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1/*
2 * linux/boot/head.S
3 *
4 * Copyright (C) 1991, 1992, 1993 Linus Torvalds
5 */
6
7/*
8 * head.S contains the 32-bit startup code.
9 *
10 * NOTE!!! Startup happens at absolute address 0x00001000, which is also where
11 * the page directory will exist. The startup code will be overwritten by
12 * the page directory. [According to comments etc elsewhere on a compressed
13 * kernel it will end up at 0x1000 + 1Mb I hope so as I assume this. - AC]
14 *
15 * Page 0 is deliberately kept safe, since System Management Mode code in
16 * laptops may need to access the BIOS data stored there. This is also
17 * useful for future device drivers that either access the BIOS via VM86
18 * mode.
19 */
20
21/*
22 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
23 */
24 .code32
25 .text
26
27#include <linux/init.h>
28#include <linux/linkage.h>
29#include <asm/segment.h>
30#include <asm/boot.h>
31#include <asm/msr.h>
32#include <asm/processor-flags.h>
33#include <asm/asm-offsets.h>
34
35 __HEAD
36 .code32
37ENTRY(startup_32)
38 /*
39 * 32bit entry is 0 and it is ABI so immutable!
40 * If we come here directly from a bootloader,
41 * kernel(text+data+bss+brk) ramdisk, zero_page, command line
42 * all need to be under the 4G limit.
43 */
44 cld
45 /*
46 * Test KEEP_SEGMENTS flag to see if the bootloader is asking
47 * us to not reload segments
48 */
49 testb $(1<<6), BP_loadflags(%esi)
50 jnz 1f
51
52 cli
53 movl $(__BOOT_DS), %eax
54 movl %eax, %ds
55 movl %eax, %es
56 movl %eax, %ss
571:
58
59/*
60 * Calculate the delta between where we were compiled to run
61 * at and where we were actually loaded at. This can only be done
62 * with a short local call on x86. Nothing else will tell us what
63 * address we are running at. The reserved chunk of the real-mode
64 * data at 0x1e4 (defined as a scratch field) are used as the stack
65 * for this calculation. Only 4 bytes are needed.
66 */
67 leal (BP_scratch+4)(%esi), %esp
68 call 1f
691: popl %ebp
70 subl $1b, %ebp
71
72/* setup a stack and make sure cpu supports long mode. */
73 movl $boot_stack_end, %eax
74 addl %ebp, %eax
75 movl %eax, %esp
76
77 call verify_cpu
78 testl %eax, %eax
79 jnz no_longmode
80
81/*
82 * Compute the delta between where we were compiled to run at
83 * and where the code will actually run at.
84 *
85 * %ebp contains the address we are loaded at by the boot loader and %ebx
86 * contains the address where we should move the kernel image temporarily
87 * for safe in-place decompression.
88 */
89
90#ifdef CONFIG_RELOCATABLE
91 movl %ebp, %ebx
92 movl BP_kernel_alignment(%esi), %eax
93 decl %eax
94 addl %eax, %ebx
95 notl %eax
96 andl %eax, %ebx
97 cmpl $LOAD_PHYSICAL_ADDR, %ebx
98 jge 1f
99#endif
100 movl $LOAD_PHYSICAL_ADDR, %ebx
1011:
102
103 /* Target address to relocate to for decompression */
104 addl $z_extract_offset, %ebx
105
106/*
107 * Prepare for entering 64 bit mode
108 */
109
110 /* Load new GDT with the 64bit segments using 32bit descriptor */
111 leal gdt(%ebp), %eax
112 movl %eax, gdt+2(%ebp)
113 lgdt gdt(%ebp)
114
115 /* Enable PAE mode */
116 movl %cr4, %eax
117 orl $X86_CR4_PAE, %eax
118 movl %eax, %cr4
119
120 /*
121 * Build early 4G boot pagetable
122 */
123 /* Initialize Page tables to 0 */
124 leal pgtable(%ebx), %edi
125 xorl %eax, %eax
126 movl $((4096*6)/4), %ecx
127 rep stosl
128
129 /* Build Level 4 */
130 leal pgtable + 0(%ebx), %edi
131 leal 0x1007 (%edi), %eax
132 movl %eax, 0(%edi)
133
134 /* Build Level 3 */
135 leal pgtable + 0x1000(%ebx), %edi
136 leal 0x1007(%edi), %eax
137 movl $4, %ecx
1381: movl %eax, 0x00(%edi)
139 addl $0x00001000, %eax
140 addl $8, %edi
141 decl %ecx
142 jnz 1b
143
144 /* Build Level 2 */
145 leal pgtable + 0x2000(%ebx), %edi
146 movl $0x00000183, %eax
147 movl $2048, %ecx
1481: movl %eax, 0(%edi)
149 addl $0x00200000, %eax
150 addl $8, %edi
151 decl %ecx
152 jnz 1b
153
154 /* Enable the boot page tables */
155 leal pgtable(%ebx), %eax
156 movl %eax, %cr3
157
158 /* Enable Long mode in EFER (Extended Feature Enable Register) */
159 movl $MSR_EFER, %ecx
160 rdmsr
161 btsl $_EFER_LME, %eax
162 wrmsr
163
164 /* After gdt is loaded */
165 xorl %eax, %eax
166 lldt %ax
167 movl $0x20, %eax
168 ltr %ax
169
170 /*
171 * Setup for the jump to 64bit mode
172 *
173 * When the jump is performend we will be in long mode but
174 * in 32bit compatibility mode with EFER.LME = 1, CS.L = 0, CS.D = 1
175 * (and in turn EFER.LMA = 1). To jump into 64bit mode we use
176 * the new gdt/idt that has __KERNEL_CS with CS.L = 1.
177 * We place all of the values on our mini stack so lret can
178 * used to perform that far jump.
179 */
180 pushl $__KERNEL_CS
181 leal startup_64(%ebp), %eax
182#ifdef CONFIG_EFI_MIXED
183 movl efi32_config(%ebp), %ebx
184 cmp $0, %ebx
185 jz 1f
186 leal handover_entry(%ebp), %eax
1871:
188#endif
189 pushl %eax
190
191 /* Enter paged protected Mode, activating Long Mode */
192 movl $(X86_CR0_PG | X86_CR0_PE), %eax /* Enable Paging and Protected mode */
193 movl %eax, %cr0
194
195 /* Jump from 32bit compatibility mode into 64bit mode. */
196 lret
197ENDPROC(startup_32)
198
199#ifdef CONFIG_EFI_MIXED
200 .org 0x190
201ENTRY(efi32_stub_entry)
202 add $0x4, %esp /* Discard return address */
203 popl %ecx
204 popl %edx
205 popl %esi
206
207 leal (BP_scratch+4)(%esi), %esp
208 call 1f
2091: pop %ebp
210 subl $1b, %ebp
211
212 movl %ecx, efi32_config(%ebp)
213 movl %edx, efi32_config+8(%ebp)
214 sgdtl efi32_boot_gdt(%ebp)
215
216 leal efi32_config(%ebp), %eax
217 movl %eax, efi_config(%ebp)
218
219 jmp startup_32
220ENDPROC(efi32_stub_entry)
221#endif
222
223 .code64
224 .org 0x200
225ENTRY(startup_64)
226 /*
227 * 64bit entry is 0x200 and it is ABI so immutable!
228 * We come here either from startup_32 or directly from a
229 * 64bit bootloader.
230 * If we come here from a bootloader, kernel(text+data+bss+brk),
231 * ramdisk, zero_page, command line could be above 4G.
232 * We depend on an identity mapped page table being provided
233 * that maps our entire kernel(text+data+bss+brk), zero page
234 * and command line.
235 */
236#ifdef CONFIG_EFI_STUB
237 /*
238 * The entry point for the PE/COFF executable is efi_pe_entry, so
239 * only legacy boot loaders will execute this jmp.
240 */
241 jmp preferred_addr
242
243ENTRY(efi_pe_entry)
244 movq %rcx, efi64_config(%rip) /* Handle */
245 movq %rdx, efi64_config+8(%rip) /* EFI System table pointer */
246
247 leaq efi64_config(%rip), %rax
248 movq %rax, efi_config(%rip)
249
250 call 1f
2511: popq %rbp
252 subq $1b, %rbp
253
254 /*
255 * Relocate efi_config->call().
256 */
257 addq %rbp, efi64_config+88(%rip)
258
259 movq %rax, %rdi
260 call make_boot_params
261 cmpq $0,%rax
262 je fail
263 mov %rax, %rsi
264 leaq startup_32(%rip), %rax
265 movl %eax, BP_code32_start(%rsi)
266 jmp 2f /* Skip the relocation */
267
268handover_entry:
269 call 1f
2701: popq %rbp
271 subq $1b, %rbp
272
273 /*
274 * Relocate efi_config->call().
275 */
276 movq efi_config(%rip), %rax
277 addq %rbp, 88(%rax)
2782:
279 movq efi_config(%rip), %rdi
280 call efi_main
281 movq %rax,%rsi
282 cmpq $0,%rax
283 jne 2f
284fail:
285 /* EFI init failed, so hang. */
286 hlt
287 jmp fail
2882:
289 movl BP_code32_start(%esi), %eax
290 leaq preferred_addr(%rax), %rax
291 jmp *%rax
292
293preferred_addr:
294#endif
295
296 /* Setup data segments. */
297 xorl %eax, %eax
298 movl %eax, %ds
299 movl %eax, %es
300 movl %eax, %ss
301 movl %eax, %fs
302 movl %eax, %gs
303
304 /*
305 * Compute the decompressed kernel start address. It is where
306 * we were loaded at aligned to a 2M boundary. %rbp contains the
307 * decompressed kernel start address.
308 *
309 * If it is a relocatable kernel then decompress and run the kernel
310 * from load address aligned to 2MB addr, otherwise decompress and
311 * run the kernel from LOAD_PHYSICAL_ADDR
312 *
313 * We cannot rely on the calculation done in 32-bit mode, since we
314 * may have been invoked via the 64-bit entry point.
315 */
316
317 /* Start with the delta to where the kernel will run at. */
318#ifdef CONFIG_RELOCATABLE
319 leaq startup_32(%rip) /* - $startup_32 */, %rbp
320 movl BP_kernel_alignment(%rsi), %eax
321 decl %eax
322 addq %rax, %rbp
323 notq %rax
324 andq %rax, %rbp
325 cmpq $LOAD_PHYSICAL_ADDR, %rbp
326 jge 1f
327#endif
328 movq $LOAD_PHYSICAL_ADDR, %rbp
3291:
330
331 /* Target address to relocate to for decompression */
332 leaq z_extract_offset(%rbp), %rbx
333
334 /* Set up the stack */
335 leaq boot_stack_end(%rbx), %rsp
336
337 /* Zero EFLAGS */
338 pushq $0
339 popfq
340
341/*
342 * Copy the compressed kernel to the end of our buffer
343 * where decompression in place becomes safe.
344 */
345 pushq %rsi
346 leaq (_bss-8)(%rip), %rsi
347 leaq (_bss-8)(%rbx), %rdi
348 movq $_bss /* - $startup_32 */, %rcx
349 shrq $3, %rcx
350 std
351 rep movsq
352 cld
353 popq %rsi
354
355/*
356 * Jump to the relocated address.
357 */
358 leaq relocated(%rbx), %rax
359 jmp *%rax
360
361#ifdef CONFIG_EFI_STUB
362 .org 0x390
363ENTRY(efi64_stub_entry)
364 movq %rdi, efi64_config(%rip) /* Handle */
365 movq %rsi, efi64_config+8(%rip) /* EFI System table pointer */
366
367 leaq efi64_config(%rip), %rax
368 movq %rax, efi_config(%rip)
369
370 movq %rdx, %rsi
371 jmp handover_entry
372ENDPROC(efi64_stub_entry)
373#endif
374
375 .text
376relocated:
377
378/*
379 * Clear BSS (stack is currently empty)
380 */
381 xorl %eax, %eax
382 leaq _bss(%rip), %rdi
383 leaq _ebss(%rip), %rcx
384 subq %rdi, %rcx
385 shrq $3, %rcx
386 rep stosq
387
388/*
389 * Adjust our own GOT
390 */
391 leaq _got(%rip), %rdx
392 leaq _egot(%rip), %rcx
3931:
394 cmpq %rcx, %rdx
395 jae 2f
396 addq %rbx, (%rdx)
397 addq $8, %rdx
398 jmp 1b
3992:
400
401/*
402 * Do the decompression, and jump to the new kernel..
403 */
404 pushq %rsi /* Save the real mode argument */
405 movq %rsi, %rdi /* real mode address */
406 leaq boot_heap(%rip), %rsi /* malloc area for uncompression */
407 leaq input_data(%rip), %rdx /* input_data */
408 movl $z_input_len, %ecx /* input_len */
409 movq %rbp, %r8 /* output target address */
410 movq $z_output_len, %r9 /* decompressed length */
411 call decompress_kernel /* returns kernel location in %rax */
412 popq %rsi
413
414/*
415 * Jump to the decompressed kernel.
416 */
417 jmp *%rax
418
419 .code32
420no_longmode:
421 /* This isn't an x86-64 CPU so hang */
4221:
423 hlt
424 jmp 1b
425
426#include "../../kernel/verify_cpu.S"
427
428 .data
429gdt:
430 .word gdt_end - gdt
431 .long gdt
432 .word 0
433 .quad 0x0000000000000000 /* NULL descriptor */
434 .quad 0x00af9a000000ffff /* __KERNEL_CS */
435 .quad 0x00cf92000000ffff /* __KERNEL_DS */
436 .quad 0x0080890000000000 /* TS descriptor */
437 .quad 0x0000000000000000 /* TS continued */
438gdt_end:
439
440#ifdef CONFIG_EFI_STUB
441efi_config:
442 .quad 0
443
444#ifdef CONFIG_EFI_MIXED
445 .global efi32_config
446efi32_config:
447 .fill 11,8,0
448 .quad efi64_thunk
449 .byte 0
450#endif
451
452 .global efi64_config
453efi64_config:
454 .fill 11,8,0
455 .quad efi_call6
456 .byte 1
457#endif /* CONFIG_EFI_STUB */
458
459/*
460 * Stack and heap for uncompression
461 */
462 .bss
463 .balign 4
464boot_heap:
465 .fill BOOT_HEAP_SIZE, 1, 0
466boot_stack:
467 .fill BOOT_STACK_SIZE, 1, 0
468boot_stack_end:
469
470/*
471 * Space for page tables (not in .bss so not zeroed)
472 */
473 .section ".pgtable","a",@nobits
474 .balign 4096
475pgtable:
476 .fill 6*4096, 1, 0
1/*
2 * linux/boot/head.S
3 *
4 * Copyright (C) 1991, 1992, 1993 Linus Torvalds
5 */
6
7/*
8 * head.S contains the 32-bit startup code.
9 *
10 * NOTE!!! Startup happens at absolute address 0x00001000, which is also where
11 * the page directory will exist. The startup code will be overwritten by
12 * the page directory. [According to comments etc elsewhere on a compressed
13 * kernel it will end up at 0x1000 + 1Mb I hope so as I assume this. - AC]
14 *
15 * Page 0 is deliberately kept safe, since System Management Mode code in
16 * laptops may need to access the BIOS data stored there. This is also
17 * useful for future device drivers that either access the BIOS via VM86
18 * mode.
19 */
20
21/*
22 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
23 */
24 .code32
25 .text
26
27#include <linux/init.h>
28#include <linux/linkage.h>
29#include <asm/segment.h>
30#include <asm/pgtable_types.h>
31#include <asm/page_types.h>
32#include <asm/boot.h>
33#include <asm/msr.h>
34#include <asm/processor-flags.h>
35#include <asm/asm-offsets.h>
36
37 __HEAD
38 .code32
39ENTRY(startup_32)
40 cld
41 /*
42 * Test KEEP_SEGMENTS flag to see if the bootloader is asking
43 * us to not reload segments
44 */
45 testb $(1<<6), BP_loadflags(%esi)
46 jnz 1f
47
48 cli
49 movl $(__KERNEL_DS), %eax
50 movl %eax, %ds
51 movl %eax, %es
52 movl %eax, %ss
531:
54
55/*
56 * Calculate the delta between where we were compiled to run
57 * at and where we were actually loaded at. This can only be done
58 * with a short local call on x86. Nothing else will tell us what
59 * address we are running at. The reserved chunk of the real-mode
60 * data at 0x1e4 (defined as a scratch field) are used as the stack
61 * for this calculation. Only 4 bytes are needed.
62 */
63 leal (BP_scratch+4)(%esi), %esp
64 call 1f
651: popl %ebp
66 subl $1b, %ebp
67
68/* setup a stack and make sure cpu supports long mode. */
69 movl $boot_stack_end, %eax
70 addl %ebp, %eax
71 movl %eax, %esp
72
73 call verify_cpu
74 testl %eax, %eax
75 jnz no_longmode
76
77/*
78 * Compute the delta between where we were compiled to run at
79 * and where the code will actually run at.
80 *
81 * %ebp contains the address we are loaded at by the boot loader and %ebx
82 * contains the address where we should move the kernel image temporarily
83 * for safe in-place decompression.
84 */
85
86#ifdef CONFIG_RELOCATABLE
87 movl %ebp, %ebx
88 movl BP_kernel_alignment(%esi), %eax
89 decl %eax
90 addl %eax, %ebx
91 notl %eax
92 andl %eax, %ebx
93#else
94 movl $LOAD_PHYSICAL_ADDR, %ebx
95#endif
96
97 /* Target address to relocate to for decompression */
98 addl $z_extract_offset, %ebx
99
100/*
101 * Prepare for entering 64 bit mode
102 */
103
104 /* Load new GDT with the 64bit segments using 32bit descriptor */
105 leal gdt(%ebp), %eax
106 movl %eax, gdt+2(%ebp)
107 lgdt gdt(%ebp)
108
109 /* Enable PAE mode */
110 movl $(X86_CR4_PAE), %eax
111 movl %eax, %cr4
112
113 /*
114 * Build early 4G boot pagetable
115 */
116 /* Initialize Page tables to 0 */
117 leal pgtable(%ebx), %edi
118 xorl %eax, %eax
119 movl $((4096*6)/4), %ecx
120 rep stosl
121
122 /* Build Level 4 */
123 leal pgtable + 0(%ebx), %edi
124 leal 0x1007 (%edi), %eax
125 movl %eax, 0(%edi)
126
127 /* Build Level 3 */
128 leal pgtable + 0x1000(%ebx), %edi
129 leal 0x1007(%edi), %eax
130 movl $4, %ecx
1311: movl %eax, 0x00(%edi)
132 addl $0x00001000, %eax
133 addl $8, %edi
134 decl %ecx
135 jnz 1b
136
137 /* Build Level 2 */
138 leal pgtable + 0x2000(%ebx), %edi
139 movl $0x00000183, %eax
140 movl $2048, %ecx
1411: movl %eax, 0(%edi)
142 addl $0x00200000, %eax
143 addl $8, %edi
144 decl %ecx
145 jnz 1b
146
147 /* Enable the boot page tables */
148 leal pgtable(%ebx), %eax
149 movl %eax, %cr3
150
151 /* Enable Long mode in EFER (Extended Feature Enable Register) */
152 movl $MSR_EFER, %ecx
153 rdmsr
154 btsl $_EFER_LME, %eax
155 wrmsr
156
157 /*
158 * Setup for the jump to 64bit mode
159 *
160 * When the jump is performend we will be in long mode but
161 * in 32bit compatibility mode with EFER.LME = 1, CS.L = 0, CS.D = 1
162 * (and in turn EFER.LMA = 1). To jump into 64bit mode we use
163 * the new gdt/idt that has __KERNEL_CS with CS.L = 1.
164 * We place all of the values on our mini stack so lret can
165 * used to perform that far jump.
166 */
167 pushl $__KERNEL_CS
168 leal startup_64(%ebp), %eax
169 pushl %eax
170
171 /* Enter paged protected Mode, activating Long Mode */
172 movl $(X86_CR0_PG | X86_CR0_PE), %eax /* Enable Paging and Protected mode */
173 movl %eax, %cr0
174
175 /* Jump from 32bit compatibility mode into 64bit mode. */
176 lret
177ENDPROC(startup_32)
178
179no_longmode:
180 /* This isn't an x86-64 CPU so hang */
1811:
182 hlt
183 jmp 1b
184
185#include "../../kernel/verify_cpu.S"
186
187 /*
188 * Be careful here startup_64 needs to be at a predictable
189 * address so I can export it in an ELF header. Bootloaders
190 * should look at the ELF header to find this address, as
191 * it may change in the future.
192 */
193 .code64
194 .org 0x200
195ENTRY(startup_64)
196 /*
197 * We come here either from startup_32 or directly from a
198 * 64bit bootloader. If we come here from a bootloader we depend on
199 * an identity mapped page table being provied that maps our
200 * entire text+data+bss and hopefully all of memory.
201 */
202#ifdef CONFIG_EFI_STUB
203 /*
204 * The entry point for the PE/COFF executable is 0x210, so only
205 * legacy boot loaders will execute this jmp.
206 */
207 jmp preferred_addr
208
209 .org 0x210
210 mov %rcx, %rdi
211 mov %rdx, %rsi
212 call efi_main
213 movq %rax,%rsi
214 cmpq $0,%rax
215 jne 2f
2161:
217 /* EFI init failed, so hang. */
218 hlt
219 jmp 1b
2202:
221 call 3f
2223:
223 popq %rax
224 subq $3b, %rax
225 subq BP_pref_address(%rsi), %rax
226 add BP_code32_start(%esi), %eax
227 leaq preferred_addr(%rax), %rax
228 jmp *%rax
229
230preferred_addr:
231#endif
232
233 /* Setup data segments. */
234 xorl %eax, %eax
235 movl %eax, %ds
236 movl %eax, %es
237 movl %eax, %ss
238 movl %eax, %fs
239 movl %eax, %gs
240 lldt %ax
241 movl $0x20, %eax
242 ltr %ax
243
244 /*
245 * Compute the decompressed kernel start address. It is where
246 * we were loaded at aligned to a 2M boundary. %rbp contains the
247 * decompressed kernel start address.
248 *
249 * If it is a relocatable kernel then decompress and run the kernel
250 * from load address aligned to 2MB addr, otherwise decompress and
251 * run the kernel from LOAD_PHYSICAL_ADDR
252 *
253 * We cannot rely on the calculation done in 32-bit mode, since we
254 * may have been invoked via the 64-bit entry point.
255 */
256
257 /* Start with the delta to where the kernel will run at. */
258#ifdef CONFIG_RELOCATABLE
259 leaq startup_32(%rip) /* - $startup_32 */, %rbp
260 movl BP_kernel_alignment(%rsi), %eax
261 decl %eax
262 addq %rax, %rbp
263 notq %rax
264 andq %rax, %rbp
265#else
266 movq $LOAD_PHYSICAL_ADDR, %rbp
267#endif
268
269 /* Target address to relocate to for decompression */
270 leaq z_extract_offset(%rbp), %rbx
271
272 /* Set up the stack */
273 leaq boot_stack_end(%rbx), %rsp
274
275 /* Zero EFLAGS */
276 pushq $0
277 popfq
278
279/*
280 * Copy the compressed kernel to the end of our buffer
281 * where decompression in place becomes safe.
282 */
283 pushq %rsi
284 leaq (_bss-8)(%rip), %rsi
285 leaq (_bss-8)(%rbx), %rdi
286 movq $_bss /* - $startup_32 */, %rcx
287 shrq $3, %rcx
288 std
289 rep movsq
290 cld
291 popq %rsi
292
293/*
294 * Jump to the relocated address.
295 */
296 leaq relocated(%rbx), %rax
297 jmp *%rax
298
299 .text
300relocated:
301
302/*
303 * Clear BSS (stack is currently empty)
304 */
305 xorl %eax, %eax
306 leaq _bss(%rip), %rdi
307 leaq _ebss(%rip), %rcx
308 subq %rdi, %rcx
309 shrq $3, %rcx
310 rep stosq
311
312/*
313 * Adjust our own GOT
314 */
315 leaq _got(%rip), %rdx
316 leaq _egot(%rip), %rcx
3171:
318 cmpq %rcx, %rdx
319 jae 2f
320 addq %rbx, (%rdx)
321 addq $8, %rdx
322 jmp 1b
3232:
324
325/*
326 * Do the decompression, and jump to the new kernel..
327 */
328 pushq %rsi /* Save the real mode argument */
329 movq %rsi, %rdi /* real mode address */
330 leaq boot_heap(%rip), %rsi /* malloc area for uncompression */
331 leaq input_data(%rip), %rdx /* input_data */
332 movl $z_input_len, %ecx /* input_len */
333 movq %rbp, %r8 /* output target address */
334 call decompress_kernel
335 popq %rsi
336
337/*
338 * Jump to the decompressed kernel.
339 */
340 jmp *%rbp
341
342 .data
343gdt:
344 .word gdt_end - gdt
345 .long gdt
346 .word 0
347 .quad 0x0000000000000000 /* NULL descriptor */
348 .quad 0x00af9a000000ffff /* __KERNEL_CS */
349 .quad 0x00cf92000000ffff /* __KERNEL_DS */
350 .quad 0x0080890000000000 /* TS descriptor */
351 .quad 0x0000000000000000 /* TS continued */
352gdt_end:
353
354/*
355 * Stack and heap for uncompression
356 */
357 .bss
358 .balign 4
359boot_heap:
360 .fill BOOT_HEAP_SIZE, 1, 0
361boot_stack:
362 .fill BOOT_STACK_SIZE, 1, 0
363boot_stack_end:
364
365/*
366 * Space for page tables (not in .bss so not zeroed)
367 */
368 .section ".pgtable","a",@nobits
369 .balign 4096
370pgtable:
371 .fill 6*4096, 1, 0