Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 LT |
2 | * Copyright (C) 1995 Linus Torvalds |
3 | * | |
4 | * Pentium III FXSR, SSE support | |
5 | * Gareth Hughes <gareth@valinux.com>, May 2000 | |
6 | */ | |
7 | ||
8 | /* | |
9 | * This file handles the architecture-dependent parts of process handling.. | |
10 | */ | |
11 | ||
12 | #include <stdarg.h> | |
13 | ||
f3705136 | 14 | #include <linux/cpu.h> |
1da177e4 LT |
15 | #include <linux/errno.h> |
16 | #include <linux/sched.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/elfcore.h> | |
21 | #include <linux/smp.h> | |
1da177e4 LT |
22 | #include <linux/stddef.h> |
23 | #include <linux/slab.h> | |
24 | #include <linux/vmalloc.h> | |
25 | #include <linux/user.h> | |
26 | #include <linux/a.out.h> | |
27 | #include <linux/interrupt.h> | |
1da177e4 LT |
28 | #include <linux/utsname.h> |
29 | #include <linux/delay.h> | |
30 | #include <linux/reboot.h> | |
31 | #include <linux/init.h> | |
32 | #include <linux/mc146818rtc.h> | |
33 | #include <linux/module.h> | |
34 | #include <linux/kallsyms.h> | |
35 | #include <linux/ptrace.h> | |
36 | #include <linux/random.h> | |
c16b63e0 | 37 | #include <linux/personality.h> |
74167347 | 38 | #include <linux/tick.h> |
7c3576d2 | 39 | #include <linux/percpu.h> |
1da177e4 LT |
40 | |
41 | #include <asm/uaccess.h> | |
42 | #include <asm/pgtable.h> | |
43 | #include <asm/system.h> | |
44 | #include <asm/io.h> | |
45 | #include <asm/ldt.h> | |
46 | #include <asm/processor.h> | |
47 | #include <asm/i387.h> | |
1da177e4 | 48 | #include <asm/desc.h> |
64ca9004 | 49 | #include <asm/vm86.h> |
1da177e4 LT |
50 | #ifdef CONFIG_MATH_EMULATION |
51 | #include <asm/math_emu.h> | |
52 | #endif | |
53 | ||
1da177e4 LT |
54 | #include <linux/err.h> |
55 | ||
f3705136 ZM |
56 | #include <asm/tlbflush.h> |
57 | #include <asm/cpu.h> | |
58 | ||
1da177e4 LT |
59 | asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); |
60 | ||
61 | static int hlt_counter; | |
62 | ||
63 | unsigned long boot_option_idle_override = 0; | |
64 | EXPORT_SYMBOL(boot_option_idle_override); | |
65 | ||
7c3576d2 JF |
66 | DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task; |
67 | EXPORT_PER_CPU_SYMBOL(current_task); | |
68 | ||
69 | DEFINE_PER_CPU(int, cpu_number); | |
70 | EXPORT_PER_CPU_SYMBOL(cpu_number); | |
71 | ||
1da177e4 LT |
72 | /* |
73 | * Return saved PC of a blocked thread. | |
74 | */ | |
75 | unsigned long thread_saved_pc(struct task_struct *tsk) | |
76 | { | |
77 | return ((unsigned long *)tsk->thread.esp)[3]; | |
78 | } | |
79 | ||
80 | /* | |
81 | * Powermanagement idle function, if any.. | |
82 | */ | |
83 | void (*pm_idle)(void); | |
129f6946 | 84 | EXPORT_SYMBOL(pm_idle); |
1da177e4 LT |
85 | static DEFINE_PER_CPU(unsigned int, cpu_idle_state); |
86 | ||
87 | void disable_hlt(void) | |
88 | { | |
89 | hlt_counter++; | |
90 | } | |
91 | ||
92 | EXPORT_SYMBOL(disable_hlt); | |
93 | ||
94 | void enable_hlt(void) | |
95 | { | |
96 | hlt_counter--; | |
97 | } | |
98 | ||
99 | EXPORT_SYMBOL(enable_hlt); | |
100 | ||
101 | /* | |
102 | * We use this if we don't have any better | |
103 | * idle routine.. | |
104 | */ | |
105 | void default_idle(void) | |
106 | { | |
107 | if (!hlt_counter && boot_cpu_data.hlt_works_ok) { | |
495ab9c0 | 108 | current_thread_info()->status &= ~TS_POLLING; |
0888f06a IM |
109 | /* |
110 | * TS_POLLING-cleared state must be visible before we | |
111 | * test NEED_RESCHED: | |
112 | */ | |
113 | smp_mb(); | |
114 | ||
72690a21 AK |
115 | local_irq_disable(); |
116 | if (!need_resched()) | |
117 | safe_halt(); /* enables interrupts racelessly */ | |
118 | else | |
119 | local_irq_enable(); | |
495ab9c0 | 120 | current_thread_info()->status |= TS_POLLING; |
1da177e4 | 121 | } else { |
72690a21 AK |
122 | /* loop is done by the caller */ |
123 | cpu_relax(); | |
1da177e4 LT |
124 | } |
125 | } | |
129f6946 AD |
126 | #ifdef CONFIG_APM_MODULE |
127 | EXPORT_SYMBOL(default_idle); | |
128 | #endif | |
1da177e4 LT |
129 | |
130 | /* | |
131 | * On SMP it's slightly faster (but much more power-consuming!) | |
132 | * to poll the ->work.need_resched flag instead of waiting for the | |
133 | * cross-CPU IPI to arrive. Use this option with caution. | |
134 | */ | |
135 | static void poll_idle (void) | |
136 | { | |
72690a21 | 137 | cpu_relax(); |
1da177e4 LT |
138 | } |
139 | ||
f3705136 ZM |
140 | #ifdef CONFIG_HOTPLUG_CPU |
141 | #include <asm/nmi.h> | |
142 | /* We don't actually take CPU down, just spin without interrupts. */ | |
143 | static inline void play_dead(void) | |
144 | { | |
e1367daf LS |
145 | /* This must be done before dead CPU ack */ |
146 | cpu_exit_clear(); | |
147 | wbinvd(); | |
148 | mb(); | |
f3705136 ZM |
149 | /* Ack it */ |
150 | __get_cpu_var(cpu_state) = CPU_DEAD; | |
151 | ||
e1367daf LS |
152 | /* |
153 | * With physical CPU hotplug, we should halt the cpu | |
154 | */ | |
f3705136 | 155 | local_irq_disable(); |
e1367daf | 156 | while (1) |
f2ab4461 | 157 | halt(); |
f3705136 ZM |
158 | } |
159 | #else | |
160 | static inline void play_dead(void) | |
161 | { | |
162 | BUG(); | |
163 | } | |
164 | #endif /* CONFIG_HOTPLUG_CPU */ | |
165 | ||
1da177e4 LT |
166 | /* |
167 | * The idle thread. There's no useful work to be | |
168 | * done, so just try to conserve power and have a | |
169 | * low exit latency (ie sit in a loop waiting for | |
170 | * somebody to say that they'd like to reschedule) | |
171 | */ | |
f3705136 | 172 | void cpu_idle(void) |
1da177e4 | 173 | { |
5bfb5d69 | 174 | int cpu = smp_processor_id(); |
f3705136 | 175 | |
495ab9c0 | 176 | current_thread_info()->status |= TS_POLLING; |
64c7c8f8 | 177 | |
1da177e4 LT |
178 | /* endless idle loop with no priority at all */ |
179 | while (1) { | |
74167347 | 180 | tick_nohz_stop_sched_tick(); |
1da177e4 LT |
181 | while (!need_resched()) { |
182 | void (*idle)(void); | |
183 | ||
184 | if (__get_cpu_var(cpu_idle_state)) | |
185 | __get_cpu_var(cpu_idle_state) = 0; | |
186 | ||
f1d1a842 | 187 | check_pgt_cache(); |
1da177e4 LT |
188 | rmb(); |
189 | idle = pm_idle; | |
190 | ||
191 | if (!idle) | |
192 | idle = default_idle; | |
193 | ||
f3705136 ZM |
194 | if (cpu_is_offline(cpu)) |
195 | play_dead(); | |
196 | ||
1da177e4 LT |
197 | __get_cpu_var(irq_stat).idle_timestamp = jiffies; |
198 | idle(); | |
199 | } | |
74167347 | 200 | tick_nohz_restart_sched_tick(); |
5bfb5d69 | 201 | preempt_enable_no_resched(); |
1da177e4 | 202 | schedule(); |
5bfb5d69 | 203 | preempt_disable(); |
1da177e4 LT |
204 | } |
205 | } | |
206 | ||
207 | void cpu_idle_wait(void) | |
208 | { | |
209 | unsigned int cpu, this_cpu = get_cpu(); | |
dc1829a4 | 210 | cpumask_t map, tmp = current->cpus_allowed; |
1da177e4 LT |
211 | |
212 | set_cpus_allowed(current, cpumask_of_cpu(this_cpu)); | |
213 | put_cpu(); | |
214 | ||
215 | cpus_clear(map); | |
216 | for_each_online_cpu(cpu) { | |
217 | per_cpu(cpu_idle_state, cpu) = 1; | |
218 | cpu_set(cpu, map); | |
219 | } | |
220 | ||
221 | __get_cpu_var(cpu_idle_state) = 0; | |
222 | ||
223 | wmb(); | |
224 | do { | |
225 | ssleep(1); | |
226 | for_each_online_cpu(cpu) { | |
227 | if (cpu_isset(cpu, map) && !per_cpu(cpu_idle_state, cpu)) | |
228 | cpu_clear(cpu, map); | |
229 | } | |
230 | cpus_and(map, map, cpu_online_map); | |
231 | } while (!cpus_empty(map)); | |
dc1829a4 IM |
232 | |
233 | set_cpus_allowed(current, tmp); | |
1da177e4 LT |
234 | } |
235 | EXPORT_SYMBOL_GPL(cpu_idle_wait); | |
236 | ||
237 | /* | |
238 | * This uses new MONITOR/MWAIT instructions on P4 processors with PNI, | |
239 | * which can obviate IPI to trigger checking of need_resched. | |
240 | * We execute MONITOR against need_resched and enter optimized wait state | |
241 | * through MWAIT. Whenever someone changes need_resched, we would be woken | |
242 | * up from MWAIT (without an IPI). | |
991528d7 VP |
243 | * |
244 | * New with Core Duo processors, MWAIT can take some hints based on CPU | |
245 | * capability. | |
1da177e4 | 246 | */ |
991528d7 | 247 | void mwait_idle_with_hints(unsigned long eax, unsigned long ecx) |
1da177e4 | 248 | { |
991528d7 | 249 | if (!need_resched()) { |
64c7c8f8 NP |
250 | __monitor((void *)¤t_thread_info()->flags, 0, 0); |
251 | smp_mb(); | |
991528d7 | 252 | if (!need_resched()) |
ea3d5226 | 253 | __mwait(eax, ecx); |
1da177e4 LT |
254 | } |
255 | } | |
256 | ||
991528d7 VP |
257 | /* Default MONITOR/MWAIT with no hints, used for default C1 state */ |
258 | static void mwait_idle(void) | |
259 | { | |
260 | local_irq_enable(); | |
72690a21 | 261 | mwait_idle_with_hints(0, 0); |
991528d7 VP |
262 | } |
263 | ||
0bb3184d | 264 | void __devinit select_idle_routine(const struct cpuinfo_x86 *c) |
1da177e4 LT |
265 | { |
266 | if (cpu_has(c, X86_FEATURE_MWAIT)) { | |
267 | printk("monitor/mwait feature present.\n"); | |
268 | /* | |
269 | * Skip, if setup has overridden idle. | |
270 | * One CPU supports mwait => All CPUs supports mwait | |
271 | */ | |
272 | if (!pm_idle) { | |
273 | printk("using mwait in idle threads.\n"); | |
274 | pm_idle = mwait_idle; | |
275 | } | |
276 | } | |
277 | } | |
278 | ||
f039b754 | 279 | static int __init idle_setup(char *str) |
1da177e4 | 280 | { |
f039b754 | 281 | if (!strcmp(str, "poll")) { |
1da177e4 LT |
282 | printk("using polling idle threads.\n"); |
283 | pm_idle = poll_idle; | |
284 | #ifdef CONFIG_X86_SMP | |
285 | if (smp_num_siblings > 1) | |
286 | printk("WARNING: polling idle and HT enabled, performance may degrade.\n"); | |
287 | #endif | |
f039b754 AK |
288 | } else if (!strcmp(str, "mwait")) |
289 | force_mwait = 1; | |
290 | else | |
291 | return -1; | |
1da177e4 LT |
292 | |
293 | boot_option_idle_override = 1; | |
f039b754 | 294 | return 0; |
1da177e4 | 295 | } |
f039b754 | 296 | early_param("idle", idle_setup); |
1da177e4 LT |
297 | |
298 | void show_regs(struct pt_regs * regs) | |
299 | { | |
300 | unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L; | |
bb1995d5 | 301 | unsigned long d0, d1, d2, d3, d6, d7; |
1da177e4 LT |
302 | |
303 | printk("\n"); | |
304 | printk("Pid: %d, comm: %20s\n", current->pid, current->comm); | |
305 | printk("EIP: %04x:[<%08lx>] CPU: %d\n",0xffff & regs->xcs,regs->eip, smp_processor_id()); | |
306 | print_symbol("EIP is at %s\n", regs->eip); | |
307 | ||
db753bdf | 308 | if (user_mode_vm(regs)) |
1da177e4 | 309 | printk(" ESP: %04x:%08lx",0xffff & regs->xss,regs->esp); |
b53e8f68 | 310 | printk(" EFLAGS: %08lx %s (%s %.*s)\n", |
96b644bd SH |
311 | regs->eflags, print_tainted(), init_utsname()->release, |
312 | (int)strcspn(init_utsname()->version, " "), | |
313 | init_utsname()->version); | |
1da177e4 LT |
314 | printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n", |
315 | regs->eax,regs->ebx,regs->ecx,regs->edx); | |
316 | printk("ESI: %08lx EDI: %08lx EBP: %08lx", | |
317 | regs->esi, regs->edi, regs->ebp); | |
464d1a78 JF |
318 | printk(" DS: %04x ES: %04x FS: %04x\n", |
319 | 0xffff & regs->xds,0xffff & regs->xes, 0xffff & regs->xfs); | |
1da177e4 | 320 | |
4bb0d3ec ZA |
321 | cr0 = read_cr0(); |
322 | cr2 = read_cr2(); | |
323 | cr3 = read_cr3(); | |
ff6e8c0d | 324 | cr4 = read_cr4_safe(); |
1da177e4 | 325 | printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4); |
bb1995d5 AS |
326 | |
327 | get_debugreg(d0, 0); | |
328 | get_debugreg(d1, 1); | |
329 | get_debugreg(d2, 2); | |
330 | get_debugreg(d3, 3); | |
331 | printk("DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n", | |
332 | d0, d1, d2, d3); | |
333 | get_debugreg(d6, 6); | |
334 | get_debugreg(d7, 7); | |
335 | printk("DR6: %08lx DR7: %08lx\n", d6, d7); | |
336 | ||
176a2718 | 337 | show_trace(NULL, regs, ®s->esp); |
1da177e4 LT |
338 | } |
339 | ||
340 | /* | |
341 | * This gets run with %ebx containing the | |
342 | * function to call, and %edx containing | |
343 | * the "args". | |
344 | */ | |
345 | extern void kernel_thread_helper(void); | |
1da177e4 LT |
346 | |
347 | /* | |
348 | * Create a kernel thread | |
349 | */ | |
350 | int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) | |
351 | { | |
352 | struct pt_regs regs; | |
353 | ||
354 | memset(®s, 0, sizeof(regs)); | |
355 | ||
356 | regs.ebx = (unsigned long) fn; | |
357 | regs.edx = (unsigned long) arg; | |
358 | ||
359 | regs.xds = __USER_DS; | |
360 | regs.xes = __USER_DS; | |
7c3576d2 | 361 | regs.xfs = __KERNEL_PERCPU; |
1da177e4 LT |
362 | regs.orig_eax = -1; |
363 | regs.eip = (unsigned long) kernel_thread_helper; | |
78be3706 | 364 | regs.xcs = __KERNEL_CS | get_kernel_rpl(); |
1da177e4 LT |
365 | regs.eflags = X86_EFLAGS_IF | X86_EFLAGS_SF | X86_EFLAGS_PF | 0x2; |
366 | ||
367 | /* Ok, create the new process.. */ | |
8cf2c519 | 368 | return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); |
1da177e4 | 369 | } |
129f6946 | 370 | EXPORT_SYMBOL(kernel_thread); |
1da177e4 LT |
371 | |
372 | /* | |
373 | * Free current thread data structures etc.. | |
374 | */ | |
375 | void exit_thread(void) | |
376 | { | |
1da177e4 | 377 | /* The process may have allocated an io port bitmap... nuke it. */ |
b3cf2576 SE |
378 | if (unlikely(test_thread_flag(TIF_IO_BITMAP))) { |
379 | struct task_struct *tsk = current; | |
380 | struct thread_struct *t = &tsk->thread; | |
1da177e4 LT |
381 | int cpu = get_cpu(); |
382 | struct tss_struct *tss = &per_cpu(init_tss, cpu); | |
383 | ||
384 | kfree(t->io_bitmap_ptr); | |
385 | t->io_bitmap_ptr = NULL; | |
b3cf2576 | 386 | clear_thread_flag(TIF_IO_BITMAP); |
1da177e4 LT |
387 | /* |
388 | * Careful, clear this in the TSS too: | |
389 | */ | |
390 | memset(tss->io_bitmap, 0xff, tss->io_bitmap_max); | |
391 | t->io_bitmap_max = 0; | |
392 | tss->io_bitmap_owner = NULL; | |
393 | tss->io_bitmap_max = 0; | |
a75c54f9 | 394 | tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET; |
1da177e4 LT |
395 | put_cpu(); |
396 | } | |
397 | } | |
398 | ||
399 | void flush_thread(void) | |
400 | { | |
401 | struct task_struct *tsk = current; | |
402 | ||
403 | memset(tsk->thread.debugreg, 0, sizeof(unsigned long)*8); | |
404 | memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array)); | |
b3cf2576 | 405 | clear_tsk_thread_flag(tsk, TIF_DEBUG); |
1da177e4 LT |
406 | /* |
407 | * Forget coprocessor state.. | |
408 | */ | |
409 | clear_fpu(tsk); | |
410 | clear_used_math(); | |
411 | } | |
412 | ||
413 | void release_thread(struct task_struct *dead_task) | |
414 | { | |
2684927c | 415 | BUG_ON(dead_task->mm); |
1da177e4 LT |
416 | release_vm86_irqs(dead_task); |
417 | } | |
418 | ||
419 | /* | |
420 | * This gets called before we allocate a new thread and copy | |
421 | * the current task into it. | |
422 | */ | |
423 | void prepare_to_copy(struct task_struct *tsk) | |
424 | { | |
425 | unlazy_fpu(tsk); | |
426 | } | |
427 | ||
428 | int copy_thread(int nr, unsigned long clone_flags, unsigned long esp, | |
429 | unsigned long unused, | |
430 | struct task_struct * p, struct pt_regs * regs) | |
431 | { | |
432 | struct pt_regs * childregs; | |
433 | struct task_struct *tsk; | |
434 | int err; | |
435 | ||
07b047fc | 436 | childregs = task_pt_regs(p); |
f48d9663 AN |
437 | *childregs = *regs; |
438 | childregs->eax = 0; | |
439 | childregs->esp = esp; | |
440 | ||
441 | p->thread.esp = (unsigned long) childregs; | |
442 | p->thread.esp0 = (unsigned long) (childregs+1); | |
1da177e4 LT |
443 | |
444 | p->thread.eip = (unsigned long) ret_from_fork; | |
445 | ||
464d1a78 | 446 | savesegment(gs,p->thread.gs); |
1da177e4 LT |
447 | |
448 | tsk = current; | |
b3cf2576 | 449 | if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) { |
52978be6 AD |
450 | p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr, |
451 | IO_BITMAP_BYTES, GFP_KERNEL); | |
1da177e4 LT |
452 | if (!p->thread.io_bitmap_ptr) { |
453 | p->thread.io_bitmap_max = 0; | |
454 | return -ENOMEM; | |
455 | } | |
b3cf2576 | 456 | set_tsk_thread_flag(p, TIF_IO_BITMAP); |
1da177e4 LT |
457 | } |
458 | ||
459 | /* | |
460 | * Set a new TLS for the child thread? | |
461 | */ | |
462 | if (clone_flags & CLONE_SETTLS) { | |
463 | struct desc_struct *desc; | |
464 | struct user_desc info; | |
465 | int idx; | |
466 | ||
467 | err = -EFAULT; | |
468 | if (copy_from_user(&info, (void __user *)childregs->esi, sizeof(info))) | |
469 | goto out; | |
470 | err = -EINVAL; | |
471 | if (LDT_empty(&info)) | |
472 | goto out; | |
473 | ||
474 | idx = info.entry_number; | |
475 | if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) | |
476 | goto out; | |
477 | ||
478 | desc = p->thread.tls_array + idx - GDT_ENTRY_TLS_MIN; | |
479 | desc->a = LDT_entry_a(&info); | |
480 | desc->b = LDT_entry_b(&info); | |
481 | } | |
482 | ||
483 | err = 0; | |
484 | out: | |
485 | if (err && p->thread.io_bitmap_ptr) { | |
486 | kfree(p->thread.io_bitmap_ptr); | |
487 | p->thread.io_bitmap_max = 0; | |
488 | } | |
489 | return err; | |
490 | } | |
491 | ||
492 | /* | |
493 | * fill in the user structure for a core dump.. | |
494 | */ | |
495 | void dump_thread(struct pt_regs * regs, struct user * dump) | |
496 | { | |
497 | int i; | |
498 | ||
499 | /* changed the size calculations - should hopefully work better. lbt */ | |
500 | dump->magic = CMAGIC; | |
501 | dump->start_code = 0; | |
502 | dump->start_stack = regs->esp & ~(PAGE_SIZE - 1); | |
503 | dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT; | |
504 | dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT; | |
505 | dump->u_dsize -= dump->u_tsize; | |
506 | dump->u_ssize = 0; | |
507 | for (i = 0; i < 8; i++) | |
508 | dump->u_debugreg[i] = current->thread.debugreg[i]; | |
509 | ||
510 | if (dump->start_stack < TASK_SIZE) | |
511 | dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT; | |
512 | ||
513 | dump->regs.ebx = regs->ebx; | |
514 | dump->regs.ecx = regs->ecx; | |
515 | dump->regs.edx = regs->edx; | |
516 | dump->regs.esi = regs->esi; | |
517 | dump->regs.edi = regs->edi; | |
518 | dump->regs.ebp = regs->ebp; | |
519 | dump->regs.eax = regs->eax; | |
520 | dump->regs.ds = regs->xds; | |
521 | dump->regs.es = regs->xes; | |
464d1a78 JF |
522 | dump->regs.fs = regs->xfs; |
523 | savesegment(gs,dump->regs.gs); | |
1da177e4 LT |
524 | dump->regs.orig_eax = regs->orig_eax; |
525 | dump->regs.eip = regs->eip; | |
526 | dump->regs.cs = regs->xcs; | |
527 | dump->regs.eflags = regs->eflags; | |
528 | dump->regs.esp = regs->esp; | |
529 | dump->regs.ss = regs->xss; | |
530 | ||
531 | dump->u_fpvalid = dump_fpu (regs, &dump->i387); | |
532 | } | |
129f6946 | 533 | EXPORT_SYMBOL(dump_thread); |
1da177e4 LT |
534 | |
535 | /* | |
536 | * Capture the user space registers if the task is not running (in user space) | |
537 | */ | |
538 | int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) | |
539 | { | |
07b047fc | 540 | struct pt_regs ptregs = *task_pt_regs(tsk); |
1da177e4 LT |
541 | ptregs.xcs &= 0xffff; |
542 | ptregs.xds &= 0xffff; | |
543 | ptregs.xes &= 0xffff; | |
544 | ptregs.xss &= 0xffff; | |
545 | ||
546 | elf_core_copy_regs(regs, &ptregs); | |
547 | ||
548 | return 1; | |
549 | } | |
550 | ||
cf99abac AA |
551 | #ifdef CONFIG_SECCOMP |
552 | void hard_disable_TSC(void) | |
553 | { | |
554 | write_cr4(read_cr4() | X86_CR4_TSD); | |
555 | } | |
556 | void disable_TSC(void) | |
557 | { | |
558 | preempt_disable(); | |
559 | if (!test_and_set_thread_flag(TIF_NOTSC)) | |
560 | /* | |
561 | * Must flip the CPU state synchronously with | |
562 | * TIF_NOTSC in the current running context. | |
563 | */ | |
564 | hard_disable_TSC(); | |
565 | preempt_enable(); | |
566 | } | |
567 | void hard_enable_TSC(void) | |
568 | { | |
569 | write_cr4(read_cr4() & ~X86_CR4_TSD); | |
570 | } | |
571 | #endif /* CONFIG_SECCOMP */ | |
572 | ||
573 | static noinline void | |
574 | __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, | |
575 | struct tss_struct *tss) | |
1da177e4 | 576 | { |
b3cf2576 SE |
577 | struct thread_struct *next; |
578 | ||
579 | next = &next_p->thread; | |
580 | ||
581 | if (test_tsk_thread_flag(next_p, TIF_DEBUG)) { | |
582 | set_debugreg(next->debugreg[0], 0); | |
583 | set_debugreg(next->debugreg[1], 1); | |
584 | set_debugreg(next->debugreg[2], 2); | |
585 | set_debugreg(next->debugreg[3], 3); | |
586 | /* no 4 and 5 */ | |
587 | set_debugreg(next->debugreg[6], 6); | |
588 | set_debugreg(next->debugreg[7], 7); | |
589 | } | |
590 | ||
cf99abac AA |
591 | #ifdef CONFIG_SECCOMP |
592 | if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^ | |
593 | test_tsk_thread_flag(next_p, TIF_NOTSC)) { | |
594 | /* prev and next are different */ | |
595 | if (test_tsk_thread_flag(next_p, TIF_NOTSC)) | |
596 | hard_disable_TSC(); | |
597 | else | |
598 | hard_enable_TSC(); | |
599 | } | |
600 | #endif | |
601 | ||
b3cf2576 | 602 | if (!test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) { |
1da177e4 LT |
603 | /* |
604 | * Disable the bitmap via an invalid offset. We still cache | |
605 | * the previous bitmap owner and the IO bitmap contents: | |
606 | */ | |
a75c54f9 | 607 | tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET; |
1da177e4 LT |
608 | return; |
609 | } | |
b3cf2576 | 610 | |
1da177e4 LT |
611 | if (likely(next == tss->io_bitmap_owner)) { |
612 | /* | |
613 | * Previous owner of the bitmap (hence the bitmap content) | |
614 | * matches the next task, we dont have to do anything but | |
615 | * to set a valid offset in the TSS: | |
616 | */ | |
a75c54f9 | 617 | tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET; |
1da177e4 LT |
618 | return; |
619 | } | |
620 | /* | |
621 | * Lazy TSS's I/O bitmap copy. We set an invalid offset here | |
622 | * and we let the task to get a GPF in case an I/O instruction | |
623 | * is performed. The handler of the GPF will verify that the | |
624 | * faulting task has a valid I/O bitmap and, it true, does the | |
625 | * real copy and restart the instruction. This will save us | |
626 | * redundant copies when the currently switched task does not | |
627 | * perform any I/O during its timeslice. | |
628 | */ | |
a75c54f9 | 629 | tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET_LAZY; |
1da177e4 | 630 | } |
1da177e4 LT |
631 | |
632 | /* | |
633 | * switch_to(x,yn) should switch tasks from x to y. | |
634 | * | |
635 | * We fsave/fwait so that an exception goes off at the right time | |
636 | * (as a call from the fsave or fwait in effect) rather than to | |
637 | * the wrong process. Lazy FP saving no longer makes any sense | |
638 | * with modern CPU's, and this simplifies a lot of things (SMP | |
639 | * and UP become the same). | |
640 | * | |
641 | * NOTE! We used to use the x86 hardware context switching. The | |
642 | * reason for not using it any more becomes apparent when you | |
643 | * try to recover gracefully from saved state that is no longer | |
644 | * valid (stale segment register values in particular). With the | |
645 | * hardware task-switch, there is no way to fix up bad state in | |
646 | * a reasonable manner. | |
647 | * | |
648 | * The fact that Intel documents the hardware task-switching to | |
649 | * be slow is a fairly red herring - this code is not noticeably | |
650 | * faster. However, there _is_ some room for improvement here, | |
651 | * so the performance issues may eventually be a valid point. | |
652 | * More important, however, is the fact that this allows us much | |
653 | * more flexibility. | |
654 | * | |
655 | * The return value (in %eax) will be the "prev" task after | |
656 | * the task-switch, and shows up in ret_from_fork in entry.S, | |
657 | * for example. | |
658 | */ | |
659 | struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct task_struct *next_p) | |
660 | { | |
661 | struct thread_struct *prev = &prev_p->thread, | |
662 | *next = &next_p->thread; | |
663 | int cpu = smp_processor_id(); | |
664 | struct tss_struct *tss = &per_cpu(init_tss, cpu); | |
665 | ||
666 | /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */ | |
667 | ||
668 | __unlazy_fpu(prev_p); | |
669 | ||
acc20761 CE |
670 | |
671 | /* we're going to use this soon, after a few expensive things */ | |
672 | if (next_p->fpu_counter > 5) | |
673 | prefetch(&next->i387.fxsave); | |
674 | ||
1da177e4 | 675 | /* |
e7a2ff59 | 676 | * Reload esp0. |
1da177e4 LT |
677 | */ |
678 | load_esp0(tss, next); | |
679 | ||
680 | /* | |
464d1a78 | 681 | * Save away %gs. No need to save %fs, as it was saved on the |
f95d47ca JF |
682 | * stack on entry. No need to save %es and %ds, as those are |
683 | * always kernel segments while inside the kernel. Doing this | |
684 | * before setting the new TLS descriptors avoids the situation | |
685 | * where we temporarily have non-reloadable segments in %fs | |
686 | * and %gs. This could be an issue if the NMI handler ever | |
687 | * used %fs or %gs (it does not today), or if the kernel is | |
688 | * running inside of a hypervisor layer. | |
1da177e4 | 689 | */ |
464d1a78 | 690 | savesegment(gs, prev->gs); |
1da177e4 LT |
691 | |
692 | /* | |
e7a2ff59 | 693 | * Load the per-thread Thread-Local Storage descriptor. |
1da177e4 | 694 | */ |
e7a2ff59 | 695 | load_TLS(next, cpu); |
1da177e4 | 696 | |
8b151144 ZA |
697 | /* |
698 | * Restore IOPL if needed. In normal use, the flags restore | |
699 | * in the switch assembly will handle this. But if the kernel | |
700 | * is running virtualized at a non-zero CPL, the popf will | |
701 | * not restore flags, so it must be done in a separate step. | |
702 | */ | |
703 | if (get_kernel_rpl() && unlikely(prev->iopl != next->iopl)) | |
704 | set_iopl_mask(next->iopl); | |
705 | ||
1da177e4 | 706 | /* |
b3cf2576 | 707 | * Now maybe handle debug registers and/or IO bitmaps |
1da177e4 | 708 | */ |
cf99abac AA |
709 | if (unlikely(task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV || |
710 | task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT)) | |
711 | __switch_to_xtra(prev_p, next_p, tss); | |
ffaa8bd6 | 712 | |
9226d125 ZA |
713 | /* |
714 | * Leave lazy mode, flushing any hypercalls made here. | |
715 | * This must be done before restoring TLS segments so | |
716 | * the GDT and LDT are properly updated, and must be | |
717 | * done before math_state_restore, so the TS bit is up | |
718 | * to date. | |
719 | */ | |
720 | arch_leave_lazy_cpu_mode(); | |
721 | ||
acc20761 CE |
722 | /* If the task has used fpu the last 5 timeslices, just do a full |
723 | * restore of the math state immediately to avoid the trap; the | |
724 | * chances of needing FPU soon are obviously high now | |
725 | */ | |
726 | if (next_p->fpu_counter > 5) | |
727 | math_state_restore(); | |
728 | ||
9226d125 ZA |
729 | /* |
730 | * Restore %gs if needed (which is common) | |
731 | */ | |
732 | if (prev->gs | next->gs) | |
733 | loadsegment(gs, next->gs); | |
734 | ||
7c3576d2 | 735 | x86_write_percpu(current_task, next_p); |
9226d125 | 736 | |
1da177e4 LT |
737 | return prev_p; |
738 | } | |
739 | ||
740 | asmlinkage int sys_fork(struct pt_regs regs) | |
741 | { | |
742 | return do_fork(SIGCHLD, regs.esp, ®s, 0, NULL, NULL); | |
743 | } | |
744 | ||
745 | asmlinkage int sys_clone(struct pt_regs regs) | |
746 | { | |
747 | unsigned long clone_flags; | |
748 | unsigned long newsp; | |
749 | int __user *parent_tidptr, *child_tidptr; | |
750 | ||
751 | clone_flags = regs.ebx; | |
752 | newsp = regs.ecx; | |
753 | parent_tidptr = (int __user *)regs.edx; | |
754 | child_tidptr = (int __user *)regs.edi; | |
755 | if (!newsp) | |
756 | newsp = regs.esp; | |
757 | return do_fork(clone_flags, newsp, ®s, 0, parent_tidptr, child_tidptr); | |
758 | } | |
759 | ||
760 | /* | |
761 | * This is trivial, and on the face of it looks like it | |
762 | * could equally well be done in user mode. | |
763 | * | |
764 | * Not so, for quite unobvious reasons - register pressure. | |
765 | * In user mode vfork() cannot have a stack frame, and if | |
766 | * done by calling the "clone()" system call directly, you | |
767 | * do not have enough call-clobbered registers to hold all | |
768 | * the information you need. | |
769 | */ | |
770 | asmlinkage int sys_vfork(struct pt_regs regs) | |
771 | { | |
772 | return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.esp, ®s, 0, NULL, NULL); | |
773 | } | |
774 | ||
775 | /* | |
776 | * sys_execve() executes a new program. | |
777 | */ | |
778 | asmlinkage int sys_execve(struct pt_regs regs) | |
779 | { | |
780 | int error; | |
781 | char * filename; | |
782 | ||
783 | filename = getname((char __user *) regs.ebx); | |
784 | error = PTR_ERR(filename); | |
785 | if (IS_ERR(filename)) | |
786 | goto out; | |
787 | error = do_execve(filename, | |
788 | (char __user * __user *) regs.ecx, | |
789 | (char __user * __user *) regs.edx, | |
790 | ®s); | |
791 | if (error == 0) { | |
792 | task_lock(current); | |
793 | current->ptrace &= ~PT_DTRACE; | |
794 | task_unlock(current); | |
795 | /* Make sure we don't return using sysenter.. */ | |
796 | set_thread_flag(TIF_IRET); | |
797 | } | |
798 | putname(filename); | |
799 | out: | |
800 | return error; | |
801 | } | |
802 | ||
803 | #define top_esp (THREAD_SIZE - sizeof(unsigned long)) | |
804 | #define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long)) | |
805 | ||
806 | unsigned long get_wchan(struct task_struct *p) | |
807 | { | |
808 | unsigned long ebp, esp, eip; | |
809 | unsigned long stack_page; | |
810 | int count = 0; | |
811 | if (!p || p == current || p->state == TASK_RUNNING) | |
812 | return 0; | |
65e0fdff | 813 | stack_page = (unsigned long)task_stack_page(p); |
1da177e4 LT |
814 | esp = p->thread.esp; |
815 | if (!stack_page || esp < stack_page || esp > top_esp+stack_page) | |
816 | return 0; | |
817 | /* include/asm-i386/system.h:switch_to() pushes ebp last. */ | |
818 | ebp = *(unsigned long *) esp; | |
819 | do { | |
820 | if (ebp < stack_page || ebp > top_ebp+stack_page) | |
821 | return 0; | |
822 | eip = *(unsigned long *) (ebp+4); | |
823 | if (!in_sched_functions(eip)) | |
824 | return eip; | |
825 | ebp = *(unsigned long *) ebp; | |
826 | } while (count++ < 16); | |
827 | return 0; | |
828 | } | |
829 | ||
830 | /* | |
831 | * sys_alloc_thread_area: get a yet unused TLS descriptor index. | |
832 | */ | |
833 | static int get_free_idx(void) | |
834 | { | |
835 | struct thread_struct *t = ¤t->thread; | |
836 | int idx; | |
837 | ||
838 | for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++) | |
839 | if (desc_empty(t->tls_array + idx)) | |
840 | return idx + GDT_ENTRY_TLS_MIN; | |
841 | return -ESRCH; | |
842 | } | |
843 | ||
844 | /* | |
845 | * Set a given TLS descriptor: | |
846 | */ | |
847 | asmlinkage int sys_set_thread_area(struct user_desc __user *u_info) | |
848 | { | |
849 | struct thread_struct *t = ¤t->thread; | |
850 | struct user_desc info; | |
851 | struct desc_struct *desc; | |
852 | int cpu, idx; | |
853 | ||
854 | if (copy_from_user(&info, u_info, sizeof(info))) | |
855 | return -EFAULT; | |
856 | idx = info.entry_number; | |
857 | ||
858 | /* | |
859 | * index -1 means the kernel should try to find and | |
860 | * allocate an empty descriptor: | |
861 | */ | |
862 | if (idx == -1) { | |
863 | idx = get_free_idx(); | |
864 | if (idx < 0) | |
865 | return idx; | |
866 | if (put_user(idx, &u_info->entry_number)) | |
867 | return -EFAULT; | |
868 | } | |
869 | ||
870 | if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) | |
871 | return -EINVAL; | |
872 | ||
873 | desc = t->tls_array + idx - GDT_ENTRY_TLS_MIN; | |
874 | ||
875 | /* | |
876 | * We must not get preempted while modifying the TLS. | |
877 | */ | |
878 | cpu = get_cpu(); | |
879 | ||
880 | if (LDT_empty(&info)) { | |
881 | desc->a = 0; | |
882 | desc->b = 0; | |
883 | } else { | |
884 | desc->a = LDT_entry_a(&info); | |
885 | desc->b = LDT_entry_b(&info); | |
886 | } | |
887 | load_TLS(t, cpu); | |
888 | ||
889 | put_cpu(); | |
890 | ||
891 | return 0; | |
892 | } | |
893 | ||
894 | /* | |
895 | * Get the current Thread-Local Storage area: | |
896 | */ | |
897 | ||
898 | #define GET_BASE(desc) ( \ | |
899 | (((desc)->a >> 16) & 0x0000ffff) | \ | |
900 | (((desc)->b << 16) & 0x00ff0000) | \ | |
901 | ( (desc)->b & 0xff000000) ) | |
902 | ||
903 | #define GET_LIMIT(desc) ( \ | |
904 | ((desc)->a & 0x0ffff) | \ | |
905 | ((desc)->b & 0xf0000) ) | |
906 | ||
907 | #define GET_32BIT(desc) (((desc)->b >> 22) & 1) | |
908 | #define GET_CONTENTS(desc) (((desc)->b >> 10) & 3) | |
909 | #define GET_WRITABLE(desc) (((desc)->b >> 9) & 1) | |
910 | #define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1) | |
911 | #define GET_PRESENT(desc) (((desc)->b >> 15) & 1) | |
912 | #define GET_USEABLE(desc) (((desc)->b >> 20) & 1) | |
913 | ||
914 | asmlinkage int sys_get_thread_area(struct user_desc __user *u_info) | |
915 | { | |
916 | struct user_desc info; | |
917 | struct desc_struct *desc; | |
918 | int idx; | |
919 | ||
920 | if (get_user(idx, &u_info->entry_number)) | |
921 | return -EFAULT; | |
922 | if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) | |
923 | return -EINVAL; | |
924 | ||
71ae18ec B |
925 | memset(&info, 0, sizeof(info)); |
926 | ||
1da177e4 LT |
927 | desc = current->thread.tls_array + idx - GDT_ENTRY_TLS_MIN; |
928 | ||
929 | info.entry_number = idx; | |
930 | info.base_addr = GET_BASE(desc); | |
931 | info.limit = GET_LIMIT(desc); | |
932 | info.seg_32bit = GET_32BIT(desc); | |
933 | info.contents = GET_CONTENTS(desc); | |
934 | info.read_exec_only = !GET_WRITABLE(desc); | |
935 | info.limit_in_pages = GET_LIMIT_PAGES(desc); | |
936 | info.seg_not_present = !GET_PRESENT(desc); | |
937 | info.useable = GET_USEABLE(desc); | |
938 | ||
939 | if (copy_to_user(u_info, &info, sizeof(info))) | |
940 | return -EFAULT; | |
941 | return 0; | |
942 | } | |
943 | ||
944 | unsigned long arch_align_stack(unsigned long sp) | |
945 | { | |
c16b63e0 | 946 | if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) |
1da177e4 LT |
947 | sp -= get_random_int() % 8192; |
948 | return sp & ~0xf; | |
949 | } |