2 * linux/arch/i386/kernel/process.c
4 * Copyright (C) 1995 Linus Torvalds
6 * Pentium III FXSR, SSE support
7 * Gareth Hughes <gareth@valinux.com>, May 2000
11 * This file handles the architecture-dependent parts of process handling..
16 #include <linux/cpu.h>
17 #include <linux/errno.h>
18 #include <linux/sched.h>
20 #include <linux/kernel.h>
22 #include <linux/elfcore.h>
23 #include <linux/smp.h>
24 #include <linux/smp_lock.h>
25 #include <linux/stddef.h>
26 #include <linux/slab.h>
27 #include <linux/vmalloc.h>
28 #include <linux/user.h>
29 #include <linux/a.out.h>
30 #include <linux/interrupt.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 #include <linux/personality.h>
42 #include <asm/uaccess.h>
43 #include <asm/pgtable.h>
44 #include <asm/system.h>
47 #include <asm/processor.h>
51 #ifdef CONFIG_MATH_EMULATION
52 #include <asm/math_emu.h>
55 #include <linux/err.h>
57 #include <asm/tlbflush.h>
61 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
63 static int hlt_counter;
65 unsigned long boot_option_idle_override = 0;
66 EXPORT_SYMBOL(boot_option_idle_override);
69 * Return saved PC of a blocked thread.
71 unsigned long thread_saved_pc(struct task_struct *tsk)
73 return ((unsigned long *)tsk->thread.esp)[3];
77 * Powermanagement idle function, if any..
79 void (*pm_idle)(void);
80 EXPORT_SYMBOL(pm_idle);
81 static DEFINE_PER_CPU(unsigned int, cpu_idle_state);
83 void disable_hlt(void)
88 EXPORT_SYMBOL(disable_hlt);
95 EXPORT_SYMBOL(enable_hlt);
98 * We use this if we don't have any better
101 void default_idle(void)
105 if (!hlt_counter && boot_cpu_data.hlt_works_ok) {
106 current_thread_info()->status &= ~TS_POLLING;
107 smp_mb__after_clear_bit();
108 while (!need_resched()) {
115 current_thread_info()->status |= TS_POLLING;
117 while (!need_resched())
121 #ifdef CONFIG_APM_MODULE
122 EXPORT_SYMBOL(default_idle);
126 * On SMP it's slightly faster (but much more power-consuming!)
127 * to poll the ->work.need_resched flag instead of waiting for the
128 * cross-CPU IPI to arrive. Use this option with caution.
130 static void poll_idle (void)
139 : : "i"(_TIF_NEED_RESCHED), "m" (current_thread_info()->flags));
142 #ifdef CONFIG_HOTPLUG_CPU
144 /* We don't actually take CPU down, just spin without interrupts. */
145 static inline void play_dead(void)
147 /* This must be done before dead CPU ack */
152 __get_cpu_var(cpu_state) = CPU_DEAD;
155 * With physical CPU hotplug, we should halt the cpu
162 static inline void play_dead(void)
166 #endif /* CONFIG_HOTPLUG_CPU */
169 * The idle thread. There's no useful work to be
170 * done, so just try to conserve power and have a
171 * low exit latency (ie sit in a loop waiting for
172 * somebody to say that they'd like to reschedule)
176 int cpu = smp_processor_id();
178 current_thread_info()->status |= TS_POLLING;
180 /* endless idle loop with no priority at all */
182 while (!need_resched()) {
185 if (__get_cpu_var(cpu_idle_state))
186 __get_cpu_var(cpu_idle_state) = 0;
194 if (cpu_is_offline(cpu))
197 __get_cpu_var(irq_stat).idle_timestamp = jiffies;
200 preempt_enable_no_resched();
206 void cpu_idle_wait(void)
208 unsigned int cpu, this_cpu = get_cpu();
209 cpumask_t map, tmp = current->cpus_allowed;
211 set_cpus_allowed(current, cpumask_of_cpu(this_cpu));
215 for_each_online_cpu(cpu) {
216 per_cpu(cpu_idle_state, cpu) = 1;
220 __get_cpu_var(cpu_idle_state) = 0;
225 for_each_online_cpu(cpu) {
226 if (cpu_isset(cpu, map) && !per_cpu(cpu_idle_state, cpu))
229 cpus_and(map, map, cpu_online_map);
230 } while (!cpus_empty(map));
232 set_cpus_allowed(current, tmp);
234 EXPORT_SYMBOL_GPL(cpu_idle_wait);
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).
243 * New with Core Duo processors, MWAIT can take some hints based on CPU
246 void mwait_idle_with_hints(unsigned long eax, unsigned long ecx)
248 if (!need_resched()) {
249 __monitor((void *)¤t_thread_info()->flags, 0, 0);
256 /* Default MONITOR/MWAIT with no hints, used for default C1 state */
257 static void mwait_idle(void)
260 while (!need_resched())
261 mwait_idle_with_hints(0, 0);
264 void __devinit select_idle_routine(const struct cpuinfo_x86 *c)
266 if (cpu_has(c, X86_FEATURE_MWAIT)) {
267 printk("monitor/mwait feature present.\n");
269 * Skip, if setup has overridden idle.
270 * One CPU supports mwait => All CPUs supports mwait
273 printk("using mwait in idle threads.\n");
274 pm_idle = mwait_idle;
279 static int __init idle_setup (char *str)
281 if (!strncmp(str, "poll", 4)) {
282 printk("using polling idle threads.\n");
284 #ifdef CONFIG_X86_SMP
285 if (smp_num_siblings > 1)
286 printk("WARNING: polling idle and HT enabled, performance may degrade.\n");
288 } else if (!strncmp(str, "halt", 4)) {
289 printk("using halt in idle threads.\n");
290 pm_idle = default_idle;
293 boot_option_idle_override = 1;
297 __setup("idle=", idle_setup);
299 void show_regs(struct pt_regs * regs)
301 unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
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);
308 if (user_mode_vm(regs))
309 printk(" ESP: %04x:%08lx",0xffff & regs->xss,regs->esp);
310 printk(" EFLAGS: %08lx %s (%s %.*s)\n",
311 regs->eflags, print_tainted(), init_utsname()->release,
312 (int)strcspn(init_utsname()->version, " "),
313 init_utsname()->version);
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);
318 printk(" DS: %04x ES: %04x GS: %04x\n",
319 0xffff & regs->xds,0xffff & regs->xes, 0xffff & regs->xgs);
324 cr4 = read_cr4_safe();
325 printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4);
326 show_trace(NULL, regs, ®s->esp);
330 * This gets run with %ebx containing the
331 * function to call, and %edx containing
334 extern void kernel_thread_helper(void);
337 * Create a kernel thread
339 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
343 memset(®s, 0, sizeof(regs));
345 regs.ebx = (unsigned long) fn;
346 regs.edx = (unsigned long) arg;
348 regs.xds = __USER_DS;
349 regs.xes = __USER_DS;
350 regs.xgs = __KERNEL_PDA;
352 regs.eip = (unsigned long) kernel_thread_helper;
353 regs.xcs = __KERNEL_CS | get_kernel_rpl();
354 regs.eflags = X86_EFLAGS_IF | X86_EFLAGS_SF | X86_EFLAGS_PF | 0x2;
356 /* Ok, create the new process.. */
357 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
359 EXPORT_SYMBOL(kernel_thread);
362 * Free current thread data structures etc..
364 void exit_thread(void)
366 /* The process may have allocated an io port bitmap... nuke it. */
367 if (unlikely(test_thread_flag(TIF_IO_BITMAP))) {
368 struct task_struct *tsk = current;
369 struct thread_struct *t = &tsk->thread;
371 struct tss_struct *tss = &per_cpu(init_tss, cpu);
373 kfree(t->io_bitmap_ptr);
374 t->io_bitmap_ptr = NULL;
375 clear_thread_flag(TIF_IO_BITMAP);
377 * Careful, clear this in the TSS too:
379 memset(tss->io_bitmap, 0xff, tss->io_bitmap_max);
380 t->io_bitmap_max = 0;
381 tss->io_bitmap_owner = NULL;
382 tss->io_bitmap_max = 0;
383 tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
388 void flush_thread(void)
390 struct task_struct *tsk = current;
392 memset(tsk->thread.debugreg, 0, sizeof(unsigned long)*8);
393 memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
394 clear_tsk_thread_flag(tsk, TIF_DEBUG);
396 * Forget coprocessor state..
402 void release_thread(struct task_struct *dead_task)
404 BUG_ON(dead_task->mm);
405 release_vm86_irqs(dead_task);
409 * This gets called before we allocate a new thread and copy
410 * the current task into it.
412 void prepare_to_copy(struct task_struct *tsk)
417 int copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
418 unsigned long unused,
419 struct task_struct * p, struct pt_regs * regs)
421 struct pt_regs * childregs;
422 struct task_struct *tsk;
425 childregs = task_pt_regs(p);
428 childregs->esp = esp;
430 p->thread.esp = (unsigned long) childregs;
431 p->thread.esp0 = (unsigned long) (childregs+1);
433 p->thread.eip = (unsigned long) ret_from_fork;
435 savesegment(fs,p->thread.fs);
438 if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) {
439 p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr,
440 IO_BITMAP_BYTES, GFP_KERNEL);
441 if (!p->thread.io_bitmap_ptr) {
442 p->thread.io_bitmap_max = 0;
445 set_tsk_thread_flag(p, TIF_IO_BITMAP);
449 * Set a new TLS for the child thread?
451 if (clone_flags & CLONE_SETTLS) {
452 struct desc_struct *desc;
453 struct user_desc info;
457 if (copy_from_user(&info, (void __user *)childregs->esi, sizeof(info)))
460 if (LDT_empty(&info))
463 idx = info.entry_number;
464 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
467 desc = p->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
468 desc->a = LDT_entry_a(&info);
469 desc->b = LDT_entry_b(&info);
474 if (err && p->thread.io_bitmap_ptr) {
475 kfree(p->thread.io_bitmap_ptr);
476 p->thread.io_bitmap_max = 0;
482 * fill in the user structure for a core dump..
484 void dump_thread(struct pt_regs * regs, struct user * dump)
488 /* changed the size calculations - should hopefully work better. lbt */
489 dump->magic = CMAGIC;
490 dump->start_code = 0;
491 dump->start_stack = regs->esp & ~(PAGE_SIZE - 1);
492 dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
493 dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
494 dump->u_dsize -= dump->u_tsize;
496 for (i = 0; i < 8; i++)
497 dump->u_debugreg[i] = current->thread.debugreg[i];
499 if (dump->start_stack < TASK_SIZE)
500 dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;
502 dump->regs.ebx = regs->ebx;
503 dump->regs.ecx = regs->ecx;
504 dump->regs.edx = regs->edx;
505 dump->regs.esi = regs->esi;
506 dump->regs.edi = regs->edi;
507 dump->regs.ebp = regs->ebp;
508 dump->regs.eax = regs->eax;
509 dump->regs.ds = regs->xds;
510 dump->regs.es = regs->xes;
511 savesegment(fs,dump->regs.fs);
512 dump->regs.gs = regs->xgs;
513 dump->regs.orig_eax = regs->orig_eax;
514 dump->regs.eip = regs->eip;
515 dump->regs.cs = regs->xcs;
516 dump->regs.eflags = regs->eflags;
517 dump->regs.esp = regs->esp;
518 dump->regs.ss = regs->xss;
520 dump->u_fpvalid = dump_fpu (regs, &dump->i387);
522 EXPORT_SYMBOL(dump_thread);
525 * Capture the user space registers if the task is not running (in user space)
527 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
529 struct pt_regs ptregs = *task_pt_regs(tsk);
530 ptregs.xcs &= 0xffff;
531 ptregs.xds &= 0xffff;
532 ptregs.xes &= 0xffff;
533 ptregs.xss &= 0xffff;
535 elf_core_copy_regs(regs, &ptregs);
540 static noinline void __switch_to_xtra(struct task_struct *next_p,
541 struct tss_struct *tss)
543 struct thread_struct *next;
545 next = &next_p->thread;
547 if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
548 set_debugreg(next->debugreg[0], 0);
549 set_debugreg(next->debugreg[1], 1);
550 set_debugreg(next->debugreg[2], 2);
551 set_debugreg(next->debugreg[3], 3);
553 set_debugreg(next->debugreg[6], 6);
554 set_debugreg(next->debugreg[7], 7);
557 if (!test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {
559 * Disable the bitmap via an invalid offset. We still cache
560 * the previous bitmap owner and the IO bitmap contents:
562 tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
566 if (likely(next == tss->io_bitmap_owner)) {
568 * Previous owner of the bitmap (hence the bitmap content)
569 * matches the next task, we dont have to do anything but
570 * to set a valid offset in the TSS:
572 tss->io_bitmap_base = IO_BITMAP_OFFSET;
576 * Lazy TSS's I/O bitmap copy. We set an invalid offset here
577 * and we let the task to get a GPF in case an I/O instruction
578 * is performed. The handler of the GPF will verify that the
579 * faulting task has a valid I/O bitmap and, it true, does the
580 * real copy and restart the instruction. This will save us
581 * redundant copies when the currently switched task does not
582 * perform any I/O during its timeslice.
584 tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET_LAZY;
588 * This function selects if the context switch from prev to next
589 * has to tweak the TSC disable bit in the cr4.
591 static inline void disable_tsc(struct task_struct *prev_p,
592 struct task_struct *next_p)
594 struct thread_info *prev, *next;
597 * gcc should eliminate the ->thread_info dereference if
598 * has_secure_computing returns 0 at compile time (SECCOMP=n).
600 prev = task_thread_info(prev_p);
601 next = task_thread_info(next_p);
603 if (has_secure_computing(prev) || has_secure_computing(next)) {
605 if (has_secure_computing(prev) &&
606 !has_secure_computing(next)) {
607 write_cr4(read_cr4() & ~X86_CR4_TSD);
608 } else if (!has_secure_computing(prev) &&
609 has_secure_computing(next))
610 write_cr4(read_cr4() | X86_CR4_TSD);
615 * switch_to(x,yn) should switch tasks from x to y.
617 * We fsave/fwait so that an exception goes off at the right time
618 * (as a call from the fsave or fwait in effect) rather than to
619 * the wrong process. Lazy FP saving no longer makes any sense
620 * with modern CPU's, and this simplifies a lot of things (SMP
621 * and UP become the same).
623 * NOTE! We used to use the x86 hardware context switching. The
624 * reason for not using it any more becomes apparent when you
625 * try to recover gracefully from saved state that is no longer
626 * valid (stale segment register values in particular). With the
627 * hardware task-switch, there is no way to fix up bad state in
628 * a reasonable manner.
630 * The fact that Intel documents the hardware task-switching to
631 * be slow is a fairly red herring - this code is not noticeably
632 * faster. However, there _is_ some room for improvement here,
633 * so the performance issues may eventually be a valid point.
634 * More important, however, is the fact that this allows us much
637 * The return value (in %eax) will be the "prev" task after
638 * the task-switch, and shows up in ret_from_fork in entry.S,
641 struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
643 struct thread_struct *prev = &prev_p->thread,
644 *next = &next_p->thread;
645 int cpu = smp_processor_id();
646 struct tss_struct *tss = &per_cpu(init_tss, cpu);
648 /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */
650 __unlazy_fpu(prev_p);
653 /* we're going to use this soon, after a few expensive things */
654 if (next_p->fpu_counter > 5)
655 prefetch(&next->i387.fxsave);
660 load_esp0(tss, next);
663 * Save away %fs. No need to save %gs, as it was saved on the
664 * stack on entry. No need to save %es and %ds, as those are
665 * always kernel segments while inside the kernel. Doing this
666 * before setting the new TLS descriptors avoids the situation
667 * where we temporarily have non-reloadable segments in %fs
668 * and %gs. This could be an issue if the NMI handler ever
669 * used %fs or %gs (it does not today), or if the kernel is
670 * running inside of a hypervisor layer.
672 savesegment(fs, prev->fs);
675 * Load the per-thread Thread-Local Storage descriptor.
680 * Restore %fs if needed.
682 * Glibc normally makes %fs be zero.
684 if (unlikely(prev->fs | next->fs))
685 loadsegment(fs, next->fs);
689 * Restore IOPL if needed.
691 if (unlikely(prev->iopl != next->iopl))
692 set_iopl_mask(next->iopl);
695 * Now maybe handle debug registers and/or IO bitmaps
697 if (unlikely((task_thread_info(next_p)->flags & _TIF_WORK_CTXSW)
698 || test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)))
699 __switch_to_xtra(next_p, tss);
701 disable_tsc(prev_p, next_p);
703 /* If the task has used fpu the last 5 timeslices, just do a full
704 * restore of the math state immediately to avoid the trap; the
705 * chances of needing FPU soon are obviously high now
707 if (next_p->fpu_counter > 5)
708 math_state_restore();
713 asmlinkage int sys_fork(struct pt_regs regs)
715 return do_fork(SIGCHLD, regs.esp, ®s, 0, NULL, NULL);
718 asmlinkage int sys_clone(struct pt_regs regs)
720 unsigned long clone_flags;
722 int __user *parent_tidptr, *child_tidptr;
724 clone_flags = regs.ebx;
726 parent_tidptr = (int __user *)regs.edx;
727 child_tidptr = (int __user *)regs.edi;
730 return do_fork(clone_flags, newsp, ®s, 0, parent_tidptr, child_tidptr);
734 * This is trivial, and on the face of it looks like it
735 * could equally well be done in user mode.
737 * Not so, for quite unobvious reasons - register pressure.
738 * In user mode vfork() cannot have a stack frame, and if
739 * done by calling the "clone()" system call directly, you
740 * do not have enough call-clobbered registers to hold all
741 * the information you need.
743 asmlinkage int sys_vfork(struct pt_regs regs)
745 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.esp, ®s, 0, NULL, NULL);
749 * sys_execve() executes a new program.
751 asmlinkage int sys_execve(struct pt_regs regs)
756 filename = getname((char __user *) regs.ebx);
757 error = PTR_ERR(filename);
758 if (IS_ERR(filename))
760 error = do_execve(filename,
761 (char __user * __user *) regs.ecx,
762 (char __user * __user *) regs.edx,
766 current->ptrace &= ~PT_DTRACE;
767 task_unlock(current);
768 /* Make sure we don't return using sysenter.. */
769 set_thread_flag(TIF_IRET);
776 #define top_esp (THREAD_SIZE - sizeof(unsigned long))
777 #define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long))
779 unsigned long get_wchan(struct task_struct *p)
781 unsigned long ebp, esp, eip;
782 unsigned long stack_page;
784 if (!p || p == current || p->state == TASK_RUNNING)
786 stack_page = (unsigned long)task_stack_page(p);
788 if (!stack_page || esp < stack_page || esp > top_esp+stack_page)
790 /* include/asm-i386/system.h:switch_to() pushes ebp last. */
791 ebp = *(unsigned long *) esp;
793 if (ebp < stack_page || ebp > top_ebp+stack_page)
795 eip = *(unsigned long *) (ebp+4);
796 if (!in_sched_functions(eip))
798 ebp = *(unsigned long *) ebp;
799 } while (count++ < 16);
804 * sys_alloc_thread_area: get a yet unused TLS descriptor index.
806 static int get_free_idx(void)
808 struct thread_struct *t = ¤t->thread;
811 for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)
812 if (desc_empty(t->tls_array + idx))
813 return idx + GDT_ENTRY_TLS_MIN;
818 * Set a given TLS descriptor:
820 asmlinkage int sys_set_thread_area(struct user_desc __user *u_info)
822 struct thread_struct *t = ¤t->thread;
823 struct user_desc info;
824 struct desc_struct *desc;
827 if (copy_from_user(&info, u_info, sizeof(info)))
829 idx = info.entry_number;
832 * index -1 means the kernel should try to find and
833 * allocate an empty descriptor:
836 idx = get_free_idx();
839 if (put_user(idx, &u_info->entry_number))
843 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
846 desc = t->tls_array + idx - GDT_ENTRY_TLS_MIN;
849 * We must not get preempted while modifying the TLS.
853 if (LDT_empty(&info)) {
857 desc->a = LDT_entry_a(&info);
858 desc->b = LDT_entry_b(&info);
868 * Get the current Thread-Local Storage area:
871 #define GET_BASE(desc) ( \
872 (((desc)->a >> 16) & 0x0000ffff) | \
873 (((desc)->b << 16) & 0x00ff0000) | \
874 ( (desc)->b & 0xff000000) )
876 #define GET_LIMIT(desc) ( \
877 ((desc)->a & 0x0ffff) | \
878 ((desc)->b & 0xf0000) )
880 #define GET_32BIT(desc) (((desc)->b >> 22) & 1)
881 #define GET_CONTENTS(desc) (((desc)->b >> 10) & 3)
882 #define GET_WRITABLE(desc) (((desc)->b >> 9) & 1)
883 #define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1)
884 #define GET_PRESENT(desc) (((desc)->b >> 15) & 1)
885 #define GET_USEABLE(desc) (((desc)->b >> 20) & 1)
887 asmlinkage int sys_get_thread_area(struct user_desc __user *u_info)
889 struct user_desc info;
890 struct desc_struct *desc;
893 if (get_user(idx, &u_info->entry_number))
895 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
898 memset(&info, 0, sizeof(info));
900 desc = current->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
902 info.entry_number = idx;
903 info.base_addr = GET_BASE(desc);
904 info.limit = GET_LIMIT(desc);
905 info.seg_32bit = GET_32BIT(desc);
906 info.contents = GET_CONTENTS(desc);
907 info.read_exec_only = !GET_WRITABLE(desc);
908 info.limit_in_pages = GET_LIMIT_PAGES(desc);
909 info.seg_not_present = !GET_PRESENT(desc);
910 info.useable = GET_USEABLE(desc);
912 if (copy_to_user(u_info, &info, sizeof(info)))
917 unsigned long arch_align_stack(unsigned long sp)
919 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
920 sp -= get_random_int() % 8192;