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 <stdarg.h>
  18
  19 #include <linux/cpu.h>
  20 #include <linux/errno.h>
  21 #include <linux/sched.h>
  22 #include <linux/fs.h>
  23 #include <linux/kernel.h>
  24 #include <linux/mm.h>
  25 #include <linux/elfcore.h>
  26 #include <linux/smp.h>
  27 #include <linux/slab.h>
  28 #include <linux/user.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/utsname.h>
  31 #include <linux/delay.h>
  32 #include <linux/module.h>
  33 #include <linux/ptrace.h>
  34 #include <linux/random.h>
  35 #include <linux/notifier.h>
  36 #include <linux/kprobes.h>
  37 #include <linux/kdebug.h>
  38 #include <linux/tick.h>
  39 #include <linux/prctl.h>
  40 #include <linux/uaccess.h>
  41 #include <linux/io.h>
  42 #include <linux/ftrace.h>
  43
  44 #include <asm/pgtable.h>
  45 #include <asm/system.h>
  46 #include <asm/processor.h>
  47 #include <asm/i387.h>
  48 #include <asm/mmu_context.h>
  49 #include <asm/pda.h>
  50 #include <asm/prctl.h>
  51 #include <asm/desc.h>
  52 #include <asm/proto.h>
  53 #include <asm/ia32.h>
  54 #include <asm/idle.h>
  55 #include <asm/syscalls.h>
  56 #include <asm/ds.h>
  57
  58 asmlinkage extern void ret_from_fork(void);
  59
  60 unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
  61
  62 static ATOMIC_NOTIFIER_HEAD(idle_notifier);
  63
  64 void idle_notifier_register(struct notifier_block *n)
  65 {
  66         atomic_notifier_chain_register(&idle_notifier, n);
  67 }
  68 EXPORT_SYMBOL_GPL(idle_notifier_register);
  69
  70 void idle_notifier_unregister(struct notifier_block *n)
  71 {
  72         atomic_notifier_chain_unregister(&idle_notifier, n);
  73 }
  74 EXPORT_SYMBOL_GPL(idle_notifier_unregister);
  75
  76 void enter_idle(void)
  77 {
  78         write_pda(isidle, 1);
  79         atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
  80 }
  81
  82 static void __exit_idle(void)
  83 {
  84         if (test_and_clear_bit_pda(0, isidle) == 0)
  85                 return;
  86         atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
  87 }
  88
  89 /* Called from interrupts to signify idle end */
  90 void exit_idle(void)
  91 {
  92         /* idle loop has pid 0 */
  93         if (current->pid)
  94                 return;
  95         __exit_idle();
  96 }
  97
  98 #ifndef CONFIG_SMP
  99 static inline void play_dead(void)
 100 {
 101         BUG();
 102 }
 103 #endif
 104
 105 /*
 106  * The idle thread. There's no useful work to be
 107  * done, so just try to conserve power and have a
 108  * low exit latency (ie sit in a loop waiting for
 109  * somebody to say that they'd like to reschedule)
 110  */
 111 void cpu_idle(void)
 112 {
 113         current_thread_info()->status |= TS_POLLING;
 114         /* endless idle loop with no priority at all */
 115         while (1) {
 116                 tick_nohz_stop_sched_tick(1);
 117                 while (!need_resched()) {
 118
 119                         rmb();
 120
 121                         if (cpu_is_offline(smp_processor_id()))
 122                                 play_dead();
 123                         /*
 124                          * Idle routines should keep interrupts disabled
 125                          * from here on, until they go to idle.
 126                          * Otherwise, idle callbacks can misfire.
 127                          */
 128                         local_irq_disable();
 129                         enter_idle();
 130                         /* Don't trace irqs off for idle */
 131                         stop_critical_timings();
 132                         pm_idle();
 133                         start_critical_timings();
 134                         /* In many cases the interrupt that ended idle
 135                            has already called exit_idle. But some idle
 136                            loops can be woken up without interrupt. */
 137                         __exit_idle();
 138                 }
 139
 140                 tick_nohz_restart_sched_tick();
 141                 preempt_enable_no_resched();
 142                 schedule();
 143                 preempt_disable();
 144         }
 145 }
 146
 147 /* Prints also some state that isn't saved in the pt_regs */
 148 void __show_regs(struct pt_regs *regs, int all)
 149 {
 150         unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs;
 151         unsigned long d0, d1, d2, d3, d6, d7;
 152         unsigned int fsindex, gsindex;
 153         unsigned int ds, cs, es;
 154
 155         printk("\n");
 156         print_modules();
 157         printk(KERN_INFO "Pid: %d, comm: %.20s %s %s %.*s\n",
 158                 current->pid, current->comm, print_tainted(),
 159                 init_utsname()->release,
 160                 (int)strcspn(init_utsname()->version, " "),
 161                 init_utsname()->version);
 162         printk(KERN_INFO "RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->ip);
 163         printk_address(regs->ip, 1);
 164         printk(KERN_INFO "RSP: %04lx:%016lx  EFLAGS: %08lx\n", regs->ss,
 165                         regs->sp, regs->flags);
 166         printk(KERN_INFO "RAX: %016lx RBX: %016lx RCX: %016lx\n",
 167                regs->ax, regs->bx, regs->cx);
 168         printk(KERN_INFO "RDX: %016lx RSI: %016lx RDI: %016lx\n",
 169                regs->dx, regs->si, regs->di);
 170         printk(KERN_INFO "RBP: %016lx R08: %016lx R09: %016lx\n",
 171                regs->bp, regs->r8, regs->r9);
 172         printk(KERN_INFO "R10: %016lx R11: %016lx R12: %016lx\n",
 173                regs->r10, regs->r11, regs->r12);
 174         printk(KERN_INFO "R13: %016lx R14: %016lx R15: %016lx\n",
 175                regs->r13, regs->r14, regs->r15);
 176
 177         asm("movl %%ds,%0" : "=r" (ds));
 178         asm("movl %%cs,%0" : "=r" (cs));
 179         asm("movl %%es,%0" : "=r" (es));
 180         asm("movl %%fs,%0" : "=r" (fsindex));
 181         asm("movl %%gs,%0" : "=r" (gsindex));
 182
 183         rdmsrl(MSR_FS_BASE, fs);
 184         rdmsrl(MSR_GS_BASE, gs);
 185         rdmsrl(MSR_KERNEL_GS_BASE, shadowgs);
 186
 187         if (!all)
 188                 return;
 189
 190         cr0 = read_cr0();
 191         cr2 = read_cr2();
 192         cr3 = read_cr3();
 193         cr4 = read_cr4();
 194
 195         printk(KERN_INFO "FS:  %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n",
 196                fs, fsindex, gs, gsindex, shadowgs);
 197         printk(KERN_INFO "CS:  %04x DS: %04x ES: %04x CR0: %016lx\n", cs, ds,
 198                         es, cr0);
 199         printk(KERN_INFO "CR2: %016lx CR3: %016lx CR4: %016lx\n", cr2, cr3,
 200                         cr4);
 201
 202         get_debugreg(d0, 0);
 203         get_debugreg(d1, 1);
 204         get_debugreg(d2, 2);
 205         printk(KERN_INFO "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2);
 206         get_debugreg(d3, 3);
 207         get_debugreg(d6, 6);
 208         get_debugreg(d7, 7);
 209         printk(KERN_INFO "DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7);
 210 }
 211
 212 void show_regs(struct pt_regs *regs)
 213 {
 214         printk(KERN_INFO "CPU %d:", smp_processor_id());
 215         __show_regs(regs, 1);
 216         show_trace(NULL, regs, (void *)(regs + 1), regs->bp);
 217 }
 218
 219 /*
 220  * Free current thread data structures etc..
 221  */
 222 void exit_thread(void)
 223 {
 224         struct task_struct *me = current;
 225         struct thread_struct *t = &me->thread;
 226
 227         if (me->thread.io_bitmap_ptr) {
 228                 struct tss_struct *tss = &per_cpu(init_tss, get_cpu());
 229
 230                 kfree(t->io_bitmap_ptr);
 231                 t->io_bitmap_ptr = NULL;
 232                 clear_thread_flag(TIF_IO_BITMAP);
 233                 /*
 234                  * Careful, clear this in the TSS too:
 235                  */
 236                 memset(tss->io_bitmap, 0xff, t->io_bitmap_max);
 237                 t->io_bitmap_max = 0;
 238                 put_cpu();
 239         }
 240
 241         ds_exit_thread(current);
 242 }
 243
 244 void flush_thread(void)
 245 {
 246         struct task_struct *tsk = current;
 247
 248         if (test_tsk_thread_flag(tsk, TIF_ABI_PENDING)) {
 249                 clear_tsk_thread_flag(tsk, TIF_ABI_PENDING);
 250                 if (test_tsk_thread_flag(tsk, TIF_IA32)) {
 251                         clear_tsk_thread_flag(tsk, TIF_IA32);
 252                 } else {
 253                         set_tsk_thread_flag(tsk, TIF_IA32);
 254                         current_thread_info()->status |= TS_COMPAT;
 255                 }
 256         }
 257         clear_tsk_thread_flag(tsk, TIF_DEBUG);
 258
 259         tsk->thread.debugreg0 = 0;
 260         tsk->thread.debugreg1 = 0;
 261         tsk->thread.debugreg2 = 0;
 262         tsk->thread.debugreg3 = 0;
 263         tsk->thread.debugreg6 = 0;
 264         tsk->thread.debugreg7 = 0;
 265         memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
 266         /*
 267          * Forget coprocessor state..
 268          */
 269         tsk->fpu_counter = 0;
 270         clear_fpu(tsk);
 271         clear_used_math();
 272 }
 273
 274 void release_thread(struct task_struct *dead_task)
 275 {
 276         if (dead_task->mm) {
 277                 if (dead_task->mm->context.size) {
 278                         printk("WARNING: dead process %8s still has LDT? <%p/%d>\n",
 279                                         dead_task->comm,
 280                                         dead_task->mm->context.ldt,
 281                                         dead_task->mm->context.size);
 282                         BUG();
 283                 }
 284         }
 285 }
 286
 287 static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr)
 288 {
 289         struct user_desc ud = {
 290                 .base_addr = addr,
 291                 .limit = 0xfffff,
 292                 .seg_32bit = 1,
 293                 .limit_in_pages = 1,
 294                 .useable = 1,
 295         };
 296         struct desc_struct *desc = t->thread.tls_array;
 297         desc += tls;
 298         fill_ldt(desc, &ud);
 299 }
 300
 301 static inline u32 read_32bit_tls(struct task_struct *t, int tls)
 302 {
 303         return get_desc_base(&t->thread.tls_array[tls]);
 304 }
 305
 306 /*
 307  * This gets called before we allocate a new thread and copy
 308  * the current task into it.
 309  */
 310 void prepare_to_copy(struct task_struct *tsk)
 311 {
 312         unlazy_fpu(tsk);
 313 }
 314
 315 int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
 316                 unsigned long unused,
 317         struct task_struct *p, struct pt_regs *regs)
 318 {
 319         int err;
 320         struct pt_regs *childregs;
 321         struct task_struct *me = current;
 322
 323         childregs = ((struct pt_regs *)
 324                         (THREAD_SIZE + task_stack_page(p))) - 1;
 325         *childregs = *regs;
 326
 327         childregs->ax = 0;
 328         childregs->sp = sp;
 329         if (sp == ~0UL)
 330                 childregs->sp = (unsigned long)childregs;
 331
 332         p->thread.sp = (unsigned long) childregs;
 333         p->thread.sp0 = (unsigned long) (childregs+1);
 334         p->thread.usersp = me->thread.usersp;
 335
 336         set_tsk_thread_flag(p, TIF_FORK);
 337
 338         p->thread.fs = me->thread.fs;
 339         p->thread.gs = me->thread.gs;
 340
 341         savesegment(gs, p->thread.gsindex);
 342         savesegment(fs, p->thread.fsindex);
 343         savesegment(es, p->thread.es);
 344         savesegment(ds, p->thread.ds);
 345
 346         if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
 347                 p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
 348                 if (!p->thread.io_bitmap_ptr) {
 349                         p->thread.io_bitmap_max = 0;
 350                         return -ENOMEM;
 351                 }
 352                 memcpy(p->thread.io_bitmap_ptr, me->thread.io_bitmap_ptr,
 353                                 IO_BITMAP_BYTES);
 354                 set_tsk_thread_flag(p, TIF_IO_BITMAP);
 355         }
 356
 357         /*
 358          * Set a new TLS for the child thread?
 359          */
 360         if (clone_flags & CLONE_SETTLS) {
 361 #ifdef CONFIG_IA32_EMULATION
 362                 if (test_thread_flag(TIF_IA32))
 363                         err = do_set_thread_area(p, -1,
 364                                 (struct user_desc __user *)childregs->si, 0);
 365                 else
 366 #endif
 367                         err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8);
 368                 if (err)
 369                         goto out;
 370         }
 371
 372         ds_copy_thread(p, me);
 373
 374         clear_tsk_thread_flag(p, TIF_DEBUGCTLMSR);
 375         p->thread.debugctlmsr = 0;
 376
 377         err = 0;
 378 out:
 379         if (err && p->thread.io_bitmap_ptr) {
 380                 kfree(p->thread.io_bitmap_ptr);
 381                 p->thread.io_bitmap_max = 0;
 382         }
 383         return err;
 384 }
 385
 386 void
 387 start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 388 {
 389         loadsegment(fs, 0);
 390         loadsegment(es, 0);
 391         loadsegment(ds, 0);
 392         load_gs_index(0);
 393         regs->ip                = new_ip;
 394         regs->sp                = new_sp;
 395         write_pda(oldrsp, new_sp);
 396         regs->cs                = __USER_CS;
 397         regs->ss                = __USER_DS;
 398         regs->flags             = 0x200;
 399         set_fs(USER_DS);
 400         /*
 401          * Free the old FP and other extended state
 402          */
 403         free_thread_xstate(current);
 404 }
 405 EXPORT_SYMBOL_GPL(start_thread);
 406
 407 static void hard_disable_TSC(void)
 408 {
 409         write_cr4(read_cr4() | X86_CR4_TSD);
 410 }
 411
 412 void disable_TSC(void)
 413 {
 414         preempt_disable();
 415         if (!test_and_set_thread_flag(TIF_NOTSC))
 416                 /*
 417                  * Must flip the CPU state synchronously with
 418                  * TIF_NOTSC in the current running context.
 419                  */
 420                 hard_disable_TSC();
 421         preempt_enable();
 422 }
 423
 424 static void hard_enable_TSC(void)
 425 {
 426         write_cr4(read_cr4() & ~X86_CR4_TSD);
 427 }
 428
 429 static void enable_TSC(void)
 430 {
 431         preempt_disable();
 432         if (test_and_clear_thread_flag(TIF_NOTSC))
 433                 /*
 434                  * Must flip the CPU state synchronously with
 435                  * TIF_NOTSC in the current running context.
 436                  */
 437                 hard_enable_TSC();
 438         preempt_enable();
 439 }
 440
 441 int get_tsc_mode(unsigned long adr)
 442 {
 443         unsigned int val;
 444
 445         if (test_thread_flag(TIF_NOTSC))
 446                 val = PR_TSC_SIGSEGV;
 447         else
 448                 val = PR_TSC_ENABLE;
 449
 450         return put_user(val, (unsigned int __user *)adr);
 451 }
 452
 453 int set_tsc_mode(unsigned int val)
 454 {
 455         if (val == PR_TSC_SIGSEGV)
 456                 disable_TSC();
 457         else if (val == PR_TSC_ENABLE)
 458                 enable_TSC();
 459         else
 460                 return -EINVAL;
 461
 462         return 0;
 463 }
 464
 465 /*
 466  * This special macro can be used to load a debugging register
 467  */
 468 #define loaddebug(thread, r) set_debugreg(thread->debugreg ## r, r)
 469
 470 static inline void __switch_to_xtra(struct task_struct *prev_p,
 471                                     struct task_struct *next_p,
 472                                     struct tss_struct *tss)
 473 {
 474         struct thread_struct *prev, *next;
 475
 476         prev = &prev_p->thread,
 477         next = &next_p->thread;
 478
 479         if (test_tsk_thread_flag(next_p, TIF_DS_AREA_MSR) ||
 480             test_tsk_thread_flag(prev_p, TIF_DS_AREA_MSR))
 481                 ds_switch_to(prev_p, next_p);
 482         else if (next->debugctlmsr != prev->debugctlmsr)
 483                 update_debugctlmsr(next->debugctlmsr);
 484
 485         if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
 486                 loaddebug(next, 0);
 487                 loaddebug(next, 1);
 488                 loaddebug(next, 2);
 489                 loaddebug(next, 3);
 490                 /* no 4 and 5 */
 491                 loaddebug(next, 6);
 492                 loaddebug(next, 7);
 493         }
 494
 495         if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^
 496             test_tsk_thread_flag(next_p, TIF_NOTSC)) {
 497                 /* prev and next are different */
 498                 if (test_tsk_thread_flag(next_p, TIF_NOTSC))
 499                         hard_disable_TSC();
 500                 else
 501                         hard_enable_TSC();
 502         }
 503
 504         if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {
 505                 /*
 506                  * Copy the relevant range of the IO bitmap.
 507                  * Normally this is 128 bytes or less:
 508                  */
 509                 memcpy(tss->io_bitmap, next->io_bitmap_ptr,
 510                        max(prev->io_bitmap_max, next->io_bitmap_max));
 511         } else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) {
 512                 /*
 513                  * Clear any possible leftover bits:
 514                  */
 515                 memset(tss->io_bitmap, 0xff, prev->io_bitmap_max);
 516         }
 517 }
 518
 519 /*
 520  *      switch_to(x,y) should switch tasks from x to y.
 521  *
 522  * This could still be optimized:
 523  * - fold all the options into a flag word and test it with a single test.
 524  * - could test fs/gs bitsliced
 525  *
 526  * Kprobes not supported here. Set the probe on schedule instead.
 527  * Function graph tracer not supported too.
 528  */
 529 __notrace_funcgraph struct task_struct *
 530 __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 531 {
 532         struct thread_struct *prev = &prev_p->thread;
 533         struct thread_struct *next = &next_p->thread;
 534         int cpu = smp_processor_id();
 535         struct tss_struct *tss = &per_cpu(init_tss, cpu);
 536         unsigned fsindex, gsindex;
 537
 538         /* we're going to use this soon, after a few expensive things */
 539         if (next_p->fpu_counter > 5)
 540                 prefetch(next->xstate);
 541
 542         /*
 543          * Reload esp0, LDT and the page table pointer:
 544          */
 545         load_sp0(tss, next);
 546
 547         /*
 548          * Switch DS and ES.
 549          * This won't pick up thread selector changes, but I guess that is ok.
 550          */
 551         savesegment(es, prev->es);
 552         if (unlikely(next->es | prev->es))
 553                 loadsegment(es, next->es);
 554
 555         savesegment(ds, prev->ds);
 556         if (unlikely(next->ds | prev->ds))
 557                 loadsegment(ds, next->ds);
 558
 559
 560         /* We must save %fs and %gs before load_TLS() because
 561          * %fs and %gs may be cleared by load_TLS().
 562          *
 563          * (e.g. xen_load_tls())
 564          */
 565         savesegment(fs, fsindex);
 566         savesegment(gs, gsindex);
 567
 568         load_TLS(next, cpu);
 569
 570         /*
 571          * Leave lazy mode, flushing any hypercalls made here.
 572          * This must be done before restoring TLS segments so
 573          * the GDT and LDT are properly updated, and must be
 574          * done before math_state_restore, so the TS bit is up
 575          * to date.
 576          */
 577         arch_leave_lazy_cpu_mode();
 578
 579         /*
 580          * Switch FS and GS.
 581          *
 582          * Segment register != 0 always requires a reload.  Also
 583          * reload when it has changed.  When prev process used 64bit
 584          * base always reload to avoid an information leak.
 585          */
 586         if (unlikely(fsindex | next->fsindex | prev->fs)) {
 587                 loadsegment(fs, next->fsindex);
 588                 /*
 589                  * Check if the user used a selector != 0; if yes
 590                  *  clear 64bit base, since overloaded base is always
 591                  *  mapped to the Null selector
 592                  */
 593                 if (fsindex)
 594                         prev->fs = 0;
 595         }
 596         /* when next process has a 64bit base use it */
 597         if (next->fs)
 598                 wrmsrl(MSR_FS_BASE, next->fs);
 599         prev->fsindex = fsindex;
 600
 601         if (unlikely(gsindex | next->gsindex | prev->gs)) {
 602                 load_gs_index(next->gsindex);
 603                 if (gsindex)
 604                         prev->gs = 0;
 605         }
 606         if (next->gs)
 607                 wrmsrl(MSR_KERNEL_GS_BASE, next->gs);
 608         prev->gsindex = gsindex;
 609
 610         /* Must be after DS reload */
 611         unlazy_fpu(prev_p);
 612
 613         /*
 614          * Switch the PDA and FPU contexts.
 615          */
 616         prev->usersp = read_pda(oldrsp);
 617         write_pda(oldrsp, next->usersp);
 618         write_pda(pcurrent, next_p);
 619
 620         write_pda(kernelstack,
 621                   (unsigned long)task_stack_page(next_p) +
 622                   THREAD_SIZE - PDA_STACKOFFSET);
 623 #ifdef CONFIG_CC_STACKPROTECTOR
 624         write_pda(stack_canary, next_p->stack_canary);
 625         /*
 626          * Build time only check to make sure the stack_canary is at
 627          * offset 40 in the pda; this is a gcc ABI requirement
 628          */
 629         BUILD_BUG_ON(offsetof(struct x8664_pda, stack_canary) != 40);
 630 #endif
 631
 632         /*
 633          * Now maybe reload the debug registers and handle I/O bitmaps
 634          */
 635         if (unlikely(task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT ||
 636                      task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV))
 637                 __switch_to_xtra(prev_p, next_p, tss);
 638
 639         /* If the task has used fpu the last 5 timeslices, just do a full
 640          * restore of the math state immediately to avoid the trap; the
 641          * chances of needing FPU soon are obviously high now
 642          *
 643          * tsk_used_math() checks prevent calling math_state_restore(),
 644          * which can sleep in the case of !tsk_used_math()
 645          */
 646         if (tsk_used_math(next_p) && next_p->fpu_counter > 5)
 647                 math_state_restore();
 648         return prev_p;
 649 }
 650
 651 /*
 652  * sys_execve() executes a new program.
 653  */
 654 asmlinkage
 655 long sys_execve(char __user *name, char __user * __user *argv,
 656                 char __user * __user *envp, struct pt_regs *regs)
 657 {
 658         long error;
 659         char *filename;
 660
 661         filename = getname(name);
 662         error = PTR_ERR(filename);
 663         if (IS_ERR(filename))
 664                 return error;
 665         error = do_execve(filename, argv, envp, regs);
 666         putname(filename);
 667         return error;
 668 }
 669
 670 void set_personality_64bit(void)
 671 {
 672         /* inherit personality from parent */
 673
 674         /* Make sure to be in 64bit mode */
 675         clear_thread_flag(TIF_IA32);
 676
 677         /* TBD: overwrites user setup. Should have two bits.
 678            But 64bit processes have always behaved this way,
 679            so it's not too bad. The main problem is just that
 680            32bit childs are affected again. */
 681         current->personality &= ~READ_IMPLIES_EXEC;
 682 }
 683
 684 asmlinkage long sys_fork(struct pt_regs *regs)
 685 {
 686         return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
 687 }
 688
 689 asmlinkage long
 690 sys_clone(unsigned long clone_flags, unsigned long newsp,
 691           void __user *parent_tid, void __user *child_tid, struct pt_regs *regs)
 692 {
 693         if (!newsp)
 694                 newsp = regs->sp;
 695         return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid);
 696 }
 697
 698 /*
 699  * This is trivial, and on the face of it looks like it
 700  * could equally well be done in user mode.
 701  *
 702  * Not so, for quite unobvious reasons - register pressure.
 703  * In user mode vfork() cannot have a stack frame, and if
 704  * done by calling the "clone()" system call directly, you
 705  * do not have enough call-clobbered registers to hold all
 706  * the information you need.
 707  */
 708 asmlinkage long sys_vfork(struct pt_regs *regs)
 709 {
 710         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs, 0,
 711                     NULL, NULL);
 712 }
 713
 714 unsigned long get_wchan(struct task_struct *p)
 715 {
 716         unsigned long stack;
 717         u64 fp, ip;
 718         int count = 0;
 719
 720         if (!p || p == current || p->state == TASK_RUNNING)
 721                 return 0;
 722         stack = (unsigned long)task_stack_page(p);
 723         if (p->thread.sp < stack || p->thread.sp >= stack+THREAD_SIZE)
 724                 return 0;
 725         fp = *(u64 *)(p->thread.sp);
 726         do {
 727                 if (fp < (unsigned long)stack ||
 728                     fp >= (unsigned long)stack+THREAD_SIZE)
 729                         return 0;
 730                 ip = *(u64 *)(fp+8);
 731                 if (!in_sched_functions(ip))
 732                         return ip;
 733                 fp = *(u64 *)fp;
 734         } while (count++ < 16);
 735         return 0;
 736 }
 737
 738 long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
 739 {
 740         int ret = 0;
 741         int doit = task == current;
 742         int cpu;
 743
 744         switch (code) {
 745         case ARCH_SET_GS:
 746                 if (addr >= TASK_SIZE_OF(task))
 747                         return -EPERM;
 748                 cpu = get_cpu();
 749                 /* handle small bases via the GDT because that's faster to
 750                    switch. */
 751                 if (addr <= 0xffffffff) {
 752                         set_32bit_tls(task, GS_TLS, addr);
 753                         if (doit) {
 754                                 load_TLS(&task->thread, cpu);
 755                                 load_gs_index(GS_TLS_SEL);
 756                         }
 757                         task->thread.gsindex = GS_TLS_SEL;
 758                         task->thread.gs = 0;
 759                 } else {
 760                         task->thread.gsindex = 0;
 761                         task->thread.gs = addr;
 762                         if (doit) {
 763                                 load_gs_index(0);
 764                                 ret = checking_wrmsrl(MSR_KERNEL_GS_BASE, addr);
 765                         }
 766                 }
 767                 put_cpu();
 768                 break;
 769         case ARCH_SET_FS:
 770                 /* Not strictly needed for fs, but do it for symmetry
 771                    with gs */
 772                 if (addr >= TASK_SIZE_OF(task))
 773                         return -EPERM;
 774                 cpu = get_cpu();
 775                 /* handle small bases via the GDT because that's faster to
 776                    switch. */
 777                 if (addr <= 0xffffffff) {
 778                         set_32bit_tls(task, FS_TLS, addr);
 779                         if (doit) {
 780                                 load_TLS(&task->thread, cpu);
 781                                 loadsegment(fs, FS_TLS_SEL);
 782                         }
 783                         task->thread.fsindex = FS_TLS_SEL;
 784                         task->thread.fs = 0;
 785                 } else {
 786                         task->thread.fsindex = 0;
 787                         task->thread.fs = addr;
 788                         if (doit) {
 789                                 /* set the selector to 0 to not confuse
 790                                    __switch_to */
 791                                 loadsegment(fs, 0);
 792                                 ret = checking_wrmsrl(MSR_FS_BASE, addr);
 793                         }
 794                 }
 795                 put_cpu();
 796                 break;
 797         case ARCH_GET_FS: {
 798                 unsigned long base;
 799                 if (task->thread.fsindex == FS_TLS_SEL)
 800                         base = read_32bit_tls(task, FS_TLS);
 801                 else if (doit)
 802                         rdmsrl(MSR_FS_BASE, base);
 803                 else
 804                         base = task->thread.fs;
 805                 ret = put_user(base, (unsigned long __user *)addr);
 806                 break;
 807         }
 808         case ARCH_GET_GS: {
 809                 unsigned long base;
 810                 unsigned gsindex;
 811                 if (task->thread.gsindex == GS_TLS_SEL)
 812                         base = read_32bit_tls(task, GS_TLS);
 813                 else if (doit) {
 814                         savesegment(gs, gsindex);
 815                         if (gsindex)
 816                                 rdmsrl(MSR_KERNEL_GS_BASE, base);
 817                         else
 818                                 base = task->thread.gs;
 819                 } else
 820                         base = task->thread.gs;
 821                 ret = put_user(base, (unsigned long __user *)addr);
 822                 break;
 823         }
 824
 825         default:
 826                 ret = -EINVAL;
 827                 break;
 828         }
 829
 830         return ret;
 831 }
 832
 833 long sys_arch_prctl(int code, unsigned long addr)
 834 {
 835         return do_arch_prctl(current, code, addr);
 836 }
 837
 838 unsigned long arch_align_stack(unsigned long sp)
 839 {
 840         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 841                 sp -= get_random_int() % 8192;
 842         return sp & ~0xf;
 843 }
 844
 845 unsigned long arch_randomize_brk(struct mm_struct *mm)
 846 {
 847         unsigned long range_end = mm->brk + 0x02000000;
 848         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 849 }