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Merge branch 'linus' into x86/x2apic
[people/ms/linux.git] / arch / x86 / kernel / cpu / common_64.c
1 #include <linux/init.h>
2 #include <linux/kernel.h>
3 #include <linux/sched.h>
4 #include <linux/string.h>
5 #include <linux/bootmem.h>
6 #include <linux/bitops.h>
7 #include <linux/module.h>
8 #include <linux/kgdb.h>
9 #include <linux/topology.h>
10 #include <linux/string.h>
11 #include <linux/delay.h>
12 #include <linux/smp.h>
13 #include <linux/module.h>
14 #include <linux/percpu.h>
15 #include <asm/processor.h>
16 #include <asm/i387.h>
17 #include <asm/msr.h>
18 #include <asm/io.h>
19 #include <asm/mmu_context.h>
20 #include <asm/mtrr.h>
21 #include <asm/mce.h>
22 #include <asm/pat.h>
23 #include <asm/numa.h>
24 #ifdef CONFIG_X86_LOCAL_APIC
25 #include <asm/mpspec.h>
26 #include <asm/apic.h>
27 #include <mach_apic.h>
28 #endif
29 #include <asm/pda.h>
30 #include <asm/pgtable.h>
31 #include <asm/processor.h>
32 #include <asm/desc.h>
33 #include <asm/atomic.h>
34 #include <asm/proto.h>
35 #include <asm/sections.h>
36 #include <asm/setup.h>
37 #include <asm/genapic.h>
38
39 #include "cpu.h"
40
41 /* We need valid kernel segments for data and code in long mode too
42 * IRET will check the segment types kkeil 2000/10/28
43 * Also sysret mandates a special GDT layout
44 */
45 /* The TLS descriptors are currently at a different place compared to i386.
46 Hopefully nobody expects them at a fixed place (Wine?) */
47 DEFINE_PER_CPU(struct gdt_page, gdt_page) = { .gdt = {
48 [GDT_ENTRY_KERNEL32_CS] = { { { 0x0000ffff, 0x00cf9b00 } } },
49 [GDT_ENTRY_KERNEL_CS] = { { { 0x0000ffff, 0x00af9b00 } } },
50 [GDT_ENTRY_KERNEL_DS] = { { { 0x0000ffff, 0x00cf9300 } } },
51 [GDT_ENTRY_DEFAULT_USER32_CS] = { { { 0x0000ffff, 0x00cffb00 } } },
52 [GDT_ENTRY_DEFAULT_USER_DS] = { { { 0x0000ffff, 0x00cff300 } } },
53 [GDT_ENTRY_DEFAULT_USER_CS] = { { { 0x0000ffff, 0x00affb00 } } },
54 } };
55 EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
56
57 __u32 cleared_cpu_caps[NCAPINTS] __cpuinitdata;
58
59 /* Current gdt points %fs at the "master" per-cpu area: after this,
60 * it's on the real one. */
61 void switch_to_new_gdt(void)
62 {
63 struct desc_ptr gdt_descr;
64
65 gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id());
66 gdt_descr.size = GDT_SIZE - 1;
67 load_gdt(&gdt_descr);
68 }
69
70 struct cpu_dev *cpu_devs[X86_VENDOR_NUM] = {};
71
72 static void __cpuinit default_init(struct cpuinfo_x86 *c)
73 {
74 display_cacheinfo(c);
75 }
76
77 static struct cpu_dev __cpuinitdata default_cpu = {
78 .c_init = default_init,
79 .c_vendor = "Unknown",
80 };
81 static struct cpu_dev *this_cpu __cpuinitdata = &default_cpu;
82
83 int __cpuinit get_model_name(struct cpuinfo_x86 *c)
84 {
85 unsigned int *v;
86
87 if (c->extended_cpuid_level < 0x80000004)
88 return 0;
89
90 v = (unsigned int *) c->x86_model_id;
91 cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]);
92 cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]);
93 cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]);
94 c->x86_model_id[48] = 0;
95 return 1;
96 }
97
98
99 void __cpuinit display_cacheinfo(struct cpuinfo_x86 *c)
100 {
101 unsigned int n, dummy, ebx, ecx, edx;
102
103 n = c->extended_cpuid_level;
104
105 if (n >= 0x80000005) {
106 cpuid(0x80000005, &dummy, &ebx, &ecx, &edx);
107 printk(KERN_INFO "CPU: L1 I Cache: %dK (%d bytes/line), "
108 "D cache %dK (%d bytes/line)\n",
109 edx>>24, edx&0xFF, ecx>>24, ecx&0xFF);
110 c->x86_cache_size = (ecx>>24) + (edx>>24);
111 /* On K8 L1 TLB is inclusive, so don't count it */
112 c->x86_tlbsize = 0;
113 }
114
115 if (n >= 0x80000006) {
116 cpuid(0x80000006, &dummy, &ebx, &ecx, &edx);
117 ecx = cpuid_ecx(0x80000006);
118 c->x86_cache_size = ecx >> 16;
119 c->x86_tlbsize += ((ebx >> 16) & 0xfff) + (ebx & 0xfff);
120
121 printk(KERN_INFO "CPU: L2 Cache: %dK (%d bytes/line)\n",
122 c->x86_cache_size, ecx & 0xFF);
123 }
124 }
125
126 void __cpuinit detect_ht(struct cpuinfo_x86 *c)
127 {
128 #ifdef CONFIG_SMP
129 u32 eax, ebx, ecx, edx;
130 int index_msb, core_bits;
131
132 cpuid(1, &eax, &ebx, &ecx, &edx);
133
134
135 if (!cpu_has(c, X86_FEATURE_HT))
136 return;
137 if (cpu_has(c, X86_FEATURE_CMP_LEGACY))
138 goto out;
139
140 smp_num_siblings = (ebx & 0xff0000) >> 16;
141
142 if (smp_num_siblings == 1) {
143 printk(KERN_INFO "CPU: Hyper-Threading is disabled\n");
144 } else if (smp_num_siblings > 1) {
145
146 if (smp_num_siblings > NR_CPUS) {
147 printk(KERN_WARNING "CPU: Unsupported number of "
148 "siblings %d", smp_num_siblings);
149 smp_num_siblings = 1;
150 return;
151 }
152
153 index_msb = get_count_order(smp_num_siblings);
154 c->phys_proc_id = phys_pkg_id(index_msb);
155
156 smp_num_siblings = smp_num_siblings / c->x86_max_cores;
157
158 index_msb = get_count_order(smp_num_siblings);
159
160 core_bits = get_count_order(c->x86_max_cores);
161
162 c->cpu_core_id = phys_pkg_id(index_msb) &
163 ((1 << core_bits) - 1);
164 }
165 out:
166 if ((c->x86_max_cores * smp_num_siblings) > 1) {
167 printk(KERN_INFO "CPU: Physical Processor ID: %d\n",
168 c->phys_proc_id);
169 printk(KERN_INFO "CPU: Processor Core ID: %d\n",
170 c->cpu_core_id);
171 }
172
173 #endif
174 }
175
176 static void __cpuinit get_cpu_vendor(struct cpuinfo_x86 *c)
177 {
178 char *v = c->x86_vendor_id;
179 int i;
180 static int printed;
181
182 for (i = 0; i < X86_VENDOR_NUM; i++) {
183 if (cpu_devs[i]) {
184 if (!strcmp(v, cpu_devs[i]->c_ident[0]) ||
185 (cpu_devs[i]->c_ident[1] &&
186 !strcmp(v, cpu_devs[i]->c_ident[1]))) {
187 c->x86_vendor = i;
188 this_cpu = cpu_devs[i];
189 return;
190 }
191 }
192 }
193 if (!printed) {
194 printed++;
195 printk(KERN_ERR "CPU: Vendor unknown, using generic init.\n");
196 printk(KERN_ERR "CPU: Your system may be unstable.\n");
197 }
198 c->x86_vendor = X86_VENDOR_UNKNOWN;
199 }
200
201 static void __init early_cpu_support_print(void)
202 {
203 int i,j;
204 struct cpu_dev *cpu_devx;
205
206 printk("KERNEL supported cpus:\n");
207 for (i = 0; i < X86_VENDOR_NUM; i++) {
208 cpu_devx = cpu_devs[i];
209 if (!cpu_devx)
210 continue;
211 for (j = 0; j < 2; j++) {
212 if (!cpu_devx->c_ident[j])
213 continue;
214 printk(" %s %s\n", cpu_devx->c_vendor,
215 cpu_devx->c_ident[j]);
216 }
217 }
218 }
219
220 static void __cpuinit early_identify_cpu(struct cpuinfo_x86 *c);
221
222 void __init early_cpu_init(void)
223 {
224 struct cpu_vendor_dev *cvdev;
225
226 for (cvdev = __x86cpuvendor_start ;
227 cvdev < __x86cpuvendor_end ;
228 cvdev++)
229 cpu_devs[cvdev->vendor] = cvdev->cpu_dev;
230 early_cpu_support_print();
231 early_identify_cpu(&boot_cpu_data);
232 }
233
234 /* Do some early cpuid on the boot CPU to get some parameter that are
235 needed before check_bugs. Everything advanced is in identify_cpu
236 below. */
237 static void __cpuinit early_identify_cpu(struct cpuinfo_x86 *c)
238 {
239 u32 tfms, xlvl;
240
241 c->loops_per_jiffy = loops_per_jiffy;
242 c->x86_cache_size = -1;
243 c->x86_vendor = X86_VENDOR_UNKNOWN;
244 c->x86_model = c->x86_mask = 0; /* So far unknown... */
245 c->x86_vendor_id[0] = '\0'; /* Unset */
246 c->x86_model_id[0] = '\0'; /* Unset */
247 c->x86_clflush_size = 64;
248 c->x86_cache_alignment = c->x86_clflush_size;
249 c->x86_max_cores = 1;
250 c->x86_coreid_bits = 0;
251 c->extended_cpuid_level = 0;
252 memset(&c->x86_capability, 0, sizeof c->x86_capability);
253
254 /* Get vendor name */
255 cpuid(0x00000000, (unsigned int *)&c->cpuid_level,
256 (unsigned int *)&c->x86_vendor_id[0],
257 (unsigned int *)&c->x86_vendor_id[8],
258 (unsigned int *)&c->x86_vendor_id[4]);
259
260 get_cpu_vendor(c);
261
262 /* Initialize the standard set of capabilities */
263 /* Note that the vendor-specific code below might override */
264
265 /* Intel-defined flags: level 0x00000001 */
266 if (c->cpuid_level >= 0x00000001) {
267 __u32 misc;
268 cpuid(0x00000001, &tfms, &misc, &c->x86_capability[4],
269 &c->x86_capability[0]);
270 c->x86 = (tfms >> 8) & 0xf;
271 c->x86_model = (tfms >> 4) & 0xf;
272 c->x86_mask = tfms & 0xf;
273 if (c->x86 == 0xf)
274 c->x86 += (tfms >> 20) & 0xff;
275 if (c->x86 >= 0x6)
276 c->x86_model += ((tfms >> 16) & 0xF) << 4;
277 if (test_cpu_cap(c, X86_FEATURE_CLFLSH))
278 c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
279 } else {
280 /* Have CPUID level 0 only - unheard of */
281 c->x86 = 4;
282 }
283
284 c->initial_apicid = (cpuid_ebx(1) >> 24) & 0xff;
285 #ifdef CONFIG_SMP
286 c->phys_proc_id = c->initial_apicid;
287 #endif
288 /* AMD-defined flags: level 0x80000001 */
289 xlvl = cpuid_eax(0x80000000);
290 c->extended_cpuid_level = xlvl;
291 if ((xlvl & 0xffff0000) == 0x80000000) {
292 if (xlvl >= 0x80000001) {
293 c->x86_capability[1] = cpuid_edx(0x80000001);
294 c->x86_capability[6] = cpuid_ecx(0x80000001);
295 }
296 if (xlvl >= 0x80000004)
297 get_model_name(c); /* Default name */
298 }
299
300 /* Transmeta-defined flags: level 0x80860001 */
301 xlvl = cpuid_eax(0x80860000);
302 if ((xlvl & 0xffff0000) == 0x80860000) {
303 /* Don't set x86_cpuid_level here for now to not confuse. */
304 if (xlvl >= 0x80860001)
305 c->x86_capability[2] = cpuid_edx(0x80860001);
306 }
307
308 c->extended_cpuid_level = cpuid_eax(0x80000000);
309 if (c->extended_cpuid_level >= 0x80000007)
310 c->x86_power = cpuid_edx(0x80000007);
311
312 if (c->extended_cpuid_level >= 0x80000008) {
313 u32 eax = cpuid_eax(0x80000008);
314
315 c->x86_virt_bits = (eax >> 8) & 0xff;
316 c->x86_phys_bits = eax & 0xff;
317 }
318
319 /* Assume all 64-bit CPUs support 32-bit syscall */
320 set_cpu_cap(c, X86_FEATURE_SYSCALL32);
321
322 if (c->x86_vendor != X86_VENDOR_UNKNOWN &&
323 cpu_devs[c->x86_vendor]->c_early_init)
324 cpu_devs[c->x86_vendor]->c_early_init(c);
325
326 validate_pat_support(c);
327
328 /* early_param could clear that, but recall get it set again */
329 if (disable_apic)
330 clear_cpu_cap(c, X86_FEATURE_APIC);
331 }
332
333 /*
334 * This does the hard work of actually picking apart the CPU stuff...
335 */
336 static void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
337 {
338 int i;
339
340 early_identify_cpu(c);
341
342 init_scattered_cpuid_features(c);
343
344 c->apicid = phys_pkg_id(0);
345
346 /*
347 * Vendor-specific initialization. In this section we
348 * canonicalize the feature flags, meaning if there are
349 * features a certain CPU supports which CPUID doesn't
350 * tell us, CPUID claiming incorrect flags, or other bugs,
351 * we handle them here.
352 *
353 * At the end of this section, c->x86_capability better
354 * indicate the features this CPU genuinely supports!
355 */
356 if (this_cpu->c_init)
357 this_cpu->c_init(c);
358
359 detect_ht(c);
360
361 /*
362 * On SMP, boot_cpu_data holds the common feature set between
363 * all CPUs; so make sure that we indicate which features are
364 * common between the CPUs. The first time this routine gets
365 * executed, c == &boot_cpu_data.
366 */
367 if (c != &boot_cpu_data) {
368 /* AND the already accumulated flags with these */
369 for (i = 0; i < NCAPINTS; i++)
370 boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
371 }
372
373 /* Clear all flags overriden by options */
374 for (i = 0; i < NCAPINTS; i++)
375 c->x86_capability[i] &= ~cleared_cpu_caps[i];
376
377 #ifdef CONFIG_X86_MCE
378 mcheck_init(c);
379 #endif
380 select_idle_routine(c);
381
382 #ifdef CONFIG_NUMA
383 numa_add_cpu(smp_processor_id());
384 #endif
385
386 }
387
388 void __cpuinit identify_boot_cpu(void)
389 {
390 identify_cpu(&boot_cpu_data);
391 }
392
393 void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c)
394 {
395 BUG_ON(c == &boot_cpu_data);
396 identify_cpu(c);
397 mtrr_ap_init();
398 }
399
400 static __init int setup_noclflush(char *arg)
401 {
402 setup_clear_cpu_cap(X86_FEATURE_CLFLSH);
403 return 1;
404 }
405 __setup("noclflush", setup_noclflush);
406
407 void __cpuinit print_cpu_info(struct cpuinfo_x86 *c)
408 {
409 if (c->x86_model_id[0])
410 printk(KERN_CONT "%s", c->x86_model_id);
411
412 if (c->x86_mask || c->cpuid_level >= 0)
413 printk(KERN_CONT " stepping %02x\n", c->x86_mask);
414 else
415 printk(KERN_CONT "\n");
416 }
417
418 static __init int setup_disablecpuid(char *arg)
419 {
420 int bit;
421 if (get_option(&arg, &bit) && bit < NCAPINTS*32)
422 setup_clear_cpu_cap(bit);
423 else
424 return 0;
425 return 1;
426 }
427 __setup("clearcpuid=", setup_disablecpuid);
428
429 cpumask_t cpu_initialized __cpuinitdata = CPU_MASK_NONE;
430
431 struct x8664_pda **_cpu_pda __read_mostly;
432 EXPORT_SYMBOL(_cpu_pda);
433
434 struct desc_ptr idt_descr = { 256 * 16 - 1, (unsigned long) idt_table };
435
436 char boot_cpu_stack[IRQSTACKSIZE] __page_aligned_bss;
437
438 unsigned long __supported_pte_mask __read_mostly = ~0UL;
439 EXPORT_SYMBOL_GPL(__supported_pte_mask);
440
441 static int do_not_nx __cpuinitdata;
442
443 /* noexec=on|off
444 Control non executable mappings for 64bit processes.
445
446 on Enable(default)
447 off Disable
448 */
449 static int __init nonx_setup(char *str)
450 {
451 if (!str)
452 return -EINVAL;
453 if (!strncmp(str, "on", 2)) {
454 __supported_pte_mask |= _PAGE_NX;
455 do_not_nx = 0;
456 } else if (!strncmp(str, "off", 3)) {
457 do_not_nx = 1;
458 __supported_pte_mask &= ~_PAGE_NX;
459 }
460 return 0;
461 }
462 early_param("noexec", nonx_setup);
463
464 int force_personality32;
465
466 /* noexec32=on|off
467 Control non executable heap for 32bit processes.
468 To control the stack too use noexec=off
469
470 on PROT_READ does not imply PROT_EXEC for 32bit processes (default)
471 off PROT_READ implies PROT_EXEC
472 */
473 static int __init nonx32_setup(char *str)
474 {
475 if (!strcmp(str, "on"))
476 force_personality32 &= ~READ_IMPLIES_EXEC;
477 else if (!strcmp(str, "off"))
478 force_personality32 |= READ_IMPLIES_EXEC;
479 return 1;
480 }
481 __setup("noexec32=", nonx32_setup);
482
483 void pda_init(int cpu)
484 {
485 struct x8664_pda *pda = cpu_pda(cpu);
486
487 /* Setup up data that may be needed in __get_free_pages early */
488 loadsegment(fs, 0);
489 loadsegment(gs, 0);
490 /* Memory clobbers used to order PDA accessed */
491 mb();
492 wrmsrl(MSR_GS_BASE, pda);
493 mb();
494
495 pda->cpunumber = cpu;
496 pda->irqcount = -1;
497 pda->kernelstack = (unsigned long)stack_thread_info() -
498 PDA_STACKOFFSET + THREAD_SIZE;
499 pda->active_mm = &init_mm;
500 pda->mmu_state = 0;
501
502 if (cpu == 0) {
503 /* others are initialized in smpboot.c */
504 pda->pcurrent = &init_task;
505 pda->irqstackptr = boot_cpu_stack;
506 } else {
507 pda->irqstackptr = (char *)
508 __get_free_pages(GFP_ATOMIC, IRQSTACK_ORDER);
509 if (!pda->irqstackptr)
510 panic("cannot allocate irqstack for cpu %d", cpu);
511
512 if (pda->nodenumber == 0 && cpu_to_node(cpu) != NUMA_NO_NODE)
513 pda->nodenumber = cpu_to_node(cpu);
514 }
515
516 pda->irqstackptr += IRQSTACKSIZE-64;
517 }
518
519 char boot_exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ +
520 DEBUG_STKSZ]
521 __attribute__((section(".bss.page_aligned")));
522
523 extern asmlinkage void ignore_sysret(void);
524
525 /* May not be marked __init: used by software suspend */
526 void syscall_init(void)
527 {
528 /*
529 * LSTAR and STAR live in a bit strange symbiosis.
530 * They both write to the same internal register. STAR allows to
531 * set CS/DS but only a 32bit target. LSTAR sets the 64bit rip.
532 */
533 wrmsrl(MSR_STAR, ((u64)__USER32_CS)<<48 | ((u64)__KERNEL_CS)<<32);
534 wrmsrl(MSR_LSTAR, system_call);
535 wrmsrl(MSR_CSTAR, ignore_sysret);
536
537 #ifdef CONFIG_IA32_EMULATION
538 syscall32_cpu_init();
539 #endif
540
541 /* Flags to clear on syscall */
542 wrmsrl(MSR_SYSCALL_MASK,
543 X86_EFLAGS_TF|X86_EFLAGS_DF|X86_EFLAGS_IF|X86_EFLAGS_IOPL);
544 }
545
546 void __cpuinit check_efer(void)
547 {
548 unsigned long efer;
549
550 rdmsrl(MSR_EFER, efer);
551 if (!(efer & EFER_NX) || do_not_nx)
552 __supported_pte_mask &= ~_PAGE_NX;
553 }
554
555 unsigned long kernel_eflags;
556
557 /*
558 * Copies of the original ist values from the tss are only accessed during
559 * debugging, no special alignment required.
560 */
561 DEFINE_PER_CPU(struct orig_ist, orig_ist);
562
563 /*
564 * cpu_init() initializes state that is per-CPU. Some data is already
565 * initialized (naturally) in the bootstrap process, such as the GDT
566 * and IDT. We reload them nevertheless, this function acts as a
567 * 'CPU state barrier', nothing should get across.
568 * A lot of state is already set up in PDA init.
569 */
570 void __cpuinit cpu_init(void)
571 {
572 int cpu = stack_smp_processor_id();
573 struct tss_struct *t = &per_cpu(init_tss, cpu);
574 struct orig_ist *orig_ist = &per_cpu(orig_ist, cpu);
575 unsigned long v;
576 char *estacks = NULL;
577 struct task_struct *me;
578 int i;
579
580 /* CPU 0 is initialised in head64.c */
581 if (cpu != 0)
582 pda_init(cpu);
583 else
584 estacks = boot_exception_stacks;
585
586 me = current;
587
588 if (cpu_test_and_set(cpu, cpu_initialized))
589 panic("CPU#%d already initialized!\n", cpu);
590
591 printk(KERN_INFO "Initializing CPU#%d\n", cpu);
592
593 clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
594
595 /*
596 * Initialize the per-CPU GDT with the boot GDT,
597 * and set up the GDT descriptor:
598 */
599
600 switch_to_new_gdt();
601 load_idt((const struct desc_ptr *)&idt_descr);
602
603 memset(me->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8);
604 syscall_init();
605
606 wrmsrl(MSR_FS_BASE, 0);
607 wrmsrl(MSR_KERNEL_GS_BASE, 0);
608 barrier();
609
610 check_efer();
611 if (cpu != 0 && x2apic)
612 enable_x2apic();
613
614 /*
615 * set up and load the per-CPU TSS
616 */
617 for (v = 0; v < N_EXCEPTION_STACKS; v++) {
618 static const unsigned int order[N_EXCEPTION_STACKS] = {
619 [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STACK_ORDER,
620 [DEBUG_STACK - 1] = DEBUG_STACK_ORDER
621 };
622 if (cpu) {
623 estacks = (char *)__get_free_pages(GFP_ATOMIC, order[v]);
624 if (!estacks)
625 panic("Cannot allocate exception stack %ld %d\n",
626 v, cpu);
627 }
628 estacks += PAGE_SIZE << order[v];
629 orig_ist->ist[v] = t->x86_tss.ist[v] = (unsigned long)estacks;
630 }
631
632 t->x86_tss.io_bitmap_base = offsetof(struct tss_struct, io_bitmap);
633 /*
634 * <= is required because the CPU will access up to
635 * 8 bits beyond the end of the IO permission bitmap.
636 */
637 for (i = 0; i <= IO_BITMAP_LONGS; i++)
638 t->io_bitmap[i] = ~0UL;
639
640 atomic_inc(&init_mm.mm_count);
641 me->active_mm = &init_mm;
642 if (me->mm)
643 BUG();
644 enter_lazy_tlb(&init_mm, me);
645
646 load_sp0(t, &current->thread);
647 set_tss_desc(cpu, t);
648 load_TR_desc();
649 load_LDT(&init_mm.context);
650
651 #ifdef CONFIG_KGDB
652 /*
653 * If the kgdb is connected no debug regs should be altered. This
654 * is only applicable when KGDB and a KGDB I/O module are built
655 * into the kernel and you are using early debugging with
656 * kgdbwait. KGDB will control the kernel HW breakpoint registers.
657 */
658 if (kgdb_connected && arch_kgdb_ops.correct_hw_break)
659 arch_kgdb_ops.correct_hw_break();
660 else {
661 #endif
662 /*
663 * Clear all 6 debug registers:
664 */
665
666 set_debugreg(0UL, 0);
667 set_debugreg(0UL, 1);
668 set_debugreg(0UL, 2);
669 set_debugreg(0UL, 3);
670 set_debugreg(0UL, 6);
671 set_debugreg(0UL, 7);
672 #ifdef CONFIG_KGDB
673 /* If the kgdb is connected no debug regs should be altered. */
674 }
675 #endif
676
677 fpu_init();
678
679 raw_local_save_flags(kernel_eflags);
680
681 if (is_uv_system())
682 uv_cpu_init();
683 }