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/config.h>
32 #include <linux/utsname.h>
33 #include <linux/delay.h>
34 #include <linux/reboot.h>
35 #include <linux/init.h>
36 #include <linux/mc146818rtc.h>
37 #include <linux/module.h>
38 #include <linux/kallsyms.h>
39 #include <linux/ptrace.h>
40 #include <linux/random.h>
41 #include <linux/kprobes.h>
43 #include <asm/uaccess.h>
44 #include <asm/pgtable.h>
45 #include <asm/system.h>
48 #include <asm/processor.h>
52 #ifdef CONFIG_MATH_EMULATION
53 #include <asm/math_emu.h>
56 #include <linux/irq.h>
57 #include <linux/err.h>
59 #include <asm/tlbflush.h>
62 asmlinkage
void ret_from_fork(void) __asm__("ret_from_fork");
64 static int hlt_counter
;
66 unsigned long boot_option_idle_override
= 0;
67 EXPORT_SYMBOL(boot_option_idle_override
);
70 * Return saved PC of a blocked thread.
72 unsigned long thread_saved_pc(struct task_struct
*tsk
)
74 return ((unsigned long *)tsk
->thread
.esp
)[3];
78 * Powermanagement idle function, if any..
80 void (*pm_idle
)(void);
81 EXPORT_SYMBOL(pm_idle
);
82 static DEFINE_PER_CPU(unsigned int, cpu_idle_state
);
84 void disable_hlt(void)
89 EXPORT_SYMBOL(disable_hlt
);
96 EXPORT_SYMBOL(enable_hlt
);
99 * We use this if we don't have any better
102 void default_idle(void)
104 if (!hlt_counter
&& boot_cpu_data
.hlt_works_ok
) {
114 #ifdef CONFIG_APM_MODULE
115 EXPORT_SYMBOL(default_idle
);
119 * On SMP it's slightly faster (but much more power-consuming!)
120 * to poll the ->work.need_resched flag instead of waiting for the
121 * cross-CPU IPI to arrive. Use this option with caution.
123 static void poll_idle (void)
130 * Deal with another CPU just having chosen a thread to
133 oldval
= test_and_clear_thread_flag(TIF_NEED_RESCHED
);
136 set_thread_flag(TIF_POLLING_NRFLAG
);
142 : : "i"(_TIF_NEED_RESCHED
), "m" (current_thread_info()->flags
));
144 clear_thread_flag(TIF_POLLING_NRFLAG
);
150 #ifdef CONFIG_HOTPLUG_CPU
152 /* We don't actually take CPU down, just spin without interrupts. */
153 static inline void play_dead(void)
156 __get_cpu_var(cpu_state
) = CPU_DEAD
;
158 /* We shouldn't have to disable interrupts while dead, but
159 * some interrupts just don't seem to go away, and this makes
160 * it "work" for testing purposes. */
162 while (__get_cpu_var(cpu_state
) != CPU_UP_PREPARE
)
167 cpu_set(smp_processor_id(), cpu_online_map
);
172 static inline void play_dead(void)
176 #endif /* CONFIG_HOTPLUG_CPU */
179 * The idle thread. There's no useful work to be
180 * done, so just try to conserve power and have a
181 * low exit latency (ie sit in a loop waiting for
182 * somebody to say that they'd like to reschedule)
186 int cpu
= raw_smp_processor_id();
188 /* endless idle loop with no priority at all */
190 while (!need_resched()) {
193 if (__get_cpu_var(cpu_idle_state
))
194 __get_cpu_var(cpu_idle_state
) = 0;
202 if (cpu_is_offline(cpu
))
205 __get_cpu_var(irq_stat
).idle_timestamp
= jiffies
;
212 void cpu_idle_wait(void)
214 unsigned int cpu
, this_cpu
= get_cpu();
217 set_cpus_allowed(current
, cpumask_of_cpu(this_cpu
));
221 for_each_online_cpu(cpu
) {
222 per_cpu(cpu_idle_state
, cpu
) = 1;
226 __get_cpu_var(cpu_idle_state
) = 0;
231 for_each_online_cpu(cpu
) {
232 if (cpu_isset(cpu
, map
) && !per_cpu(cpu_idle_state
, cpu
))
235 cpus_and(map
, map
, cpu_online_map
);
236 } while (!cpus_empty(map
));
238 EXPORT_SYMBOL_GPL(cpu_idle_wait
);
241 * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
242 * which can obviate IPI to trigger checking of need_resched.
243 * We execute MONITOR against need_resched and enter optimized wait state
244 * through MWAIT. Whenever someone changes need_resched, we would be woken
245 * up from MWAIT (without an IPI).
247 static void mwait_idle(void)
251 if (!need_resched()) {
252 set_thread_flag(TIF_POLLING_NRFLAG
);
254 __monitor((void *)¤t_thread_info()->flags
, 0, 0);
258 } while (!need_resched());
259 clear_thread_flag(TIF_POLLING_NRFLAG
);
263 void __devinit
select_idle_routine(const struct cpuinfo_x86
*c
)
265 if (cpu_has(c
, X86_FEATURE_MWAIT
)) {
266 printk("monitor/mwait feature present.\n");
268 * Skip, if setup has overridden idle.
269 * One CPU supports mwait => All CPUs supports mwait
272 printk("using mwait in idle threads.\n");
273 pm_idle
= mwait_idle
;
278 static int __init
idle_setup (char *str
)
280 if (!strncmp(str
, "poll", 4)) {
281 printk("using polling idle threads.\n");
283 #ifdef CONFIG_X86_SMP
284 if (smp_num_siblings
> 1)
285 printk("WARNING: polling idle and HT enabled, performance may degrade.\n");
287 } else if (!strncmp(str
, "halt", 4)) {
288 printk("using halt in idle threads.\n");
289 pm_idle
= default_idle
;
292 boot_option_idle_override
= 1;
296 __setup("idle=", idle_setup
);
298 void show_regs(struct pt_regs
* regs
)
300 unsigned long cr0
= 0L, cr2
= 0L, cr3
= 0L, cr4
= 0L;
303 printk("Pid: %d, comm: %20s\n", current
->pid
, current
->comm
);
304 printk("EIP: %04x:[<%08lx>] CPU: %d\n",0xffff & regs
->xcs
,regs
->eip
, smp_processor_id());
305 print_symbol("EIP is at %s\n", regs
->eip
);
308 printk(" ESP: %04x:%08lx",0xffff & regs
->xss
,regs
->esp
);
309 printk(" EFLAGS: %08lx %s (%s)\n",
310 regs
->eflags
, print_tainted(), system_utsname
.release
);
311 printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
312 regs
->eax
,regs
->ebx
,regs
->ecx
,regs
->edx
);
313 printk("ESI: %08lx EDI: %08lx EBP: %08lx",
314 regs
->esi
, regs
->edi
, regs
->ebp
);
315 printk(" DS: %04x ES: %04x\n",
316 0xffff & regs
->xds
,0xffff & regs
->xes
);
318 __asm__("movl %%cr0, %0": "=r" (cr0
));
319 __asm__("movl %%cr2, %0": "=r" (cr2
));
320 __asm__("movl %%cr3, %0": "=r" (cr3
));
321 /* This could fault if %cr4 does not exist */
322 __asm__("1: movl %%cr4, %0 \n"
324 ".section __ex_table,\"a\" \n"
327 : "=r" (cr4
): "0" (0));
328 printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0
, cr2
, cr3
, cr4
);
329 show_trace(NULL
, ®s
->esp
);
333 * This gets run with %ebx containing the
334 * function to call, and %edx containing
337 extern void kernel_thread_helper(void);
338 __asm__(".section .text\n"
340 "kernel_thread_helper:\n\t"
349 * Create a kernel thread
351 int kernel_thread(int (*fn
)(void *), void * arg
, unsigned long flags
)
355 memset(®s
, 0, sizeof(regs
));
357 regs
.ebx
= (unsigned long) fn
;
358 regs
.edx
= (unsigned long) arg
;
360 regs
.xds
= __USER_DS
;
361 regs
.xes
= __USER_DS
;
363 regs
.eip
= (unsigned long) kernel_thread_helper
;
364 regs
.xcs
= __KERNEL_CS
;
365 regs
.eflags
= X86_EFLAGS_IF
| X86_EFLAGS_SF
| X86_EFLAGS_PF
| 0x2;
367 /* Ok, create the new process.. */
368 return do_fork(flags
| CLONE_VM
| CLONE_UNTRACED
, 0, ®s
, 0, NULL
, NULL
);
370 EXPORT_SYMBOL(kernel_thread
);
373 * Free current thread data structures etc..
375 void exit_thread(void)
377 struct task_struct
*tsk
= current
;
378 struct thread_struct
*t
= &tsk
->thread
;
381 * Remove function-return probe instances associated with this task
382 * and put them back on the free list. Do not insert an exit probe for
383 * this function, it will be disabled by kprobe_flush_task if you do.
385 kprobe_flush_task(tsk
);
387 /* The process may have allocated an io port bitmap... nuke it. */
388 if (unlikely(NULL
!= t
->io_bitmap_ptr
)) {
390 struct tss_struct
*tss
= &per_cpu(init_tss
, cpu
);
392 kfree(t
->io_bitmap_ptr
);
393 t
->io_bitmap_ptr
= NULL
;
395 * Careful, clear this in the TSS too:
397 memset(tss
->io_bitmap
, 0xff, tss
->io_bitmap_max
);
398 t
->io_bitmap_max
= 0;
399 tss
->io_bitmap_owner
= NULL
;
400 tss
->io_bitmap_max
= 0;
401 tss
->io_bitmap_base
= INVALID_IO_BITMAP_OFFSET
;
406 void flush_thread(void)
408 struct task_struct
*tsk
= current
;
411 * Remove function-return probe instances associated with this task
412 * and put them back on the free list. Do not insert an exit probe for
413 * this function, it will be disabled by kprobe_flush_task if you do.
415 kprobe_flush_task(tsk
);
417 memset(tsk
->thread
.debugreg
, 0, sizeof(unsigned long)*8);
418 memset(tsk
->thread
.tls_array
, 0, sizeof(tsk
->thread
.tls_array
));
420 * Forget coprocessor state..
426 void release_thread(struct task_struct
*dead_task
)
429 // temporary debugging check
430 if (dead_task
->mm
->context
.size
) {
431 printk("WARNING: dead process %8s still has LDT? <%p/%d>\n",
433 dead_task
->mm
->context
.ldt
,
434 dead_task
->mm
->context
.size
);
439 release_vm86_irqs(dead_task
);
443 * This gets called before we allocate a new thread and copy
444 * the current task into it.
446 void prepare_to_copy(struct task_struct
*tsk
)
451 int copy_thread(int nr
, unsigned long clone_flags
, unsigned long esp
,
452 unsigned long unused
,
453 struct task_struct
* p
, struct pt_regs
* regs
)
455 struct pt_regs
* childregs
;
456 struct task_struct
*tsk
;
459 childregs
= ((struct pt_regs
*) (THREAD_SIZE
+ (unsigned long) p
->thread_info
)) - 1;
461 * The below -8 is to reserve 8 bytes on top of the ring0 stack.
462 * This is necessary to guarantee that the entire "struct pt_regs"
463 * is accessable even if the CPU haven't stored the SS/ESP registers
464 * on the stack (interrupt gate does not save these registers
465 * when switching to the same priv ring).
466 * Therefore beware: accessing the xss/esp fields of the
467 * "struct pt_regs" is possible, but they may contain the
468 * completely wrong values.
470 childregs
= (struct pt_regs
*) ((unsigned long) childregs
- 8);
473 childregs
->esp
= esp
;
475 p
->thread
.esp
= (unsigned long) childregs
;
476 p
->thread
.esp0
= (unsigned long) (childregs
+1);
478 p
->thread
.eip
= (unsigned long) ret_from_fork
;
480 savesegment(fs
,p
->thread
.fs
);
481 savesegment(gs
,p
->thread
.gs
);
484 if (unlikely(NULL
!= tsk
->thread
.io_bitmap_ptr
)) {
485 p
->thread
.io_bitmap_ptr
= kmalloc(IO_BITMAP_BYTES
, GFP_KERNEL
);
486 if (!p
->thread
.io_bitmap_ptr
) {
487 p
->thread
.io_bitmap_max
= 0;
490 memcpy(p
->thread
.io_bitmap_ptr
, tsk
->thread
.io_bitmap_ptr
,
495 * Set a new TLS for the child thread?
497 if (clone_flags
& CLONE_SETTLS
) {
498 struct desc_struct
*desc
;
499 struct user_desc info
;
503 if (copy_from_user(&info
, (void __user
*)childregs
->esi
, sizeof(info
)))
506 if (LDT_empty(&info
))
509 idx
= info
.entry_number
;
510 if (idx
< GDT_ENTRY_TLS_MIN
|| idx
> GDT_ENTRY_TLS_MAX
)
513 desc
= p
->thread
.tls_array
+ idx
- GDT_ENTRY_TLS_MIN
;
514 desc
->a
= LDT_entry_a(&info
);
515 desc
->b
= LDT_entry_b(&info
);
520 if (err
&& p
->thread
.io_bitmap_ptr
) {
521 kfree(p
->thread
.io_bitmap_ptr
);
522 p
->thread
.io_bitmap_max
= 0;
528 * fill in the user structure for a core dump..
530 void dump_thread(struct pt_regs
* regs
, struct user
* dump
)
534 /* changed the size calculations - should hopefully work better. lbt */
535 dump
->magic
= CMAGIC
;
536 dump
->start_code
= 0;
537 dump
->start_stack
= regs
->esp
& ~(PAGE_SIZE
- 1);
538 dump
->u_tsize
= ((unsigned long) current
->mm
->end_code
) >> PAGE_SHIFT
;
539 dump
->u_dsize
= ((unsigned long) (current
->mm
->brk
+ (PAGE_SIZE
-1))) >> PAGE_SHIFT
;
540 dump
->u_dsize
-= dump
->u_tsize
;
542 for (i
= 0; i
< 8; i
++)
543 dump
->u_debugreg
[i
] = current
->thread
.debugreg
[i
];
545 if (dump
->start_stack
< TASK_SIZE
)
546 dump
->u_ssize
= ((unsigned long) (TASK_SIZE
- dump
->start_stack
)) >> PAGE_SHIFT
;
548 dump
->regs
.ebx
= regs
->ebx
;
549 dump
->regs
.ecx
= regs
->ecx
;
550 dump
->regs
.edx
= regs
->edx
;
551 dump
->regs
.esi
= regs
->esi
;
552 dump
->regs
.edi
= regs
->edi
;
553 dump
->regs
.ebp
= regs
->ebp
;
554 dump
->regs
.eax
= regs
->eax
;
555 dump
->regs
.ds
= regs
->xds
;
556 dump
->regs
.es
= regs
->xes
;
557 savesegment(fs
,dump
->regs
.fs
);
558 savesegment(gs
,dump
->regs
.gs
);
559 dump
->regs
.orig_eax
= regs
->orig_eax
;
560 dump
->regs
.eip
= regs
->eip
;
561 dump
->regs
.cs
= regs
->xcs
;
562 dump
->regs
.eflags
= regs
->eflags
;
563 dump
->regs
.esp
= regs
->esp
;
564 dump
->regs
.ss
= regs
->xss
;
566 dump
->u_fpvalid
= dump_fpu (regs
, &dump
->i387
);
568 EXPORT_SYMBOL(dump_thread
);
571 * Capture the user space registers if the task is not running (in user space)
573 int dump_task_regs(struct task_struct
*tsk
, elf_gregset_t
*regs
)
575 struct pt_regs ptregs
;
577 ptregs
= *(struct pt_regs
*)
578 ((unsigned long)tsk
->thread_info
+THREAD_SIZE
- sizeof(ptregs
));
579 ptregs
.xcs
&= 0xffff;
580 ptregs
.xds
&= 0xffff;
581 ptregs
.xes
&= 0xffff;
582 ptregs
.xss
&= 0xffff;
584 elf_core_copy_regs(regs
, &ptregs
);
590 handle_io_bitmap(struct thread_struct
*next
, struct tss_struct
*tss
)
592 if (!next
->io_bitmap_ptr
) {
594 * Disable the bitmap via an invalid offset. We still cache
595 * the previous bitmap owner and the IO bitmap contents:
597 tss
->io_bitmap_base
= INVALID_IO_BITMAP_OFFSET
;
600 if (likely(next
== tss
->io_bitmap_owner
)) {
602 * Previous owner of the bitmap (hence the bitmap content)
603 * matches the next task, we dont have to do anything but
604 * to set a valid offset in the TSS:
606 tss
->io_bitmap_base
= IO_BITMAP_OFFSET
;
610 * Lazy TSS's I/O bitmap copy. We set an invalid offset here
611 * and we let the task to get a GPF in case an I/O instruction
612 * is performed. The handler of the GPF will verify that the
613 * faulting task has a valid I/O bitmap and, it true, does the
614 * real copy and restart the instruction. This will save us
615 * redundant copies when the currently switched task does not
616 * perform any I/O during its timeslice.
618 tss
->io_bitmap_base
= INVALID_IO_BITMAP_OFFSET_LAZY
;
622 * switch_to(x,yn) should switch tasks from x to y.
624 * We fsave/fwait so that an exception goes off at the right time
625 * (as a call from the fsave or fwait in effect) rather than to
626 * the wrong process. Lazy FP saving no longer makes any sense
627 * with modern CPU's, and this simplifies a lot of things (SMP
628 * and UP become the same).
630 * NOTE! We used to use the x86 hardware context switching. The
631 * reason for not using it any more becomes apparent when you
632 * try to recover gracefully from saved state that is no longer
633 * valid (stale segment register values in particular). With the
634 * hardware task-switch, there is no way to fix up bad state in
635 * a reasonable manner.
637 * The fact that Intel documents the hardware task-switching to
638 * be slow is a fairly red herring - this code is not noticeably
639 * faster. However, there _is_ some room for improvement here,
640 * so the performance issues may eventually be a valid point.
641 * More important, however, is the fact that this allows us much
644 * The return value (in %eax) will be the "prev" task after
645 * the task-switch, and shows up in ret_from_fork in entry.S,
648 struct task_struct fastcall
* __switch_to(struct task_struct
*prev_p
, struct task_struct
*next_p
)
650 struct thread_struct
*prev
= &prev_p
->thread
,
651 *next
= &next_p
->thread
;
652 int cpu
= smp_processor_id();
653 struct tss_struct
*tss
= &per_cpu(init_tss
, cpu
);
655 /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */
657 __unlazy_fpu(prev_p
);
660 * Reload esp0, LDT and the page table pointer:
662 load_esp0(tss
, next
);
665 * Load the per-thread Thread-Local Storage descriptor.
670 * Save away %fs and %gs. No need to save %es and %ds, as
671 * those are always kernel segments while inside the kernel.
673 asm volatile("mov %%fs,%0":"=m" (prev
->fs
));
674 asm volatile("mov %%gs,%0":"=m" (prev
->gs
));
677 * Restore %fs and %gs if needed.
679 if (unlikely(prev
->fs
| prev
->gs
| next
->fs
| next
->gs
)) {
680 loadsegment(fs
, next
->fs
);
681 loadsegment(gs
, next
->gs
);
685 * Now maybe reload the debug registers
687 if (unlikely(next
->debugreg
[7])) {
688 set_debugreg(current
->thread
.debugreg
[0], 0);
689 set_debugreg(current
->thread
.debugreg
[1], 1);
690 set_debugreg(current
->thread
.debugreg
[2], 2);
691 set_debugreg(current
->thread
.debugreg
[3], 3);
693 set_debugreg(current
->thread
.debugreg
[6], 6);
694 set_debugreg(current
->thread
.debugreg
[7], 7);
697 if (unlikely(prev
->io_bitmap_ptr
|| next
->io_bitmap_ptr
))
698 handle_io_bitmap(next
, tss
);
703 asmlinkage
int sys_fork(struct pt_regs regs
)
705 return do_fork(SIGCHLD
, regs
.esp
, ®s
, 0, NULL
, NULL
);
708 asmlinkage
int sys_clone(struct pt_regs regs
)
710 unsigned long clone_flags
;
712 int __user
*parent_tidptr
, *child_tidptr
;
714 clone_flags
= regs
.ebx
;
716 parent_tidptr
= (int __user
*)regs
.edx
;
717 child_tidptr
= (int __user
*)regs
.edi
;
720 return do_fork(clone_flags
, newsp
, ®s
, 0, parent_tidptr
, child_tidptr
);
724 * This is trivial, and on the face of it looks like it
725 * could equally well be done in user mode.
727 * Not so, for quite unobvious reasons - register pressure.
728 * In user mode vfork() cannot have a stack frame, and if
729 * done by calling the "clone()" system call directly, you
730 * do not have enough call-clobbered registers to hold all
731 * the information you need.
733 asmlinkage
int sys_vfork(struct pt_regs regs
)
735 return do_fork(CLONE_VFORK
| CLONE_VM
| SIGCHLD
, regs
.esp
, ®s
, 0, NULL
, NULL
);
739 * sys_execve() executes a new program.
741 asmlinkage
int sys_execve(struct pt_regs regs
)
746 filename
= getname((char __user
*) regs
.ebx
);
747 error
= PTR_ERR(filename
);
748 if (IS_ERR(filename
))
750 error
= do_execve(filename
,
751 (char __user
* __user
*) regs
.ecx
,
752 (char __user
* __user
*) regs
.edx
,
756 current
->ptrace
&= ~PT_DTRACE
;
757 task_unlock(current
);
758 /* Make sure we don't return using sysenter.. */
759 set_thread_flag(TIF_IRET
);
766 #define top_esp (THREAD_SIZE - sizeof(unsigned long))
767 #define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long))
769 unsigned long get_wchan(struct task_struct
*p
)
771 unsigned long ebp
, esp
, eip
;
772 unsigned long stack_page
;
774 if (!p
|| p
== current
|| p
->state
== TASK_RUNNING
)
776 stack_page
= (unsigned long)p
->thread_info
;
778 if (!stack_page
|| esp
< stack_page
|| esp
> top_esp
+stack_page
)
780 /* include/asm-i386/system.h:switch_to() pushes ebp last. */
781 ebp
= *(unsigned long *) esp
;
783 if (ebp
< stack_page
|| ebp
> top_ebp
+stack_page
)
785 eip
= *(unsigned long *) (ebp
+4);
786 if (!in_sched_functions(eip
))
788 ebp
= *(unsigned long *) ebp
;
789 } while (count
++ < 16);
792 EXPORT_SYMBOL(get_wchan
);
795 * sys_alloc_thread_area: get a yet unused TLS descriptor index.
797 static int get_free_idx(void)
799 struct thread_struct
*t
= ¤t
->thread
;
802 for (idx
= 0; idx
< GDT_ENTRY_TLS_ENTRIES
; idx
++)
803 if (desc_empty(t
->tls_array
+ idx
))
804 return idx
+ GDT_ENTRY_TLS_MIN
;
809 * Set a given TLS descriptor:
811 asmlinkage
int sys_set_thread_area(struct user_desc __user
*u_info
)
813 struct thread_struct
*t
= ¤t
->thread
;
814 struct user_desc info
;
815 struct desc_struct
*desc
;
818 if (copy_from_user(&info
, u_info
, sizeof(info
)))
820 idx
= info
.entry_number
;
823 * index -1 means the kernel should try to find and
824 * allocate an empty descriptor:
827 idx
= get_free_idx();
830 if (put_user(idx
, &u_info
->entry_number
))
834 if (idx
< GDT_ENTRY_TLS_MIN
|| idx
> GDT_ENTRY_TLS_MAX
)
837 desc
= t
->tls_array
+ idx
- GDT_ENTRY_TLS_MIN
;
840 * We must not get preempted while modifying the TLS.
844 if (LDT_empty(&info
)) {
848 desc
->a
= LDT_entry_a(&info
);
849 desc
->b
= LDT_entry_b(&info
);
859 * Get the current Thread-Local Storage area:
862 #define GET_BASE(desc) ( \
863 (((desc)->a >> 16) & 0x0000ffff) | \
864 (((desc)->b << 16) & 0x00ff0000) | \
865 ( (desc)->b & 0xff000000) )
867 #define GET_LIMIT(desc) ( \
868 ((desc)->a & 0x0ffff) | \
869 ((desc)->b & 0xf0000) )
871 #define GET_32BIT(desc) (((desc)->b >> 22) & 1)
872 #define GET_CONTENTS(desc) (((desc)->b >> 10) & 3)
873 #define GET_WRITABLE(desc) (((desc)->b >> 9) & 1)
874 #define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1)
875 #define GET_PRESENT(desc) (((desc)->b >> 15) & 1)
876 #define GET_USEABLE(desc) (((desc)->b >> 20) & 1)
878 asmlinkage
int sys_get_thread_area(struct user_desc __user
*u_info
)
880 struct user_desc info
;
881 struct desc_struct
*desc
;
884 if (get_user(idx
, &u_info
->entry_number
))
886 if (idx
< GDT_ENTRY_TLS_MIN
|| idx
> GDT_ENTRY_TLS_MAX
)
889 desc
= current
->thread
.tls_array
+ idx
- GDT_ENTRY_TLS_MIN
;
891 info
.entry_number
= idx
;
892 info
.base_addr
= GET_BASE(desc
);
893 info
.limit
= GET_LIMIT(desc
);
894 info
.seg_32bit
= GET_32BIT(desc
);
895 info
.contents
= GET_CONTENTS(desc
);
896 info
.read_exec_only
= !GET_WRITABLE(desc
);
897 info
.limit_in_pages
= GET_LIMIT_PAGES(desc
);
898 info
.seg_not_present
= !GET_PRESENT(desc
);
899 info
.useable
= GET_USEABLE(desc
);
901 if (copy_to_user(u_info
, &info
, sizeof(info
)))
906 unsigned long arch_align_stack(unsigned long sp
)
908 if (randomize_va_space
)
909 sp
-= get_random_int() % 8192;