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/errno.h>
17 #include <linux/sched.h>
19 #include <linux/kernel.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/version.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/mman.h>
40 #include <linux/random.h>
42 #include <asm/uaccess.h>
43 #include <asm/pgtable.h>
44 #include <asm/system.h>
47 #include <asm/processor.h>
51 #include <asm/atomic_kmap.h>
52 #ifdef CONFIG_MATH_EMULATION
53 #include <asm/math_emu.h>
56 #include <linux/irq.h>
57 #include <linux/err.h>
59 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
64 * Return saved PC of a blocked thread.
66 unsigned long thread_saved_pc(struct task_struct *tsk)
68 return ((unsigned long *)tsk->thread.esp)[3];
72 * Powermanagement idle function, if any..
74 void (*pm_idle)(void);
76 void disable_hlt(void)
81 EXPORT_SYMBOL(disable_hlt);
88 EXPORT_SYMBOL(enable_hlt);
91 * We use this if we don't have any better
94 void default_idle(void)
96 if (!hlt_counter && current_cpu_data.hlt_works_ok) {
106 * On SMP it's slightly faster (but much more power-consuming!)
107 * to poll the ->work.need_resched flag instead of waiting for the
108 * cross-CPU IPI to arrive. Use this option with caution.
110 static void poll_idle (void)
117 * Deal with another CPU just having chosen a thread to
120 oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
123 set_thread_flag(TIF_POLLING_NRFLAG);
129 : : "i"(_TIF_NEED_RESCHED), "m" (current_thread_info()->flags));
131 clear_thread_flag(TIF_POLLING_NRFLAG);
138 * The idle thread. There's no useful work to be
139 * done, so just try to conserve power and have a
140 * low exit latency (ie sit in a loop waiting for
141 * somebody to say that they'd like to reschedule)
145 /* endless idle loop with no priority at all */
147 while (!need_resched()) {
148 void (*idle)(void) = pm_idle;
153 irq_stat[smp_processor_id()].idle_timestamp = jiffies;
161 * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
162 * which can obviate IPI to trigger checking of need_resched.
163 * We execute MONITOR against need_resched and enter optimized wait state
164 * through MWAIT. Whenever someone changes need_resched, we would be woken
165 * up from MWAIT (without an IPI).
167 static void mwait_idle(void)
171 if (!need_resched()) {
172 set_thread_flag(TIF_POLLING_NRFLAG);
174 __monitor((void *)¤t_thread_info()->flags, 0, 0);
178 } while (!need_resched());
179 clear_thread_flag(TIF_POLLING_NRFLAG);
183 void __init select_idle_routine(const struct cpuinfo_x86 *c)
185 if (cpu_has(c, X86_FEATURE_MWAIT)) {
186 printk("monitor/mwait feature present.\n");
188 * Skip, if setup has overridden idle.
189 * Also, take care of system with asymmetric CPUs.
190 * Use, mwait_idle only if all cpus support it.
191 * If not, we fallback to default_idle()
194 printk("using mwait in idle threads.\n");
195 pm_idle = mwait_idle;
199 pm_idle = default_idle;
203 static int __init idle_setup (char *str)
205 if (!strncmp(str, "poll", 4)) {
206 printk("using polling idle threads.\n");
208 #ifdef CONFIG_X86_SMP
209 if (smp_num_siblings > 1)
210 printk("WARNING: polling idle and HT enabled, performance may degrade.\n");
212 } else if (!strncmp(str, "halt", 4)) {
213 printk("using halt in idle threads.\n");
214 pm_idle = default_idle;
220 __setup("idle=", idle_setup);
222 void stack_overflow(unsigned long esp, unsigned long eip)
224 int panicing = ((esp&(THREAD_SIZE-1)) <= STACK_PANIC);
226 printk( "esp: 0x%lx masked: 0x%lx STACK_PANIC:0x%lx %d %d\n",
227 esp, (esp&(THREAD_SIZE-1)), STACK_PANIC, (((esp&(THREAD_SIZE-1)) <= STACK_PANIC)), panicing );
230 print_symbol("stack overflow from %s\n", eip);
232 print_symbol("excessive stack use from %s\n", eip);
233 printk("esp: %p\n", (void*)esp);
234 show_trace(current,(void*)esp);
237 panic("stack overflow\n");
240 void show_regs(struct pt_regs * regs)
242 unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
245 printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
246 printk("EIP: %04x:[<%08lx>] CPU: %d\n",0xffff & regs->xcs,regs->eip, smp_processor_id());
247 print_symbol("EIP is at %s\n", regs->eip);
250 printk(" ESP: %04x:%08lx",0xffff & regs->xss,regs->esp);
251 printk(" EFLAGS: %08lx %s (%s)\n",regs->eflags, print_tainted(),UTS_RELEASE);
252 printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
253 regs->eax,regs->ebx,regs->ecx,regs->edx);
254 printk("ESI: %08lx EDI: %08lx EBP: %08lx",
255 regs->esi, regs->edi, regs->ebp);
256 printk(" DS: %04x ES: %04x\n",
257 0xffff & regs->xds,0xffff & regs->xes);
259 __asm__("movl %%cr0, %0": "=r" (cr0));
260 __asm__("movl %%cr2, %0": "=r" (cr2));
261 __asm__("movl %%cr3, %0": "=r" (cr3));
262 /* This could fault if %cr4 does not exist */
263 __asm__("1: movl %%cr4, %0 \n"
265 ".section __ex_table,\"a\" \n"
268 : "=r" (cr4): "0" (0));
269 printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4);
270 show_trace(NULL, ®s->esp);
273 EXPORT_SYMBOL_GPL(show_regs);
276 * This gets run with %ebx containing the
277 * function to call, and %edx containing
280 extern void kernel_thread_helper(void);
281 __asm__(".section .text\n"
283 "kernel_thread_helper:\n\t"
292 * Create a kernel thread
294 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
298 memset(®s, 0, sizeof(regs));
300 regs.ebx = (unsigned long) fn;
301 regs.edx = (unsigned long) arg;
303 regs.xds = __USER_DS;
304 regs.xes = __USER_DS;
306 regs.eip = (unsigned long) kernel_thread_helper;
307 regs.xcs = __KERNEL_CS;
308 regs.eflags = X86_EFLAGS_IF | X86_EFLAGS_SF | X86_EFLAGS_PF | 0x2;
310 /* Ok, create the new process.. */
311 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
315 * Free current thread data structures etc..
317 void exit_thread(void)
319 struct task_struct *tsk = current;
321 /* The process may have allocated an io port bitmap... nuke it. */
322 if (unlikely(NULL != tsk->thread.io_bitmap_ptr)) {
324 struct tss_struct *tss = init_tss + cpu;
325 kfree(tsk->thread.io_bitmap_ptr);
326 tsk->thread.io_bitmap_ptr = NULL;
327 tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
332 void flush_thread(void)
334 struct task_struct *tsk = current;
336 memset(tsk->thread.debugreg, 0, sizeof(unsigned long)*8);
337 #ifdef CONFIG_X86_HIGH_ENTRY
338 clear_thread_flag(TIF_DB7);
340 memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
342 * Forget coprocessor state..
348 void release_thread(struct task_struct *dead_task)
351 // temporary debugging check
352 if (dead_task->mm->context.size) {
353 printk("WARNING: dead process %8s still has LDT? <%d>\n",
355 dead_task->mm->context.size);
360 release_x86_irqs(dead_task);
364 * This gets called before we allocate a new thread and copy
365 * the current task into it.
367 void prepare_to_copy(struct task_struct *tsk)
372 int copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
373 unsigned long unused,
374 struct task_struct * p, struct pt_regs * regs)
376 struct pt_regs * childregs;
377 struct task_struct *tsk;
380 childregs = ((struct pt_regs *) (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
383 childregs->esp = esp;
384 p->set_child_tid = p->clear_child_tid = NULL;
386 p->thread.esp = (unsigned long) childregs;
387 p->thread.esp0 = (unsigned long) (childregs+1);
390 * get the two stack pages, for the virtual stack.
392 * IMPORTANT: this code relies on the fact that the task
393 * structure is an THREAD_SIZE aligned piece of physical memory.
395 for (i = 0; i < ARRAY_SIZE(p->thread.stack_page); i++)
396 p->thread.stack_page[i] =
397 virt_to_page((unsigned long)p->thread_info + (i*PAGE_SIZE));
399 p->thread.eip = (unsigned long) ret_from_fork;
400 p->thread_info->real_stack = p->thread_info;
402 savesegment(fs,p->thread.fs);
403 savesegment(gs,p->thread.gs);
406 if (unlikely(NULL != tsk->thread.io_bitmap_ptr)) {
407 p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
408 if (!p->thread.io_bitmap_ptr)
410 memcpy(p->thread.io_bitmap_ptr, tsk->thread.io_bitmap_ptr,
415 * Set a new TLS for the child thread?
417 if (clone_flags & CLONE_SETTLS) {
418 struct desc_struct *desc;
419 struct user_desc info;
423 if (copy_from_user(&info, (void __user *)childregs->esi, sizeof(info)))
426 if (LDT_empty(&info))
429 idx = info.entry_number;
430 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
433 desc = p->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
434 desc->a = LDT_entry_a(&info);
435 desc->b = LDT_entry_b(&info);
440 if (err && p->thread.io_bitmap_ptr)
441 kfree(p->thread.io_bitmap_ptr);
446 * fill in the user structure for a core dump..
448 void dump_thread(struct pt_regs * regs, struct user * dump)
452 /* changed the size calculations - should hopefully work better. lbt */
453 dump->magic = CMAGIC;
454 dump->start_code = 0;
455 dump->start_stack = regs->esp & ~(PAGE_SIZE - 1);
456 dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
457 dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
458 dump->u_dsize -= dump->u_tsize;
460 for (i = 0; i < 8; i++)
461 dump->u_debugreg[i] = current->thread.debugreg[i];
463 if (dump->start_stack < TASK_SIZE)
464 dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;
466 dump->regs.ebx = regs->ebx;
467 dump->regs.ecx = regs->ecx;
468 dump->regs.edx = regs->edx;
469 dump->regs.esi = regs->esi;
470 dump->regs.edi = regs->edi;
471 dump->regs.ebp = regs->ebp;
472 dump->regs.eax = regs->eax;
473 dump->regs.ds = regs->xds;
474 dump->regs.es = regs->xes;
475 savesegment(fs,dump->regs.fs);
476 savesegment(gs,dump->regs.gs);
477 dump->regs.orig_eax = regs->orig_eax;
478 dump->regs.eip = regs->eip;
479 dump->regs.cs = regs->xcs;
480 dump->regs.eflags = regs->eflags;
481 dump->regs.esp = regs->esp;
482 dump->regs.ss = regs->xss;
484 dump->u_fpvalid = dump_fpu (regs, &dump->i387);
488 * Capture the user space registers if the task is not running (in user space)
490 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
492 struct pt_regs ptregs;
494 ptregs = *(struct pt_regs *)
495 ((unsigned long)tsk->thread_info+THREAD_SIZE - sizeof(ptregs));
496 ptregs.xcs &= 0xffff;
497 ptregs.xds &= 0xffff;
498 ptregs.xes &= 0xffff;
499 ptregs.xss &= 0xffff;
501 elf_core_copy_regs(regs, &ptregs);
507 * This special macro can be used to load a debugging register
509 #define loaddebug(thread,register) \
510 __asm__("movl %0,%%db" #register \
512 :"r" (thread->debugreg[register]))
515 * switch_to(x,yn) should switch tasks from x to y.
517 * We fsave/fwait so that an exception goes off at the right time
518 * (as a call from the fsave or fwait in effect) rather than to
519 * the wrong process. Lazy FP saving no longer makes any sense
520 * with modern CPU's, and this simplifies a lot of things (SMP
521 * and UP become the same).
523 * NOTE! We used to use the x86 hardware context switching. The
524 * reason for not using it any more becomes apparent when you
525 * try to recover gracefully from saved state that is no longer
526 * valid (stale segment register values in particular). With the
527 * hardware task-switch, there is no way to fix up bad state in
528 * a reasonable manner.
530 * The fact that Intel documents the hardware task-switching to
531 * be slow is a fairly red herring - this code is not noticeably
532 * faster. However, there _is_ some room for improvement here,
533 * so the performance issues may eventually be a valid point.
534 * More important, however, is the fact that this allows us much
537 * The return value (in %eax) will be the "prev" task after
538 * the task-switch, and shows up in ret_from_fork in entry.S,
541 struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
543 struct thread_struct *prev = &prev_p->thread,
544 *next = &next_p->thread;
545 int cpu = smp_processor_id();
546 struct tss_struct *tss = init_tss + cpu;
548 /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */
550 __unlazy_fpu(prev_p);
552 load_user_cs_desc(cpu, next_p->mm);
554 #ifdef CONFIG_X86_HIGH_ENTRY
558 * Set the ptes of the virtual stack. (NOTE: a one-page TLB flush is
559 * needed because otherwise NMIs could interrupt the
560 * user-return code with a virtual stack and stale TLBs.)
562 for (i = 0; i < ARRAY_SIZE(next->stack_page); i++) {
563 __kunmap_atomic_type(KM_VSTACK_TOP-i);
564 __kmap_atomic(next->stack_page[i], KM_VSTACK_TOP-i);
567 * NOTE: here we rely on the task being the stack as well
569 next_p->thread_info->virtual_stack =
570 (void *)__kmap_atomic_vaddr(KM_VSTACK_TOP);
572 #if defined(CONFIG_PREEMPT) && defined(CONFIG_SMP)
574 * If next was preempted on entry from userspace to kernel,
575 * and now it's on a different cpu, we need to adjust %esp.
576 * This assumes that entry.S does not copy %esp while on the
577 * virtual stack (with interrupts enabled): which is so,
578 * except within __SWITCH_KERNELSPACE itself.
580 if (unlikely(next->esp >= TASK_SIZE)) {
581 next->esp &= THREAD_SIZE - 1;
582 next->esp |= (unsigned long) next_p->thread_info->virtual_stack;
587 * Reload esp0, LDT and the page table pointer:
589 load_virtual_esp0(tss, next_p);
592 * Load the per-thread Thread-Local Storage descriptor.
597 * Save away %fs and %gs. No need to save %es and %ds, as
598 * those are always kernel segments while inside the kernel.
600 asm volatile("movl %%fs,%0":"=m" (*(int *)&prev->fs));
601 asm volatile("movl %%gs,%0":"=m" (*(int *)&prev->gs));
604 * Restore %fs and %gs if needed.
606 if (unlikely(prev->fs | prev->gs | next->fs | next->gs)) {
607 loadsegment(fs, next->fs);
608 loadsegment(gs, next->gs);
612 * Now maybe reload the debug registers
614 if (unlikely(next->debugreg[7])) {
624 if (unlikely(prev->io_bitmap_ptr || next->io_bitmap_ptr)) {
625 if (next->io_bitmap_ptr) {
627 * 4 cachelines copy ... not good, but not that
628 * bad either. Anyone got something better?
629 * This only affects processes which use ioperm().
630 * [Putting the TSSs into 4k-tlb mapped regions
631 * and playing VM tricks to switch the IO bitmap
632 * is not really acceptable.]
634 memcpy(tss->io_bitmap, next->io_bitmap_ptr,
636 tss->io_bitmap_base = IO_BITMAP_OFFSET;
639 * a bitmap offset pointing outside of the TSS limit
640 * causes a nicely controllable SIGSEGV if a process
641 * tries to use a port IO instruction. The first
642 * sys_ioperm() call sets up the bitmap properly.
644 tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
649 asmlinkage int sys_fork(struct pt_regs regs)
651 return do_fork(SIGCHLD, regs.esp, ®s, 0, NULL, NULL);
654 asmlinkage int sys_clone(struct pt_regs regs)
656 unsigned long clone_flags;
658 int __user *parent_tidptr, *child_tidptr;
660 clone_flags = regs.ebx;
662 parent_tidptr = (int __user *)regs.edx;
663 child_tidptr = (int __user *)regs.edi;
666 return do_fork(clone_flags & ~CLONE_IDLETASK, newsp, ®s, 0, parent_tidptr, child_tidptr);
670 * This is trivial, and on the face of it looks like it
671 * could equally well be done in user mode.
673 * Not so, for quite unobvious reasons - register pressure.
674 * In user mode vfork() cannot have a stack frame, and if
675 * done by calling the "clone()" system call directly, you
676 * do not have enough call-clobbered registers to hold all
677 * the information you need.
679 asmlinkage int sys_vfork(struct pt_regs regs)
681 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.esp, ®s, 0, NULL, NULL);
685 * sys_execve() executes a new program.
687 asmlinkage int sys_execve(struct pt_regs regs)
692 filename = getname((char __user *) regs.ebx);
693 error = PTR_ERR(filename);
694 if (IS_ERR(filename))
696 error = do_execve(filename,
697 (char __user * __user *) regs.ecx,
698 (char __user * __user *) regs.edx,
701 current->ptrace &= ~PT_DTRACE;
702 /* Make sure we don't return using sysenter.. */
703 set_thread_flag(TIF_IRET);
710 #define top_esp (THREAD_SIZE - sizeof(unsigned long))
711 #define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long))
713 unsigned long get_wchan(struct task_struct *p)
715 unsigned long ebp, esp, eip;
716 unsigned long stack_page;
718 if (!p || p == current || p->state == TASK_RUNNING)
720 stack_page = (unsigned long)p->thread_info;
722 if (!stack_page || esp < stack_page || esp > top_esp+stack_page)
724 /* include/asm-i386/system.h:switch_to() pushes ebp last. */
725 ebp = *(unsigned long *) esp;
727 if (ebp < stack_page || ebp > top_ebp+stack_page)
729 eip = *(unsigned long *) (ebp+4);
730 if (!in_sched_functions(eip))
732 ebp = *(unsigned long *) ebp;
733 } while (count++ < 16);
738 * sys_alloc_thread_area: get a yet unused TLS descriptor index.
740 static int get_free_idx(void)
742 struct thread_struct *t = ¤t->thread;
745 for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)
746 if (desc_empty(t->tls_array + idx))
747 return idx + GDT_ENTRY_TLS_MIN;
752 * Set a given TLS descriptor:
754 asmlinkage int sys_set_thread_area(struct user_desc __user *u_info)
756 struct thread_struct *t = ¤t->thread;
757 struct user_desc info;
758 struct desc_struct *desc;
761 if (copy_from_user(&info, u_info, sizeof(info)))
763 idx = info.entry_number;
766 * index -1 means the kernel should try to find and
767 * allocate an empty descriptor:
770 idx = get_free_idx();
773 if (put_user(idx, &u_info->entry_number))
777 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
780 desc = t->tls_array + idx - GDT_ENTRY_TLS_MIN;
783 * We must not get preempted while modifying the TLS.
787 if (LDT_empty(&info)) {
791 desc->a = LDT_entry_a(&info);
792 desc->b = LDT_entry_b(&info);
802 * Get the current Thread-Local Storage area:
805 #define GET_BASE(desc) ( \
806 (((desc)->a >> 16) & 0x0000ffff) | \
807 (((desc)->b << 16) & 0x00ff0000) | \
808 ( (desc)->b & 0xff000000) )
810 #define GET_LIMIT(desc) ( \
811 ((desc)->a & 0x0ffff) | \
812 ((desc)->b & 0xf0000) )
814 #define GET_32BIT(desc) (((desc)->b >> 22) & 1)
815 #define GET_CONTENTS(desc) (((desc)->b >> 10) & 3)
816 #define GET_WRITABLE(desc) (((desc)->b >> 9) & 1)
817 #define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1)
818 #define GET_PRESENT(desc) (((desc)->b >> 15) & 1)
819 #define GET_USEABLE(desc) (((desc)->b >> 20) & 1)
821 asmlinkage int sys_get_thread_area(struct user_desc __user *u_info)
823 struct user_desc info;
824 struct desc_struct *desc;
827 if (get_user(idx, &u_info->entry_number))
829 if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
832 desc = current->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
834 info.entry_number = idx;
835 info.base_addr = GET_BASE(desc);
836 info.limit = GET_LIMIT(desc);
837 info.seg_32bit = GET_32BIT(desc);
838 info.contents = GET_CONTENTS(desc);
839 info.read_exec_only = !GET_WRITABLE(desc);
840 info.limit_in_pages = GET_LIMIT_PAGES(desc);
841 info.seg_not_present = !GET_PRESENT(desc);
842 info.useable = GET_USEABLE(desc);
844 if (copy_to_user(u_info, &info, sizeof(info)))
850 unsigned long arch_align_stack(unsigned long sp)
852 if (current->flags & PF_RELOCEXEC)
853 sp -= ((get_random_int() % 65536) << 4);
858 void arch_add_exec_range(struct mm_struct *mm, unsigned long limit)
860 if (limit > mm->context.exec_limit) {
861 mm->context.exec_limit = limit;
862 set_user_cs(&mm->context.user_cs, limit);
863 if (mm == current->mm)
864 load_user_cs_desc(smp_processor_id(), mm);
868 void arch_remove_exec_range(struct mm_struct *mm, unsigned long old_end)
870 struct vm_area_struct *vma;
871 unsigned long limit = 0;
873 if (old_end == mm->context.exec_limit) {
874 for (vma = mm->mmap; vma; vma = vma->vm_next)
875 if ((vma->vm_flags & VM_EXEC) && (vma->vm_end > limit))
878 mm->context.exec_limit = limit;
879 set_user_cs(&mm->context.user_cs, limit);
880 if (mm == current->mm)
881 load_user_cs_desc(smp_processor_id(), mm);
885 void arch_flush_exec_range(struct mm_struct *mm)
887 mm->context.exec_limit = 0;
888 set_user_cs(&mm->context.user_cs, 0);
892 * Generate random brk address between 128MB and 196MB. (if the layout
895 void randomize_brk(unsigned long old_brk)
897 unsigned long new_brk, range_start, range_end;
899 range_start = 0x08000000;
900 if (current->mm->brk >= range_start)
901 range_start = current->mm->brk;
902 range_end = range_start + 0x02000000;
903 new_brk = randomize_range(range_start, range_end, 0);
905 current->mm->brk = new_brk;