[PATCH] Add initalization of the RDTSCP auxilliary values
[deliverable/linux.git] / arch / x86_64 / kernel / head.S
CommitLineData
1da177e4
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1/*
2 * linux/arch/x86_64/kernel/head.S -- start in 32bit and switch to 64bit
3 *
4 * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
5 * Copyright (C) 2000 Pavel Machek <pavel@suse.cz>
6 * Copyright (C) 2000 Karsten Keil <kkeil@suse.de>
7 * Copyright (C) 2001,2002 Andi Kleen <ak@suse.de>
8 *
9 * $Id: head.S,v 1.49 2002/03/19 17:39:25 ak Exp $
10 */
11
12
13#include <linux/linkage.h>
14#include <linux/threads.h>
f6c2e333 15#include <linux/init.h>
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16#include <asm/desc.h>
17#include <asm/segment.h>
18#include <asm/page.h>
19#include <asm/msr.h>
20#include <asm/cache.h>
21
22/* we are not able to switch in one step to the final KERNEL ADRESS SPACE
23 * because we need identity-mapped pages on setup so define __START_KERNEL to
24 * 0x100000 for this stage
25 *
26 */
27
28 .text
eaeae0cc 29 .section .bootstrap.text
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30 .code32
31 .globl startup_32
32/* %bx: 1 if coming from smp trampoline on secondary cpu */
33startup_32:
34
35 /*
36 * At this point the CPU runs in 32bit protected mode (CS.D = 1) with
37 * paging disabled and the point of this file is to switch to 64bit
38 * long mode with a kernel mapping for kerneland to jump into the
39 * kernel virtual addresses.
40 * There is no stack until we set one up.
41 */
42
43 /* Initialize the %ds segment register */
44 movl $__KERNEL_DS,%eax
45 movl %eax,%ds
46
47 /* Load new GDT with the 64bit segments using 32bit descriptor */
48 lgdt pGDT32 - __START_KERNEL_map
49
50 /* If the CPU doesn't support CPUID this will double fault.
51 * Unfortunately it is hard to check for CPUID without a stack.
52 */
53
54 /* Check if extended functions are implemented */
55 movl $0x80000000, %eax
56 cpuid
57 cmpl $0x80000000, %eax
58 jbe no_long_mode
59 /* Check if long mode is implemented */
60 mov $0x80000001, %eax
61 cpuid
62 btl $29, %edx
63 jnc no_long_mode
64
65 /*
66 * Prepare for entering 64bits mode
67 */
68
69 /* Enable PAE mode */
70 xorl %eax, %eax
71 btsl $5, %eax
72 movl %eax, %cr4
73
74 /* Setup early boot stage 4 level pagetables */
f6c2e333 75 movl $(boot_level4_pgt - __START_KERNEL_map), %eax
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76 movl %eax, %cr3
77
78 /* Setup EFER (Extended Feature Enable Register) */
79 movl $MSR_EFER, %ecx
80 rdmsr
81
82 /* Enable Long Mode */
83 btsl $_EFER_LME, %eax
84
85 /* Make changes effective */
86 wrmsr
87
88 xorl %eax, %eax
89 btsl $31, %eax /* Enable paging and in turn activate Long Mode */
90 btsl $0, %eax /* Enable protected mode */
91 /* Make changes effective */
92 movl %eax, %cr0
93 /*
94 * At this point we're in long mode but in 32bit compatibility mode
95 * with EFER.LME = 1, CS.L = 0, CS.D = 1 (and in turn
96 * EFER.LMA = 1). Now we want to jump in 64bit mode, to do that we use
97 * the new gdt/idt that has __KERNEL_CS with CS.L = 1.
98 */
99 ljmp $__KERNEL_CS, $(startup_64 - __START_KERNEL_map)
100
101 .code64
102 .org 0x100
103 .globl startup_64
104startup_64:
105 /* We come here either from startup_32
106 * or directly from a 64bit bootloader.
107 * Since we may have come directly from a bootloader we
108 * reload the page tables here.
109 */
110
111 /* Enable PAE mode and PGE */
112 xorq %rax, %rax
113 btsq $5, %rax
114 btsq $7, %rax
115 movq %rax, %cr4
116
117 /* Setup early boot stage 4 level pagetables. */
f6c2e333 118 movq $(boot_level4_pgt - __START_KERNEL_map), %rax
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119 movq %rax, %cr3
120
121 /* Check if nx is implemented */
122 movl $0x80000001, %eax
123 cpuid
124 movl %edx,%edi
125
126 /* Setup EFER (Extended Feature Enable Register) */
127 movl $MSR_EFER, %ecx
128 rdmsr
129
130 /* Enable System Call */
131 btsl $_EFER_SCE, %eax
132
133 /* No Execute supported? */
134 btl $20,%edi
135 jnc 1f
136 btsl $_EFER_NX, %eax
1371:
138 /* Make changes effective */
139 wrmsr
140
141 /* Setup cr0 */
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142#define CR0_PM 1 /* protected mode */
143#define CR0_MP (1<<1)
144#define CR0_ET (1<<4)
145#define CR0_NE (1<<5)
146#define CR0_WP (1<<16)
147#define CR0_AM (1<<18)
148#define CR0_PAGING (1<<31)
149 movl $CR0_PM|CR0_MP|CR0_ET|CR0_NE|CR0_WP|CR0_AM|CR0_PAGING,%eax
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150 /* Make changes effective */
151 movq %rax, %cr0
152
153 /* Setup a boot time stack */
154 movq init_rsp(%rip),%rsp
155
156 /* zero EFLAGS after setting rsp */
157 pushq $0
158 popfq
159
160 /*
161 * We must switch to a new descriptor in kernel space for the GDT
162 * because soon the kernel won't have access anymore to the userspace
163 * addresses where we're currently running on. We have to do that here
164 * because in 32bit we couldn't load a 64bit linear address.
165 */
166 lgdt cpu_gdt_descr
167
168 /*
169 * Setup up a dummy PDA. this is just for some early bootup code
170 * that does in_interrupt()
171 */
172 movl $MSR_GS_BASE,%ecx
173 movq $empty_zero_page,%rax
174 movq %rax,%rdx
175 shrq $32,%rdx
176 wrmsr
177
178 /* set up data segments. actually 0 would do too */
179 movl $__KERNEL_DS,%eax
180 movl %eax,%ds
181 movl %eax,%ss
182 movl %eax,%es
183
184 /* esi is pointer to real mode structure with interesting info.
185 pass it to C */
186 movl %esi, %edi
187
188 /* Finally jump to run C code and to be on real kernel address
189 * Since we are running on identity-mapped space we have to jump
190 * to the full 64bit address , this is only possible as indirect
191 * jump
192 */
193 movq initial_code(%rip),%rax
c05991ed 194 pushq $0 # fake return address
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195 jmp *%rax
196
e57113bc
JB
197 /* SMP bootup changes these two */
198 .align 8
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199 .globl initial_code
200initial_code:
201 .quad x86_64_start_kernel
202 .globl init_rsp
203init_rsp:
204 .quad init_thread_union+THREAD_SIZE-8
205
206ENTRY(early_idt_handler)
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207 cmpl $2,early_recursion_flag(%rip)
208 jz 1f
209 incl early_recursion_flag(%rip)
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210 xorl %eax,%eax
211 movq 8(%rsp),%rsi # get rip
212 movq (%rsp),%rdx
213 movq %cr2,%rcx
214 leaq early_idt_msg(%rip),%rdi
215 call early_printk
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216 cmpl $2,early_recursion_flag(%rip)
217 jz 1f
218 call dump_stack
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219#ifdef CONFIG_KALLSYMS
220 leaq early_idt_ripmsg(%rip),%rdi
221 movq 8(%rsp),%rsi # get rip again
222 call __print_symbol
223#endif
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2241: hlt
225 jmp 1b
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226early_recursion_flag:
227 .long 0
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228
229early_idt_msg:
230 .asciz "PANIC: early exception rip %lx error %lx cr2 %lx\n"
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231early_idt_ripmsg:
232 .asciz "RIP %s\n"
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233
234.code32
235ENTRY(no_long_mode)
236 /* This isn't an x86-64 CPU so hang */
2371:
238 jmp 1b
239
240.org 0xf00
241 .globl pGDT32
242pGDT32:
e57113bc 243 .word gdt_end-cpu_gdt_table-1
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244 .long cpu_gdt_table-__START_KERNEL_map
245
246.org 0xf10
247ljumpvector:
248 .long startup_64-__START_KERNEL_map
249 .word __KERNEL_CS
250
251ENTRY(stext)
252ENTRY(_stext)
253
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JB
254 $page = 0
255#define NEXT_PAGE(name) \
256 $page = $page + 1; \
257 .org $page * 0x1000; \
258 phys_/**/name = $page * 0x1000 + __PHYSICAL_START; \
259ENTRY(name)
260
261NEXT_PAGE(init_level4_pgt)
f6c2e333
SS
262 /* This gets initialized in x86_64_start_kernel */
263 .fill 512,8,0
1da177e4 264
f0cf5d1a
JB
265NEXT_PAGE(level3_ident_pgt)
266 .quad phys_level2_ident_pgt | 0x007
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267 .fill 511,8,0
268
f0cf5d1a 269NEXT_PAGE(level3_kernel_pgt)
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270 .fill 510,8,0
271 /* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */
f0cf5d1a 272 .quad phys_level2_kernel_pgt | 0x007
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273 .fill 1,8,0
274
f0cf5d1a 275NEXT_PAGE(level2_ident_pgt)
1da177e4 276 /* 40MB for bootup. */
f0cf5d1a
JB
277 i = 0
278 .rept 20
279 .quad i << 21 | 0x083
280 i = i + 1
281 .endr
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282 /* Temporary mappings for the super early allocator in arch/x86_64/mm/init.c */
283 .globl temp_boot_pmds
284temp_boot_pmds:
285 .fill 492,8,0
286
f0cf5d1a 287NEXT_PAGE(level2_kernel_pgt)
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288 /* 40MB kernel mapping. The kernel code cannot be bigger than that.
289 When you change this change KERNEL_TEXT_SIZE in page.h too. */
290 /* (2^48-(2*1024*1024*1024)-((2^39)*511)-((2^30)*510)) = 0 */
f0cf5d1a
JB
291 i = 0
292 .rept 20
293 .quad i << 21 | 0x183
294 i = i + 1
295 .endr
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296 /* Module mapping starts here */
297 .fill 492,8,0
298
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JB
299NEXT_PAGE(level3_physmem_pgt)
300 .quad phys_level2_kernel_pgt | 0x007 /* so that __va works even before pagetable_init */
301 .fill 511,8,0
1da177e4 302
f0cf5d1a 303#undef NEXT_PAGE
1da177e4 304
f0cf5d1a 305 .data
1da177e4 306
1da177e4 307#ifdef CONFIG_ACPI_SLEEP
f0cf5d1a 308 .align PAGE_SIZE
1da177e4 309ENTRY(wakeup_level4_pgt)
f0cf5d1a 310 .quad phys_level3_ident_pgt | 0x007
1da177e4 311 .fill 255,8,0
f0cf5d1a 312 .quad phys_level3_physmem_pgt | 0x007
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313 .fill 254,8,0
314 /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
f0cf5d1a 315 .quad phys_level3_kernel_pgt | 0x007
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316#endif
317
f6c2e333
SS
318#ifndef CONFIG_HOTPLUG_CPU
319 __INITDATA
320#endif
321 /*
322 * This default setting generates an ident mapping at address 0x100000
323 * and a mapping for the kernel that precisely maps virtual address
324 * 0xffffffff80000000 to physical address 0x000000. (always using
325 * 2Mbyte large pages provided by PAE mode)
326 */
327 .align PAGE_SIZE
328ENTRY(boot_level4_pgt)
f0cf5d1a 329 .quad phys_level3_ident_pgt | 0x007
f6c2e333 330 .fill 255,8,0
f0cf5d1a 331 .quad phys_level3_physmem_pgt | 0x007
f6c2e333
SS
332 .fill 254,8,0
333 /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
f0cf5d1a 334 .quad phys_level3_kernel_pgt | 0x007
f6c2e333 335
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336 .data
337
338 .align 16
339 .globl cpu_gdt_descr
340cpu_gdt_descr:
e57113bc 341 .word gdt_end-cpu_gdt_table-1
1da177e4
LT
342gdt:
343 .quad cpu_gdt_table
344#ifdef CONFIG_SMP
345 .rept NR_CPUS-1
346 .word 0
347 .quad 0
348 .endr
349#endif
350
351/* We need valid kernel segments for data and code in long mode too
352 * IRET will check the segment types kkeil 2000/10/28
353 * Also sysret mandates a special GDT layout
354 */
355
e57113bc
JB
356 .section .data.page_aligned, "aw"
357 .align PAGE_SIZE
1da177e4
LT
358
359/* The TLS descriptors are currently at a different place compared to i386.
360 Hopefully nobody expects them at a fixed place (Wine?) */
361
362ENTRY(cpu_gdt_table)
363 .quad 0x0000000000000000 /* NULL descriptor */
cdc4b9c0 364 .quad 0x0 /* unused */
1da177e4
LT
365 .quad 0x00af9a000000ffff /* __KERNEL_CS */
366 .quad 0x00cf92000000ffff /* __KERNEL_DS */
367 .quad 0x00cffa000000ffff /* __USER32_CS */
368 .quad 0x00cff2000000ffff /* __USER_DS, __USER32_DS */
369 .quad 0x00affa000000ffff /* __USER_CS */
370 .quad 0x00cf9a000000ffff /* __KERNEL32_CS */
371 .quad 0,0 /* TSS */
372 .quad 0,0 /* LDT */
373 .quad 0,0,0 /* three TLS descriptors */
cdc4b9c0 374 .quad 0 /* unused */
1da177e4
LT
375gdt_end:
376 /* asm/segment.h:GDT_ENTRIES must match this */
377 /* This should be a multiple of the cache line size */
c11efdf9
RT
378 /* GDTs of other CPUs are now dynamically allocated */
379
380 /* zero the remaining page */
381 .fill PAGE_SIZE / 8 - GDT_ENTRIES,8,0
1da177e4 382
e57113bc
JB
383 .section .bss, "aw", @nobits
384 .align L1_CACHE_BYTES
385ENTRY(idt_table)
386 .skip 256 * 16
1da177e4 387
e57113bc
JB
388 .section .bss.page_aligned, "aw", @nobits
389 .align PAGE_SIZE
390ENTRY(empty_zero_page)
391 .skip PAGE_SIZE
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