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/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/utsname.h>
31 #include <linux/delay.h>
32 #include <linux/reboot.h>
33 #include <linux/init.h>
34 #include <linux/mc146818rtc.h>
35 #include <linux/module.h>
36 #include <linux/kallsyms.h>
37 #include <linux/ptrace.h>
38 #include <linux/random.h>
39 #include <linux/personality.h>
40 #include <linux/tick.h>
41 #include <linux/percpu.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/err.h>
58 #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
);
68 DEFINE_PER_CPU(struct task_struct
*, current_task
) = &init_task
;
69 EXPORT_PER_CPU_SYMBOL(current_task
);
71 DEFINE_PER_CPU(int, cpu_number
);
72 EXPORT_PER_CPU_SYMBOL(cpu_number
);
75 * Return saved PC of a blocked thread.
77 unsigned long thread_saved_pc(struct task_struct
*tsk
)
79 return ((unsigned long *)tsk
->thread
.esp
)[3];
83 * Powermanagement idle function, if any..
85 void (*pm_idle
)(void);
86 EXPORT_SYMBOL(pm_idle
);
87 static DEFINE_PER_CPU(unsigned int, cpu_idle_state
);
89 void disable_hlt(void)
94 EXPORT_SYMBOL(disable_hlt
);
101 EXPORT_SYMBOL(enable_hlt
);
104 * We use this if we don't have any better
107 void default_idle(void)
109 if (!hlt_counter
&& boot_cpu_data
.hlt_works_ok
) {
110 current_thread_info()->status
&= ~TS_POLLING
;
112 * TS_POLLING-cleared state must be visible before we
119 safe_halt(); /* enables interrupts racelessly */
122 current_thread_info()->status
|= TS_POLLING
;
124 /* loop is done by the caller */
128 #ifdef CONFIG_APM_MODULE
129 EXPORT_SYMBOL(default_idle
);
133 * On SMP it's slightly faster (but much more power-consuming!)
134 * to poll the ->work.need_resched flag instead of waiting for the
135 * cross-CPU IPI to arrive. Use this option with caution.
137 static void poll_idle (void)
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 tick_nohz_stop_sched_tick();
183 while (!need_resched()) {
186 if (__get_cpu_var(cpu_idle_state
))
187 __get_cpu_var(cpu_idle_state
) = 0;
196 if (cpu_is_offline(cpu
))
199 __get_cpu_var(irq_stat
).idle_timestamp
= jiffies
;
202 tick_nohz_restart_sched_tick();
203 preempt_enable_no_resched();
209 void cpu_idle_wait(void)
211 unsigned int cpu
, this_cpu
= get_cpu();
212 cpumask_t map
, tmp
= current
->cpus_allowed
;
214 set_cpus_allowed(current
, cpumask_of_cpu(this_cpu
));
218 for_each_online_cpu(cpu
) {
219 per_cpu(cpu_idle_state
, cpu
) = 1;
223 __get_cpu_var(cpu_idle_state
) = 0;
228 for_each_online_cpu(cpu
) {
229 if (cpu_isset(cpu
, map
) && !per_cpu(cpu_idle_state
, cpu
))
232 cpus_and(map
, map
, cpu_online_map
);
233 } while (!cpus_empty(map
));
235 set_cpus_allowed(current
, tmp
);
237 EXPORT_SYMBOL_GPL(cpu_idle_wait
);
240 * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
241 * which can obviate IPI to trigger checking of need_resched.
242 * We execute MONITOR against need_resched and enter optimized wait state
243 * through MWAIT. Whenever someone changes need_resched, we would be woken
244 * up from MWAIT (without an IPI).
246 * New with Core Duo processors, MWAIT can take some hints based on CPU
249 void mwait_idle_with_hints(unsigned long eax
, unsigned long ecx
)
251 if (!need_resched()) {
252 __monitor((void *)¤t_thread_info()->flags
, 0, 0);
259 /* Default MONITOR/MWAIT with no hints, used for default C1 state */
260 static void mwait_idle(void)
263 mwait_idle_with_hints(0, 0);
266 void __devinit
select_idle_routine(const struct cpuinfo_x86
*c
)
268 if (cpu_has(c
, X86_FEATURE_MWAIT
)) {
269 printk("monitor/mwait feature present.\n");
271 * Skip, if setup has overridden idle.
272 * One CPU supports mwait => All CPUs supports mwait
275 printk("using mwait in idle threads.\n");
276 pm_idle
= mwait_idle
;
281 static int __init
idle_setup(char *str
)
283 if (!strcmp(str
, "poll")) {
284 printk("using polling idle threads.\n");
286 #ifdef CONFIG_X86_SMP
287 if (smp_num_siblings
> 1)
288 printk("WARNING: polling idle and HT enabled, performance may degrade.\n");
290 } else if (!strcmp(str
, "mwait"))
295 boot_option_idle_override
= 1;
298 early_param("idle", idle_setup
);
300 void show_regs(struct pt_regs
* regs
)
302 unsigned long cr0
= 0L, cr2
= 0L, cr3
= 0L, cr4
= 0L;
303 unsigned long d0
, d1
, d2
, d3
, d6
, d7
;
306 printk("Pid: %d, comm: %20s\n", current
->pid
, current
->comm
);
307 printk("EIP: %04x:[<%08lx>] CPU: %d\n",0xffff & regs
->xcs
,regs
->eip
, smp_processor_id());
308 print_symbol("EIP is at %s\n", regs
->eip
);
310 if (user_mode_vm(regs
))
311 printk(" ESP: %04x:%08lx",0xffff & regs
->xss
,regs
->esp
);
312 printk(" EFLAGS: %08lx %s (%s %.*s)\n",
313 regs
->eflags
, print_tainted(), init_utsname()->release
,
314 (int)strcspn(init_utsname()->version
, " "),
315 init_utsname()->version
);
316 printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
317 regs
->eax
,regs
->ebx
,regs
->ecx
,regs
->edx
);
318 printk("ESI: %08lx EDI: %08lx EBP: %08lx",
319 regs
->esi
, regs
->edi
, regs
->ebp
);
320 printk(" DS: %04x ES: %04x FS: %04x\n",
321 0xffff & regs
->xds
,0xffff & regs
->xes
, 0xffff & regs
->xfs
);
326 cr4
= read_cr4_safe();
327 printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0
, cr2
, cr3
, cr4
);
333 printk("DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
337 printk("DR6: %08lx DR7: %08lx\n", d6
, d7
);
339 show_trace(NULL
, regs
, ®s
->esp
);
343 * This gets run with %ebx containing the
344 * function to call, and %edx containing
347 extern void kernel_thread_helper(void);
350 * Create a kernel thread
352 int kernel_thread(int (*fn
)(void *), void * arg
, unsigned long flags
)
356 memset(®s
, 0, sizeof(regs
));
358 regs
.ebx
= (unsigned long) fn
;
359 regs
.edx
= (unsigned long) arg
;
361 regs
.xds
= __USER_DS
;
362 regs
.xes
= __USER_DS
;
363 regs
.xfs
= __KERNEL_PERCPU
;
365 regs
.eip
= (unsigned long) kernel_thread_helper
;
366 regs
.xcs
= __KERNEL_CS
| get_kernel_rpl();
367 regs
.eflags
= X86_EFLAGS_IF
| X86_EFLAGS_SF
| X86_EFLAGS_PF
| 0x2;
369 /* Ok, create the new process.. */
370 return do_fork(flags
| CLONE_VM
| CLONE_UNTRACED
, 0, ®s
, 0, NULL
, NULL
);
372 EXPORT_SYMBOL(kernel_thread
);
375 * Free current thread data structures etc..
377 void exit_thread(void)
379 /* The process may have allocated an io port bitmap... nuke it. */
380 if (unlikely(test_thread_flag(TIF_IO_BITMAP
))) {
381 struct task_struct
*tsk
= current
;
382 struct thread_struct
*t
= &tsk
->thread
;
384 struct tss_struct
*tss
= &per_cpu(init_tss
, cpu
);
386 kfree(t
->io_bitmap_ptr
);
387 t
->io_bitmap_ptr
= NULL
;
388 clear_thread_flag(TIF_IO_BITMAP
);
390 * Careful, clear this in the TSS too:
392 memset(tss
->io_bitmap
, 0xff, tss
->io_bitmap_max
);
393 t
->io_bitmap_max
= 0;
394 tss
->io_bitmap_owner
= NULL
;
395 tss
->io_bitmap_max
= 0;
396 tss
->x86_tss
.io_bitmap_base
= INVALID_IO_BITMAP_OFFSET
;
401 void flush_thread(void)
403 struct task_struct
*tsk
= current
;
405 memset(tsk
->thread
.debugreg
, 0, sizeof(unsigned long)*8);
406 memset(tsk
->thread
.tls_array
, 0, sizeof(tsk
->thread
.tls_array
));
407 clear_tsk_thread_flag(tsk
, TIF_DEBUG
);
409 * Forget coprocessor state..
415 void release_thread(struct task_struct
*dead_task
)
417 BUG_ON(dead_task
->mm
);
418 release_vm86_irqs(dead_task
);
422 * This gets called before we allocate a new thread and copy
423 * the current task into it.
425 void prepare_to_copy(struct task_struct
*tsk
)
430 int copy_thread(int nr
, unsigned long clone_flags
, unsigned long esp
,
431 unsigned long unused
,
432 struct task_struct
* p
, struct pt_regs
* regs
)
434 struct pt_regs
* childregs
;
435 struct task_struct
*tsk
;
438 childregs
= task_pt_regs(p
);
441 childregs
->esp
= esp
;
443 p
->thread
.esp
= (unsigned long) childregs
;
444 p
->thread
.esp0
= (unsigned long) (childregs
+1);
446 p
->thread
.eip
= (unsigned long) ret_from_fork
;
448 savesegment(gs
,p
->thread
.gs
);
451 if (unlikely(test_tsk_thread_flag(tsk
, TIF_IO_BITMAP
))) {
452 p
->thread
.io_bitmap_ptr
= kmemdup(tsk
->thread
.io_bitmap_ptr
,
453 IO_BITMAP_BYTES
, GFP_KERNEL
);
454 if (!p
->thread
.io_bitmap_ptr
) {
455 p
->thread
.io_bitmap_max
= 0;
458 set_tsk_thread_flag(p
, TIF_IO_BITMAP
);
462 * Set a new TLS for the child thread?
464 if (clone_flags
& CLONE_SETTLS
) {
465 struct desc_struct
*desc
;
466 struct user_desc info
;
470 if (copy_from_user(&info
, (void __user
*)childregs
->esi
, sizeof(info
)))
473 if (LDT_empty(&info
))
476 idx
= info
.entry_number
;
477 if (idx
< GDT_ENTRY_TLS_MIN
|| idx
> GDT_ENTRY_TLS_MAX
)
480 desc
= p
->thread
.tls_array
+ idx
- GDT_ENTRY_TLS_MIN
;
481 desc
->a
= LDT_entry_a(&info
);
482 desc
->b
= LDT_entry_b(&info
);
487 if (err
&& p
->thread
.io_bitmap_ptr
) {
488 kfree(p
->thread
.io_bitmap_ptr
);
489 p
->thread
.io_bitmap_max
= 0;
495 * fill in the user structure for a core dump..
497 void dump_thread(struct pt_regs
* regs
, struct user
* dump
)
501 /* changed the size calculations - should hopefully work better. lbt */
502 dump
->magic
= CMAGIC
;
503 dump
->start_code
= 0;
504 dump
->start_stack
= regs
->esp
& ~(PAGE_SIZE
- 1);
505 dump
->u_tsize
= ((unsigned long) current
->mm
->end_code
) >> PAGE_SHIFT
;
506 dump
->u_dsize
= ((unsigned long) (current
->mm
->brk
+ (PAGE_SIZE
-1))) >> PAGE_SHIFT
;
507 dump
->u_dsize
-= dump
->u_tsize
;
509 for (i
= 0; i
< 8; i
++)
510 dump
->u_debugreg
[i
] = current
->thread
.debugreg
[i
];
512 if (dump
->start_stack
< TASK_SIZE
)
513 dump
->u_ssize
= ((unsigned long) (TASK_SIZE
- dump
->start_stack
)) >> PAGE_SHIFT
;
515 dump
->regs
.ebx
= regs
->ebx
;
516 dump
->regs
.ecx
= regs
->ecx
;
517 dump
->regs
.edx
= regs
->edx
;
518 dump
->regs
.esi
= regs
->esi
;
519 dump
->regs
.edi
= regs
->edi
;
520 dump
->regs
.ebp
= regs
->ebp
;
521 dump
->regs
.eax
= regs
->eax
;
522 dump
->regs
.ds
= regs
->xds
;
523 dump
->regs
.es
= regs
->xes
;
524 dump
->regs
.fs
= regs
->xfs
;
525 savesegment(gs
,dump
->regs
.gs
);
526 dump
->regs
.orig_eax
= regs
->orig_eax
;
527 dump
->regs
.eip
= regs
->eip
;
528 dump
->regs
.cs
= regs
->xcs
;
529 dump
->regs
.eflags
= regs
->eflags
;
530 dump
->regs
.esp
= regs
->esp
;
531 dump
->regs
.ss
= regs
->xss
;
533 dump
->u_fpvalid
= dump_fpu (regs
, &dump
->i387
);
535 EXPORT_SYMBOL(dump_thread
);
538 * Capture the user space registers if the task is not running (in user space)
540 int dump_task_regs(struct task_struct
*tsk
, elf_gregset_t
*regs
)
542 struct pt_regs ptregs
= *task_pt_regs(tsk
);
543 ptregs
.xcs
&= 0xffff;
544 ptregs
.xds
&= 0xffff;
545 ptregs
.xes
&= 0xffff;
546 ptregs
.xss
&= 0xffff;
548 elf_core_copy_regs(regs
, &ptregs
);
553 #ifdef CONFIG_SECCOMP
554 void hard_disable_TSC(void)
556 write_cr4(read_cr4() | X86_CR4_TSD
);
558 void disable_TSC(void)
561 if (!test_and_set_thread_flag(TIF_NOTSC
))
563 * Must flip the CPU state synchronously with
564 * TIF_NOTSC in the current running context.
569 void hard_enable_TSC(void)
571 write_cr4(read_cr4() & ~X86_CR4_TSD
);
573 #endif /* CONFIG_SECCOMP */
576 __switch_to_xtra(struct task_struct
*prev_p
, struct task_struct
*next_p
,
577 struct tss_struct
*tss
)
579 struct thread_struct
*next
;
581 next
= &next_p
->thread
;
583 if (test_tsk_thread_flag(next_p
, TIF_DEBUG
)) {
584 set_debugreg(next
->debugreg
[0], 0);
585 set_debugreg(next
->debugreg
[1], 1);
586 set_debugreg(next
->debugreg
[2], 2);
587 set_debugreg(next
->debugreg
[3], 3);
589 set_debugreg(next
->debugreg
[6], 6);
590 set_debugreg(next
->debugreg
[7], 7);
593 #ifdef CONFIG_SECCOMP
594 if (test_tsk_thread_flag(prev_p
, TIF_NOTSC
) ^
595 test_tsk_thread_flag(next_p
, TIF_NOTSC
)) {
596 /* prev and next are different */
597 if (test_tsk_thread_flag(next_p
, TIF_NOTSC
))
604 if (!test_tsk_thread_flag(next_p
, TIF_IO_BITMAP
)) {
606 * Disable the bitmap via an invalid offset. We still cache
607 * the previous bitmap owner and the IO bitmap contents:
609 tss
->x86_tss
.io_bitmap_base
= INVALID_IO_BITMAP_OFFSET
;
613 if (likely(next
== tss
->io_bitmap_owner
)) {
615 * Previous owner of the bitmap (hence the bitmap content)
616 * matches the next task, we dont have to do anything but
617 * to set a valid offset in the TSS:
619 tss
->x86_tss
.io_bitmap_base
= IO_BITMAP_OFFSET
;
623 * Lazy TSS's I/O bitmap copy. We set an invalid offset here
624 * and we let the task to get a GPF in case an I/O instruction
625 * is performed. The handler of the GPF will verify that the
626 * faulting task has a valid I/O bitmap and, it true, does the
627 * real copy and restart the instruction. This will save us
628 * redundant copies when the currently switched task does not
629 * perform any I/O during its timeslice.
631 tss
->x86_tss
.io_bitmap_base
= INVALID_IO_BITMAP_OFFSET_LAZY
;
635 * switch_to(x,yn) should switch tasks from x to y.
637 * We fsave/fwait so that an exception goes off at the right time
638 * (as a call from the fsave or fwait in effect) rather than to
639 * the wrong process. Lazy FP saving no longer makes any sense
640 * with modern CPU's, and this simplifies a lot of things (SMP
641 * and UP become the same).
643 * NOTE! We used to use the x86 hardware context switching. The
644 * reason for not using it any more becomes apparent when you
645 * try to recover gracefully from saved state that is no longer
646 * valid (stale segment register values in particular). With the
647 * hardware task-switch, there is no way to fix up bad state in
648 * a reasonable manner.
650 * The fact that Intel documents the hardware task-switching to
651 * be slow is a fairly red herring - this code is not noticeably
652 * faster. However, there _is_ some room for improvement here,
653 * so the performance issues may eventually be a valid point.
654 * More important, however, is the fact that this allows us much
657 * The return value (in %eax) will be the "prev" task after
658 * the task-switch, and shows up in ret_from_fork in entry.S,
661 struct task_struct fastcall
* __switch_to(struct task_struct
*prev_p
, struct task_struct
*next_p
)
663 struct thread_struct
*prev
= &prev_p
->thread
,
664 *next
= &next_p
->thread
;
665 int cpu
= smp_processor_id();
666 struct tss_struct
*tss
= &per_cpu(init_tss
, cpu
);
668 /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */
670 __unlazy_fpu(prev_p
);
673 /* we're going to use this soon, after a few expensive things */
674 if (next_p
->fpu_counter
> 5)
675 prefetch(&next
->i387
.fxsave
);
680 load_esp0(tss
, next
);
683 * Save away %gs. No need to save %fs, as it was saved on the
684 * stack on entry. No need to save %es and %ds, as those are
685 * always kernel segments while inside the kernel. Doing this
686 * before setting the new TLS descriptors avoids the situation
687 * where we temporarily have non-reloadable segments in %fs
688 * and %gs. This could be an issue if the NMI handler ever
689 * used %fs or %gs (it does not today), or if the kernel is
690 * running inside of a hypervisor layer.
692 savesegment(gs
, prev
->gs
);
695 * Load the per-thread Thread-Local Storage descriptor.
700 * Restore IOPL if needed. In normal use, the flags restore
701 * in the switch assembly will handle this. But if the kernel
702 * is running virtualized at a non-zero CPL, the popf will
703 * not restore flags, so it must be done in a separate step.
705 if (get_kernel_rpl() && unlikely(prev
->iopl
!= next
->iopl
))
706 set_iopl_mask(next
->iopl
);
709 * Now maybe handle debug registers and/or IO bitmaps
711 if (unlikely(task_thread_info(prev_p
)->flags
& _TIF_WORK_CTXSW_PREV
||
712 task_thread_info(next_p
)->flags
& _TIF_WORK_CTXSW_NEXT
))
713 __switch_to_xtra(prev_p
, next_p
, tss
);
716 * Leave lazy mode, flushing any hypercalls made here.
717 * This must be done before restoring TLS segments so
718 * the GDT and LDT are properly updated, and must be
719 * done before math_state_restore, so the TS bit is up
722 arch_leave_lazy_cpu_mode();
724 /* If the task has used fpu the last 5 timeslices, just do a full
725 * restore of the math state immediately to avoid the trap; the
726 * chances of needing FPU soon are obviously high now
728 if (next_p
->fpu_counter
> 5)
729 math_state_restore();
732 * Restore %gs if needed (which is common)
734 if (prev
->gs
| next
->gs
)
735 loadsegment(gs
, next
->gs
);
737 x86_write_percpu(current_task
, next_p
);
742 asmlinkage
int sys_fork(struct pt_regs regs
)
744 return do_fork(SIGCHLD
, regs
.esp
, ®s
, 0, NULL
, NULL
);
747 asmlinkage
int sys_clone(struct pt_regs regs
)
749 unsigned long clone_flags
;
751 int __user
*parent_tidptr
, *child_tidptr
;
753 clone_flags
= regs
.ebx
;
755 parent_tidptr
= (int __user
*)regs
.edx
;
756 child_tidptr
= (int __user
*)regs
.edi
;
759 return do_fork(clone_flags
, newsp
, ®s
, 0, parent_tidptr
, child_tidptr
);
763 * This is trivial, and on the face of it looks like it
764 * could equally well be done in user mode.
766 * Not so, for quite unobvious reasons - register pressure.
767 * In user mode vfork() cannot have a stack frame, and if
768 * done by calling the "clone()" system call directly, you
769 * do not have enough call-clobbered registers to hold all
770 * the information you need.
772 asmlinkage
int sys_vfork(struct pt_regs regs
)
774 return do_fork(CLONE_VFORK
| CLONE_VM
| SIGCHLD
, regs
.esp
, ®s
, 0, NULL
, NULL
);
778 * sys_execve() executes a new program.
780 asmlinkage
int sys_execve(struct pt_regs regs
)
785 filename
= getname((char __user
*) regs
.ebx
);
786 error
= PTR_ERR(filename
);
787 if (IS_ERR(filename
))
789 error
= do_execve(filename
,
790 (char __user
* __user
*) regs
.ecx
,
791 (char __user
* __user
*) regs
.edx
,
795 current
->ptrace
&= ~PT_DTRACE
;
796 task_unlock(current
);
797 /* Make sure we don't return using sysenter.. */
798 set_thread_flag(TIF_IRET
);
805 #define top_esp (THREAD_SIZE - sizeof(unsigned long))
806 #define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long))
808 unsigned long get_wchan(struct task_struct
*p
)
810 unsigned long ebp
, esp
, eip
;
811 unsigned long stack_page
;
813 if (!p
|| p
== current
|| p
->state
== TASK_RUNNING
)
815 stack_page
= (unsigned long)task_stack_page(p
);
817 if (!stack_page
|| esp
< stack_page
|| esp
> top_esp
+stack_page
)
819 /* include/asm-i386/system.h:switch_to() pushes ebp last. */
820 ebp
= *(unsigned long *) esp
;
822 if (ebp
< stack_page
|| ebp
> top_ebp
+stack_page
)
824 eip
= *(unsigned long *) (ebp
+4);
825 if (!in_sched_functions(eip
))
827 ebp
= *(unsigned long *) ebp
;
828 } while (count
++ < 16);
833 * sys_alloc_thread_area: get a yet unused TLS descriptor index.
835 static int get_free_idx(void)
837 struct thread_struct
*t
= ¤t
->thread
;
840 for (idx
= 0; idx
< GDT_ENTRY_TLS_ENTRIES
; idx
++)
841 if (desc_empty(t
->tls_array
+ idx
))
842 return idx
+ GDT_ENTRY_TLS_MIN
;
847 * Set a given TLS descriptor:
849 asmlinkage
int sys_set_thread_area(struct user_desc __user
*u_info
)
851 struct thread_struct
*t
= ¤t
->thread
;
852 struct user_desc info
;
853 struct desc_struct
*desc
;
856 if (copy_from_user(&info
, u_info
, sizeof(info
)))
858 idx
= info
.entry_number
;
861 * index -1 means the kernel should try to find and
862 * allocate an empty descriptor:
865 idx
= get_free_idx();
868 if (put_user(idx
, &u_info
->entry_number
))
872 if (idx
< GDT_ENTRY_TLS_MIN
|| idx
> GDT_ENTRY_TLS_MAX
)
875 desc
= t
->tls_array
+ idx
- GDT_ENTRY_TLS_MIN
;
878 * We must not get preempted while modifying the TLS.
882 if (LDT_empty(&info
)) {
886 desc
->a
= LDT_entry_a(&info
);
887 desc
->b
= LDT_entry_b(&info
);
897 * Get the current Thread-Local Storage area:
900 #define GET_BASE(desc) ( \
901 (((desc)->a >> 16) & 0x0000ffff) | \
902 (((desc)->b << 16) & 0x00ff0000) | \
903 ( (desc)->b & 0xff000000) )
905 #define GET_LIMIT(desc) ( \
906 ((desc)->a & 0x0ffff) | \
907 ((desc)->b & 0xf0000) )
909 #define GET_32BIT(desc) (((desc)->b >> 22) & 1)
910 #define GET_CONTENTS(desc) (((desc)->b >> 10) & 3)
911 #define GET_WRITABLE(desc) (((desc)->b >> 9) & 1)
912 #define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1)
913 #define GET_PRESENT(desc) (((desc)->b >> 15) & 1)
914 #define GET_USEABLE(desc) (((desc)->b >> 20) & 1)
916 asmlinkage
int sys_get_thread_area(struct user_desc __user
*u_info
)
918 struct user_desc info
;
919 struct desc_struct
*desc
;
922 if (get_user(idx
, &u_info
->entry_number
))
924 if (idx
< GDT_ENTRY_TLS_MIN
|| idx
> GDT_ENTRY_TLS_MAX
)
927 memset(&info
, 0, sizeof(info
));
929 desc
= current
->thread
.tls_array
+ idx
- GDT_ENTRY_TLS_MIN
;
931 info
.entry_number
= idx
;
932 info
.base_addr
= GET_BASE(desc
);
933 info
.limit
= GET_LIMIT(desc
);
934 info
.seg_32bit
= GET_32BIT(desc
);
935 info
.contents
= GET_CONTENTS(desc
);
936 info
.read_exec_only
= !GET_WRITABLE(desc
);
937 info
.limit_in_pages
= GET_LIMIT_PAGES(desc
);
938 info
.seg_not_present
= !GET_PRESENT(desc
);
939 info
.useable
= GET_USEABLE(desc
);
941 if (copy_to_user(u_info
, &info
, sizeof(info
)))
946 unsigned long arch_align_stack(unsigned long sp
)
948 if (!(current
->personality
& ADDR_NO_RANDOMIZE
) && randomize_va_space
)
949 sp
-= get_random_int() % 8192;