arch/x86/kernel/process_64.c

   1 /*
   2  *  Copyright (C) 1995  Linus Torvalds
   3  *
   4  *  Pentium III FXSR, SSE support
   5  *      Gareth Hughes <gareth@valinux.com>, May 2000
   6  *
   7  *  X86-64 port
   8  *      Andi Kleen.
   9  *
  10  *      CPU hotplug support - ashok.raj@intel.com
  11  */
  12
  13 /*
  14  * This file handles the architecture-dependent parts of process handling..
  15  */
  16
  17 #include <linux/stackprotector.h>
  18 #include <linux/cpu.h>
  19 #include <linux/errno.h>
  20 #include <linux/sched.h>
  21 #include <linux/fs.h>
  22 #include <linux/kernel.h>
  23 #include <linux/mm.h>
  24 #include <linux/elfcore.h>
  25 #include <linux/smp.h>
  26 #include <linux/slab.h>
  27 #include <linux/user.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/utsname.h>
  30 #include <linux/delay.h>
  31 #include <linux/module.h>
  32 #include <linux/ptrace.h>
  33 #include <linux/notifier.h>
  34 #include <linux/kprobes.h>
  35 #include <linux/kdebug.h>
  36 #include <linux/tick.h>
  37 #include <linux/prctl.h>
  38 #include <linux/uaccess.h>
  39 #include <linux/io.h>
  40 #include <linux/ftrace.h>
  41 #include <linux/dmi.h>
  42
  43 #include <asm/pgtable.h>
  44 #include <asm/system.h>
  45 #include <asm/processor.h>
  46 #include <asm/i387.h>
  47 #include <asm/mmu_context.h>
  48 #include <asm/prctl.h>
  49 #include <asm/desc.h>
  50 #include <asm/proto.h>
  51 #include <asm/ia32.h>
  52 #include <asm/idle.h>
  53 #include <asm/syscalls.h>
  54 #include <asm/ds.h>
  55
  56 asmlinkage extern void ret_from_fork(void);
  57
  58 DEFINE_PER_CPU(unsigned long, old_rsp);
  59 static DEFINE_PER_CPU(unsigned char, is_idle);
  60
  61 unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
  62
  63 static ATOMIC_NOTIFIER_HEAD(idle_notifier);
  64
  65 void idle_notifier_register(struct notifier_block *n)
  66 {
  67         atomic_notifier_chain_register(&idle_notifier, n);
  68 }
  69 EXPORT_SYMBOL_GPL(idle_notifier_register);
  70
  71 void idle_notifier_unregister(struct notifier_block *n)
  72 {
  73         atomic_notifier_chain_unregister(&idle_notifier, n);
  74 }
  75 EXPORT_SYMBOL_GPL(idle_notifier_unregister);
  76
  77 void enter_idle(void)
  78 {
  79         percpu_write(is_idle, 1);
  80         atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
  81 }
  82
  83 static void __exit_idle(void)
  84 {
  85         if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
  86                 return;
  87         atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
  88 }
  89
  90 /* Called from interrupts to signify idle end */
  91 void exit_idle(void)
  92 {
  93         /* idle loop has pid 0 */
  94         if (current->pid)
  95                 return;
  96         __exit_idle();
  97 }
  98
  99 #ifndef CONFIG_SMP
 100 static inline void play_dead(void)
 101 {
 102         BUG();
 103 }
 104 #endif
 105
 106 /*
 107  * The idle thread. There's no useful work to be
 108  * done, so just try to conserve power and have a
 109  * low exit latency (ie sit in a loop waiting for
 110  * somebody to say that they'd like to reschedule)
 111  */
 112 void cpu_idle(void)
 113 {
 114         current_thread_info()->status |= TS_POLLING;
 115
 116         /*
 117          * If we're the non-boot CPU, nothing set the stack canary up
 118          * for us.  CPU0 already has it initialized but no harm in
 119          * doing it again.  This is a good place for updating it, as
 120          * we wont ever return from this function (so the invalid
 121          * canaries already on the stack wont ever trigger).
 122          */
 123         boot_init_stack_canary();
 124
 125         /* endless idle loop with no priority at all */
 126         while (1) {
 127                 tick_nohz_stop_sched_tick(1);
 128                 while (!need_resched()) {
 129
 130                         rmb();
 131
 132                         if (cpu_is_offline(smp_processor_id()))
 133                                 play_dead();
 134                         /*
 135                          * Idle routines should keep interrupts disabled
 136                          * from here on, until they go to idle.
 137                          * Otherwise, idle callbacks can misfire.
 138                          */
 139                         local_irq_disable();
 140                         enter_idle();
 141                         /* Don't trace irqs off for idle */
 142                         stop_critical_timings();
 143                         pm_idle();
 144                         start_critical_timings();
 145                         /* In many cases the interrupt that ended idle
 146                            has already called exit_idle. But some idle
 147                            loops can be woken up without interrupt. */
 148                         __exit_idle();
 149                 }
 150
 151                 tick_nohz_restart_sched_tick();
 152                 preempt_enable_no_resched();
 153                 schedule();
 154                 preempt_disable();
 155         }
 156 }
 157
 158 /* Prints also some state that isn't saved in the pt_regs */
 159 void __show_regs(struct pt_regs *regs, int all)
 160 {
 161         unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs;
 162         unsigned long d0, d1, d2, d3, d6, d7;
 163         unsigned int fsindex, gsindex;
 164         unsigned int ds, cs, es;
 165         const char *board;
 166
 167         printk("\n");
 168         print_modules();
 169         board = dmi_get_system_info(DMI_PRODUCT_NAME);
 170         if (!board)
 171                 board = "";
 172         printk(KERN_INFO "Pid: %d, comm: %.20s %s %s %.*s %s\n",
 173                 current->pid, current->comm, print_tainted(),
 174                 init_utsname()->release,
 175                 (int)strcspn(init_utsname()->version, " "),
 176                 init_utsname()->version, board);
 177         printk(KERN_INFO "RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->ip);
 178         printk_address(regs->ip, 1);
 179         printk(KERN_INFO "RSP: %04lx:%016lx  EFLAGS: %08lx\n", regs->ss,
 180                         regs->sp, regs->flags);
 181         printk(KERN_INFO "RAX: %016lx RBX: %016lx RCX: %016lx\n",
 182                regs->ax, regs->bx, regs->cx);
 183         printk(KERN_INFO "RDX: %016lx RSI: %016lx RDI: %016lx\n",
 184                regs->dx, regs->si, regs->di);
 185         printk(KERN_INFO "RBP: %016lx R08: %016lx R09: %016lx\n",
 186                regs->bp, regs->r8, regs->r9);
 187         printk(KERN_INFO "R10: %016lx R11: %016lx R12: %016lx\n",
 188                regs->r10, regs->r11, regs->r12);
 189         printk(KERN_INFO "R13: %016lx R14: %016lx R15: %016lx\n",
 190                regs->r13, regs->r14, regs->r15);
 191
 192         asm("movl %%ds,%0" : "=r" (ds));
 193         asm("movl %%cs,%0" : "=r" (cs));
 194         asm("movl %%es,%0" : "=r" (es));
 195         asm("movl %%fs,%0" : "=r" (fsindex));
 196         asm("movl %%gs,%0" : "=r" (gsindex));
 197
 198         rdmsrl(MSR_FS_BASE, fs);
 199         rdmsrl(MSR_GS_BASE, gs);
 200         rdmsrl(MSR_KERNEL_GS_BASE, shadowgs);
 201
 202         if (!all)
 203                 return;
 204
 205         cr0 = read_cr0();
 206         cr2 = read_cr2();
 207         cr3 = read_cr3();
 208         cr4 = read_cr4();
 209
 210         printk(KERN_INFO "FS:  %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n",
 211                fs, fsindex, gs, gsindex, shadowgs);
 212         printk(KERN_INFO "CS:  %04x DS: %04x ES: %04x CR0: %016lx\n", cs, ds,
 213                         es, cr0);
 214         printk(KERN_INFO "CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2, cr3,
 215                         cr4);
 216
 217         get_debugreg(d0, 0);
 218         get_debugreg(d1, 1);
 219         get_debugreg(d2, 2);
 220         printk(KERN_INFO "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2);
 221         get_debugreg(d3, 3);
 222         get_debugreg(d6, 6);
 223         get_debugreg(d7, 7);
 224         printk(KERN_INFO "DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7);
 225 }
 226
 227 void show_regs(struct pt_regs *regs)
 228 {
 229         printk(KERN_INFO "CPU %d:", smp_processor_id());
 230         __show_regs(regs, 1);
 231         show_trace(NULL, regs, (void *)(regs + 1), regs->bp);
 232 }
 233
 234 void release_thread(struct task_struct *dead_task)
 235 {
 236         if (dead_task->mm) {
 237                 if (dead_task->mm->context.size) {
 238                         printk("WARNING: dead process %8s still has LDT? <%p/%d>\n",
 239                                         dead_task->comm,
 240                                         dead_task->mm->context.ldt,
 241                                         dead_task->mm->context.size);
 242                         BUG();
 243                 }
 244         }
 245 }
 246
 247 static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr)
 248 {
 249         struct user_desc ud = {
 250                 .base_addr = addr,
 251                 .limit = 0xfffff,
 252                 .seg_32bit = 1,
 253                 .limit_in_pages = 1,
 254                 .useable = 1,
 255         };
 256         struct desc_struct *desc = t->thread.tls_array;
 257         desc += tls;
 258         fill_ldt(desc, &ud);
 259 }
 260
 261 static inline u32 read_32bit_tls(struct task_struct *t, int tls)
 262 {
 263         return get_desc_base(&t->thread.tls_array[tls]);
 264 }
 265
 266 /*
 267  * This gets called before we allocate a new thread and copy
 268  * the current task into it.
 269  */
 270 void prepare_to_copy(struct task_struct *tsk)
 271 {
 272         unlazy_fpu(tsk);
 273 }
 274
 275 int copy_thread(unsigned long clone_flags, unsigned long sp,
 276                 unsigned long unused,
 277         struct task_struct *p, struct pt_regs *regs)
 278 {
 279         int err;
 280         struct pt_regs *childregs;
 281         struct task_struct *me = current;
 282
 283         childregs = ((struct pt_regs *)
 284                         (THREAD_SIZE + task_stack_page(p))) - 1;
 285         *childregs = *regs;
 286
 287         childregs->ax = 0;
 288         childregs->sp = sp;
 289         if (sp == ~0UL)
 290                 childregs->sp = (unsigned long)childregs;
 291
 292         p->thread.sp = (unsigned long) childregs;
 293         p->thread.sp0 = (unsigned long) (childregs+1);
 294         p->thread.usersp = me->thread.usersp;
 295
 296         set_tsk_thread_flag(p, TIF_FORK);
 297
 298         p->thread.fs = me->thread.fs;
 299         p->thread.gs = me->thread.gs;
 300
 301         savesegment(gs, p->thread.gsindex);
 302         savesegment(fs, p->thread.fsindex);
 303         savesegment(es, p->thread.es);
 304         savesegment(ds, p->thread.ds);
 305
 306         if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
 307                 p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
 308                 if (!p->thread.io_bitmap_ptr) {
 309                         p->thread.io_bitmap_max = 0;
 310                         return -ENOMEM;
 311                 }
 312                 memcpy(p->thread.io_bitmap_ptr, me->thread.io_bitmap_ptr,
 313                                 IO_BITMAP_BYTES);
 314                 set_tsk_thread_flag(p, TIF_IO_BITMAP);
 315         }
 316
 317         /*
 318          * Set a new TLS for the child thread?
 319          */
 320         if (clone_flags & CLONE_SETTLS) {
 321 #ifdef CONFIG_IA32_EMULATION
 322                 if (test_thread_flag(TIF_IA32))
 323                         err = do_set_thread_area(p, -1,
 324                                 (struct user_desc __user *)childregs->si, 0);
 325                 else
 326 #endif
 327                         err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8);
 328                 if (err)
 329                         goto out;
 330         }
 331
 332         clear_tsk_thread_flag(p, TIF_DS_AREA_MSR);
 333         p->thread.ds_ctx = NULL;
 334
 335         clear_tsk_thread_flag(p, TIF_DEBUGCTLMSR);
 336         p->thread.debugctlmsr = 0;
 337
 338         err = 0;
 339 out:
 340         if (err && p->thread.io_bitmap_ptr) {
 341                 kfree(p->thread.io_bitmap_ptr);
 342                 p->thread.io_bitmap_max = 0;
 343         }
 344         return err;
 345 }
 346
 347 void
 348 start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 349 {
 350         loadsegment(fs, 0);
 351         loadsegment(es, 0);
 352         loadsegment(ds, 0);
 353         load_gs_index(0);
 354         regs->ip                = new_ip;
 355         regs->sp                = new_sp;
 356         percpu_write(old_rsp, new_sp);
 357         regs->cs                = __USER_CS;
 358         regs->ss                = __USER_DS;
 359         regs->flags             = 0x200;
 360         set_fs(USER_DS);
 361         /*
 362          * Free the old FP and other extended state
 363          */
 364         free_thread_xstate(current);
 365 }
 366 EXPORT_SYMBOL_GPL(start_thread);
 367
 368 /*
 369  *      switch_to(x,y) should switch tasks from x to y.
 370  *
 371  * This could still be optimized:
 372  * - fold all the options into a flag word and test it with a single test.
 373  * - could test fs/gs bitsliced
 374  *
 375  * Kprobes not supported here. Set the probe on schedule instead.
 376  * Function graph tracer not supported too.
 377  */
 378 __notrace_funcgraph struct task_struct *
 379 __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 380 {
 381         struct thread_struct *prev = &prev_p->thread;
 382         struct thread_struct *next = &next_p->thread;
 383         int cpu = smp_processor_id();
 384         struct tss_struct *tss = &per_cpu(init_tss, cpu);
 385         unsigned fsindex, gsindex;
 386         bool preload_fpu;
 387
 388         /*
 389          * If the task has used fpu the last 5 timeslices, just do a full
 390          * restore of the math state immediately to avoid the trap; the
 391          * chances of needing FPU soon are obviously high now
 392          */
 393         preload_fpu = tsk_used_math(next_p) && next_p->fpu_counter > 5;
 394
 395         /* we're going to use this soon, after a few expensive things */
 396         if (preload_fpu)
 397                 prefetch(next->xstate);
 398
 399         /*
 400          * Reload esp0, LDT and the page table pointer:
 401          */
 402         load_sp0(tss, next);
 403
 404         /*
 405          * Switch DS and ES.
 406          * This won't pick up thread selector changes, but I guess that is ok.
 407          */
 408         savesegment(es, prev->es);
 409         if (unlikely(next->es | prev->es))
 410                 loadsegment(es, next->es);
 411
 412         savesegment(ds, prev->ds);
 413         if (unlikely(next->ds | prev->ds))
 414                 loadsegment(ds, next->ds);
 415
 416
 417         /* We must save %fs and %gs before load_TLS() because
 418          * %fs and %gs may be cleared by load_TLS().
 419          *
 420          * (e.g. xen_load_tls())
 421          */
 422         savesegment(fs, fsindex);
 423         savesegment(gs, gsindex);
 424
 425         load_TLS(next, cpu);
 426
 427         /* Must be after DS reload */
 428         unlazy_fpu(prev_p);
 429
 430         /* Make sure cpu is ready for new context */
 431         if (preload_fpu)
 432                 clts();
 433
 434         /*
 435          * Leave lazy mode, flushing any hypercalls made here.
 436          * This must be done before restoring TLS segments so
 437          * the GDT and LDT are properly updated, and must be
 438          * done before math_state_restore, so the TS bit is up
 439          * to date.
 440          */
 441         arch_end_context_switch(next_p);
 442
 443         /*
 444          * Switch FS and GS.
 445          *
 446          * Segment register != 0 always requires a reload.  Also
 447          * reload when it has changed.  When prev process used 64bit
 448          * base always reload to avoid an information leak.
 449          */
 450         if (unlikely(fsindex | next->fsindex | prev->fs)) {
 451                 loadsegment(fs, next->fsindex);
 452                 /*
 453                  * Check if the user used a selector != 0; if yes
 454                  *  clear 64bit base, since overloaded base is always
 455                  *  mapped to the Null selector
 456                  */
 457                 if (fsindex)
 458                         prev->fs = 0;
 459         }
 460         /* when next process has a 64bit base use it */
 461         if (next->fs)
 462                 wrmsrl(MSR_FS_BASE, next->fs);
 463         prev->fsindex = fsindex;
 464
 465         if (unlikely(gsindex | next->gsindex | prev->gs)) {
 466                 load_gs_index(next->gsindex);
 467                 if (gsindex)
 468                         prev->gs = 0;
 469         }
 470         if (next->gs)
 471                 wrmsrl(MSR_KERNEL_GS_BASE, next->gs);
 472         prev->gsindex = gsindex;
 473
 474         /*
 475          * Switch the PDA and FPU contexts.
 476          */
 477         prev->usersp = percpu_read(old_rsp);
 478         percpu_write(old_rsp, next->usersp);
 479         percpu_write(current_task, next_p);
 480
 481         percpu_write(kernel_stack,
 482                   (unsigned long)task_stack_page(next_p) +
 483                   THREAD_SIZE - KERNEL_STACK_OFFSET);
 484
 485         /*
 486          * Now maybe reload the debug registers and handle I/O bitmaps
 487          */
 488         if (unlikely(task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT ||
 489                      task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV))
 490                 __switch_to_xtra(prev_p, next_p, tss);
 491
 492         /*
 493          * Preload the FPU context, now that we've determined that the
 494          * task is likely to be using it.
 495          */
 496         if (preload_fpu)
 497                 __math_state_restore();
 498         return prev_p;
 499 }
 500
 501 /*
 502  * sys_execve() executes a new program.
 503  */
 504 asmlinkage
 505 long sys_execve(char __user *name, char __user * __user *argv,
 506                 char __user * __user *envp, struct pt_regs *regs)
 507 {
 508         long error;
 509         char *filename;
 510
 511         filename = getname(name);
 512         error = PTR_ERR(filename);
 513         if (IS_ERR(filename))
 514                 return error;
 515         error = do_execve(filename, argv, envp, regs);
 516         putname(filename);
 517         return error;
 518 }
 519
 520 void set_personality_64bit(void)
 521 {
 522         /* inherit personality from parent */
 523
 524         /* Make sure to be in 64bit mode */
 525         clear_thread_flag(TIF_IA32);
 526
 527         /* TBD: overwrites user setup. Should have two bits.
 528            But 64bit processes have always behaved this way,
 529            so it's not too bad. The main problem is just that
 530            32bit childs are affected again. */
 531         current->personality &= ~READ_IMPLIES_EXEC;
 532 }
 533
 534 asmlinkage long
 535 sys_clone(unsigned long clone_flags, unsigned long newsp,
 536           void __user *parent_tid, void __user *child_tid, struct pt_regs *regs)
 537 {
 538         if (!newsp)
 539                 newsp = regs->sp;
 540         return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid);
 541 }
 542
 543 unsigned long get_wchan(struct task_struct *p)
 544 {
 545         unsigned long stack;
 546         u64 fp, ip;
 547         int count = 0;
 548
 549         if (!p || p == current || p->state == TASK_RUNNING)
 550                 return 0;
 551         stack = (unsigned long)task_stack_page(p);
 552         if (p->thread.sp < stack || p->thread.sp >= stack+THREAD_SIZE)
 553                 return 0;
 554         fp = *(u64 *)(p->thread.sp);
 555         do {
 556                 if (fp < (unsigned long)stack ||
 557                     fp >= (unsigned long)stack+THREAD_SIZE)
 558                         return 0;
 559                 ip = *(u64 *)(fp+8);
 560                 if (!in_sched_functions(ip))
 561                         return ip;
 562                 fp = *(u64 *)fp;
 563         } while (count++ < 16);
 564         return 0;
 565 }
 566
 567 long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
 568 {
 569         int ret = 0;
 570         int doit = task == current;
 571         int cpu;
 572
 573         switch (code) {
 574         case ARCH_SET_GS:
 575                 if (addr >= TASK_SIZE_OF(task))
 576                         return -EPERM;
 577                 cpu = get_cpu();
 578                 /* handle small bases via the GDT because that's faster to
 579                    switch. */
 580                 if (addr <= 0xffffffff) {
 581                         set_32bit_tls(task, GS_TLS, addr);
 582                         if (doit) {
 583                                 load_TLS(&task->thread, cpu);
 584                                 load_gs_index(GS_TLS_SEL);
 585                         }
 586                         task->thread.gsindex = GS_TLS_SEL;
 587                         task->thread.gs = 0;
 588                 } else {
 589                         task->thread.gsindex = 0;
 590                         task->thread.gs = addr;
 591                         if (doit) {
 592                                 load_gs_index(0);
 593                                 ret = checking_wrmsrl(MSR_KERNEL_GS_BASE, addr);
 594                         }
 595                 }
 596                 put_cpu();
 597                 break;
 598         case ARCH_SET_FS:
 599                 /* Not strictly needed for fs, but do it for symmetry
 600                    with gs */
 601                 if (addr >= TASK_SIZE_OF(task))
 602                         return -EPERM;
 603                 cpu = get_cpu();
 604                 /* handle small bases via the GDT because that's faster to
 605                    switch. */
 606                 if (addr <= 0xffffffff) {
 607                         set_32bit_tls(task, FS_TLS, addr);
 608                         if (doit) {
 609                                 load_TLS(&task->thread, cpu);
 610                                 loadsegment(fs, FS_TLS_SEL);
 611                         }
 612                         task->thread.fsindex = FS_TLS_SEL;
 613                         task->thread.fs = 0;
 614                 } else {
 615                         task->thread.fsindex = 0;
 616                         task->thread.fs = addr;
 617                         if (doit) {
 618                                 /* set the selector to 0 to not confuse
 619                                    __switch_to */
 620                                 loadsegment(fs, 0);
 621                                 ret = checking_wrmsrl(MSR_FS_BASE, addr);
 622                         }
 623                 }
 624                 put_cpu();
 625                 break;
 626         case ARCH_GET_FS: {
 627                 unsigned long base;
 628                 if (task->thread.fsindex == FS_TLS_SEL)
 629                         base = read_32bit_tls(task, FS_TLS);
 630                 else if (doit)
 631                         rdmsrl(MSR_FS_BASE, base);
 632                 else
 633                         base = task->thread.fs;
 634                 ret = put_user(base, (unsigned long __user *)addr);
 635                 break;
 636         }
 637         case ARCH_GET_GS: {
 638                 unsigned long base;
 639                 unsigned gsindex;
 640                 if (task->thread.gsindex == GS_TLS_SEL)
 641                         base = read_32bit_tls(task, GS_TLS);
 642                 else if (doit) {
 643                         savesegment(gs, gsindex);
 644                         if (gsindex)
 645                                 rdmsrl(MSR_KERNEL_GS_BASE, base);
 646                         else
 647                                 base = task->thread.gs;
 648                 } else
 649                         base = task->thread.gs;
 650                 ret = put_user(base, (unsigned long __user *)addr);
 651                 break;
 652         }
 653
 654         default:
 655                 ret = -EINVAL;
 656                 break;
 657         }
 658
 659         return ret;
 660 }
 661
 662 long sys_arch_prctl(int code, unsigned long addr)
 663 {
 664         return do_arch_prctl(current, code, addr);
 665 }
 666
 667 unsigned long KSTK_ESP(struct task_struct *task)
 668 {
 669         return (test_tsk_thread_flag(task, TIF_IA32)) ?
 670                         (task_pt_regs(task)->sp) : ((task)->thread.usersp);
 671 }