Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/arch/x86-64/kernel/process.c | |
3 | * | |
4 | * Copyright (C) 1995 Linus Torvalds | |
5 | * | |
6 | * Pentium III FXSR, SSE support | |
7 | * Gareth Hughes <gareth@valinux.com>, May 2000 | |
8 | * | |
9 | * X86-64 port | |
10 | * Andi Kleen. | |
76e4f660 AR |
11 | * |
12 | * CPU hotplug support - ashok.raj@intel.com | |
1da177e4 LT |
13 | */ |
14 | ||
15 | /* | |
16 | * This file handles the architecture-dependent parts of process handling.. | |
17 | */ | |
18 | ||
19 | #include <stdarg.h> | |
20 | ||
76e4f660 | 21 | #include <linux/cpu.h> |
1da177e4 LT |
22 | #include <linux/errno.h> |
23 | #include <linux/sched.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/mm.h> | |
26 | #include <linux/elfcore.h> | |
27 | #include <linux/smp.h> | |
28 | #include <linux/slab.h> | |
29 | #include <linux/user.h> | |
30 | #include <linux/module.h> | |
31 | #include <linux/a.out.h> | |
32 | #include <linux/interrupt.h> | |
33 | #include <linux/delay.h> | |
1da177e4 LT |
34 | #include <linux/ptrace.h> |
35 | #include <linux/utsname.h> | |
36 | #include <linux/random.h> | |
95833c83 | 37 | #include <linux/notifier.h> |
c6fd91f0 | 38 | #include <linux/kprobes.h> |
1eeb66a1 | 39 | #include <linux/kdebug.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/processor.h> | |
46 | #include <asm/i387.h> | |
47 | #include <asm/mmu_context.h> | |
48 | #include <asm/pda.h> | |
49 | #include <asm/prctl.h> | |
1da177e4 LT |
50 | #include <asm/desc.h> |
51 | #include <asm/proto.h> | |
52 | #include <asm/ia32.h> | |
95833c83 | 53 | #include <asm/idle.h> |
1da177e4 LT |
54 | |
55 | asmlinkage extern void ret_from_fork(void); | |
56 | ||
57 | unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED; | |
58 | ||
1da177e4 LT |
59 | unsigned long boot_option_idle_override = 0; |
60 | EXPORT_SYMBOL(boot_option_idle_override); | |
61 | ||
62 | /* | |
63 | * Powermanagement idle function, if any.. | |
64 | */ | |
65 | void (*pm_idle)(void); | |
2ee60e17 | 66 | EXPORT_SYMBOL(pm_idle); |
1da177e4 LT |
67 | static DEFINE_PER_CPU(unsigned int, cpu_idle_state); |
68 | ||
e041c683 | 69 | static ATOMIC_NOTIFIER_HEAD(idle_notifier); |
95833c83 AK |
70 | |
71 | void idle_notifier_register(struct notifier_block *n) | |
72 | { | |
e041c683 | 73 | atomic_notifier_chain_register(&idle_notifier, n); |
95833c83 AK |
74 | } |
75 | EXPORT_SYMBOL_GPL(idle_notifier_register); | |
76 | ||
77 | void idle_notifier_unregister(struct notifier_block *n) | |
78 | { | |
e041c683 | 79 | atomic_notifier_chain_unregister(&idle_notifier, n); |
95833c83 AK |
80 | } |
81 | EXPORT_SYMBOL(idle_notifier_unregister); | |
82 | ||
95833c83 AK |
83 | void enter_idle(void) |
84 | { | |
a15da49d | 85 | write_pda(isidle, 1); |
e041c683 | 86 | atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL); |
95833c83 AK |
87 | } |
88 | ||
89 | static void __exit_idle(void) | |
90 | { | |
9446868b | 91 | if (test_and_clear_bit_pda(0, isidle) == 0) |
a15da49d | 92 | return; |
e041c683 | 93 | atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL); |
95833c83 AK |
94 | } |
95 | ||
96 | /* Called from interrupts to signify idle end */ | |
97 | void exit_idle(void) | |
98 | { | |
a15da49d AK |
99 | /* idle loop has pid 0 */ |
100 | if (current->pid) | |
95833c83 AK |
101 | return; |
102 | __exit_idle(); | |
103 | } | |
104 | ||
1da177e4 LT |
105 | /* |
106 | * We use this if we don't have any better | |
107 | * idle routine.. | |
108 | */ | |
cdb04527 | 109 | static void default_idle(void) |
1da177e4 | 110 | { |
495ab9c0 | 111 | current_thread_info()->status &= ~TS_POLLING; |
0888f06a IM |
112 | /* |
113 | * TS_POLLING-cleared state must be visible before we | |
114 | * test NEED_RESCHED: | |
115 | */ | |
116 | smp_mb(); | |
72690a21 AK |
117 | local_irq_disable(); |
118 | if (!need_resched()) { | |
119 | /* Enables interrupts one instruction before HLT. | |
120 | x86 special cases this so there is no race. */ | |
121 | safe_halt(); | |
122 | } else | |
123 | local_irq_enable(); | |
495ab9c0 | 124 | current_thread_info()->status |= TS_POLLING; |
1da177e4 LT |
125 | } |
126 | ||
127 | /* | |
128 | * On SMP it's slightly faster (but much more power-consuming!) | |
129 | * to poll the ->need_resched flag instead of waiting for the | |
130 | * cross-CPU IPI to arrive. Use this option with caution. | |
131 | */ | |
132 | static void poll_idle (void) | |
133 | { | |
d331e739 | 134 | local_irq_enable(); |
72690a21 | 135 | cpu_relax(); |
1da177e4 LT |
136 | } |
137 | ||
138 | void cpu_idle_wait(void) | |
139 | { | |
140 | unsigned int cpu, this_cpu = get_cpu(); | |
dc1829a4 | 141 | cpumask_t map, tmp = current->cpus_allowed; |
1da177e4 LT |
142 | |
143 | set_cpus_allowed(current, cpumask_of_cpu(this_cpu)); | |
144 | put_cpu(); | |
145 | ||
146 | cpus_clear(map); | |
147 | for_each_online_cpu(cpu) { | |
148 | per_cpu(cpu_idle_state, cpu) = 1; | |
149 | cpu_set(cpu, map); | |
150 | } | |
151 | ||
152 | __get_cpu_var(cpu_idle_state) = 0; | |
153 | ||
154 | wmb(); | |
155 | do { | |
156 | ssleep(1); | |
157 | for_each_online_cpu(cpu) { | |
a88cde13 AK |
158 | if (cpu_isset(cpu, map) && |
159 | !per_cpu(cpu_idle_state, cpu)) | |
1da177e4 LT |
160 | cpu_clear(cpu, map); |
161 | } | |
162 | cpus_and(map, map, cpu_online_map); | |
163 | } while (!cpus_empty(map)); | |
dc1829a4 IM |
164 | |
165 | set_cpus_allowed(current, tmp); | |
1da177e4 LT |
166 | } |
167 | EXPORT_SYMBOL_GPL(cpu_idle_wait); | |
168 | ||
76e4f660 AR |
169 | #ifdef CONFIG_HOTPLUG_CPU |
170 | DECLARE_PER_CPU(int, cpu_state); | |
171 | ||
172 | #include <asm/nmi.h> | |
1fa744e6 | 173 | /* We halt the CPU with physical CPU hotplug */ |
76e4f660 AR |
174 | static inline void play_dead(void) |
175 | { | |
176 | idle_task_exit(); | |
177 | wbinvd(); | |
178 | mb(); | |
179 | /* Ack it */ | |
180 | __get_cpu_var(cpu_state) = CPU_DEAD; | |
181 | ||
1fa744e6 | 182 | local_irq_disable(); |
76e4f660 | 183 | while (1) |
1fa744e6 | 184 | halt(); |
76e4f660 AR |
185 | } |
186 | #else | |
187 | static inline void play_dead(void) | |
188 | { | |
189 | BUG(); | |
190 | } | |
191 | #endif /* CONFIG_HOTPLUG_CPU */ | |
192 | ||
1da177e4 LT |
193 | /* |
194 | * The idle thread. There's no useful work to be | |
195 | * done, so just try to conserve power and have a | |
196 | * low exit latency (ie sit in a loop waiting for | |
197 | * somebody to say that they'd like to reschedule) | |
198 | */ | |
199 | void cpu_idle (void) | |
200 | { | |
495ab9c0 | 201 | current_thread_info()->status |= TS_POLLING; |
1da177e4 LT |
202 | /* endless idle loop with no priority at all */ |
203 | while (1) { | |
204 | while (!need_resched()) { | |
205 | void (*idle)(void); | |
206 | ||
207 | if (__get_cpu_var(cpu_idle_state)) | |
208 | __get_cpu_var(cpu_idle_state) = 0; | |
209 | ||
210 | rmb(); | |
211 | idle = pm_idle; | |
212 | if (!idle) | |
213 | idle = default_idle; | |
76e4f660 AR |
214 | if (cpu_is_offline(smp_processor_id())) |
215 | play_dead(); | |
d331e739 VP |
216 | /* |
217 | * Idle routines should keep interrupts disabled | |
218 | * from here on, until they go to idle. | |
219 | * Otherwise, idle callbacks can misfire. | |
220 | */ | |
221 | local_irq_disable(); | |
95833c83 | 222 | enter_idle(); |
1da177e4 | 223 | idle(); |
a15da49d AK |
224 | /* In many cases the interrupt that ended idle |
225 | has already called exit_idle. But some idle | |
226 | loops can be woken up without interrupt. */ | |
95833c83 | 227 | __exit_idle(); |
1da177e4 LT |
228 | } |
229 | ||
5bfb5d69 | 230 | preempt_enable_no_resched(); |
1da177e4 | 231 | schedule(); |
5bfb5d69 | 232 | preempt_disable(); |
1da177e4 LT |
233 | } |
234 | } | |
235 | ||
236 | /* | |
237 | * This uses new MONITOR/MWAIT instructions on P4 processors with PNI, | |
238 | * which can obviate IPI to trigger checking of need_resched. | |
239 | * We execute MONITOR against need_resched and enter optimized wait state | |
240 | * through MWAIT. Whenever someone changes need_resched, we would be woken | |
241 | * up from MWAIT (without an IPI). | |
991528d7 VP |
242 | * |
243 | * New with Core Duo processors, MWAIT can take some hints based on CPU | |
244 | * capability. | |
1da177e4 | 245 | */ |
991528d7 | 246 | void mwait_idle_with_hints(unsigned long eax, unsigned long ecx) |
1da177e4 | 247 | { |
991528d7 | 248 | if (!need_resched()) { |
64c7c8f8 NP |
249 | __monitor((void *)¤t_thread_info()->flags, 0, 0); |
250 | smp_mb(); | |
991528d7 VP |
251 | if (!need_resched()) |
252 | __mwait(eax, ecx); | |
1da177e4 LT |
253 | } |
254 | } | |
255 | ||
991528d7 VP |
256 | /* Default MONITOR/MWAIT with no hints, used for default C1 state */ |
257 | static void mwait_idle(void) | |
258 | { | |
d331e739 VP |
259 | if (!need_resched()) { |
260 | __monitor((void *)¤t_thread_info()->flags, 0, 0); | |
261 | smp_mb(); | |
262 | if (!need_resched()) | |
263 | __sti_mwait(0, 0); | |
264 | else | |
265 | local_irq_enable(); | |
266 | } else { | |
267 | local_irq_enable(); | |
268 | } | |
991528d7 VP |
269 | } |
270 | ||
e6982c67 | 271 | void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c) |
1da177e4 LT |
272 | { |
273 | static int printed; | |
274 | if (cpu_has(c, X86_FEATURE_MWAIT)) { | |
275 | /* | |
276 | * Skip, if setup has overridden idle. | |
277 | * One CPU supports mwait => All CPUs supports mwait | |
278 | */ | |
279 | if (!pm_idle) { | |
280 | if (!printed) { | |
281 | printk("using mwait in idle threads.\n"); | |
282 | printed = 1; | |
283 | } | |
284 | pm_idle = mwait_idle; | |
285 | } | |
286 | } | |
287 | } | |
288 | ||
289 | static int __init idle_setup (char *str) | |
290 | { | |
f039b754 | 291 | if (!strcmp(str, "poll")) { |
1da177e4 LT |
292 | printk("using polling idle threads.\n"); |
293 | pm_idle = poll_idle; | |
f039b754 AK |
294 | } else if (!strcmp(str, "mwait")) |
295 | force_mwait = 1; | |
296 | else | |
297 | return -1; | |
1da177e4 LT |
298 | |
299 | boot_option_idle_override = 1; | |
f039b754 | 300 | return 0; |
1da177e4 | 301 | } |
f039b754 | 302 | early_param("idle", idle_setup); |
1da177e4 LT |
303 | |
304 | /* Prints also some state that isn't saved in the pt_regs */ | |
305 | void __show_regs(struct pt_regs * regs) | |
306 | { | |
307 | unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs; | |
308 | unsigned int fsindex,gsindex; | |
309 | unsigned int ds,cs,es; | |
310 | ||
311 | printk("\n"); | |
312 | print_modules(); | |
9acf23c4 AK |
313 | printk("Pid: %d, comm: %.20s %s %s %.*s\n", |
314 | current->pid, current->comm, print_tainted(), | |
96b644bd SH |
315 | init_utsname()->release, |
316 | (int)strcspn(init_utsname()->version, " "), | |
317 | init_utsname()->version); | |
1da177e4 LT |
318 | printk("RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->rip); |
319 | printk_address(regs->rip); | |
3ac94932 | 320 | printk("RSP: %04lx:%016lx EFLAGS: %08lx\n", regs->ss, regs->rsp, |
a88cde13 | 321 | regs->eflags); |
1da177e4 LT |
322 | printk("RAX: %016lx RBX: %016lx RCX: %016lx\n", |
323 | regs->rax, regs->rbx, regs->rcx); | |
324 | printk("RDX: %016lx RSI: %016lx RDI: %016lx\n", | |
325 | regs->rdx, regs->rsi, regs->rdi); | |
326 | printk("RBP: %016lx R08: %016lx R09: %016lx\n", | |
327 | regs->rbp, regs->r8, regs->r9); | |
328 | printk("R10: %016lx R11: %016lx R12: %016lx\n", | |
329 | regs->r10, regs->r11, regs->r12); | |
330 | printk("R13: %016lx R14: %016lx R15: %016lx\n", | |
331 | regs->r13, regs->r14, regs->r15); | |
332 | ||
333 | asm("movl %%ds,%0" : "=r" (ds)); | |
334 | asm("movl %%cs,%0" : "=r" (cs)); | |
335 | asm("movl %%es,%0" : "=r" (es)); | |
336 | asm("movl %%fs,%0" : "=r" (fsindex)); | |
337 | asm("movl %%gs,%0" : "=r" (gsindex)); | |
338 | ||
339 | rdmsrl(MSR_FS_BASE, fs); | |
340 | rdmsrl(MSR_GS_BASE, gs); | |
341 | rdmsrl(MSR_KERNEL_GS_BASE, shadowgs); | |
342 | ||
343 | asm("movq %%cr0, %0": "=r" (cr0)); | |
344 | asm("movq %%cr2, %0": "=r" (cr2)); | |
345 | asm("movq %%cr3, %0": "=r" (cr3)); | |
346 | asm("movq %%cr4, %0": "=r" (cr4)); | |
347 | ||
348 | printk("FS: %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n", | |
349 | fs,fsindex,gs,gsindex,shadowgs); | |
350 | printk("CS: %04x DS: %04x ES: %04x CR0: %016lx\n", cs, ds, es, cr0); | |
351 | printk("CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2, cr3, cr4); | |
352 | } | |
353 | ||
354 | void show_regs(struct pt_regs *regs) | |
355 | { | |
c078d326 | 356 | printk("CPU %d:", smp_processor_id()); |
1da177e4 | 357 | __show_regs(regs); |
b538ed27 | 358 | show_trace(NULL, regs, (void *)(regs + 1)); |
1da177e4 LT |
359 | } |
360 | ||
361 | /* | |
362 | * Free current thread data structures etc.. | |
363 | */ | |
364 | void exit_thread(void) | |
365 | { | |
366 | struct task_struct *me = current; | |
367 | struct thread_struct *t = &me->thread; | |
73649dab | 368 | |
1da177e4 LT |
369 | if (me->thread.io_bitmap_ptr) { |
370 | struct tss_struct *tss = &per_cpu(init_tss, get_cpu()); | |
371 | ||
372 | kfree(t->io_bitmap_ptr); | |
373 | t->io_bitmap_ptr = NULL; | |
d3a4f48d | 374 | clear_thread_flag(TIF_IO_BITMAP); |
1da177e4 LT |
375 | /* |
376 | * Careful, clear this in the TSS too: | |
377 | */ | |
378 | memset(tss->io_bitmap, 0xff, t->io_bitmap_max); | |
379 | t->io_bitmap_max = 0; | |
380 | put_cpu(); | |
381 | } | |
382 | } | |
383 | ||
384 | void flush_thread(void) | |
385 | { | |
386 | struct task_struct *tsk = current; | |
1da177e4 | 387 | |
303cd153 MD |
388 | if (test_tsk_thread_flag(tsk, TIF_ABI_PENDING)) { |
389 | clear_tsk_thread_flag(tsk, TIF_ABI_PENDING); | |
390 | if (test_tsk_thread_flag(tsk, TIF_IA32)) { | |
391 | clear_tsk_thread_flag(tsk, TIF_IA32); | |
392 | } else { | |
393 | set_tsk_thread_flag(tsk, TIF_IA32); | |
4d9bc79c | 394 | current_thread_info()->status |= TS_COMPAT; |
303cd153 | 395 | } |
4d9bc79c | 396 | } |
303cd153 | 397 | clear_tsk_thread_flag(tsk, TIF_DEBUG); |
1da177e4 LT |
398 | |
399 | tsk->thread.debugreg0 = 0; | |
400 | tsk->thread.debugreg1 = 0; | |
401 | tsk->thread.debugreg2 = 0; | |
402 | tsk->thread.debugreg3 = 0; | |
403 | tsk->thread.debugreg6 = 0; | |
404 | tsk->thread.debugreg7 = 0; | |
405 | memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array)); | |
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 | { | |
415 | if (dead_task->mm) { | |
416 | if (dead_task->mm->context.size) { | |
417 | printk("WARNING: dead process %8s still has LDT? <%p/%d>\n", | |
418 | dead_task->comm, | |
419 | dead_task->mm->context.ldt, | |
420 | dead_task->mm->context.size); | |
421 | BUG(); | |
422 | } | |
423 | } | |
424 | } | |
425 | ||
426 | static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr) | |
427 | { | |
428 | struct user_desc ud = { | |
429 | .base_addr = addr, | |
430 | .limit = 0xfffff, | |
431 | .seg_32bit = 1, | |
432 | .limit_in_pages = 1, | |
433 | .useable = 1, | |
434 | }; | |
435 | struct n_desc_struct *desc = (void *)t->thread.tls_array; | |
436 | desc += tls; | |
437 | desc->a = LDT_entry_a(&ud); | |
438 | desc->b = LDT_entry_b(&ud); | |
439 | } | |
440 | ||
441 | static inline u32 read_32bit_tls(struct task_struct *t, int tls) | |
442 | { | |
443 | struct desc_struct *desc = (void *)t->thread.tls_array; | |
444 | desc += tls; | |
445 | return desc->base0 | | |
446 | (((u32)desc->base1) << 16) | | |
447 | (((u32)desc->base2) << 24); | |
448 | } | |
449 | ||
450 | /* | |
451 | * This gets called before we allocate a new thread and copy | |
452 | * the current task into it. | |
453 | */ | |
454 | void prepare_to_copy(struct task_struct *tsk) | |
455 | { | |
456 | unlazy_fpu(tsk); | |
457 | } | |
458 | ||
459 | int copy_thread(int nr, unsigned long clone_flags, unsigned long rsp, | |
460 | unsigned long unused, | |
461 | struct task_struct * p, struct pt_regs * regs) | |
462 | { | |
463 | int err; | |
464 | struct pt_regs * childregs; | |
465 | struct task_struct *me = current; | |
466 | ||
a88cde13 | 467 | childregs = ((struct pt_regs *) |
57eafdc2 | 468 | (THREAD_SIZE + task_stack_page(p))) - 1; |
1da177e4 LT |
469 | *childregs = *regs; |
470 | ||
471 | childregs->rax = 0; | |
472 | childregs->rsp = rsp; | |
a88cde13 | 473 | if (rsp == ~0UL) |
1da177e4 | 474 | childregs->rsp = (unsigned long)childregs; |
1da177e4 LT |
475 | |
476 | p->thread.rsp = (unsigned long) childregs; | |
477 | p->thread.rsp0 = (unsigned long) (childregs+1); | |
478 | p->thread.userrsp = me->thread.userrsp; | |
479 | ||
e4f17c43 | 480 | set_tsk_thread_flag(p, TIF_FORK); |
1da177e4 LT |
481 | |
482 | p->thread.fs = me->thread.fs; | |
483 | p->thread.gs = me->thread.gs; | |
484 | ||
fd51f666 L |
485 | asm("mov %%gs,%0" : "=m" (p->thread.gsindex)); |
486 | asm("mov %%fs,%0" : "=m" (p->thread.fsindex)); | |
487 | asm("mov %%es,%0" : "=m" (p->thread.es)); | |
488 | asm("mov %%ds,%0" : "=m" (p->thread.ds)); | |
1da177e4 | 489 | |
d3a4f48d | 490 | if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) { |
1da177e4 LT |
491 | p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL); |
492 | if (!p->thread.io_bitmap_ptr) { | |
493 | p->thread.io_bitmap_max = 0; | |
494 | return -ENOMEM; | |
495 | } | |
a88cde13 AK |
496 | memcpy(p->thread.io_bitmap_ptr, me->thread.io_bitmap_ptr, |
497 | IO_BITMAP_BYTES); | |
d3a4f48d | 498 | set_tsk_thread_flag(p, TIF_IO_BITMAP); |
1da177e4 LT |
499 | } |
500 | ||
501 | /* | |
502 | * Set a new TLS for the child thread? | |
503 | */ | |
504 | if (clone_flags & CLONE_SETTLS) { | |
505 | #ifdef CONFIG_IA32_EMULATION | |
506 | if (test_thread_flag(TIF_IA32)) | |
507 | err = ia32_child_tls(p, childregs); | |
508 | else | |
509 | #endif | |
510 | err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8); | |
511 | if (err) | |
512 | goto out; | |
513 | } | |
514 | err = 0; | |
515 | out: | |
516 | if (err && p->thread.io_bitmap_ptr) { | |
517 | kfree(p->thread.io_bitmap_ptr); | |
518 | p->thread.io_bitmap_max = 0; | |
519 | } | |
520 | return err; | |
521 | } | |
522 | ||
523 | /* | |
524 | * This special macro can be used to load a debugging register | |
525 | */ | |
2b514e74 | 526 | #define loaddebug(thread,r) set_debugreg(thread->debugreg ## r, r) |
1da177e4 | 527 | |
d3a4f48d SE |
528 | static inline void __switch_to_xtra(struct task_struct *prev_p, |
529 | struct task_struct *next_p, | |
530 | struct tss_struct *tss) | |
531 | { | |
532 | struct thread_struct *prev, *next; | |
533 | ||
534 | prev = &prev_p->thread, | |
535 | next = &next_p->thread; | |
536 | ||
537 | if (test_tsk_thread_flag(next_p, TIF_DEBUG)) { | |
538 | loaddebug(next, 0); | |
539 | loaddebug(next, 1); | |
540 | loaddebug(next, 2); | |
541 | loaddebug(next, 3); | |
542 | /* no 4 and 5 */ | |
543 | loaddebug(next, 6); | |
544 | loaddebug(next, 7); | |
545 | } | |
546 | ||
547 | if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) { | |
548 | /* | |
549 | * Copy the relevant range of the IO bitmap. | |
550 | * Normally this is 128 bytes or less: | |
551 | */ | |
552 | memcpy(tss->io_bitmap, next->io_bitmap_ptr, | |
553 | max(prev->io_bitmap_max, next->io_bitmap_max)); | |
554 | } else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) { | |
555 | /* | |
556 | * Clear any possible leftover bits: | |
557 | */ | |
558 | memset(tss->io_bitmap, 0xff, prev->io_bitmap_max); | |
559 | } | |
560 | } | |
561 | ||
1da177e4 LT |
562 | /* |
563 | * switch_to(x,y) should switch tasks from x to y. | |
564 | * | |
565 | * This could still be optimized: | |
566 | * - fold all the options into a flag word and test it with a single test. | |
567 | * - could test fs/gs bitsliced | |
099f318b AK |
568 | * |
569 | * Kprobes not supported here. Set the probe on schedule instead. | |
1da177e4 | 570 | */ |
099f318b | 571 | __kprobes struct task_struct * |
a88cde13 | 572 | __switch_to(struct task_struct *prev_p, struct task_struct *next_p) |
1da177e4 LT |
573 | { |
574 | struct thread_struct *prev = &prev_p->thread, | |
575 | *next = &next_p->thread; | |
576 | int cpu = smp_processor_id(); | |
577 | struct tss_struct *tss = &per_cpu(init_tss, cpu); | |
578 | ||
e07e23e1 AV |
579 | /* we're going to use this soon, after a few expensive things */ |
580 | if (next_p->fpu_counter>5) | |
581 | prefetch(&next->i387.fxsave); | |
582 | ||
1da177e4 LT |
583 | /* |
584 | * Reload esp0, LDT and the page table pointer: | |
585 | */ | |
586 | tss->rsp0 = next->rsp0; | |
587 | ||
588 | /* | |
589 | * Switch DS and ES. | |
590 | * This won't pick up thread selector changes, but I guess that is ok. | |
591 | */ | |
fd51f666 | 592 | asm volatile("mov %%es,%0" : "=m" (prev->es)); |
1da177e4 LT |
593 | if (unlikely(next->es | prev->es)) |
594 | loadsegment(es, next->es); | |
595 | ||
fd51f666 | 596 | asm volatile ("mov %%ds,%0" : "=m" (prev->ds)); |
1da177e4 LT |
597 | if (unlikely(next->ds | prev->ds)) |
598 | loadsegment(ds, next->ds); | |
599 | ||
600 | load_TLS(next, cpu); | |
601 | ||
602 | /* | |
603 | * Switch FS and GS. | |
604 | */ | |
605 | { | |
606 | unsigned fsindex; | |
607 | asm volatile("movl %%fs,%0" : "=r" (fsindex)); | |
608 | /* segment register != 0 always requires a reload. | |
609 | also reload when it has changed. | |
610 | when prev process used 64bit base always reload | |
611 | to avoid an information leak. */ | |
612 | if (unlikely(fsindex | next->fsindex | prev->fs)) { | |
613 | loadsegment(fs, next->fsindex); | |
614 | /* check if the user used a selector != 0 | |
615 | * if yes clear 64bit base, since overloaded base | |
616 | * is always mapped to the Null selector | |
617 | */ | |
618 | if (fsindex) | |
619 | prev->fs = 0; | |
620 | } | |
621 | /* when next process has a 64bit base use it */ | |
622 | if (next->fs) | |
623 | wrmsrl(MSR_FS_BASE, next->fs); | |
624 | prev->fsindex = fsindex; | |
625 | } | |
626 | { | |
627 | unsigned gsindex; | |
628 | asm volatile("movl %%gs,%0" : "=r" (gsindex)); | |
629 | if (unlikely(gsindex | next->gsindex | prev->gs)) { | |
630 | load_gs_index(next->gsindex); | |
631 | if (gsindex) | |
632 | prev->gs = 0; | |
633 | } | |
634 | if (next->gs) | |
635 | wrmsrl(MSR_KERNEL_GS_BASE, next->gs); | |
636 | prev->gsindex = gsindex; | |
637 | } | |
638 | ||
0a5ace2a AK |
639 | /* Must be after DS reload */ |
640 | unlazy_fpu(prev_p); | |
641 | ||
1da177e4 | 642 | /* |
45948d77 | 643 | * Switch the PDA and FPU contexts. |
1da177e4 LT |
644 | */ |
645 | prev->userrsp = read_pda(oldrsp); | |
646 | write_pda(oldrsp, next->userrsp); | |
647 | write_pda(pcurrent, next_p); | |
18bd057b | 648 | |
a88cde13 | 649 | write_pda(kernelstack, |
7b0bda74 | 650 | (unsigned long)task_stack_page(next_p) + THREAD_SIZE - PDA_STACKOFFSET); |
0a425405 AV |
651 | #ifdef CONFIG_CC_STACKPROTECTOR |
652 | write_pda(stack_canary, next_p->stack_canary); | |
653 | /* | |
654 | * Build time only check to make sure the stack_canary is at | |
655 | * offset 40 in the pda; this is a gcc ABI requirement | |
656 | */ | |
657 | BUILD_BUG_ON(offsetof(struct x8664_pda, stack_canary) != 40); | |
658 | #endif | |
1da177e4 LT |
659 | |
660 | /* | |
d3a4f48d | 661 | * Now maybe reload the debug registers and handle I/O bitmaps |
1da177e4 | 662 | */ |
d3a4f48d SE |
663 | if (unlikely((task_thread_info(next_p)->flags & _TIF_WORK_CTXSW)) |
664 | || test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) | |
665 | __switch_to_xtra(prev_p, next_p, tss); | |
1da177e4 | 666 | |
e07e23e1 AV |
667 | /* If the task has used fpu the last 5 timeslices, just do a full |
668 | * restore of the math state immediately to avoid the trap; the | |
669 | * chances of needing FPU soon are obviously high now | |
670 | */ | |
671 | if (next_p->fpu_counter>5) | |
672 | math_state_restore(); | |
1da177e4 LT |
673 | return prev_p; |
674 | } | |
675 | ||
676 | /* | |
677 | * sys_execve() executes a new program. | |
678 | */ | |
679 | asmlinkage | |
680 | long sys_execve(char __user *name, char __user * __user *argv, | |
681 | char __user * __user *envp, struct pt_regs regs) | |
682 | { | |
683 | long error; | |
684 | char * filename; | |
685 | ||
686 | filename = getname(name); | |
687 | error = PTR_ERR(filename); | |
688 | if (IS_ERR(filename)) | |
689 | return error; | |
690 | error = do_execve(filename, argv, envp, ®s); | |
691 | if (error == 0) { | |
692 | task_lock(current); | |
693 | current->ptrace &= ~PT_DTRACE; | |
694 | task_unlock(current); | |
695 | } | |
696 | putname(filename); | |
697 | return error; | |
698 | } | |
699 | ||
700 | void set_personality_64bit(void) | |
701 | { | |
702 | /* inherit personality from parent */ | |
703 | ||
704 | /* Make sure to be in 64bit mode */ | |
705 | clear_thread_flag(TIF_IA32); | |
706 | ||
707 | /* TBD: overwrites user setup. Should have two bits. | |
708 | But 64bit processes have always behaved this way, | |
709 | so it's not too bad. The main problem is just that | |
710 | 32bit childs are affected again. */ | |
711 | current->personality &= ~READ_IMPLIES_EXEC; | |
712 | } | |
713 | ||
714 | asmlinkage long sys_fork(struct pt_regs *regs) | |
715 | { | |
716 | return do_fork(SIGCHLD, regs->rsp, regs, 0, NULL, NULL); | |
717 | } | |
718 | ||
a88cde13 AK |
719 | asmlinkage long |
720 | sys_clone(unsigned long clone_flags, unsigned long newsp, | |
721 | void __user *parent_tid, void __user *child_tid, struct pt_regs *regs) | |
1da177e4 LT |
722 | { |
723 | if (!newsp) | |
724 | newsp = regs->rsp; | |
725 | return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid); | |
726 | } | |
727 | ||
728 | /* | |
729 | * This is trivial, and on the face of it looks like it | |
730 | * could equally well be done in user mode. | |
731 | * | |
732 | * Not so, for quite unobvious reasons - register pressure. | |
733 | * In user mode vfork() cannot have a stack frame, and if | |
734 | * done by calling the "clone()" system call directly, you | |
735 | * do not have enough call-clobbered registers to hold all | |
736 | * the information you need. | |
737 | */ | |
738 | asmlinkage long sys_vfork(struct pt_regs *regs) | |
739 | { | |
740 | return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->rsp, regs, 0, | |
741 | NULL, NULL); | |
742 | } | |
743 | ||
744 | unsigned long get_wchan(struct task_struct *p) | |
745 | { | |
746 | unsigned long stack; | |
747 | u64 fp,rip; | |
748 | int count = 0; | |
749 | ||
750 | if (!p || p == current || p->state==TASK_RUNNING) | |
751 | return 0; | |
57eafdc2 | 752 | stack = (unsigned long)task_stack_page(p); |
1da177e4 LT |
753 | if (p->thread.rsp < stack || p->thread.rsp > stack+THREAD_SIZE) |
754 | return 0; | |
755 | fp = *(u64 *)(p->thread.rsp); | |
756 | do { | |
a88cde13 AK |
757 | if (fp < (unsigned long)stack || |
758 | fp > (unsigned long)stack+THREAD_SIZE) | |
1da177e4 LT |
759 | return 0; |
760 | rip = *(u64 *)(fp+8); | |
761 | if (!in_sched_functions(rip)) | |
762 | return rip; | |
763 | fp = *(u64 *)fp; | |
764 | } while (count++ < 16); | |
765 | return 0; | |
766 | } | |
767 | ||
768 | long do_arch_prctl(struct task_struct *task, int code, unsigned long addr) | |
769 | { | |
770 | int ret = 0; | |
771 | int doit = task == current; | |
772 | int cpu; | |
773 | ||
774 | switch (code) { | |
775 | case ARCH_SET_GS: | |
84929801 | 776 | if (addr >= TASK_SIZE_OF(task)) |
1da177e4 LT |
777 | return -EPERM; |
778 | cpu = get_cpu(); | |
779 | /* handle small bases via the GDT because that's faster to | |
780 | switch. */ | |
781 | if (addr <= 0xffffffff) { | |
782 | set_32bit_tls(task, GS_TLS, addr); | |
783 | if (doit) { | |
784 | load_TLS(&task->thread, cpu); | |
785 | load_gs_index(GS_TLS_SEL); | |
786 | } | |
787 | task->thread.gsindex = GS_TLS_SEL; | |
788 | task->thread.gs = 0; | |
789 | } else { | |
790 | task->thread.gsindex = 0; | |
791 | task->thread.gs = addr; | |
792 | if (doit) { | |
a88cde13 AK |
793 | load_gs_index(0); |
794 | ret = checking_wrmsrl(MSR_KERNEL_GS_BASE, addr); | |
1da177e4 LT |
795 | } |
796 | } | |
797 | put_cpu(); | |
798 | break; | |
799 | case ARCH_SET_FS: | |
800 | /* Not strictly needed for fs, but do it for symmetry | |
801 | with gs */ | |
84929801 | 802 | if (addr >= TASK_SIZE_OF(task)) |
1da177e4 LT |
803 | return -EPERM; |
804 | cpu = get_cpu(); | |
805 | /* handle small bases via the GDT because that's faster to | |
806 | switch. */ | |
807 | if (addr <= 0xffffffff) { | |
808 | set_32bit_tls(task, FS_TLS, addr); | |
809 | if (doit) { | |
810 | load_TLS(&task->thread, cpu); | |
a88cde13 | 811 | asm volatile("movl %0,%%fs" :: "r"(FS_TLS_SEL)); |
1da177e4 LT |
812 | } |
813 | task->thread.fsindex = FS_TLS_SEL; | |
814 | task->thread.fs = 0; | |
815 | } else { | |
816 | task->thread.fsindex = 0; | |
817 | task->thread.fs = addr; | |
818 | if (doit) { | |
819 | /* set the selector to 0 to not confuse | |
820 | __switch_to */ | |
a88cde13 AK |
821 | asm volatile("movl %0,%%fs" :: "r" (0)); |
822 | ret = checking_wrmsrl(MSR_FS_BASE, addr); | |
1da177e4 LT |
823 | } |
824 | } | |
825 | put_cpu(); | |
826 | break; | |
827 | case ARCH_GET_FS: { | |
828 | unsigned long base; | |
829 | if (task->thread.fsindex == FS_TLS_SEL) | |
830 | base = read_32bit_tls(task, FS_TLS); | |
a88cde13 | 831 | else if (doit) |
1da177e4 | 832 | rdmsrl(MSR_FS_BASE, base); |
a88cde13 | 833 | else |
1da177e4 LT |
834 | base = task->thread.fs; |
835 | ret = put_user(base, (unsigned long __user *)addr); | |
836 | break; | |
837 | } | |
838 | case ARCH_GET_GS: { | |
839 | unsigned long base; | |
97c2803c | 840 | unsigned gsindex; |
1da177e4 LT |
841 | if (task->thread.gsindex == GS_TLS_SEL) |
842 | base = read_32bit_tls(task, GS_TLS); | |
97c2803c JB |
843 | else if (doit) { |
844 | asm("movl %%gs,%0" : "=r" (gsindex)); | |
845 | if (gsindex) | |
846 | rdmsrl(MSR_KERNEL_GS_BASE, base); | |
847 | else | |
848 | base = task->thread.gs; | |
849 | } | |
a88cde13 | 850 | else |
1da177e4 LT |
851 | base = task->thread.gs; |
852 | ret = put_user(base, (unsigned long __user *)addr); | |
853 | break; | |
854 | } | |
855 | ||
856 | default: | |
857 | ret = -EINVAL; | |
858 | break; | |
859 | } | |
860 | ||
861 | return ret; | |
862 | } | |
863 | ||
864 | long sys_arch_prctl(int code, unsigned long addr) | |
865 | { | |
866 | return do_arch_prctl(current, code, addr); | |
867 | } | |
868 | ||
869 | /* | |
870 | * Capture the user space registers if the task is not running (in user space) | |
871 | */ | |
872 | int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) | |
873 | { | |
874 | struct pt_regs *pp, ptregs; | |
875 | ||
bb049232 | 876 | pp = task_pt_regs(tsk); |
1da177e4 LT |
877 | |
878 | ptregs = *pp; | |
879 | ptregs.cs &= 0xffff; | |
880 | ptregs.ss &= 0xffff; | |
881 | ||
882 | elf_core_copy_regs(regs, &ptregs); | |
883 | ||
884 | return 1; | |
885 | } | |
886 | ||
887 | unsigned long arch_align_stack(unsigned long sp) | |
888 | { | |
c16b63e0 | 889 | if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) |
1da177e4 LT |
890 | sp -= get_random_int() % 8192; |
891 | return sp & ~0xf; | |
892 | } |