains the 32-bit startup code. | |
10 | * | |
11 | * NOTE!!! Startup happens at absolute address 0x00001000, which is also where | |
12 | * the page directory will exist. The startup code will be overwritten by | |
13 | * the page directory. [According to comments etc elsewhere on a compressed | |
14 | * kernel it will end up at 0x1000 + 1Mb I hope so as I assume this. - AC] | |
15 | * | |
16 | * Page 0 is deliberately kept safe, since System Management Mode code in | |
17 | * laptops may need to access the BIOS data stored there. This is also | |
18 | * useful for future device drivers that either access the BIOS via VM86 | |
19 | * mode. | |
20 | */ | |
21 | ||
22 | /* | |
f4549448 | 23 | * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996 |
1da177e4 | 24 | */ |
b40d68d5 PA |
25 | .code32 |
26 | .text | |
1da177e4 | 27 | |
1dc818c1 | 28 | #include <linux/init.h> |
1da177e4 LT |
29 | #include <linux/linkage.h> |
30 | #include <asm/segment.h> | |
7c539764 | 31 | #include <asm/boot.h> |
1ab60e0f | 32 | #include <asm/msr.h> |
e83e31f4 | 33 | #include <asm/processor-flags.h> |
bd53147d | 34 | #include <asm/asm-offsets.h> |
fb148d83 | 35 | #include <asm/bootparam.h> |
1da177e4 | 36 | |
6d92bc9d L |
37 | /* |
38 | * Locally defined symbols should be marked hidden: | |
39 | */ | |
40 | .hidden _bss | |
41 | .hidden _ebss | |
42 | .hidden _got | |
43 | .hidden _egot | |
44 | ||
1dc818c1 | 45 | __HEAD |
1da177e4 | 46 | .code32 |
2d4eeecb | 47 | ENTRY(startup_32) |
8ee2f2df YL |
48 | /* |
49 | * 32bit entry is 0 and it is ABI so immutable! | |
50 | * If we come here directly from a bootloader, | |
51 | * kernel(text+data+bss+brk) ramdisk, zero_page, command line | |
52 | * all need to be under the 4G limit. | |
53 | */ | |
1da177e4 | 54 | cld |
b40d68d5 PA |
55 | /* |
56 | * Test KEEP_SEGMENTS flag to see if the bootloader is asking | |
57 | * us to not reload segments | |
58 | */ | |
fb148d83 | 59 | testb $KEEP_SEGMENTS, BP_loadflags(%esi) |
bd53147d EB |
60 | jnz 1f |
61 | ||
1da177e4 | 62 | cli |
2dead15f | 63 | movl $(__BOOT_DS), %eax |
1ab60e0f VG |
64 | movl %eax, %ds |
65 | movl %eax, %es | |
66 | movl %eax, %ss | |
bd53147d | 67 | 1: |
1ab60e0f | 68 | |
b40d68d5 PA |
69 | /* |
70 | * Calculate the delta between where we were compiled to run | |
1ab60e0f VG |
71 | * at and where we were actually loaded at. This can only be done |
72 | * with a short local call on x86. Nothing else will tell us what | |
73 | * address we are running at. The reserved chunk of the real-mode | |
85414b69 PA |
74 | * data at 0x1e4 (defined as a scratch field) are used as the stack |
75 | * for this calculation. Only 4 bytes are needed. | |
1ab60e0f | 76 | */ |
bd2a3698 | 77 | leal (BP_scratch+4)(%esi), %esp |
1ab60e0f VG |
78 | call 1f |
79 | 1: popl %ebp | |
80 | subl $1b, %ebp | |
81 | ||
a4831e08 | 82 | /* setup a stack and make sure cpu supports long mode. */ |
7c539764 | 83 | movl $boot_stack_end, %eax |
a4831e08 VG |
84 | addl %ebp, %eax |
85 | movl %eax, %esp | |
86 | ||
87 | call verify_cpu | |
88 | testl %eax, %eax | |
89 | jnz no_longmode | |
90 | ||
b40d68d5 PA |
91 | /* |
92 | * Compute the delta between where we were compiled to run at | |
1ab60e0f | 93 | * and where the code will actually run at. |
b40d68d5 PA |
94 | * |
95 | * %ebp contains the address we are loaded at by the boot loader and %ebx | |
1ab60e0f VG |
96 | * contains the address where we should move the kernel image temporarily |
97 | * for safe in-place decompression. | |
98 | */ | |
99 | ||
100 | #ifdef CONFIG_RELOCATABLE | |
101 | movl %ebp, %ebx | |
37ba7ab5 PA |
102 | movl BP_kernel_alignment(%esi), %eax |
103 | decl %eax | |
104 | addl %eax, %ebx | |
105 | notl %eax | |
106 | andl %eax, %ebx | |
8ab3820f KC |
107 | cmpl $LOAD_PHYSICAL_ADDR, %ebx |
108 | jge 1f | |
1ab60e0f | 109 | #endif |
8ab3820f KC |
110 | movl $LOAD_PHYSICAL_ADDR, %ebx |
111 | 1: | |
1ab60e0f | 112 | |
02a884c0 | 113 | /* Target address to relocate to for decompression */ |
974f221c YL |
114 | movl BP_init_size(%esi), %eax |
115 | subl $_end, %eax | |
116 | addl %eax, %ebx | |
1da177e4 LT |
117 | |
118 | /* | |
1ab60e0f | 119 | * Prepare for entering 64 bit mode |
1da177e4 | 120 | */ |
1ab60e0f VG |
121 | |
122 | /* Load new GDT with the 64bit segments using 32bit descriptor */ | |
064025f7 | 123 | addl %ebp, gdt+2(%ebp) |
1ab60e0f VG |
124 | lgdt gdt(%ebp) |
125 | ||
126 | /* Enable PAE mode */ | |
108d3f44 MF |
127 | movl %cr4, %eax |
128 | orl $X86_CR4_PAE, %eax | |
1ab60e0f VG |
129 | movl %eax, %cr4 |
130 | ||
131 | /* | |
132 | * Build early 4G boot pagetable | |
133 | */ | |
b40d68d5 | 134 | /* Initialize Page tables to 0 */ |
1ab60e0f VG |
135 | leal pgtable(%ebx), %edi |
136 | xorl %eax, %eax | |
3a94707d | 137 | movl $(BOOT_INIT_PGT_SIZE/4), %ecx |
1ab60e0f VG |
138 | rep stosl |
139 | ||
140 | /* Build Level 4 */ | |
141 | leal pgtable + 0(%ebx), %edi | |
142 | leal 0x1007 (%edi), %eax | |
143 | movl %eax, 0(%edi) | |
144 | ||
145 | /* Build Level 3 */ | |
146 | leal pgtable + 0x1000(%ebx), %edi | |
147 | leal 0x1007(%edi), %eax | |
148 | movl $4, %ecx | |
149 | 1: movl %eax, 0x00(%edi) | |
150 | addl $0x00001000, %eax | |
151 | addl $8, %edi | |
152 | decl %ecx | |
153 | jnz 1b | |
154 | ||
155 | /* Build Level 2 */ | |
156 | leal pgtable + 0x2000(%ebx), %edi | |
157 | movl $0x00000183, %eax | |
158 | movl $2048, %ecx | |
159 | 1: movl %eax, 0(%edi) | |
160 | addl $0x00200000, %eax | |
161 | addl $8, %edi | |
162 | decl %ecx | |
163 | jnz 1b | |
164 | ||
165 | /* Enable the boot page tables */ | |
166 | leal pgtable(%ebx), %eax | |
167 | movl %eax, %cr3 | |
168 | ||
169 | /* Enable Long mode in EFER (Extended Feature Enable Register) */ | |
170 | movl $MSR_EFER, %ecx | |
171 | rdmsr | |
172 | btsl $_EFER_LME, %eax | |
173 | wrmsr | |
174 | ||
d3c433bf YL |
175 | /* After gdt is loaded */ |
176 | xorl %eax, %eax | |
177 | lldt %ax | |
40e4f2d1 | 178 | movl $__BOOT_TSS, %eax |
d3c433bf YL |
179 | ltr %ax |
180 | ||
b40d68d5 PA |
181 | /* |
182 | * Setup for the jump to 64bit mode | |
1ab60e0f VG |
183 | * |
184 | * When the jump is performend we will be in long mode but | |
185 | * in 32bit compatibility mode with EFER.LME = 1, CS.L = 0, CS.D = 1 | |
186 | * (and in turn EFER.LMA = 1). To jump into 64bit mode we use | |
187 | * the new gdt/idt that has __KERNEL_CS with CS.L = 1. | |
188 | * We place all of the values on our mini stack so lret can | |
189 | * used to perform that far jump. | |
190 | */ | |
191 | pushl $__KERNEL_CS | |
192 | leal startup_64(%ebp), %eax | |
b8ff87a6 MF |
193 | #ifdef CONFIG_EFI_MIXED |
194 | movl efi32_config(%ebp), %ebx | |
195 | cmp $0, %ebx | |
196 | jz 1f | |
197 | leal handover_entry(%ebp), %eax | |
198 | 1: | |
199 | #endif | |
1ab60e0f VG |
200 | pushl %eax |
201 | ||
202 | /* Enter paged protected Mode, activating Long Mode */ | |
e83e31f4 | 203 | movl $(X86_CR0_PG | X86_CR0_PE), %eax /* Enable Paging and Protected mode */ |
1ab60e0f VG |
204 | movl %eax, %cr0 |
205 | ||
206 | /* Jump from 32bit compatibility mode into 64bit mode. */ | |
207 | lret | |
2d4eeecb | 208 | ENDPROC(startup_32) |
1ab60e0f | 209 | |
b8ff87a6 MF |
210 | #ifdef CONFIG_EFI_MIXED |
211 | .org 0x190 | |
212 | ENTRY(efi32_stub_entry) | |
213 | add $0x4, %esp /* Discard return address */ | |
214 | popl %ecx | |
215 | popl %edx | |
216 | popl %esi | |
217 | ||
218 | leal (BP_scratch+4)(%esi), %esp | |
219 | call 1f | |
220 | 1: pop %ebp | |
221 | subl $1b, %ebp | |
222 | ||
223 | movl %ecx, efi32_config(%ebp) | |
224 | movl %edx, efi32_config+8(%ebp) | |
225 | sgdtl efi32_boot_gdt(%ebp) | |
226 | ||
227 | leal efi32_config(%ebp), %eax | |
228 | movl %eax, efi_config(%ebp) | |
229 | ||
230 | jmp startup_32 | |
231 | ENDPROC(efi32_stub_entry) | |
232 | #endif | |
233 | ||
1ab60e0f | 234 | .code64 |
a4831e08 | 235 | .org 0x200 |
1ab60e0f | 236 | ENTRY(startup_64) |
b40d68d5 | 237 | /* |
8ee2f2df | 238 | * 64bit entry is 0x200 and it is ABI so immutable! |
b40d68d5 | 239 | * We come here either from startup_32 or directly from a |
8ee2f2df YL |
240 | * 64bit bootloader. |
241 | * If we come here from a bootloader, kernel(text+data+bss+brk), | |
242 | * ramdisk, zero_page, command line could be above 4G. | |
243 | * We depend on an identity mapped page table being provided | |
244 | * that maps our entire kernel(text+data+bss+brk), zero page | |
245 | * and command line. | |
1ab60e0f VG |
246 | */ |
247 | ||
248 | /* Setup data segments. */ | |
249 | xorl %eax, %eax | |
250 | movl %eax, %ds | |
251 | movl %eax, %es | |
252 | movl %eax, %ss | |
08da5a2c ZA |
253 | movl %eax, %fs |
254 | movl %eax, %gs | |
1ab60e0f | 255 | |
b40d68d5 PA |
256 | /* |
257 | * Compute the decompressed kernel start address. It is where | |
1ab60e0f VG |
258 | * we were loaded at aligned to a 2M boundary. %rbp contains the |
259 | * decompressed kernel start address. | |
260 | * | |
261 | * If it is a relocatable kernel then decompress and run the kernel | |
262 | * from load address aligned to 2MB addr, otherwise decompress and | |
40b387a8 | 263 | * run the kernel from LOAD_PHYSICAL_ADDR |
02a884c0 PA |
264 | * |
265 | * We cannot rely on the calculation done in 32-bit mode, since we | |
266 | * may have been invoked via the 64-bit entry point. | |
1ab60e0f VG |
267 | */ |
268 | ||
269 | /* Start with the delta to where the kernel will run at. */ | |
270 | #ifdef CONFIG_RELOCATABLE | |
271 | leaq startup_32(%rip) /* - $startup_32 */, %rbp | |
37ba7ab5 PA |
272 | movl BP_kernel_alignment(%rsi), %eax |
273 | decl %eax | |
274 | addq %rax, %rbp | |
275 | notq %rax | |
276 | andq %rax, %rbp | |
8ab3820f KC |
277 | cmpq $LOAD_PHYSICAL_ADDR, %rbp |
278 | jge 1f | |
1ab60e0f | 279 | #endif |
8ab3820f KC |
280 | movq $LOAD_PHYSICAL_ADDR, %rbp |
281 | 1: | |
1ab60e0f | 282 | |
02a884c0 | 283 | /* Target address to relocate to for decompression */ |
974f221c YL |
284 | movl BP_init_size(%rsi), %ebx |
285 | subl $_end, %ebx | |
286 | addq %rbp, %rbx | |
1ab60e0f | 287 | |
0a137736 PA |
288 | /* Set up the stack */ |
289 | leaq boot_stack_end(%rbx), %rsp | |
290 | ||
34bbb000 KS |
291 | #ifdef CONFIG_X86_5LEVEL |
292 | /* Check if 5-level paging has already enabled */ | |
293 | movq %cr4, %rax | |
294 | testl $X86_CR4_LA57, %eax | |
295 | jnz lvl5 | |
296 | ||
297 | /* | |
298 | * At this point we are in long mode with 4-level paging enabled, | |
299 | * but we want to enable 5-level paging. | |
300 | * | |
301 | * The problem is that we cannot do it directly. Setting LA57 in | |
302 | * long mode would trigger #GP. So we need to switch off long mode | |
303 | * first. | |
304 | * | |
305 | * NOTE: This is not going to work if bootloader put us above 4G | |
306 | * limit. | |
307 | * | |
308 | * The first step is go into compatibility mode. | |
309 | */ | |
310 | ||
311 | /* Clear additional page table */ | |
312 | leaq lvl5_pgtable(%rbx), %rdi | |
313 | xorq %rax, %rax | |
314 | movq $(PAGE_SIZE/8), %rcx | |
315 | rep stosq | |
316 | ||
317 | /* | |
318 | * Setup current CR3 as the first and only entry in a new top level | |
319 | * page table. | |
320 | */ | |
321 | movq %cr3, %rdi | |
322 | leaq 0x7 (%rdi), %rax | |
323 | movq %rax, lvl5_pgtable(%rbx) | |
324 | ||
325 | /* Switch to compatibility mode (CS.L = 0 CS.D = 1) via far return */ | |
326 | pushq $__KERNEL32_CS | |
327 | leaq compatible_mode(%rip), %rax | |
328 | pushq %rax | |
329 | lretq | |
330 | lvl5: | |
331 | #endif | |
332 | ||
0a137736 PA |
333 | /* Zero EFLAGS */ |
334 | pushq $0 | |
335 | popfq | |
336 | ||
b40d68d5 PA |
337 | /* |
338 | * Copy the compressed kernel to the end of our buffer | |
1ab60e0f VG |
339 | * where decompression in place becomes safe. |
340 | */ | |
36d3793c PA |
341 | pushq %rsi |
342 | leaq (_bss-8)(%rip), %rsi | |
343 | leaq (_bss-8)(%rbx), %rdi | |
5b11f1ce | 344 | movq $_bss /* - $startup_32 */, %rcx |
36d3793c PA |
345 | shrq $3, %rcx |
346 | std | |
347 | rep movsq | |
348 | cld | |
349 | popq %rsi | |
1ab60e0f VG |
350 | |
351 | /* | |
352 | * Jump to the relocated address. | |
353 | */ | |
354 | leaq relocated(%rbx), %rax | |
355 | jmp *%rax | |
356 | ||
b8ff87a6 | 357 | #ifdef CONFIG_EFI_STUB |
9e085cef JS |
358 | |
359 | /* The entry point for the PE/COFF executable is efi_pe_entry. */ | |
360 | ENTRY(efi_pe_entry) | |
361 | movq %rcx, efi64_config(%rip) /* Handle */ | |
362 | movq %rdx, efi64_config+8(%rip) /* EFI System table pointer */ | |
363 | ||
364 | leaq efi64_config(%rip), %rax | |
365 | movq %rax, efi_config(%rip) | |
366 | ||
367 | call 1f | |
368 | 1: popq %rbp | |
369 | subq $1b, %rbp | |
370 | ||
371 | /* | |
372 | * Relocate efi_config->call(). | |
373 | */ | |
374 | addq %rbp, efi64_config+40(%rip) | |
375 | ||
376 | movq %rax, %rdi | |
377 | call make_boot_params | |
378 | cmpq $0,%rax | |
379 | je fail | |
380 | mov %rax, %rsi | |
381 | leaq startup_32(%rip), %rax | |
382 | movl %eax, BP_code32_start(%rsi) | |
383 | jmp 2f /* Skip the relocation */ | |
384 | ||
385 | handover_entry: | |
386 | call 1f | |
387 | 1: popq %rbp | |
388 | subq $1b, %rbp | |
389 | ||
390 | /* | |
391 | * Relocate efi_config->call(). | |
392 | */ | |
393 | movq efi_config(%rip), %rax | |
394 | addq %rbp, 40(%rax) | |
395 | 2: | |
396 | movq efi_config(%rip), %rdi | |
397 | call efi_main | |
398 | movq %rax,%rsi | |
399 | cmpq $0,%rax | |
400 | jne 2f | |
401 | fail: | |
402 | /* EFI init failed, so hang. */ | |
403 | hlt | |
404 | jmp fail | |
405 | 2: | |
406 | movl BP_code32_start(%esi), %eax | |
407 | leaq startup_64(%rax), %rax | |
408 | jmp *%rax | |
409 | ENDPROC(efi_pe_entry) | |
410 | ||
b8ff87a6 MF |
411 | .org 0x390 |
412 | ENTRY(efi64_stub_entry) | |
413 | movq %rdi, efi64_config(%rip) /* Handle */ | |
414 | movq %rsi, efi64_config+8(%rip) /* EFI System table pointer */ | |
415 | ||
416 | leaq efi64_config(%rip), %rax | |
417 | movq %rax, efi_config(%rip) | |
418 | ||
419 | movq %rdx, %rsi | |
420 | jmp handover_entry | |
421 | ENDPROC(efi64_stub_entry) | |
422 | #endif | |
423 | ||
b40d68d5 | 424 | .text |
1ab60e0f VG |
425 | relocated: |
426 | ||
1da177e4 | 427 | /* |
0a137736 | 428 | * Clear BSS (stack is currently empty) |
1da177e4 | 429 | */ |
36d3793c PA |
430 | xorl %eax, %eax |
431 | leaq _bss(%rip), %rdi | |
432 | leaq _ebss(%rip), %rcx | |
1ab60e0f | 433 | subq %rdi, %rcx |
36d3793c PA |
434 | shrq $3, %rcx |
435 | rep stosq | |
1ab60e0f | 436 | |
f3670394 LT |
437 | /* |
438 | * Adjust our own GOT | |
439 | */ | |
440 | leaq _got(%rip), %rdx | |
441 | leaq _egot(%rip), %rcx | |
442 | 1: | |
443 | cmpq %rcx, %rdx | |
444 | jae 2f | |
445 | addq %rbx, (%rdx) | |
446 | addq $8, %rdx | |
447 | jmp 1b | |
448 | 2: | |
449 | ||
1da177e4 | 450 | /* |
c0402881 | 451 | * Do the extraction, and jump to the new kernel.. |
1da177e4 | 452 | */ |
02a884c0 PA |
453 | pushq %rsi /* Save the real mode argument */ |
454 | movq %rsi, %rdi /* real mode address */ | |
455 | leaq boot_heap(%rip), %rsi /* malloc area for uncompression */ | |
456 | leaq input_data(%rip), %rdx /* input_data */ | |
457 | movl $z_input_len, %ecx /* input_len */ | |
458 | movq %rbp, %r8 /* output target address */ | |
e6023367 | 459 | movq $z_output_len, %r9 /* decompressed length, end of relocs */ |
c0402881 | 460 | call extract_kernel /* returns kernel location in %rax */ |
1ab60e0f | 461 | popq %rsi |
1da177e4 | 462 | |
1da177e4 | 463 | /* |
1ab60e0f | 464 | * Jump to the decompressed kernel. |
1da177e4 | 465 | */ |
8ab3820f | 466 | jmp *%rax |
1da177e4 | 467 | |
187a8a73 | 468 | .code32 |
34bbb000 KS |
469 | #ifdef CONFIG_X86_5LEVEL |
470 | compatible_mode: | |
471 | /* Setup data and stack segments */ | |
472 | movl $__KERNEL_DS, %eax | |
473 | movl %eax, %ds | |
474 | movl %eax, %ss | |
475 | ||
476 | /* Disable paging */ | |
477 | movl %cr0, %eax | |
478 | btrl $X86_CR0_PG_BIT, %eax | |
479 | movl %eax, %cr0 | |
480 | ||
481 | /* Point CR3 to 5-level paging */ | |
482 | leal lvl5_pgtable(%ebx), %eax | |
483 | movl %eax, %cr3 | |
484 | ||
485 | /* Enable PAE and LA57 mode */ | |
486 | movl %cr4, %eax | |
487 | orl $(X86_CR4_PAE | X86_CR4_LA57), %eax | |
488 | movl %eax, %cr4 | |
489 | ||
490 | /* Calculate address we are running at */ | |
491 | call 1f | |
492 | 1: popl %edi | |
493 | subl $1b, %edi | |
494 | ||
495 | /* Prepare stack for far return to Long Mode */ | |
496 | pushl $__KERNEL_CS | |
497 | leal lvl5(%edi), %eax | |
498 | push %eax | |
499 | ||
500 | /* Enable paging back */ | |
501 | movl $(X86_CR0_PG | X86_CR0_PE), %eax | |
502 | movl %eax, %cr0 | |
503 | ||
504 | lret | |
505 | #endif | |
506 | ||
187a8a73 YL |
507 | no_longmode: |
508 | /* This isn't an x86-64 CPU so hang */ | |
509 | 1: | |
510 | hlt | |
511 | jmp 1b | |
512 | ||
513 | #include "../../kernel/verify_cpu.S" | |
514 | ||
1ab60e0f VG |
515 | .data |
516 | gdt: | |
517 | .word gdt_end - gdt | |
518 | .long gdt | |
519 | .word 0 | |
34bbb000 | 520 | .quad 0x00cf9a000000ffff /* __KERNEL32_CS */ |
1ab60e0f VG |
521 | .quad 0x00af9a000000ffff /* __KERNEL_CS */ |
522 | .quad 0x00cf92000000ffff /* __KERNEL_DS */ | |
08da5a2c ZA |
523 | .quad 0x0080890000000000 /* TS descriptor */ |
524 | .quad 0x0000000000000000 /* TS continued */ | |
1ab60e0f | 525 | gdt_end: |
7c539764 | 526 | |
3db4cafd | 527 | #ifdef CONFIG_EFI_STUB |
54b52d87 MF |
528 | efi_config: |
529 | .quad 0 | |
530 | ||
b8ff87a6 MF |
531 | #ifdef CONFIG_EFI_MIXED |
532 | .global efi32_config | |
533 | efi32_config: | |
a2cd2f3f | 534 | .fill 5,8,0 |
b8ff87a6 MF |
535 | .quad efi64_thunk |
536 | .byte 0 | |
537 | #endif | |
538 | ||
54b52d87 MF |
539 | .global efi64_config |
540 | efi64_config: | |
a2cd2f3f | 541 | .fill 5,8,0 |
62fa6e69 | 542 | .quad efi_call |
54b52d87 | 543 | .byte 1 |
3db4cafd MF |
544 | #endif /* CONFIG_EFI_STUB */ |
545 | ||
b40d68d5 PA |
546 | /* |
547 | * Stack and heap for uncompression | |
548 | */ | |
549 | .bss | |
550 | .balign 4 | |
7c539764 AH |
551 | boot_heap: |
552 | .fill BOOT_HEAP_SIZE, 1, 0 | |
553 | boot_stack: | |
554 | .fill BOOT_STACK_SIZE, 1, 0 | |
555 | boot_stack_end: | |
5b11f1ce PA |
556 | |
557 | /* | |
558 | * Space for page tables (not in .bss so not zeroed) | |
559 | */ | |
560 | .section ".pgtable","a",@nobits | |
561 | .balign 4096 | |
562 | pgtable: | |
3a94707d | 563 | .fill BOOT_PGT_SIZE, 1, 0 |
34bbb000 KS |
564 | #ifdef CONFIG_X86_5LEVEL |
565 | lvl5_pgtable: | |
566 | .fill PAGE_SIZE, 1, 0 | |
567 | #endif |