2 * Copyright (C) 1995 Linus Torvalds
4 * Pentium III FXSR, SSE support
5 * Gareth Hughes <gareth@valinux.com>, May 2000
9 * This file handles the architecture-dependent parts of process handling..
14 #include <linux/cpu.h>
15 #include <linux/errno.h>
16 #include <linux/sched.h>
18 #include <linux/kernel.h>
20 #include <linux/elfcore.h>
21 #include <linux/smp.h>
22 #include <linux/stddef.h>
23 #include <linux/slab.h>
24 #include <linux/vmalloc.h>
25 #include <linux/user.h>
26 #include <linux/a.out.h>
27 #include <linux/interrupt.h>
28 #include <linux/utsname.h>
29 #include <linux/delay.h>
30 #include <linux/reboot.h>
31 #include <linux/init.h>
32 #include <linux/mc146818rtc.h>
33 #include <linux/module.h>
34 #include <linux/kallsyms.h>
35 #include <linux/ptrace.h>
36 #include <linux/random.h>
37 #include <linux/personality.h>
38 #include <linux/tick.h>
39 #include <linux/percpu.h>
41 #include <asm/uaccess.h>
42 #include <asm/pgtable.h>
43 #include <asm/system.h>
46 #include <asm/processor.h>
50 #ifdef CONFIG_MATH_EMULATION
51 #include <asm/math_emu.h>
54 #include <linux/err.h>
56 #include <asm/tlbflush.h>
58 #include <asm/kdebug.h>
60 asmlinkage
void ret_from_fork(void) __asm__("ret_from_fork");
62 static int hlt_counter
;
64 unsigned long boot_option_idle_override
= 0;
65 EXPORT_SYMBOL(boot_option_idle_override
);
67 DEFINE_PER_CPU(struct task_struct
*, current_task
) = &init_task
;
68 EXPORT_PER_CPU_SYMBOL(current_task
);
70 DEFINE_PER_CPU(int, cpu_number
);
71 EXPORT_PER_CPU_SYMBOL(cpu_number
);
74 * Return saved PC of a blocked thread.
76 unsigned long thread_saved_pc(struct task_struct
*tsk
)
78 return ((unsigned long *)tsk
->thread
.sp
)[3];
82 * Powermanagement idle function, if any..
84 void (*pm_idle
)(void);
85 EXPORT_SYMBOL(pm_idle
);
86 static DEFINE_PER_CPU(unsigned int, cpu_idle_state
);
88 void disable_hlt(void)
93 EXPORT_SYMBOL(disable_hlt
);
100 EXPORT_SYMBOL(enable_hlt
);
103 * We use this if we don't have any better
106 void default_idle(void)
108 if (!hlt_counter
&& boot_cpu_data
.hlt_works_ok
) {
109 current_thread_info()->status
&= ~TS_POLLING
;
111 * TS_POLLING-cleared state must be visible before we
117 if (!need_resched()) {
122 t0n
= ktime_to_ns(t0
);
123 safe_halt(); /* enables interrupts racelessly */
126 t1n
= ktime_to_ns(t1
);
127 sched_clock_idle_wakeup_event(t1n
- t0n
);
130 current_thread_info()->status
|= TS_POLLING
;
132 /* loop is done by the caller */
136 #ifdef CONFIG_APM_MODULE
137 EXPORT_SYMBOL(default_idle
);
141 * On SMP it's slightly faster (but much more power-consuming!)
142 * to poll the ->work.need_resched flag instead of waiting for the
143 * cross-CPU IPI to arrive. Use this option with caution.
145 static void poll_idle(void)
150 #ifdef CONFIG_HOTPLUG_CPU
152 /* We don't actually take CPU down, just spin without interrupts. */
153 static inline void play_dead(void)
155 /* This must be done before dead CPU ack */
160 __get_cpu_var(cpu_state
) = CPU_DEAD
;
163 * With physical CPU hotplug, we should halt the cpu
170 static inline void play_dead(void)
174 #endif /* CONFIG_HOTPLUG_CPU */
177 * The idle thread. There's no useful work to be
178 * done, so just try to conserve power and have a
179 * low exit latency (ie sit in a loop waiting for
180 * somebody to say that they'd like to reschedule)
184 int cpu
= smp_processor_id();
186 current_thread_info()->status
|= TS_POLLING
;
188 /* endless idle loop with no priority at all */
190 tick_nohz_stop_sched_tick();
191 while (!need_resched()) {
194 if (__get_cpu_var(cpu_idle_state
))
195 __get_cpu_var(cpu_idle_state
) = 0;
204 if (cpu_is_offline(cpu
))
207 __get_cpu_var(irq_stat
).idle_timestamp
= jiffies
;
210 tick_nohz_restart_sched_tick();
211 preempt_enable_no_resched();
217 static void do_nothing(void *unused
)
221 void cpu_idle_wait(void)
223 unsigned int cpu
, this_cpu
= get_cpu();
224 cpumask_t map
, tmp
= current
->cpus_allowed
;
226 set_cpus_allowed(current
, cpumask_of_cpu(this_cpu
));
230 for_each_online_cpu(cpu
) {
231 per_cpu(cpu_idle_state
, cpu
) = 1;
235 __get_cpu_var(cpu_idle_state
) = 0;
240 for_each_online_cpu(cpu
) {
241 if (cpu_isset(cpu
, map
) && !per_cpu(cpu_idle_state
, cpu
))
244 cpus_and(map
, map
, cpu_online_map
);
246 * We waited 1 sec, if a CPU still did not call idle
247 * it may be because it is in idle and not waking up
248 * because it has nothing to do.
249 * Give all the remaining CPUS a kick.
251 smp_call_function_mask(map
, do_nothing
, 0, 0);
252 } while (!cpus_empty(map
));
254 set_cpus_allowed(current
, tmp
);
256 EXPORT_SYMBOL_GPL(cpu_idle_wait
);
259 * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
260 * which can obviate IPI to trigger checking of need_resched.
261 * We execute MONITOR against need_resched and enter optimized wait state
262 * through MWAIT. Whenever someone changes need_resched, we would be woken
263 * up from MWAIT (without an IPI).
265 * New with Core Duo processors, MWAIT can take some hints based on CPU
268 void mwait_idle_with_hints(unsigned long ax
, unsigned long cx
)
270 if (!need_resched()) {
271 __monitor((void *)¤t_thread_info()->flags
, 0, 0);
278 /* Default MONITOR/MWAIT with no hints, used for default C1 state */
279 static void mwait_idle(void)
282 mwait_idle_with_hints(0, 0);
285 void __cpuinit
select_idle_routine(const struct cpuinfo_x86
*c
)
287 if (cpu_has(c
, X86_FEATURE_MWAIT
)) {
288 printk("monitor/mwait feature present.\n");
290 * Skip, if setup has overridden idle.
291 * One CPU supports mwait => All CPUs supports mwait
294 printk("using mwait in idle threads.\n");
295 pm_idle
= mwait_idle
;
300 static int __init
idle_setup(char *str
)
302 if (!strcmp(str
, "poll")) {
303 printk("using polling idle threads.\n");
305 #ifdef CONFIG_X86_SMP
306 if (smp_num_siblings
> 1)
307 printk("WARNING: polling idle and HT enabled, performance may degrade.\n");
309 } else if (!strcmp(str
, "mwait"))
314 boot_option_idle_override
= 1;
317 early_param("idle", idle_setup
);
319 void __show_registers(struct pt_regs
*regs
, int all
)
321 unsigned long cr0
= 0L, cr2
= 0L, cr3
= 0L, cr4
= 0L;
322 unsigned long d0
, d1
, d2
, d3
, d6
, d7
;
324 unsigned short ss
, gs
;
326 if (user_mode_vm(regs
)) {
328 ss
= regs
->ss
& 0xffff;
331 sp
= (unsigned long) (®s
->sp
);
337 printk("Pid: %d, comm: %s %s (%s %.*s)\n",
338 task_pid_nr(current
), current
->comm
,
339 print_tainted(), init_utsname()->release
,
340 (int)strcspn(init_utsname()->version
, " "),
341 init_utsname()->version
);
343 printk("EIP: %04x:[<%08lx>] EFLAGS: %08lx CPU: %d\n",
344 0xffff & regs
->cs
, regs
->ip
, regs
->flags
,
346 print_symbol("EIP is at %s\n", regs
->ip
);
348 printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
349 regs
->ax
, regs
->bx
, regs
->cx
, regs
->dx
);
350 printk("ESI: %08lx EDI: %08lx EBP: %08lx ESP: %08lx\n",
351 regs
->si
, regs
->di
, regs
->bp
, sp
);
352 printk(" DS: %04x ES: %04x FS: %04x GS: %04x SS: %04x\n",
353 regs
->ds
& 0xffff, regs
->es
& 0xffff,
354 regs
->fs
& 0xffff, gs
, ss
);
362 cr4
= read_cr4_safe();
363 printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n",
370 printk("DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
375 printk("DR6: %08lx DR7: %08lx\n",
379 void show_regs(struct pt_regs
*regs
)
381 __show_registers(regs
, 1);
382 show_trace(NULL
, regs
, ®s
->sp
);
386 * This gets run with %bx containing the
387 * function to call, and %dx containing
390 extern void kernel_thread_helper(void);
393 * Create a kernel thread
395 int kernel_thread(int (*fn
)(void *), void * arg
, unsigned long flags
)
399 memset(®s
, 0, sizeof(regs
));
401 regs
.bx
= (unsigned long) fn
;
402 regs
.dx
= (unsigned long) arg
;
406 regs
.fs
= __KERNEL_PERCPU
;
408 regs
.ip
= (unsigned long) kernel_thread_helper
;
409 regs
.cs
= __KERNEL_CS
| get_kernel_rpl();
410 regs
.flags
= X86_EFLAGS_IF
| X86_EFLAGS_SF
| X86_EFLAGS_PF
| 0x2;
412 /* Ok, create the new process.. */
413 return do_fork(flags
| CLONE_VM
| CLONE_UNTRACED
, 0, ®s
, 0, NULL
, NULL
);
415 EXPORT_SYMBOL(kernel_thread
);
418 * Free current thread data structures etc..
420 void exit_thread(void)
422 /* The process may have allocated an io port bitmap... nuke it. */
423 if (unlikely(test_thread_flag(TIF_IO_BITMAP
))) {
424 struct task_struct
*tsk
= current
;
425 struct thread_struct
*t
= &tsk
->thread
;
427 struct tss_struct
*tss
= &per_cpu(init_tss
, cpu
);
429 kfree(t
->io_bitmap_ptr
);
430 t
->io_bitmap_ptr
= NULL
;
431 clear_thread_flag(TIF_IO_BITMAP
);
433 * Careful, clear this in the TSS too:
435 memset(tss
->io_bitmap
, 0xff, tss
->io_bitmap_max
);
436 t
->io_bitmap_max
= 0;
437 tss
->io_bitmap_owner
= NULL
;
438 tss
->io_bitmap_max
= 0;
439 tss
->x86_tss
.io_bitmap_base
= INVALID_IO_BITMAP_OFFSET
;
444 void flush_thread(void)
446 struct task_struct
*tsk
= current
;
448 tsk
->thread
.debugreg0
= 0;
449 tsk
->thread
.debugreg1
= 0;
450 tsk
->thread
.debugreg2
= 0;
451 tsk
->thread
.debugreg3
= 0;
452 tsk
->thread
.debugreg6
= 0;
453 tsk
->thread
.debugreg7
= 0;
454 memset(tsk
->thread
.tls_array
, 0, sizeof(tsk
->thread
.tls_array
));
455 clear_tsk_thread_flag(tsk
, TIF_DEBUG
);
457 * Forget coprocessor state..
463 void release_thread(struct task_struct
*dead_task
)
465 BUG_ON(dead_task
->mm
);
466 release_vm86_irqs(dead_task
);
470 * This gets called before we allocate a new thread and copy
471 * the current task into it.
473 void prepare_to_copy(struct task_struct
*tsk
)
478 int copy_thread(int nr
, unsigned long clone_flags
, unsigned long sp
,
479 unsigned long unused
,
480 struct task_struct
* p
, struct pt_regs
* regs
)
482 struct pt_regs
* childregs
;
483 struct task_struct
*tsk
;
486 childregs
= task_pt_regs(p
);
491 p
->thread
.sp
= (unsigned long) childregs
;
492 p
->thread
.sp0
= (unsigned long) (childregs
+1);
494 p
->thread
.ip
= (unsigned long) ret_from_fork
;
496 savesegment(gs
, p
->thread
.gs
);
499 if (unlikely(test_tsk_thread_flag(tsk
, TIF_IO_BITMAP
))) {
500 p
->thread
.io_bitmap_ptr
= kmemdup(tsk
->thread
.io_bitmap_ptr
,
501 IO_BITMAP_BYTES
, GFP_KERNEL
);
502 if (!p
->thread
.io_bitmap_ptr
) {
503 p
->thread
.io_bitmap_max
= 0;
506 set_tsk_thread_flag(p
, TIF_IO_BITMAP
);
512 * Set a new TLS for the child thread?
514 if (clone_flags
& CLONE_SETTLS
)
515 err
= do_set_thread_area(p
, -1,
516 (struct user_desc __user
*)childregs
->si
, 0);
518 if (err
&& p
->thread
.io_bitmap_ptr
) {
519 kfree(p
->thread
.io_bitmap_ptr
);
520 p
->thread
.io_bitmap_max
= 0;
526 * fill in the user structure for a core dump..
528 void dump_thread(struct pt_regs
* regs
, struct user
* dump
)
532 /* changed the size calculations - should hopefully work better. lbt */
533 dump
->magic
= CMAGIC
;
534 dump
->start_code
= 0;
535 dump
->start_stack
= regs
->sp
& ~(PAGE_SIZE
- 1);
536 dump
->u_tsize
= ((unsigned long) current
->mm
->end_code
) >> PAGE_SHIFT
;
537 dump
->u_dsize
= ((unsigned long) (current
->mm
->brk
+ (PAGE_SIZE
-1))) >> PAGE_SHIFT
;
538 dump
->u_dsize
-= dump
->u_tsize
;
540 dump
->u_debugreg
[0] = current
->thread
.debugreg0
;
541 dump
->u_debugreg
[1] = current
->thread
.debugreg1
;
542 dump
->u_debugreg
[2] = current
->thread
.debugreg2
;
543 dump
->u_debugreg
[3] = current
->thread
.debugreg3
;
544 dump
->u_debugreg
[4] = 0;
545 dump
->u_debugreg
[5] = 0;
546 dump
->u_debugreg
[6] = current
->thread
.debugreg6
;
547 dump
->u_debugreg
[7] = current
->thread
.debugreg7
;
549 if (dump
->start_stack
< TASK_SIZE
)
550 dump
->u_ssize
= ((unsigned long) (TASK_SIZE
- dump
->start_stack
)) >> PAGE_SHIFT
;
552 dump
->regs
.bx
= regs
->bx
;
553 dump
->regs
.cx
= regs
->cx
;
554 dump
->regs
.dx
= regs
->dx
;
555 dump
->regs
.si
= regs
->si
;
556 dump
->regs
.di
= regs
->di
;
557 dump
->regs
.bp
= regs
->bp
;
558 dump
->regs
.ax
= regs
->ax
;
559 dump
->regs
.ds
= (u16
)regs
->ds
;
560 dump
->regs
.es
= (u16
)regs
->es
;
561 dump
->regs
.fs
= (u16
)regs
->fs
;
563 dump
->regs
.orig_ax
= regs
->orig_ax
;
564 dump
->regs
.ip
= regs
->ip
;
565 dump
->regs
.cs
= (u16
)regs
->cs
;
566 dump
->regs
.flags
= regs
->flags
;
567 dump
->regs
.sp
= regs
->sp
;
568 dump
->regs
.ss
= (u16
)regs
->ss
;
570 dump
->u_fpvalid
= dump_fpu (regs
, &dump
->i387
);
572 EXPORT_SYMBOL(dump_thread
);
575 * Capture the user space registers if the task is not running (in user space)
577 int dump_task_regs(struct task_struct
*tsk
, elf_gregset_t
*regs
)
579 struct pt_regs ptregs
= *task_pt_regs(tsk
);
585 elf_core_copy_regs(regs
, &ptregs
);
590 #ifdef CONFIG_SECCOMP
591 void hard_disable_TSC(void)
593 write_cr4(read_cr4() | X86_CR4_TSD
);
595 void disable_TSC(void)
598 if (!test_and_set_thread_flag(TIF_NOTSC
))
600 * Must flip the CPU state synchronously with
601 * TIF_NOTSC in the current running context.
606 void hard_enable_TSC(void)
608 write_cr4(read_cr4() & ~X86_CR4_TSD
);
610 #endif /* CONFIG_SECCOMP */
613 __switch_to_xtra(struct task_struct
*prev_p
, struct task_struct
*next_p
,
614 struct tss_struct
*tss
)
616 struct thread_struct
*prev
, *next
;
617 unsigned long debugctl
;
619 prev
= &prev_p
->thread
;
620 next
= &next_p
->thread
;
622 debugctl
= prev
->debugctlmsr
;
623 if (next
->ds_area_msr
!= prev
->ds_area_msr
) {
624 /* we clear debugctl to make sure DS
625 * is not in use when we change it */
627 wrmsrl(MSR_IA32_DEBUGCTLMSR
, 0);
628 wrmsr(MSR_IA32_DS_AREA
, next
->ds_area_msr
, 0);
631 if (next
->debugctlmsr
!= debugctl
)
632 wrmsr(MSR_IA32_DEBUGCTLMSR
, next
->debugctlmsr
, 0);
634 if (test_tsk_thread_flag(next_p
, TIF_DEBUG
)) {
635 set_debugreg(next
->debugreg0
, 0);
636 set_debugreg(next
->debugreg1
, 1);
637 set_debugreg(next
->debugreg2
, 2);
638 set_debugreg(next
->debugreg3
, 3);
640 set_debugreg(next
->debugreg6
, 6);
641 set_debugreg(next
->debugreg7
, 7);
644 #ifdef CONFIG_SECCOMP
645 if (test_tsk_thread_flag(prev_p
, TIF_NOTSC
) ^
646 test_tsk_thread_flag(next_p
, TIF_NOTSC
)) {
647 /* prev and next are different */
648 if (test_tsk_thread_flag(next_p
, TIF_NOTSC
))
655 if (test_tsk_thread_flag(prev_p
, TIF_BTS_TRACE_TS
))
656 ptrace_bts_take_timestamp(prev_p
, BTS_TASK_DEPARTS
);
658 if (test_tsk_thread_flag(next_p
, TIF_BTS_TRACE_TS
))
659 ptrace_bts_take_timestamp(next_p
, BTS_TASK_ARRIVES
);
662 if (!test_tsk_thread_flag(next_p
, TIF_IO_BITMAP
)) {
664 * Disable the bitmap via an invalid offset. We still cache
665 * the previous bitmap owner and the IO bitmap contents:
667 tss
->x86_tss
.io_bitmap_base
= INVALID_IO_BITMAP_OFFSET
;
671 if (likely(next
== tss
->io_bitmap_owner
)) {
673 * Previous owner of the bitmap (hence the bitmap content)
674 * matches the next task, we dont have to do anything but
675 * to set a valid offset in the TSS:
677 tss
->x86_tss
.io_bitmap_base
= IO_BITMAP_OFFSET
;
681 * Lazy TSS's I/O bitmap copy. We set an invalid offset here
682 * and we let the task to get a GPF in case an I/O instruction
683 * is performed. The handler of the GPF will verify that the
684 * faulting task has a valid I/O bitmap and, it true, does the
685 * real copy and restart the instruction. This will save us
686 * redundant copies when the currently switched task does not
687 * perform any I/O during its timeslice.
689 tss
->x86_tss
.io_bitmap_base
= INVALID_IO_BITMAP_OFFSET_LAZY
;
693 * switch_to(x,yn) should switch tasks from x to y.
695 * We fsave/fwait so that an exception goes off at the right time
696 * (as a call from the fsave or fwait in effect) rather than to
697 * the wrong process. Lazy FP saving no longer makes any sense
698 * with modern CPU's, and this simplifies a lot of things (SMP
699 * and UP become the same).
701 * NOTE! We used to use the x86 hardware context switching. The
702 * reason for not using it any more becomes apparent when you
703 * try to recover gracefully from saved state that is no longer
704 * valid (stale segment register values in particular). With the
705 * hardware task-switch, there is no way to fix up bad state in
706 * a reasonable manner.
708 * The fact that Intel documents the hardware task-switching to
709 * be slow is a fairly red herring - this code is not noticeably
710 * faster. However, there _is_ some room for improvement here,
711 * so the performance issues may eventually be a valid point.
712 * More important, however, is the fact that this allows us much
715 * The return value (in %ax) will be the "prev" task after
716 * the task-switch, and shows up in ret_from_fork in entry.S,
719 struct task_struct
* __switch_to(struct task_struct
*prev_p
, struct task_struct
*next_p
)
721 struct thread_struct
*prev
= &prev_p
->thread
,
722 *next
= &next_p
->thread
;
723 int cpu
= smp_processor_id();
724 struct tss_struct
*tss
= &per_cpu(init_tss
, cpu
);
726 /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */
728 __unlazy_fpu(prev_p
);
731 /* we're going to use this soon, after a few expensive things */
732 if (next_p
->fpu_counter
> 5)
733 prefetch(&next
->i387
.fxsave
);
741 * Save away %gs. No need to save %fs, as it was saved on the
742 * stack on entry. No need to save %es and %ds, as those are
743 * always kernel segments while inside the kernel. Doing this
744 * before setting the new TLS descriptors avoids the situation
745 * where we temporarily have non-reloadable segments in %fs
746 * and %gs. This could be an issue if the NMI handler ever
747 * used %fs or %gs (it does not today), or if the kernel is
748 * running inside of a hypervisor layer.
750 savesegment(gs
, prev
->gs
);
753 * Load the per-thread Thread-Local Storage descriptor.
758 * Restore IOPL if needed. In normal use, the flags restore
759 * in the switch assembly will handle this. But if the kernel
760 * is running virtualized at a non-zero CPL, the popf will
761 * not restore flags, so it must be done in a separate step.
763 if (get_kernel_rpl() && unlikely(prev
->iopl
!= next
->iopl
))
764 set_iopl_mask(next
->iopl
);
767 * Now maybe handle debug registers and/or IO bitmaps
769 if (unlikely(task_thread_info(prev_p
)->flags
& _TIF_WORK_CTXSW_PREV
||
770 task_thread_info(next_p
)->flags
& _TIF_WORK_CTXSW_NEXT
))
771 __switch_to_xtra(prev_p
, next_p
, tss
);
774 * Leave lazy mode, flushing any hypercalls made here.
775 * This must be done before restoring TLS segments so
776 * the GDT and LDT are properly updated, and must be
777 * done before math_state_restore, so the TS bit is up
780 arch_leave_lazy_cpu_mode();
782 /* If the task has used fpu the last 5 timeslices, just do a full
783 * restore of the math state immediately to avoid the trap; the
784 * chances of needing FPU soon are obviously high now
786 if (next_p
->fpu_counter
> 5)
787 math_state_restore();
790 * Restore %gs if needed (which is common)
792 if (prev
->gs
| next
->gs
)
793 loadsegment(gs
, next
->gs
);
795 x86_write_percpu(current_task
, next_p
);
800 asmlinkage
int sys_fork(struct pt_regs regs
)
802 return do_fork(SIGCHLD
, regs
.sp
, ®s
, 0, NULL
, NULL
);
805 asmlinkage
int sys_clone(struct pt_regs regs
)
807 unsigned long clone_flags
;
809 int __user
*parent_tidptr
, *child_tidptr
;
811 clone_flags
= regs
.bx
;
813 parent_tidptr
= (int __user
*)regs
.dx
;
814 child_tidptr
= (int __user
*)regs
.di
;
817 return do_fork(clone_flags
, newsp
, ®s
, 0, parent_tidptr
, child_tidptr
);
821 * This is trivial, and on the face of it looks like it
822 * could equally well be done in user mode.
824 * Not so, for quite unobvious reasons - register pressure.
825 * In user mode vfork() cannot have a stack frame, and if
826 * done by calling the "clone()" system call directly, you
827 * do not have enough call-clobbered registers to hold all
828 * the information you need.
830 asmlinkage
int sys_vfork(struct pt_regs regs
)
832 return do_fork(CLONE_VFORK
| CLONE_VM
| SIGCHLD
, regs
.sp
, ®s
, 0, NULL
, NULL
);
836 * sys_execve() executes a new program.
838 asmlinkage
int sys_execve(struct pt_regs regs
)
843 filename
= getname((char __user
*) regs
.bx
);
844 error
= PTR_ERR(filename
);
845 if (IS_ERR(filename
))
847 error
= do_execve(filename
,
848 (char __user
* __user
*) regs
.cx
,
849 (char __user
* __user
*) regs
.dx
,
852 /* Make sure we don't return using sysenter.. */
853 set_thread_flag(TIF_IRET
);
860 #define top_esp (THREAD_SIZE - sizeof(unsigned long))
861 #define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long))
863 unsigned long get_wchan(struct task_struct
*p
)
865 unsigned long bp
, sp
, ip
;
866 unsigned long stack_page
;
868 if (!p
|| p
== current
|| p
->state
== TASK_RUNNING
)
870 stack_page
= (unsigned long)task_stack_page(p
);
872 if (!stack_page
|| sp
< stack_page
|| sp
> top_esp
+stack_page
)
874 /* include/asm-i386/system.h:switch_to() pushes bp last. */
875 bp
= *(unsigned long *) sp
;
877 if (bp
< stack_page
|| bp
> top_ebp
+stack_page
)
879 ip
= *(unsigned long *) (bp
+4);
880 if (!in_sched_functions(ip
))
882 bp
= *(unsigned long *) bp
;
883 } while (count
++ < 16);
887 unsigned long arch_align_stack(unsigned long sp
)
889 if (!(current
->personality
& ADDR_NO_RANDOMIZE
) && randomize_va_space
)
890 sp
-= get_random_int() % 8192;
894 unsigned long arch_randomize_brk(struct mm_struct
*mm
)
896 unsigned long range_end
= mm
->brk
+ 0x02000000;
897 return randomize_range(mm
->brk
, range_end
, 0) ? : mm
->brk
;