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[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / i386 / kernel / process.c
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1da177e4
LT		 1/*
2 * linux/arch/i386/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
10/*
11 * This file handles the architecture-dependent parts of process handling..
12 */
13
14#include <stdarg.h>
15
16#include <linux/errno.h>
17#include <linux/sched.h>
18#include <linux/fs.h>
19#include <linux/kernel.h>
20#include <linux/mm.h>
21#include <linux/elfcore.h>
22#include <linux/smp.h>
23#include <linux/smp_lock.h>
24#include <linux/stddef.h>
25#include <linux/slab.h>
26#include <linux/vmalloc.h>
27#include <linux/user.h>
28#include <linux/a.out.h>
29#include <linux/interrupt.h>
30#include <linux/config.h>
31#include <linux/utsname.h>
32#include <linux/delay.h>
33#include <linux/reboot.h>
34#include <linux/init.h>
35#include <linux/mc146818rtc.h>
36#include <linux/module.h>
37#include <linux/kallsyms.h>
38#include <linux/ptrace.h>
39#include <linux/random.h>
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>
48#include <asm/irq.h>
49#include <asm/desc.h>
50#ifdef CONFIG_MATH_EMULATION
51#include <asm/math_emu.h>
52#endif
53
54#include <linux/irq.h>
55#include <linux/err.h>
56
57asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
58
59static int hlt_counter;
60
61unsigned long boot_option_idle_override = 0;
62EXPORT_SYMBOL(boot_option_idle_override);
63
64/*
65 * Return saved PC of a blocked thread.
66 */
67unsigned long thread_saved_pc(struct task_struct *tsk)
68{
69 return ((unsigned long *)tsk->thread.esp)[3];
70}
71
72/*
73 * Powermanagement idle function, if any..
74 */
75void (*pm_idle)(void);
76static DEFINE_PER_CPU(unsigned int, cpu_idle_state);
77
78void disable_hlt(void)
79{
80 hlt_counter++;
81}
82
83EXPORT_SYMBOL(disable_hlt);
84
85void enable_hlt(void)
86{
87 hlt_counter--;
88}
89
90EXPORT_SYMBOL(enable_hlt);
91
92/*
93 * We use this if we don't have any better
94 * idle routine..
95 */
96void default_idle(void)
97{
98 if (!hlt_counter && boot_cpu_data.hlt_works_ok) {
99 local_irq_disable();
100 if (!need_resched())
101 safe_halt();
102 else
103 local_irq_enable();
104 } else {
105 cpu_relax();
106 }
107}
108
109/*
110 * On SMP it's slightly faster (but much more power-consuming!)
111 * to poll the ->work.need_resched flag instead of waiting for the
112 * cross-CPU IPI to arrive. Use this option with caution.
113 */
114static void poll_idle (void)
115{
116 int oldval;
117
118 local_irq_enable();
119
120 /*
121 * Deal with another CPU just having chosen a thread to
122 * run here:
123 */
124 oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
125
126 if (!oldval) {
127 set_thread_flag(TIF_POLLING_NRFLAG);
128 asm volatile(
129 "2:"
130 "testl %0, %1;"
131 "rep; nop;"
132 "je 2b;"
133 : : "i"(_TIF_NEED_RESCHED), "m" (current_thread_info()->flags));
134
135 clear_thread_flag(TIF_POLLING_NRFLAG);
136 } else {
137 set_need_resched();
138 }
139}
140
141/*
142 * The idle thread. There's no useful work to be
143 * done, so just try to conserve power and have a
144 * low exit latency (ie sit in a loop waiting for
145 * somebody to say that they'd like to reschedule)
146 */
147void cpu_idle (void)
148{
149 /* endless idle loop with no priority at all */
150 while (1) {
151 while (!need_resched()) {
152 void (*idle)(void);
153
154 if (__get_cpu_var(cpu_idle_state))
155 __get_cpu_var(cpu_idle_state) = 0;
156
157 rmb();
158 idle = pm_idle;
159
160 if (!idle)
161 idle = default_idle;
162
163 __get_cpu_var(irq_stat).idle_timestamp = jiffies;
164 idle();
165 }
166 schedule();
167 }
168}
169
170void cpu_idle_wait(void)
171{
172 unsigned int cpu, this_cpu = get_cpu();
173 cpumask_t map;
174
175 set_cpus_allowed(current, cpumask_of_cpu(this_cpu));
176 put_cpu();
177
178 cpus_clear(map);
179 for_each_online_cpu(cpu) {
180 per_cpu(cpu_idle_state, cpu) = 1;
181 cpu_set(cpu, map);
182 }
183
184 __get_cpu_var(cpu_idle_state) = 0;
185
186 wmb();
187 do {
188 ssleep(1);
189 for_each_online_cpu(cpu) {
190 if (cpu_isset(cpu, map) && !per_cpu(cpu_idle_state, cpu))
191 cpu_clear(cpu, map);
192 }
193 cpus_and(map, map, cpu_online_map);
194 } while (!cpus_empty(map));
195}
196EXPORT_SYMBOL_GPL(cpu_idle_wait);
197
198/*
199 * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
200 * which can obviate IPI to trigger checking of need_resched.
201 * We execute MONITOR against need_resched and enter optimized wait state
202 * through MWAIT. Whenever someone changes need_resched, we would be woken
203 * up from MWAIT (without an IPI).
204 */
205static void mwait_idle(void)
206{
207 local_irq_enable();
208
209 if (!need_resched()) {
210 set_thread_flag(TIF_POLLING_NRFLAG);
211 do {
212 __monitor((void *)&current_thread_info()->flags, 0, 0);
213 if (need_resched())
214 break;
215 __mwait(0, 0);
216 } while (!need_resched());
217 clear_thread_flag(TIF_POLLING_NRFLAG);
218 }
219}
220
221void __init select_idle_routine(const struct cpuinfo_x86 *c)
222{
223 if (cpu_has(c, X86_FEATURE_MWAIT)) {
224 printk("monitor/mwait feature present.\n");
225 /*
226 * Skip, if setup has overridden idle.
227 * One CPU supports mwait => All CPUs supports mwait
228 */
229 if (!pm_idle) {
230 printk("using mwait in idle threads.\n");
231 pm_idle = mwait_idle;
232 }
233 }
234}
235
236static int __init idle_setup (char *str)
237{
238 if (!strncmp(str, "poll", 4)) {
239 printk("using polling idle threads.\n");
240 pm_idle = poll_idle;
241#ifdef CONFIG_X86_SMP
242 if (smp_num_siblings > 1)
243 printk("WARNING: polling idle and HT enabled, performance may degrade.\n");
244#endif
245 } else if (!strncmp(str, "halt", 4)) {
246 printk("using halt in idle threads.\n");
247 pm_idle = default_idle;
248 }
249
250 boot_option_idle_override = 1;
251 return 1;
252}
253
254__setup("idle=", idle_setup);
255
256void show_regs(struct pt_regs * regs)
257{
258 unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
259
260 printk("\n");
261 printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
262 printk("EIP: %04x:[<%08lx>] CPU: %d\n",0xffff & regs->xcs,regs->eip, smp_processor_id());
263 print_symbol("EIP is at %s\n", regs->eip);
264
265 if (regs->xcs & 3)
266 printk(" ESP: %04x:%08lx",0xffff & regs->xss,regs->esp);
267 printk(" EFLAGS: %08lx %s (%s)\n",
268 regs->eflags, print_tainted(), system_utsname.release);
269 printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
270 regs->eax,regs->ebx,regs->ecx,regs->edx);
271 printk("ESI: %08lx EDI: %08lx EBP: %08lx",
272 regs->esi, regs->edi, regs->ebp);
273 printk(" DS: %04x ES: %04x\n",
274 0xffff & regs->xds,0xffff & regs->xes);
275
276 __asm__("movl %%cr0, %0": "=r" (cr0));
277 __asm__("movl %%cr2, %0": "=r" (cr2));
278 __asm__("movl %%cr3, %0": "=r" (cr3));
279 /* This could fault if %cr4 does not exist */
280 __asm__("1: movl %%cr4, %0 \n"
281 "2: \n"
282 ".section __ex_table,\"a\" \n"
283 ".long 1b,2b \n"
284 ".previous \n"
285 : "=r" (cr4): "0" (0));
286 printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4);
287 show_trace(NULL, &regs->esp);
288}
289
290/*
291 * This gets run with %ebx containing the
292 * function to call, and %edx containing
293 * the "args".
294 */
295extern void kernel_thread_helper(void);
296__asm__(".section .text\n"
297 ".align 4\n"
298 "kernel_thread_helper:\n\t"
299 "movl %edx,%eax\n\t"
300 "pushl %edx\n\t"
301 "call *%ebx\n\t"
302 "pushl %eax\n\t"
303 "call do_exit\n"
304 ".previous");
305
306/*
307 * Create a kernel thread
308 */
309int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
310{
311 struct pt_regs regs;
312
313 memset(&regs, 0, sizeof(regs));
314
315 regs.ebx = (unsigned long) fn;
316 regs.edx = (unsigned long) arg;
317
318 regs.xds = __USER_DS;
319 regs.xes = __USER_DS;
320 regs.orig_eax = -1;
321 regs.eip = (unsigned long) kernel_thread_helper;
322 regs.xcs = __KERNEL_CS;
323 regs.eflags = X86_EFLAGS_IF | X86_EFLAGS_SF | X86_EFLAGS_PF | 0x2;
324
325 /* Ok, create the new process.. */
326 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
327}
328
329/*
330 * Free current thread data structures etc..
331 */
332void exit_thread(void)
333{
334 struct task_struct *tsk = current;
335 struct thread_struct *t = &tsk->thread;
336
337 /* The process may have allocated an io port bitmap... nuke it. */
338 if (unlikely(NULL != t->io_bitmap_ptr)) {
339 int cpu = get_cpu();
340 struct tss_struct *tss = &per_cpu(init_tss, cpu);
341
342 kfree(t->io_bitmap_ptr);
343 t->io_bitmap_ptr = NULL;
344 /*
345 * Careful, clear this in the TSS too:
346 */
347 memset(tss->io_bitmap, 0xff, tss->io_bitmap_max);
348 t->io_bitmap_max = 0;
349 tss->io_bitmap_owner = NULL;
350 tss->io_bitmap_max = 0;
351 tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
352 put_cpu();
353 }
354}
355
356void flush_thread(void)
357{
358 struct task_struct *tsk = current;
359
360 memset(tsk->thread.debugreg, 0, sizeof(unsigned long)*8);
361 memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
362 /*
363 * Forget coprocessor state..
364 */
365 clear_fpu(tsk);
366 clear_used_math();
367}
368
369void release_thread(struct task_struct *dead_task)
370{
371 if (dead_task->mm) {
372 // temporary debugging check
373 if (dead_task->mm->context.size) {
374 printk("WARNING: dead process %8s still has LDT? <%p/%d>\n",
375 dead_task->comm,
376 dead_task->mm->context.ldt,
377 dead_task->mm->context.size);
378 BUG();
379 }
380 }
381
382 release_vm86_irqs(dead_task);
383}
384
385/*
386 * This gets called before we allocate a new thread and copy
387 * the current task into it.
388 */
389void prepare_to_copy(struct task_struct *tsk)
390{
391 unlazy_fpu(tsk);
392}
393
394int copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
395 unsigned long unused,
396 struct task_struct * p, struct pt_regs * regs)
397{
398 struct pt_regs * childregs;
399 struct task_struct *tsk;
400 int err;
401
402 childregs = ((struct pt_regs *) (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
403 *childregs = *regs;
404 childregs->eax = 0;
405 childregs->esp = esp;
406
407 p->thread.esp = (unsigned long) childregs;
5df24082
SS		 408 /*
409 * The below -8 is to reserve 8 bytes on top of the ring0 stack.
410 * This is necessary to guarantee that the entire "struct pt_regs"
411 * is accessable even if the CPU haven't stored the SS/ESP registers
412 * on the stack (interrupt gate does not save these registers
413 * when switching to the same priv ring).
414 * Therefore beware: accessing the xss/esp fields of the
415 * "struct pt_regs" is possible, but they may contain the
416 * completely wrong values.
417 */
418 p->thread.esp0 = (unsigned long) (childregs+1) - 8;
1da177e4
LT		 419
420 p->thread.eip = (unsigned long) ret_from_fork;
421
422 savesegment(fs,p->thread.fs);
423 savesegment(gs,p->thread.gs);
424
425 tsk = current;
426 if (unlikely(NULL != tsk->thread.io_bitmap_ptr)) {
427 p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
428 if (!p->thread.io_bitmap_ptr) {
429 p->thread.io_bitmap_max = 0;
430 return -ENOMEM;
431 }
432 memcpy(p->thread.io_bitmap_ptr, tsk->thread.io_bitmap_ptr,
433 IO_BITMAP_BYTES);
434 }
435
436 /*
437 * Set a new TLS for the child thread?
438 */
439 if (clone_flags & CLONE_SETTLS) {
440 struct desc_struct *desc;
441 struct user_desc info;
442 int idx;
443
444 err = -EFAULT;
445 if (copy_from_user(&info, (void __user *)childregs->esi, sizeof(info)))
446 goto out;
447 err = -EINVAL;
448 if (LDT_empty(&info))
449 goto out;
450
451 idx = info.entry_number;
452 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
453 goto out;
454
455 desc = p->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
456 desc->a = LDT_entry_a(&info);
457 desc->b = LDT_entry_b(&info);
458 }
459
460 err = 0;
461 out:
462 if (err && p->thread.io_bitmap_ptr) {
463 kfree(p->thread.io_bitmap_ptr);
464 p->thread.io_bitmap_max = 0;
465 }
466 return err;
467}
468
469/*
470 * fill in the user structure for a core dump..
471 */
472void dump_thread(struct pt_regs * regs, struct user * dump)
473{
474 int i;
475
476/* changed the size calculations - should hopefully work better. lbt */
477 dump->magic = CMAGIC;
478 dump->start_code = 0;
479 dump->start_stack = regs->esp & ~(PAGE_SIZE - 1);
480 dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
481 dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
482 dump->u_dsize -= dump->u_tsize;
483 dump->u_ssize = 0;
484 for (i = 0; i < 8; i++)
485 dump->u_debugreg[i] = current->thread.debugreg[i];
486
487 if (dump->start_stack < TASK_SIZE)
488 dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;
489
490 dump->regs.ebx = regs->ebx;
491 dump->regs.ecx = regs->ecx;
492 dump->regs.edx = regs->edx;
493 dump->regs.esi = regs->esi;
494 dump->regs.edi = regs->edi;
495 dump->regs.ebp = regs->ebp;
496 dump->regs.eax = regs->eax;
497 dump->regs.ds = regs->xds;
498 dump->regs.es = regs->xes;
499 savesegment(fs,dump->regs.fs);
500 savesegment(gs,dump->regs.gs);
501 dump->regs.orig_eax = regs->orig_eax;
502 dump->regs.eip = regs->eip;
503 dump->regs.cs = regs->xcs;
504 dump->regs.eflags = regs->eflags;
505 dump->regs.esp = regs->esp;
506 dump->regs.ss = regs->xss;
507
508 dump->u_fpvalid = dump_fpu (regs, &dump->i387);
509}
510
511/*
512 * Capture the user space registers if the task is not running (in user space)
513 */
514int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
515{
516 struct pt_regs ptregs;
517
518 ptregs = *(struct pt_regs *)
519 ((unsigned long)tsk->thread_info+THREAD_SIZE - sizeof(ptregs));
520 ptregs.xcs &= 0xffff;
521 ptregs.xds &= 0xffff;
522 ptregs.xes &= 0xffff;
523 ptregs.xss &= 0xffff;
524
525 elf_core_copy_regs(regs, &ptregs);
526
527 return 1;
528}
529
530static inline void
531handle_io_bitmap(struct thread_struct *next, struct tss_struct *tss)
532{
533 if (!next->io_bitmap_ptr) {
534 /*
535 * Disable the bitmap via an invalid offset. We still cache
536 * the previous bitmap owner and the IO bitmap contents:
537 */
538 tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
539 return;
540 }
541 if (likely(next == tss->io_bitmap_owner)) {
542 /*
543 * Previous owner of the bitmap (hence the bitmap content)
544 * matches the next task, we dont have to do anything but
545 * to set a valid offset in the TSS:
546 */
547 tss->io_bitmap_base = IO_BITMAP_OFFSET;
548 return;
549 }
550 /*
551 * Lazy TSS's I/O bitmap copy. We set an invalid offset here
552 * and we let the task to get a GPF in case an I/O instruction
553 * is performed. The handler of the GPF will verify that the
554 * faulting task has a valid I/O bitmap and, it true, does the
555 * real copy and restart the instruction. This will save us
556 * redundant copies when the currently switched task does not
557 * perform any I/O during its timeslice.
558 */
559 tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET_LAZY;
560}
1da177e4
LT		 561
562/*
563 * switch_to(x,yn) should switch tasks from x to y.
564 *
565 * We fsave/fwait so that an exception goes off at the right time
566 * (as a call from the fsave or fwait in effect) rather than to
567 * the wrong process. Lazy FP saving no longer makes any sense
568 * with modern CPU's, and this simplifies a lot of things (SMP
569 * and UP become the same).
570 *
571 * NOTE! We used to use the x86 hardware context switching. The
572 * reason for not using it any more becomes apparent when you
573 * try to recover gracefully from saved state that is no longer
574 * valid (stale segment register values in particular). With the
575 * hardware task-switch, there is no way to fix up bad state in
576 * a reasonable manner.
577 *
578 * The fact that Intel documents the hardware task-switching to
579 * be slow is a fairly red herring - this code is not noticeably
580 * faster. However, there _is_ some room for improvement here,
581 * so the performance issues may eventually be a valid point.
582 * More important, however, is the fact that this allows us much
583 * more flexibility.
584 *
585 * The return value (in %eax) will be the "prev" task after
586 * the task-switch, and shows up in ret_from_fork in entry.S,
587 * for example.
588 */
589struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
590{
591 struct thread_struct *prev = &prev_p->thread,
592 *next = &next_p->thread;
593 int cpu = smp_processor_id();
594 struct tss_struct *tss = &per_cpu(init_tss, cpu);
595
596 /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */
597
598 __unlazy_fpu(prev_p);
599
600 /*
601 * Reload esp0, LDT and the page table pointer:
602 */
603 load_esp0(tss, next);
604
605 /*
606 * Load the per-thread Thread-Local Storage descriptor.
607 */
608 load_TLS(next, cpu);
609
610 /*
611 * Save away %fs and %gs. No need to save %es and %ds, as
612 * those are always kernel segments while inside the kernel.
613 */
fd51f666
L		 614 asm volatile("mov %%fs,%0":"=m" (prev->fs));
615 asm volatile("mov %%gs,%0":"=m" (prev->gs));
1da177e4
LT		 616
617 /*
618 * Restore %fs and %gs if needed.
619 */
620 if (unlikely(prev->fs | prev->gs | next->fs | next->gs)) {
621 loadsegment(fs, next->fs);
622 loadsegment(gs, next->gs);
623 }
624
625 /*
626 * Now maybe reload the debug registers
627 */
628 if (unlikely(next->debugreg[7])) {
629 loaddebug(next, 0);
630 loaddebug(next, 1);
631 loaddebug(next, 2);
632 loaddebug(next, 3);
633 /* no 4 and 5 */
634 loaddebug(next, 6);
635 loaddebug(next, 7);
636 }
637
638 if (unlikely(prev->io_bitmap_ptr || next->io_bitmap_ptr))
639 handle_io_bitmap(next, tss);
640
641 return prev_p;
642}
643
644asmlinkage int sys_fork(struct pt_regs regs)
645{
646 return do_fork(SIGCHLD, regs.esp, &regs, 0, NULL, NULL);
647}
648
649asmlinkage int sys_clone(struct pt_regs regs)
650{
651 unsigned long clone_flags;
652 unsigned long newsp;
653 int __user *parent_tidptr, *child_tidptr;
654
655 clone_flags = regs.ebx;
656 newsp = regs.ecx;
657 parent_tidptr = (int __user *)regs.edx;
658 child_tidptr = (int __user *)regs.edi;
659 if (!newsp)
660 newsp = regs.esp;
661 return do_fork(clone_flags, newsp, &regs, 0, parent_tidptr, child_tidptr);
662}
663
664/*
665 * This is trivial, and on the face of it looks like it
666 * could equally well be done in user mode.
667 *
668 * Not so, for quite unobvious reasons - register pressure.
669 * In user mode vfork() cannot have a stack frame, and if
670 * done by calling the "clone()" system call directly, you
671 * do not have enough call-clobbered registers to hold all
672 * the information you need.
673 */
674asmlinkage int sys_vfork(struct pt_regs regs)
675{
676 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.esp, &regs, 0, NULL, NULL);
677}
678
679/*
680 * sys_execve() executes a new program.
681 */
682asmlinkage int sys_execve(struct pt_regs regs)
683{
684 int error;
685 char * filename;
686
687 filename = getname((char __user *) regs.ebx);
688 error = PTR_ERR(filename);
689 if (IS_ERR(filename))
690 goto out;
691 error = do_execve(filename,
692 (char __user * __user *) regs.ecx,
693 (char __user * __user *) regs.edx,
694 &regs);
695 if (error == 0) {
696 task_lock(current);
697 current->ptrace &= ~PT_DTRACE;
698 task_unlock(current);
699 /* Make sure we don't return using sysenter.. */
700 set_thread_flag(TIF_IRET);
701 }
702 putname(filename);
703out:
704 return error;
705}
706
707#define top_esp (THREAD_SIZE - sizeof(unsigned long))
708#define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long))
709
710unsigned long get_wchan(struct task_struct *p)
711{
712 unsigned long ebp, esp, eip;
713 unsigned long stack_page;
714 int count = 0;
715 if (!p || p == current || p->state == TASK_RUNNING)
716 return 0;
717 stack_page = (unsigned long)p->thread_info;
718 esp = p->thread.esp;
719 if (!stack_page || esp < stack_page || esp > top_esp+stack_page)
720 return 0;
721 /* include/asm-i386/system.h:switch_to() pushes ebp last. */
722 ebp = *(unsigned long *) esp;
723 do {
724 if (ebp < stack_page || ebp > top_ebp+stack_page)
725 return 0;
726 eip = *(unsigned long *) (ebp+4);
727 if (!in_sched_functions(eip))
728 return eip;
729 ebp = *(unsigned long *) ebp;
730 } while (count++ < 16);
731 return 0;
732}
733
734/*
735 * sys_alloc_thread_area: get a yet unused TLS descriptor index.
736 */
737static int get_free_idx(void)
738{
739 struct thread_struct *t = &current->thread;
740 int idx;
741
742 for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)
743 if (desc_empty(t->tls_array + idx))
744 return idx + GDT_ENTRY_TLS_MIN;
745 return -ESRCH;
746}
747
748/*
749 * Set a given TLS descriptor:
750 */
751asmlinkage int sys_set_thread_area(struct user_desc __user *u_info)
752{
753 struct thread_struct *t = &current->thread;
754 struct user_desc info;
755 struct desc_struct *desc;
756 int cpu, idx;
757
758 if (copy_from_user(&info, u_info, sizeof(info)))
759 return -EFAULT;
760 idx = info.entry_number;
761
762 /*
763 * index -1 means the kernel should try to find and
764 * allocate an empty descriptor:
765 */
766 if (idx == -1) {
767 idx = get_free_idx();
768 if (idx < 0)
769 return idx;
770 if (put_user(idx, &u_info->entry_number))
771 return -EFAULT;
772 }
773
774 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
775 return -EINVAL;
776
777 desc = t->tls_array + idx - GDT_ENTRY_TLS_MIN;
778
779 /*
780 * We must not get preempted while modifying the TLS.
781 */
782 cpu = get_cpu();
783
784 if (LDT_empty(&info)) {
785 desc->a = 0;
786 desc->b = 0;
787 } else {
788 desc->a = LDT_entry_a(&info);
789 desc->b = LDT_entry_b(&info);
790 }
791 load_TLS(t, cpu);
792
793 put_cpu();
794
795 return 0;
796}
797
798/*
799 * Get the current Thread-Local Storage area:
800 */
801
802#define GET_BASE(desc) ( \
803 (((desc)->a >> 16) & 0x0000ffff) | \
804 (((desc)->b << 16) & 0x00ff0000) | \
805 ( (desc)->b & 0xff000000) )
806
807#define GET_LIMIT(desc) ( \
808 ((desc)->a & 0x0ffff) | \
809 ((desc)->b & 0xf0000) )
810
811#define GET_32BIT(desc) (((desc)->b >> 22) & 1)
812#define GET_CONTENTS(desc) (((desc)->b >> 10) & 3)
813#define GET_WRITABLE(desc) (((desc)->b >> 9) & 1)
814#define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1)
815#define GET_PRESENT(desc) (((desc)->b >> 15) & 1)
816#define GET_USEABLE(desc) (((desc)->b >> 20) & 1)
817
818asmlinkage int sys_get_thread_area(struct user_desc __user *u_info)
819{
820 struct user_desc info;
821 struct desc_struct *desc;
822 int idx;
823
824 if (get_user(idx, &u_info->entry_number))
825 return -EFAULT;
826 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
827 return -EINVAL;
828
829 desc = current->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
830
831 info.entry_number = idx;
832 info.base_addr = GET_BASE(desc);
833 info.limit = GET_LIMIT(desc);
834 info.seg_32bit = GET_32BIT(desc);
835 info.contents = GET_CONTENTS(desc);
836 info.read_exec_only = !GET_WRITABLE(desc);
837 info.limit_in_pages = GET_LIMIT_PAGES(desc);
838 info.seg_not_present = !GET_PRESENT(desc);
839 info.useable = GET_USEABLE(desc);
840
841 if (copy_to_user(u_info, &info, sizeof(info)))
842 return -EFAULT;
843 return 0;
844}
845
846unsigned long arch_align_stack(unsigned long sp)
847{
848 if (randomize_va_space)
849 sp -= get_random_int() % 8192;
850 return sp & ~0xf;
851}
kernel source for telekom puls (alcatel/mediatek)