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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/boot.h>
31#include <asm/msr.h>
32#include <asm/processor-flags.h>
33#include <asm/asm-offsets.h>
34#include <asm/bootparam.h>
35
36/*
37 * Locally defined symbols should be marked hidden:
38 */
39 .hidden _bss
40 .hidden _ebss
41 .hidden _got
42 .hidden _egot
43
44 __HEAD
45 .code32
46ENTRY(startup_32)
47 /*
48 * 32bit entry is 0 and it is ABI so immutable!
49 * If we come here directly from a bootloader,
50 * kernel(text+data+bss+brk) ramdisk, zero_page, command line
51 * all need to be under the 4G limit.
52 */
53 cld
54 /*
55 * Test KEEP_SEGMENTS flag to see if the bootloader is asking
56 * us to not reload segments
57 */
58 testb $KEEP_SEGMENTS, BP_loadflags(%esi)
59 jnz 1f
60
61 cli
62 movl $(__BOOT_DS), %eax
63 movl %eax, %ds
64 movl %eax, %es
65 movl %eax, %ss
661:
67
68/*
69 * Calculate the delta between where we were compiled to run
70 * at and where we were actually loaded at. This can only be done
71 * with a short local call on x86. Nothing else will tell us what
72 * address we are running at. The reserved chunk of the real-mode
73 * data at 0x1e4 (defined as a scratch field) are used as the stack
74 * for this calculation. Only 4 bytes are needed.
75 */
76 leal (BP_scratch+4)(%esi), %esp
77 call 1f
781: popl %ebp
79 subl $1b, %ebp
80
81/* setup a stack and make sure cpu supports long mode. */
82 movl $boot_stack_end, %eax
83 addl %ebp, %eax
84 movl %eax, %esp
85
86 call verify_cpu
87 testl %eax, %eax
88 jnz no_longmode
89
90/*
91 * Compute the delta between where we were compiled to run at
92 * and where the code will actually run at.
93 *
94 * %ebp contains the address we are loaded at by the boot loader and %ebx
95 * contains the address where we should move the kernel image temporarily
96 * for safe in-place decompression.
97 */
98
99#ifdef CONFIG_RELOCATABLE
100 movl %ebp, %ebx
101 movl BP_kernel_alignment(%esi), %eax
102 decl %eax
103 addl %eax, %ebx
104 notl %eax
105 andl %eax, %ebx
106 cmpl $LOAD_PHYSICAL_ADDR, %ebx
107 jge 1f
108#endif
109 movl $LOAD_PHYSICAL_ADDR, %ebx
1101:
111
112 /* Target address to relocate to for decompression */
113 addl $z_extract_offset, %ebx
114
115/*
116 * Prepare for entering 64 bit mode
117 */
118
119 /* Load new GDT with the 64bit segments using 32bit descriptor */
120 leal gdt(%ebp), %eax
121 movl %eax, gdt+2(%ebp)
122 lgdt gdt(%ebp)
123
124 /* Enable PAE mode */
125 movl %cr4, %eax
126 orl $X86_CR4_PAE, %eax
127 movl %eax, %cr4
128
129 /*
130 * Build early 4G boot pagetable
131 */
132 /* Initialize Page tables to 0 */
133 leal pgtable(%ebx), %edi
134 xorl %eax, %eax
135 movl $((4096*6)/4), %ecx
136 rep stosl
137
138 /* Build Level 4 */
139 leal pgtable + 0(%ebx), %edi
140 leal 0x1007 (%edi), %eax
141 movl %eax, 0(%edi)
142
143 /* Build Level 3 */
144 leal pgtable + 0x1000(%ebx), %edi
145 leal 0x1007(%edi), %eax
146 movl $4, %ecx
1471: movl %eax, 0x00(%edi)
148 addl $0x00001000, %eax
149 addl $8, %edi
150 decl %ecx
151 jnz 1b
152
153 /* Build Level 2 */
154 leal pgtable + 0x2000(%ebx), %edi
155 movl $0x00000183, %eax
156 movl $2048, %ecx
1571: movl %eax, 0(%edi)
158 addl $0x00200000, %eax
159 addl $8, %edi
160 decl %ecx
161 jnz 1b
162
163 /* Enable the boot page tables */
164 leal pgtable(%ebx), %eax
165 movl %eax, %cr3
166
167 /* Enable Long mode in EFER (Extended Feature Enable Register) */
168 movl $MSR_EFER, %ecx
169 rdmsr
170 btsl $_EFER_LME, %eax
171 wrmsr
172
173 /* After gdt is loaded */
174 xorl %eax, %eax
175 lldt %ax
176 movl $__BOOT_TSS, %eax
177 ltr %ax
178
179 /*
180 * Setup for the jump to 64bit mode
181 *
182 * When the jump is performend we will be in long mode but
183 * in 32bit compatibility mode with EFER.LME = 1, CS.L = 0, CS.D = 1
184 * (and in turn EFER.LMA = 1). To jump into 64bit mode we use
185 * the new gdt/idt that has __KERNEL_CS with CS.L = 1.
186 * We place all of the values on our mini stack so lret can
187 * used to perform that far jump.
188 */
189 pushl $__KERNEL_CS
190 leal startup_64(%ebp), %eax
191#ifdef CONFIG_EFI_MIXED
192 movl efi32_config(%ebp), %ebx
193 cmp $0, %ebx
194 jz 1f
195 leal handover_entry(%ebp), %eax
1961:
197#endif
198 pushl %eax
199
200 /* Enter paged protected Mode, activating Long Mode */
201 movl $(X86_CR0_PG | X86_CR0_PE), %eax /* Enable Paging and Protected mode */
202 movl %eax, %cr0
203
204 /* Jump from 32bit compatibility mode into 64bit mode. */
205 lret
206ENDPROC(startup_32)
207
208#ifdef CONFIG_EFI_MIXED
209 .org 0x190
210ENTRY(efi32_stub_entry)
211 add $0x4, %esp /* Discard return address */
212 popl %ecx
213 popl %edx
214 popl %esi
215
216 leal (BP_scratch+4)(%esi), %esp
217 call 1f
2181: pop %ebp
219 subl $1b, %ebp
220
221 movl %ecx, efi32_config(%ebp)
222 movl %edx, efi32_config+8(%ebp)
223 sgdtl efi32_boot_gdt(%ebp)
224
225 leal efi32_config(%ebp), %eax
226 movl %eax, efi_config(%ebp)
227
228 jmp startup_32
229ENDPROC(efi32_stub_entry)
230#endif
231
232 .code64
233 .org 0x200
234ENTRY(startup_64)
235 /*
236 * 64bit entry is 0x200 and it is ABI so immutable!
237 * We come here either from startup_32 or directly from a
238 * 64bit bootloader.
239 * If we come here from a bootloader, kernel(text+data+bss+brk),
240 * ramdisk, zero_page, command line could be above 4G.
241 * We depend on an identity mapped page table being provided
242 * that maps our entire kernel(text+data+bss+brk), zero page
243 * and command line.
244 */
245#ifdef CONFIG_EFI_STUB
246 /*
247 * The entry point for the PE/COFF executable is efi_pe_entry, so
248 * only legacy boot loaders will execute this jmp.
249 */
250 jmp preferred_addr
251
252ENTRY(efi_pe_entry)
253 movq %rcx, efi64_config(%rip) /* Handle */
254 movq %rdx, efi64_config+8(%rip) /* EFI System table pointer */
255
256 leaq efi64_config(%rip), %rax
257 movq %rax, efi_config(%rip)
258
259 call 1f
2601: popq %rbp
261 subq $1b, %rbp
262
263 /*
264 * Relocate efi_config->call().
265 */
266 addq %rbp, efi64_config+88(%rip)
267
268 movq %rax, %rdi
269 call make_boot_params
270 cmpq $0,%rax
271 je fail
272 mov %rax, %rsi
273 leaq startup_32(%rip), %rax
274 movl %eax, BP_code32_start(%rsi)
275 jmp 2f /* Skip the relocation */
276
277handover_entry:
278 call 1f
2791: popq %rbp
280 subq $1b, %rbp
281
282 /*
283 * Relocate efi_config->call().
284 */
285 movq efi_config(%rip), %rax
286 addq %rbp, 88(%rax)
2872:
288 movq efi_config(%rip), %rdi
289 call efi_main
290 movq %rax,%rsi
291 cmpq $0,%rax
292 jne 2f
293fail:
294 /* EFI init failed, so hang. */
295 hlt
296 jmp fail
2972:
298 movl BP_code32_start(%esi), %eax
299 leaq preferred_addr(%rax), %rax
300 jmp *%rax
301
302preferred_addr:
303#endif
304
305 /* Setup data segments. */
306 xorl %eax, %eax
307 movl %eax, %ds
308 movl %eax, %es
309 movl %eax, %ss
310 movl %eax, %fs
311 movl %eax, %gs
312
313 /*
314 * Compute the decompressed kernel start address. It is where
315 * we were loaded at aligned to a 2M boundary. %rbp contains the
316 * decompressed kernel start address.
317 *
318 * If it is a relocatable kernel then decompress and run the kernel
319 * from load address aligned to 2MB addr, otherwise decompress and
320 * run the kernel from LOAD_PHYSICAL_ADDR
321 *
322 * We cannot rely on the calculation done in 32-bit mode, since we
323 * may have been invoked via the 64-bit entry point.
324 */
325
326 /* Start with the delta to where the kernel will run at. */
327#ifdef CONFIG_RELOCATABLE
328 leaq startup_32(%rip) /* - $startup_32 */, %rbp
329 movl BP_kernel_alignment(%rsi), %eax
330 decl %eax
331 addq %rax, %rbp
332 notq %rax
333 andq %rax, %rbp
334 cmpq $LOAD_PHYSICAL_ADDR, %rbp
335 jge 1f
336#endif
337 movq $LOAD_PHYSICAL_ADDR, %rbp
3381:
339
340 /* Target address to relocate to for decompression */
341 leaq z_extract_offset(%rbp), %rbx
342
343 /* Set up the stack */
344 leaq boot_stack_end(%rbx), %rsp
345
346 /* Zero EFLAGS */
347 pushq $0
348 popfq
349
350/*
351 * Copy the compressed kernel to the end of our buffer
352 * where decompression in place becomes safe.
353 */
354 pushq %rsi
355 leaq (_bss-8)(%rip), %rsi
356 leaq (_bss-8)(%rbx), %rdi
357 movq $_bss /* - $startup_32 */, %rcx
358 shrq $3, %rcx
359 std
360 rep movsq
361 cld
362 popq %rsi
363
364/*
365 * Jump to the relocated address.
366 */
367 leaq relocated(%rbx), %rax
368 jmp *%rax
369
370#ifdef CONFIG_EFI_STUB
371 .org 0x390
372ENTRY(efi64_stub_entry)
373 movq %rdi, efi64_config(%rip) /* Handle */
374 movq %rsi, efi64_config+8(%rip) /* EFI System table pointer */
375
376 leaq efi64_config(%rip), %rax
377 movq %rax, efi_config(%rip)
378
379 movq %rdx, %rsi
380 jmp handover_entry
381ENDPROC(efi64_stub_entry)
382#endif
383
384 .text
385relocated:
386
387/*
388 * Clear BSS (stack is currently empty)
389 */
390 xorl %eax, %eax
391 leaq _bss(%rip), %rdi
392 leaq _ebss(%rip), %rcx
393 subq %rdi, %rcx
394 shrq $3, %rcx
395 rep stosq
396
397/*
398 * Adjust our own GOT
399 */
400 leaq _got(%rip), %rdx
401 leaq _egot(%rip), %rcx
4021:
403 cmpq %rcx, %rdx
404 jae 2f
405 addq %rbx, (%rdx)
406 addq $8, %rdx
407 jmp 1b
4082:
409
410/*
411 * Do the decompression, and jump to the new kernel..
412 */
413 pushq %rsi /* Save the real mode argument */
414 movq $z_run_size, %r9 /* size of kernel with .bss and .brk */
415 pushq %r9
416 movq %rsi, %rdi /* real mode address */
417 leaq boot_heap(%rip), %rsi /* malloc area for uncompression */
418 leaq input_data(%rip), %rdx /* input_data */
419 movl $z_input_len, %ecx /* input_len */
420 movq %rbp, %r8 /* output target address */
421 movq $z_output_len, %r9 /* decompressed length, end of relocs */
422 call decompress_kernel /* returns kernel location in %rax */
423 popq %r9
424 popq %rsi
425
426/*
427 * Jump to the decompressed kernel.
428 */
429 jmp *%rax
430
431 .code32
432no_longmode:
433 /* This isn't an x86-64 CPU so hang */
4341:
435 hlt
436 jmp 1b
437
438#include "../../kernel/verify_cpu.S"
439
440 .data
441gdt:
442 .word gdt_end - gdt
443 .long gdt
444 .word 0
445 .quad 0x0000000000000000 /* NULL descriptor */
446 .quad 0x00af9a000000ffff /* __KERNEL_CS */
447 .quad 0x00cf92000000ffff /* __KERNEL_DS */
448 .quad 0x0080890000000000 /* TS descriptor */
449 .quad 0x0000000000000000 /* TS continued */
450gdt_end:
451
452#ifdef CONFIG_EFI_STUB
453efi_config:
454 .quad 0
455
456#ifdef CONFIG_EFI_MIXED
457 .global efi32_config
458efi32_config:
459 .fill 11,8,0
460 .quad efi64_thunk
461 .byte 0
462#endif
463
464 .global efi64_config
465efi64_config:
466 .fill 11,8,0
467 .quad efi_call
468 .byte 1
469#endif /* CONFIG_EFI_STUB */
470
471/*
472 * Stack and heap for uncompression
473 */
474 .bss
475 .balign 4
476boot_heap:
477 .fill BOOT_HEAP_SIZE, 1, 0
478boot_stack:
479 .fill BOOT_STACK_SIZE, 1, 0
480boot_stack_end:
481
482/*
483 * Space for page tables (not in .bss so not zeroed)
484 */
485 .section ".pgtable","a",@nobits
486 .balign 4096
487pgtable:
488 .fill 6*4096, 1, 0