Merge branch 'drm-nouveau-fixes-3.8' of git://anongit.freedesktop.org/git/nouveau...
[deliverable/linux.git] / arch / x86 / boot / compressed / head_64.S
CommitLineData
1da177e4
LT
1/*
2 * linux/boot/head.S
3 *
4 * Copyright (C) 1991, 1992, 1993 Linus Torvalds
1da177e4
LT
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/*
f4549448 22 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
1da177e4 23 */
b40d68d5
PA
24 .code32
25 .text
1da177e4 26
1dc818c1 27#include <linux/init.h>
1da177e4
LT
28#include <linux/linkage.h>
29#include <asm/segment.h>
0341c14d
JF
30#include <asm/pgtable_types.h>
31#include <asm/page_types.h>
7c539764 32#include <asm/boot.h>
1ab60e0f 33#include <asm/msr.h>
e83e31f4 34#include <asm/processor-flags.h>
bd53147d 35#include <asm/asm-offsets.h>
1da177e4 36
1dc818c1 37 __HEAD
1da177e4 38 .code32
2d4eeecb 39ENTRY(startup_32)
1da177e4 40 cld
b40d68d5
PA
41 /*
42 * Test KEEP_SEGMENTS flag to see if the bootloader is asking
43 * us to not reload segments
44 */
bd53147d
EB
45 testb $(1<<6), BP_loadflags(%esi)
46 jnz 1f
47
1da177e4 48 cli
1ab60e0f
VG
49 movl $(__KERNEL_DS), %eax
50 movl %eax, %ds
51 movl %eax, %es
52 movl %eax, %ss
bd53147d 531:
1ab60e0f 54
b40d68d5
PA
55/*
56 * Calculate the delta between where we were compiled to run
1ab60e0f
VG
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
85414b69
PA
60 * data at 0x1e4 (defined as a scratch field) are used as the stack
61 * for this calculation. Only 4 bytes are needed.
1ab60e0f 62 */
bd2a3698 63 leal (BP_scratch+4)(%esi), %esp
1ab60e0f
VG
64 call 1f
651: popl %ebp
66 subl $1b, %ebp
67
a4831e08 68/* setup a stack and make sure cpu supports long mode. */
7c539764 69 movl $boot_stack_end, %eax
a4831e08
VG
70 addl %ebp, %eax
71 movl %eax, %esp
72
73 call verify_cpu
74 testl %eax, %eax
75 jnz no_longmode
76
b40d68d5
PA
77/*
78 * Compute the delta between where we were compiled to run at
1ab60e0f 79 * and where the code will actually run at.
b40d68d5
PA
80 *
81 * %ebp contains the address we are loaded at by the boot loader and %ebx
1ab60e0f
VG
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
37ba7ab5
PA
88 movl BP_kernel_alignment(%esi), %eax
89 decl %eax
90 addl %eax, %ebx
91 notl %eax
92 andl %eax, %ebx
1ab60e0f 93#else
40b387a8 94 movl $LOAD_PHYSICAL_ADDR, %ebx
1ab60e0f
VG
95#endif
96
02a884c0
PA
97 /* Target address to relocate to for decompression */
98 addl $z_extract_offset, %ebx
1da177e4
LT
99
100/*
1ab60e0f 101 * Prepare for entering 64 bit mode
1da177e4 102 */
1ab60e0f
VG
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 */
4868402d 110 movl $(X86_CR4_PAE), %eax
1ab60e0f
VG
111 movl %eax, %cr4
112
113 /*
114 * Build early 4G boot pagetable
115 */
b40d68d5 116 /* Initialize Page tables to 0 */
1ab60e0f
VG
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
b40d68d5
PA
157 /*
158 * Setup for the jump to 64bit mode
1ab60e0f
VG
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 */
e83e31f4 172 movl $(X86_CR0_PG | X86_CR0_PE), %eax /* Enable Paging and Protected mode */
1ab60e0f
VG
173 movl %eax, %cr0
174
175 /* Jump from 32bit compatibility mode into 64bit mode. */
176 lret
2d4eeecb 177ENDPROC(startup_32)
1ab60e0f 178
a4831e08
VG
179no_longmode:
180 /* This isn't an x86-64 CPU so hang */
1811:
182 hlt
183 jmp 1b
184
c5cbac69 185#include "../../kernel/verify_cpu.S"
a4831e08 186
b40d68d5
PA
187 /*
188 * Be careful here startup_64 needs to be at a predictable
1ab60e0f
VG
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
a4831e08 194 .org 0x200
1ab60e0f 195ENTRY(startup_64)
b40d68d5
PA
196 /*
197 * We come here either from startup_32 or directly from a
1ab60e0f
VG
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 */
291f3632 202#ifdef CONFIG_EFI_STUB
b1994304 203 /*
99f857db
DW
204 * The entry point for the PE/COFF executable is efi_pe_entry, so
205 * only legacy boot loaders will execute this jmp.
b1994304
MF
206 */
207 jmp preferred_addr
208
99f857db 209ENTRY(efi_pe_entry)
291f3632
MF
210 mov %rcx, %rdi
211 mov %rdx, %rsi
9ca8f72a
MF
212 pushq %rdi
213 pushq %rsi
214 call make_boot_params
215 cmpq $0,%rax
216 je 1f
217 mov %rax, %rdx
218 popq %rsi
219 popq %rdi
220
99f857db 221ENTRY(efi_stub_entry)
291f3632 222 call efi_main
291f3632 223 movq %rax,%rsi
b1994304
MF
224 cmpq $0,%rax
225 jne 2f
291f3632 2261:
b1994304
MF
227 /* EFI init failed, so hang. */
228 hlt
229 jmp 1b
2302:
231 call 3f
2323:
291f3632 233 popq %rax
b1994304 234 subq $3b, %rax
291f3632
MF
235 subq BP_pref_address(%rsi), %rax
236 add BP_code32_start(%esi), %eax
237 leaq preferred_addr(%rax), %rax
238 jmp *%rax
239
240preferred_addr:
241#endif
1ab60e0f
VG
242
243 /* Setup data segments. */
244 xorl %eax, %eax
245 movl %eax, %ds
246 movl %eax, %es
247 movl %eax, %ss
08da5a2c
ZA
248 movl %eax, %fs
249 movl %eax, %gs
250 lldt %ax
251 movl $0x20, %eax
252 ltr %ax
1ab60e0f 253
b40d68d5
PA
254 /*
255 * Compute the decompressed kernel start address. It is where
1ab60e0f
VG
256 * we were loaded at aligned to a 2M boundary. %rbp contains the
257 * decompressed kernel start address.
258 *
259 * If it is a relocatable kernel then decompress and run the kernel
260 * from load address aligned to 2MB addr, otherwise decompress and
40b387a8 261 * run the kernel from LOAD_PHYSICAL_ADDR
02a884c0
PA
262 *
263 * We cannot rely on the calculation done in 32-bit mode, since we
264 * may have been invoked via the 64-bit entry point.
1ab60e0f
VG
265 */
266
267 /* Start with the delta to where the kernel will run at. */
268#ifdef CONFIG_RELOCATABLE
269 leaq startup_32(%rip) /* - $startup_32 */, %rbp
37ba7ab5
PA
270 movl BP_kernel_alignment(%rsi), %eax
271 decl %eax
272 addq %rax, %rbp
273 notq %rax
274 andq %rax, %rbp
1ab60e0f 275#else
40b387a8 276 movq $LOAD_PHYSICAL_ADDR, %rbp
1ab60e0f
VG
277#endif
278
02a884c0
PA
279 /* Target address to relocate to for decompression */
280 leaq z_extract_offset(%rbp), %rbx
1ab60e0f 281
0a137736
PA
282 /* Set up the stack */
283 leaq boot_stack_end(%rbx), %rsp
284
285 /* Zero EFLAGS */
286 pushq $0
287 popfq
288
b40d68d5
PA
289/*
290 * Copy the compressed kernel to the end of our buffer
1ab60e0f
VG
291 * where decompression in place becomes safe.
292 */
36d3793c
PA
293 pushq %rsi
294 leaq (_bss-8)(%rip), %rsi
295 leaq (_bss-8)(%rbx), %rdi
5b11f1ce 296 movq $_bss /* - $startup_32 */, %rcx
36d3793c
PA
297 shrq $3, %rcx
298 std
299 rep movsq
300 cld
301 popq %rsi
1ab60e0f
VG
302
303/*
304 * Jump to the relocated address.
305 */
306 leaq relocated(%rbx), %rax
307 jmp *%rax
308
b40d68d5 309 .text
1ab60e0f
VG
310relocated:
311
1da177e4 312/*
0a137736 313 * Clear BSS (stack is currently empty)
1da177e4 314 */
36d3793c
PA
315 xorl %eax, %eax
316 leaq _bss(%rip), %rdi
317 leaq _ebss(%rip), %rcx
1ab60e0f 318 subq %rdi, %rcx
36d3793c
PA
319 shrq $3, %rcx
320 rep stosq
1ab60e0f 321
22a57f58
PA
322/*
323 * Adjust our own GOT
324 */
325 leaq _got(%rip), %rdx
326 leaq _egot(%rip), %rcx
3271:
328 cmpq %rcx, %rdx
329 jae 2f
330 addq %rbx, (%rdx)
331 addq $8, %rdx
332 jmp 1b
3332:
334
1da177e4
LT
335/*
336 * Do the decompression, and jump to the new kernel..
337 */
02a884c0
PA
338 pushq %rsi /* Save the real mode argument */
339 movq %rsi, %rdi /* real mode address */
340 leaq boot_heap(%rip), %rsi /* malloc area for uncompression */
341 leaq input_data(%rip), %rdx /* input_data */
342 movl $z_input_len, %ecx /* input_len */
343 movq %rbp, %r8 /* output target address */
1ab60e0f
VG
344 call decompress_kernel
345 popq %rsi
1da177e4 346
1da177e4 347/*
1ab60e0f 348 * Jump to the decompressed kernel.
1da177e4 349 */
1ab60e0f 350 jmp *%rbp
1da177e4 351
1ab60e0f
VG
352 .data
353gdt:
354 .word gdt_end - gdt
355 .long gdt
356 .word 0
357 .quad 0x0000000000000000 /* NULL descriptor */
358 .quad 0x00af9a000000ffff /* __KERNEL_CS */
359 .quad 0x00cf92000000ffff /* __KERNEL_DS */
08da5a2c
ZA
360 .quad 0x0080890000000000 /* TS descriptor */
361 .quad 0x0000000000000000 /* TS continued */
1ab60e0f 362gdt_end:
7c539764 363
b40d68d5
PA
364/*
365 * Stack and heap for uncompression
366 */
367 .bss
368 .balign 4
7c539764
AH
369boot_heap:
370 .fill BOOT_HEAP_SIZE, 1, 0
371boot_stack:
372 .fill BOOT_STACK_SIZE, 1, 0
373boot_stack_end:
5b11f1ce
PA
374
375/*
376 * Space for page tables (not in .bss so not zeroed)
377 */
378 .section ".pgtable","a",@nobits
379 .balign 4096
380pgtable:
381 .fill 6*4096, 1, 0
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