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   1 /*
   2  *  linux/arch/x86-64/kernel/process.c
   3  *
   4  *  Copyright (C) 1995  Linus Torvalds
   5  *
   6  *  Pentium III FXSR, SSE support
   7  *      Gareth Hughes <gareth@valinux.com>, May 2000
   8  *
   9  *  X86-64 port
  10  *      Andi Kleen.
  11  *
  12  *      CPU hotplug support - ashok.raj@intel.com
  13  */
  14
  15 /*
  16  * This file handles the architecture-dependent parts of process handling..
  17  */
  18
  19 #include <stdarg.h>
  20
  21 #include <linux/cpu.h>
  22 #include <linux/errno.h>
  23 #include <linux/sched.h>
  24 #include <linux/kernel.h>
  25 #include <linux/mm.h>
  26 #include <linux/elfcore.h>
  27 #include <linux/smp.h>
  28 #include <linux/slab.h>
  29 #include <linux/user.h>
  30 #include <linux/module.h>
  31 #include <linux/a.out.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/delay.h>
  34 #include <linux/ptrace.h>
  35 #include <linux/utsname.h>
  36 #include <linux/random.h>
  37 #include <linux/notifier.h>
  38 #include <linux/kprobes.h>
  39
  40 #include <asm/uaccess.h>
  41 #include <asm/pgtable.h>
  42 #include <asm/system.h>
  43 #include <asm/io.h>
  44 #include <asm/processor.h>
  45 #include <asm/i387.h>
  46 #include <asm/mmu_context.h>
  47 #include <asm/pda.h>
  48 #include <asm/prctl.h>
  49 #include <asm/kdebug.h>
  50 #include <asm/desc.h>
  51 #include <asm/proto.h>
  52 #include <asm/ia32.h>
  53 #include <asm/idle.h>
  54
  55 asmlinkage extern void ret_from_fork(void);
  56
  57 unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
  58
  59 unsigned long boot_option_idle_override = 0;
  60 EXPORT_SYMBOL(boot_option_idle_override);
  61
  62 /*
  63  * Powermanagement idle function, if any..
  64  */
  65 void (*pm_idle)(void);
  66 EXPORT_SYMBOL(pm_idle);
  67 static DEFINE_PER_CPU(unsigned int, cpu_idle_state);
  68
  69 static ATOMIC_NOTIFIER_HEAD(idle_notifier);
  70
  71 void idle_notifier_register(struct notifier_block *n)
  72 {
  73         atomic_notifier_chain_register(&idle_notifier, n);
  74 }
  75 EXPORT_SYMBOL_GPL(idle_notifier_register);
  76
  77 void idle_notifier_unregister(struct notifier_block *n)
  78 {
  79         atomic_notifier_chain_unregister(&idle_notifier, n);
  80 }
  81 EXPORT_SYMBOL(idle_notifier_unregister);
  82
  83 void enter_idle(void)
  84 {
  85         write_pda(isidle, 1);
  86         atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
  87 }
  88
  89 static void __exit_idle(void)
  90 {
  91         if (read_pda(isidle) == 0)
  92                 return;
  93         write_pda(isidle, 0);
  94         atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
  95 }
  96
  97 /* Called from interrupts to signify idle end */
  98 void exit_idle(void)
  99 {
 100         /* idle loop has pid 0 */
 101         if (current->pid)
 102                 return;
 103         __exit_idle();
 104 }
 105
 106 /*
 107  * We use this if we don't have any better
 108  * idle routine..
 109  */
 110 static void default_idle(void)
 111 {
 112         local_irq_enable();
 113
 114         current_thread_info()->status &= ~TS_POLLING;
 115         smp_mb__after_clear_bit();
 116         while (!need_resched()) {
 117                 local_irq_disable();
 118                 if (!need_resched())
 119                         safe_halt();
 120                 else
 121                         local_irq_enable();
 122         }
 123         current_thread_info()->status |= TS_POLLING;
 124 }
 125
 126 /*
 127  * On SMP it's slightly faster (but much more power-consuming!)
 128  * to poll the ->need_resched flag instead of waiting for the
 129  * cross-CPU IPI to arrive. Use this option with caution.
 130  */
 131 static void poll_idle (void)
 132 {
 133         local_irq_enable();
 134
 135         asm volatile(
 136                 "2:"
 137                 "testl %0,%1;"
 138                 "rep; nop;"
 139                 "je 2b;"
 140                 : :
 141                 "i" (_TIF_NEED_RESCHED),
 142                 "m" (current_thread_info()->flags));
 143 }
 144
 145 void cpu_idle_wait(void)
 146 {
 147         unsigned int cpu, this_cpu = get_cpu();
 148         cpumask_t map;
 149
 150         set_cpus_allowed(current, cpumask_of_cpu(this_cpu));
 151         put_cpu();
 152
 153         cpus_clear(map);
 154         for_each_online_cpu(cpu) {
 155                 per_cpu(cpu_idle_state, cpu) = 1;
 156                 cpu_set(cpu, map);
 157         }
 158
 159         __get_cpu_var(cpu_idle_state) = 0;
 160
 161         wmb();
 162         do {
 163                 ssleep(1);
 164                 for_each_online_cpu(cpu) {
 165                         if (cpu_isset(cpu, map) &&
 166                                         !per_cpu(cpu_idle_state, cpu))
 167                                 cpu_clear(cpu, map);
 168                 }
 169                 cpus_and(map, map, cpu_online_map);
 170         } while (!cpus_empty(map));
 171 }
 172 EXPORT_SYMBOL_GPL(cpu_idle_wait);
 173
 174 #ifdef CONFIG_HOTPLUG_CPU
 175 DECLARE_PER_CPU(int, cpu_state);
 176
 177 #include <asm/nmi.h>
 178 /* We halt the CPU with physical CPU hotplug */
 179 static inline void play_dead(void)
 180 {
 181         idle_task_exit();
 182         wbinvd();
 183         mb();
 184         /* Ack it */
 185         __get_cpu_var(cpu_state) = CPU_DEAD;
 186
 187         local_irq_disable();
 188         while (1)
 189                 halt();
 190 }
 191 #else
 192 static inline void play_dead(void)
 193 {
 194         BUG();
 195 }
 196 #endif /* CONFIG_HOTPLUG_CPU */
 197
 198 /*
 199  * The idle thread. There's no useful work to be
 200  * done, so just try to conserve power and have a
 201  * low exit latency (ie sit in a loop waiting for
 202  * somebody to say that they'd like to reschedule)
 203  */
 204 void cpu_idle (void)
 205 {
 206         current_thread_info()->status |= TS_POLLING;
 207         /* endless idle loop with no priority at all */
 208         while (1) {
 209                 while (!need_resched()) {
 210                         void (*idle)(void);
 211
 212                         if (__get_cpu_var(cpu_idle_state))
 213                                 __get_cpu_var(cpu_idle_state) = 0;
 214
 215                         rmb();
 216                         idle = pm_idle;
 217                         if (!idle)
 218                                 idle = default_idle;
 219                         if (cpu_is_offline(smp_processor_id()))
 220                                 play_dead();
 221                         enter_idle();
 222                         idle();
 223                         /* In many cases the interrupt that ended idle
 224                            has already called exit_idle. But some idle
 225                            loops can be woken up without interrupt. */
 226                         __exit_idle();
 227                 }
 228
 229                 preempt_enable_no_resched();
 230                 schedule();
 231                 preempt_disable();
 232         }
 233 }
 234
 235 /*
 236  * This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
 237  * which can obviate IPI to trigger checking of need_resched.
 238  * We execute MONITOR against need_resched and enter optimized wait state
 239  * through MWAIT. Whenever someone changes need_resched, we would be woken
 240  * up from MWAIT (without an IPI).
 241  *
 242  * New with Core Duo processors, MWAIT can take some hints based on CPU
 243  * capability.
 244  */
 245 void mwait_idle_with_hints(unsigned long eax, unsigned long ecx)
 246 {
 247         if (!need_resched()) {
 248                 __monitor((void *)&current_thread_info()->flags, 0, 0);
 249                 smp_mb();
 250                 if (!need_resched())
 251                         __mwait(eax, ecx);
 252         }
 253 }
 254
 255 /* Default MONITOR/MWAIT with no hints, used for default C1 state */
 256 static void mwait_idle(void)
 257 {
 258         local_irq_enable();
 259         while (!need_resched())
 260                 mwait_idle_with_hints(0,0);
 261 }
 262
 263 void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
 264 {
 265         static int printed;
 266         if (cpu_has(c, X86_FEATURE_MWAIT)) {
 267                 /*
 268                  * Skip, if setup has overridden idle.
 269                  * One CPU supports mwait => All CPUs supports mwait
 270                  */
 271                 if (!pm_idle) {
 272                         if (!printed) {
 273                                 printk("using mwait in idle threads.\n");
 274                                 printed = 1;
 275                         }
 276                         pm_idle = mwait_idle;
 277                 }
 278         }
 279 }
 280
 281 static int __init idle_setup (char *str)
 282 {
 283         if (!strncmp(str, "poll", 4)) {
 284                 printk("using polling idle threads.\n");
 285                 pm_idle = poll_idle;
 286         }
 287
 288         boot_option_idle_override = 1;
 289         return 1;
 290 }
 291
 292 __setup("idle=", idle_setup);
 293
 294 /* Prints also some state that isn't saved in the pt_regs */
 295 void __show_regs(struct pt_regs * regs)
 296 {
 297         unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs;
 298         unsigned int fsindex,gsindex;
 299         unsigned int ds,cs,es;
 300
 301         printk("\n");
 302         print_modules();
 303         printk("Pid: %d, comm: %.20s %s %s %.*s\n",
 304                 current->pid, current->comm, print_tainted(),
 305                 init_utsname()->release,
 306                 (int)strcspn(init_utsname()->version, " "),
 307                 init_utsname()->version);
 308         printk("RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->rip);
 309         printk_address(regs->rip);
 310         printk("RSP: %04lx:%016lx  EFLAGS: %08lx\n", regs->ss, regs->rsp,
 311                 regs->eflags);
 312         printk("RAX: %016lx RBX: %016lx RCX: %016lx\n",
 313                regs->rax, regs->rbx, regs->rcx);
 314         printk("RDX: %016lx RSI: %016lx RDI: %016lx\n",
 315                regs->rdx, regs->rsi, regs->rdi);
 316         printk("RBP: %016lx R08: %016lx R09: %016lx\n",
 317                regs->rbp, regs->r8, regs->r9);
 318         printk("R10: %016lx R11: %016lx R12: %016lx\n",
 319                regs->r10, regs->r11, regs->r12);
 320         printk("R13: %016lx R14: %016lx R15: %016lx\n",
 321                regs->r13, regs->r14, regs->r15);
 322
 323         asm("movl %%ds,%0" : "=r" (ds));
 324         asm("movl %%cs,%0" : "=r" (cs));
 325         asm("movl %%es,%0" : "=r" (es));
 326         asm("movl %%fs,%0" : "=r" (fsindex));
 327         asm("movl %%gs,%0" : "=r" (gsindex));
 328
 329         rdmsrl(MSR_FS_BASE, fs);
 330         rdmsrl(MSR_GS_BASE, gs);
 331         rdmsrl(MSR_KERNEL_GS_BASE, shadowgs);
 332
 333         asm("movq %%cr0, %0": "=r" (cr0));
 334         asm("movq %%cr2, %0": "=r" (cr2));
 335         asm("movq %%cr3, %0": "=r" (cr3));
 336         asm("movq %%cr4, %0": "=r" (cr4));
 337
 338         printk("FS:  %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n",
 339                fs,fsindex,gs,gsindex,shadowgs);
 340         printk("CS:  %04x DS: %04x ES: %04x CR0: %016lx\n", cs, ds, es, cr0);
 341         printk("CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2, cr3, cr4);
 342 }
 343
 344 void show_regs(struct pt_regs *regs)
 345 {
 346         printk("CPU %d:", smp_processor_id());
 347         __show_regs(regs);
 348         show_trace(NULL, regs, (void *)(regs + 1));
 349 }
 350
 351 /*
 352  * Free current thread data structures etc..
 353  */
 354 void exit_thread(void)
 355 {
 356         struct task_struct *me = current;
 357         struct thread_struct *t = &me->thread;
 358
 359         if (me->thread.io_bitmap_ptr) {
 360                 struct tss_struct *tss = &per_cpu(init_tss, get_cpu());
 361
 362                 kfree(t->io_bitmap_ptr);
 363                 t->io_bitmap_ptr = NULL;
 364                 clear_thread_flag(TIF_IO_BITMAP);
 365                 /*
 366                  * Careful, clear this in the TSS too:
 367                  */
 368                 memset(tss->io_bitmap, 0xff, t->io_bitmap_max);
 369                 t->io_bitmap_max = 0;
 370                 put_cpu();
 371         }
 372 }
 373
 374 void flush_thread(void)
 375 {
 376         struct task_struct *tsk = current;
 377         struct thread_info *t = current_thread_info();
 378
 379         if (t->flags & _TIF_ABI_PENDING) {
 380                 t->flags ^= (_TIF_ABI_PENDING | _TIF_IA32);
 381                 if (t->flags & _TIF_IA32)
 382                         current_thread_info()->status |= TS_COMPAT;
 383         }
 384         t->flags &= ~_TIF_DEBUG;
 385
 386         tsk->thread.debugreg0 = 0;
 387         tsk->thread.debugreg1 = 0;
 388         tsk->thread.debugreg2 = 0;
 389         tsk->thread.debugreg3 = 0;
 390         tsk->thread.debugreg6 = 0;
 391         tsk->thread.debugreg7 = 0;
 392         memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
 393         /*
 394          * Forget coprocessor state..
 395          */
 396         clear_fpu(tsk);
 397         clear_used_math();
 398 }
 399
 400 void release_thread(struct task_struct *dead_task)
 401 {
 402         if (dead_task->mm) {
 403                 if (dead_task->mm->context.size) {
 404                         printk("WARNING: dead process %8s still has LDT? <%p/%d>\n",
 405                                         dead_task->comm,
 406                                         dead_task->mm->context.ldt,
 407                                         dead_task->mm->context.size);
 408                         BUG();
 409                 }
 410         }
 411 }
 412
 413 static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr)
 414 {
 415         struct user_desc ud = {
 416                 .base_addr = addr,
 417                 .limit = 0xfffff,
 418                 .seg_32bit = 1,
 419                 .limit_in_pages = 1,
 420                 .useable = 1,
 421         };
 422         struct n_desc_struct *desc = (void *)t->thread.tls_array;
 423         desc += tls;
 424         desc->a = LDT_entry_a(&ud);
 425         desc->b = LDT_entry_b(&ud);
 426 }
 427
 428 static inline u32 read_32bit_tls(struct task_struct *t, int tls)
 429 {
 430         struct desc_struct *desc = (void *)t->thread.tls_array;
 431         desc += tls;
 432         return desc->base0 |
 433                 (((u32)desc->base1) << 16) |
 434                 (((u32)desc->base2) << 24);
 435 }
 436
 437 /*
 438  * This gets called before we allocate a new thread and copy
 439  * the current task into it.
 440  */
 441 void prepare_to_copy(struct task_struct *tsk)
 442 {
 443         unlazy_fpu(tsk);
 444 }
 445
 446 int copy_thread(int nr, unsigned long clone_flags, unsigned long rsp,
 447                 unsigned long unused,
 448         struct task_struct * p, struct pt_regs * regs)
 449 {
 450         int err;
 451         struct pt_regs * childregs;
 452         struct task_struct *me = current;
 453
 454         childregs = ((struct pt_regs *)
 455                         (THREAD_SIZE + task_stack_page(p))) - 1;
 456         *childregs = *regs;
 457
 458         childregs->rax = 0;
 459         childregs->rsp = rsp;
 460         if (rsp == ~0UL)
 461                 childregs->rsp = (unsigned long)childregs;
 462
 463         p->thread.rsp = (unsigned long) childregs;
 464         p->thread.rsp0 = (unsigned long) (childregs+1);
 465         p->thread.userrsp = me->thread.userrsp;
 466
 467         set_tsk_thread_flag(p, TIF_FORK);
 468
 469         p->thread.fs = me->thread.fs;
 470         p->thread.gs = me->thread.gs;
 471
 472         asm("mov %%gs,%0" : "=m" (p->thread.gsindex));
 473         asm("mov %%fs,%0" : "=m" (p->thread.fsindex));
 474         asm("mov %%es,%0" : "=m" (p->thread.es));
 475         asm("mov %%ds,%0" : "=m" (p->thread.ds));
 476
 477         if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
 478                 p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
 479                 if (!p->thread.io_bitmap_ptr) {
 480                         p->thread.io_bitmap_max = 0;
 481                         return -ENOMEM;
 482                 }
 483                 memcpy(p->thread.io_bitmap_ptr, me->thread.io_bitmap_ptr,
 484                                 IO_BITMAP_BYTES);
 485                 set_tsk_thread_flag(p, TIF_IO_BITMAP);
 486         }
 487
 488         /*
 489          * Set a new TLS for the child thread?
 490          */
 491         if (clone_flags & CLONE_SETTLS) {
 492 #ifdef CONFIG_IA32_EMULATION
 493                 if (test_thread_flag(TIF_IA32))
 494                         err = ia32_child_tls(p, childregs);
 495                 else
 496 #endif
 497                         err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8);
 498                 if (err)
 499                         goto out;
 500         }
 501         err = 0;
 502 out:
 503         if (err && p->thread.io_bitmap_ptr) {
 504                 kfree(p->thread.io_bitmap_ptr);
 505                 p->thread.io_bitmap_max = 0;
 506         }
 507         return err;
 508 }
 509
 510 /*
 511  * This special macro can be used to load a debugging register
 512  */
 513 #define loaddebug(thread,r) set_debugreg(thread->debugreg ## r, r)
 514
 515 static inline void __switch_to_xtra(struct task_struct *prev_p,
 516                                     struct task_struct *next_p,
 517                                     struct tss_struct *tss)
 518 {
 519         struct thread_struct *prev, *next;
 520
 521         prev = &prev_p->thread,
 522         next = &next_p->thread;
 523
 524         if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
 525                 loaddebug(next, 0);
 526                 loaddebug(next, 1);
 527                 loaddebug(next, 2);
 528                 loaddebug(next, 3);
 529                 /* no 4 and 5 */
 530                 loaddebug(next, 6);
 531                 loaddebug(next, 7);
 532         }
 533
 534         if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {
 535                 /*
 536                  * Copy the relevant range of the IO bitmap.
 537                  * Normally this is 128 bytes or less:
 538                  */
 539                 memcpy(tss->io_bitmap, next->io_bitmap_ptr,
 540                        max(prev->io_bitmap_max, next->io_bitmap_max));
 541         } else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) {
 542                 /*
 543                  * Clear any possible leftover bits:
 544                  */
 545                 memset(tss->io_bitmap, 0xff, prev->io_bitmap_max);
 546         }
 547 }
 548
 549 /*
 550  *      switch_to(x,y) should switch tasks from x to y.
 551  *
 552  * This could still be optimized:
 553  * - fold all the options into a flag word and test it with a single test.
 554  * - could test fs/gs bitsliced
 555  *
 556  * Kprobes not supported here. Set the probe on schedule instead.
 557  */
 558 __kprobes struct task_struct *
 559 __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 560 {
 561         struct thread_struct *prev = &prev_p->thread,
 562                                  *next = &next_p->thread;
 563         int cpu = smp_processor_id();
 564         struct tss_struct *tss = &per_cpu(init_tss, cpu);
 565
 566         /* we're going to use this soon, after a few expensive things */
 567         if (next_p->fpu_counter>5)
 568                 prefetch(&next->i387.fxsave);
 569
 570         /*
 571          * Reload esp0, LDT and the page table pointer:
 572          */
 573         tss->rsp0 = next->rsp0;
 574
 575         /*
 576          * Switch DS and ES.
 577          * This won't pick up thread selector changes, but I guess that is ok.
 578          */
 579         asm volatile("mov %%es,%0" : "=m" (prev->es));
 580         if (unlikely(next->es | prev->es))
 581                 loadsegment(es, next->es);
 582
 583         asm volatile ("mov %%ds,%0" : "=m" (prev->ds));
 584         if (unlikely(next->ds | prev->ds))
 585                 loadsegment(ds, next->ds);
 586
 587         load_TLS(next, cpu);
 588
 589         /*
 590          * Switch FS and GS.
 591          */
 592         {
 593                 unsigned fsindex;
 594                 asm volatile("movl %%fs,%0" : "=r" (fsindex));
 595                 /* segment register != 0 always requires a reload.
 596                    also reload when it has changed.
 597                    when prev process used 64bit base always reload
 598                    to avoid an information leak. */
 599                 if (unlikely(fsindex | next->fsindex | prev->fs)) {
 600                         loadsegment(fs, next->fsindex);
 601                         /* check if the user used a selector != 0
 602                          * if yes clear 64bit base, since overloaded base
 603                          * is always mapped to the Null selector
 604                          */
 605                         if (fsindex)
 606                         prev->fs = 0;
 607                 }
 608                 /* when next process has a 64bit base use it */
 609                 if (next->fs)
 610                         wrmsrl(MSR_FS_BASE, next->fs);
 611                 prev->fsindex = fsindex;
 612         }
 613         {
 614                 unsigned gsindex;
 615                 asm volatile("movl %%gs,%0" : "=r" (gsindex));
 616                 if (unlikely(gsindex | next->gsindex | prev->gs)) {
 617                         load_gs_index(next->gsindex);
 618                         if (gsindex)
 619                         prev->gs = 0;
 620                 }
 621                 if (next->gs)
 622                         wrmsrl(MSR_KERNEL_GS_BASE, next->gs);
 623                 prev->gsindex = gsindex;
 624         }
 625
 626         /* Must be after DS reload */
 627         unlazy_fpu(prev_p);
 628
 629         /*
 630          * Switch the PDA and FPU contexts.
 631          */
 632         prev->userrsp = read_pda(oldrsp);
 633         write_pda(oldrsp, next->userrsp);
 634         write_pda(pcurrent, next_p);
 635
 636         write_pda(kernelstack,
 637         (unsigned long)task_stack_page(next_p) + THREAD_SIZE - PDA_STACKOFFSET);
 638 #ifdef CONFIG_CC_STACKPROTECTOR
 639         write_pda(stack_canary, next_p->stack_canary);
 640         /*
 641          * Build time only check to make sure the stack_canary is at
 642          * offset 40 in the pda; this is a gcc ABI requirement
 643          */
 644         BUILD_BUG_ON(offsetof(struct x8664_pda, stack_canary) != 40);
 645 #endif
 646
 647         /*
 648          * Now maybe reload the debug registers and handle I/O bitmaps
 649          */
 650         if (unlikely((task_thread_info(next_p)->flags & _TIF_WORK_CTXSW))
 651             || test_tsk_thread_flag(prev_p, TIF_IO_BITMAP))
 652                 __switch_to_xtra(prev_p, next_p, tss);
 653
 654         /* If the task has used fpu the last 5 timeslices, just do a full
 655          * restore of the math state immediately to avoid the trap; the
 656          * chances of needing FPU soon are obviously high now
 657          */
 658         if (next_p->fpu_counter>5)
 659                 math_state_restore();
 660         return prev_p;
 661 }
 662
 663 /*
 664  * sys_execve() executes a new program.
 665  */
 666 asmlinkage
 667 long sys_execve(char __user *name, char __user * __user *argv,
 668                 char __user * __user *envp, struct pt_regs regs)
 669 {
 670         long error;
 671         char * filename;
 672
 673         filename = getname(name);
 674         error = PTR_ERR(filename);
 675         if (IS_ERR(filename))
 676                 return error;
 677         error = do_execve(filename, argv, envp, &regs);
 678         if (error == 0) {
 679                 task_lock(current);
 680                 current->ptrace &= ~PT_DTRACE;
 681                 task_unlock(current);
 682         }
 683         putname(filename);
 684         return error;
 685 }
 686
 687 void set_personality_64bit(void)
 688 {
 689         /* inherit personality from parent */
 690
 691         /* Make sure to be in 64bit mode */
 692         clear_thread_flag(TIF_IA32);
 693
 694         /* TBD: overwrites user setup. Should have two bits.
 695            But 64bit processes have always behaved this way,
 696            so it's not too bad. The main problem is just that
 697            32bit childs are affected again. */
 698         current->personality &= ~READ_IMPLIES_EXEC;
 699 }
 700
 701 asmlinkage long sys_fork(struct pt_regs *regs)
 702 {
 703         return do_fork(SIGCHLD, regs->rsp, regs, 0, NULL, NULL);
 704 }
 705
 706 asmlinkage long
 707 sys_clone(unsigned long clone_flags, unsigned long newsp,
 708           void __user *parent_tid, void __user *child_tid, struct pt_regs *regs)
 709 {
 710         if (!newsp)
 711                 newsp = regs->rsp;
 712         return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid);
 713 }
 714
 715 /*
 716  * This is trivial, and on the face of it looks like it
 717  * could equally well be done in user mode.
 718  *
 719  * Not so, for quite unobvious reasons - register pressure.
 720  * In user mode vfork() cannot have a stack frame, and if
 721  * done by calling the "clone()" system call directly, you
 722  * do not have enough call-clobbered registers to hold all
 723  * the information you need.
 724  */
 725 asmlinkage long sys_vfork(struct pt_regs *regs)
 726 {
 727         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->rsp, regs, 0,
 728                     NULL, NULL);
 729 }
 730
 731 unsigned long get_wchan(struct task_struct *p)
 732 {
 733         unsigned long stack;
 734         u64 fp,rip;
 735         int count = 0;
 736
 737         if (!p || p == current || p->state==TASK_RUNNING)
 738                 return 0;
 739         stack = (unsigned long)task_stack_page(p);
 740         if (p->thread.rsp < stack || p->thread.rsp > stack+THREAD_SIZE)
 741                 return 0;
 742         fp = *(u64 *)(p->thread.rsp);
 743         do {
 744                 if (fp < (unsigned long)stack ||
 745                     fp > (unsigned long)stack+THREAD_SIZE)
 746                         return 0;
 747                 rip = *(u64 *)(fp+8);
 748                 if (!in_sched_functions(rip))
 749                         return rip;
 750                 fp = *(u64 *)fp;
 751         } while (count++ < 16);
 752         return 0;
 753 }
 754
 755 long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
 756 {
 757         int ret = 0;
 758         int doit = task == current;
 759         int cpu;
 760
 761         switch (code) {
 762         case ARCH_SET_GS:
 763                 if (addr >= TASK_SIZE_OF(task))
 764                         return -EPERM;
 765                 cpu = get_cpu();
 766                 /* handle small bases via the GDT because that's faster to
 767                    switch. */
 768                 if (addr <= 0xffffffff) {
 769                         set_32bit_tls(task, GS_TLS, addr);
 770                         if (doit) {
 771                                 load_TLS(&task->thread, cpu);
 772                                 load_gs_index(GS_TLS_SEL);
 773                         }
 774                         task->thread.gsindex = GS_TLS_SEL;
 775                         task->thread.gs = 0;
 776                 } else {
 777                         task->thread.gsindex = 0;
 778                         task->thread.gs = addr;
 779                         if (doit) {
 780                                 load_gs_index(0);
 781                                 ret = checking_wrmsrl(MSR_KERNEL_GS_BASE, addr);
 782                         }
 783                 }
 784                 put_cpu();
 785                 break;
 786         case ARCH_SET_FS:
 787                 /* Not strictly needed for fs, but do it for symmetry
 788                    with gs */
 789                 if (addr >= TASK_SIZE_OF(task))
 790                         return -EPERM;
 791                 cpu = get_cpu();
 792                 /* handle small bases via the GDT because that's faster to
 793                    switch. */
 794                 if (addr <= 0xffffffff) {
 795                         set_32bit_tls(task, FS_TLS, addr);
 796                         if (doit) {
 797                                 load_TLS(&task->thread, cpu);
 798                                 asm volatile("movl %0,%%fs" :: "r"(FS_TLS_SEL));
 799                         }
 800                         task->thread.fsindex = FS_TLS_SEL;
 801                         task->thread.fs = 0;
 802                 } else {
 803                         task->thread.fsindex = 0;
 804                         task->thread.fs = addr;
 805                         if (doit) {
 806                                 /* set the selector to 0 to not confuse
 807                                    __switch_to */
 808                                 asm volatile("movl %0,%%fs" :: "r" (0));
 809                                 ret = checking_wrmsrl(MSR_FS_BASE, addr);
 810                         }
 811                 }
 812                 put_cpu();
 813                 break;
 814         case ARCH_GET_FS: {
 815                 unsigned long base;
 816                 if (task->thread.fsindex == FS_TLS_SEL)
 817                         base = read_32bit_tls(task, FS_TLS);
 818                 else if (doit)
 819                         rdmsrl(MSR_FS_BASE, base);
 820                 else
 821                         base = task->thread.fs;
 822                 ret = put_user(base, (unsigned long __user *)addr);
 823                 break;
 824         }
 825         case ARCH_GET_GS: {
 826                 unsigned long base;
 827                 unsigned gsindex;
 828                 if (task->thread.gsindex == GS_TLS_SEL)
 829                         base = read_32bit_tls(task, GS_TLS);
 830                 else if (doit) {
 831                         asm("movl %%gs,%0" : "=r" (gsindex));
 832                         if (gsindex)
 833                                 rdmsrl(MSR_KERNEL_GS_BASE, base);
 834                         else
 835                                 base = task->thread.gs;
 836                 }
 837                 else
 838                         base = task->thread.gs;
 839                 ret = put_user(base, (unsigned long __user *)addr);
 840                 break;
 841         }
 842
 843         default:
 844                 ret = -EINVAL;
 845                 break;
 846         }
 847
 848         return ret;
 849 }
 850
 851 long sys_arch_prctl(int code, unsigned long addr)
 852 {
 853         return do_arch_prctl(current, code, addr);
 854 }
 855
 856 /*
 857  * Capture the user space registers if the task is not running (in user space)
 858  */
 859 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
 860 {
 861         struct pt_regs *pp, ptregs;
 862
 863         pp = task_pt_regs(tsk);
 864
 865         ptregs = *pp;
 866         ptregs.cs &= 0xffff;
 867         ptregs.ss &= 0xffff;
 868
 869         elf_core_copy_regs(regs, &ptregs);
 870
 871         return 1;
 872 }
 873
 874 unsigned long arch_align_stack(unsigned long sp)
 875 {
 876         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 877                 sp -= get_random_int() % 8192;
 878         return sp & ~0xf;
 879 }