arch/x86/kernel/traps_32.c

   1 /*
   2  *  Copyright (C) 1991, 1992  Linus Torvalds
   3  *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
   4  *
   5  *  Pentium III FXSR, SSE support
   6  *      Gareth Hughes <gareth@valinux.com>, May 2000
   7  */
   8
   9 /*
  10  * 'Traps.c' handles hardware traps and faults after we have saved some
  11  * state in 'asm.s'.
  12  */
  13 #include <linux/interrupt.h>
  14 #include <linux/kallsyms.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/highmem.h>
  17 #include <linux/kprobes.h>
  18 #include <linux/uaccess.h>
  19 #include <linux/utsname.h>
  20 #include <linux/kdebug.h>
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/ptrace.h>
  24 #include <linux/string.h>
  25 #include <linux/unwind.h>
  26 #include <linux/delay.h>
  27 #include <linux/errno.h>
  28 #include <linux/kexec.h>
  29 #include <linux/sched.h>
  30 #include <linux/timer.h>
  31 #include <linux/init.h>
  32 #include <linux/bug.h>
  33 #include <linux/nmi.h>
  34 #include <linux/mm.h>
  35
  36 #ifdef CONFIG_EISA
  37 #include <linux/ioport.h>
  38 #include <linux/eisa.h>
  39 #endif
  40
  41 #ifdef CONFIG_MCA
  42 #include <linux/mca.h>
  43 #endif
  44
  45 #if defined(CONFIG_EDAC)
  46 #include <linux/edac.h>
  47 #endif
  48
  49 #include <asm/processor-flags.h>
  50 #include <asm/arch_hooks.h>
  51 #include <asm/stacktrace.h>
  52 #include <asm/processor.h>
  53 #include <asm/debugreg.h>
  54 #include <asm/atomic.h>
  55 #include <asm/system.h>
  56 #include <asm/unwind.h>
  57 #include <asm/desc.h>
  58 #include <asm/i387.h>
  59 #include <asm/nmi.h>
  60 #include <asm/smp.h>
  61 #include <asm/io.h>
  62 #include <asm/traps.h>
  63
  64 #include "mach_traps.h"
  65 #include "cpu/mcheck/mce.h"
  66
  67 DECLARE_BITMAP(used_vectors, NR_VECTORS);
  68 EXPORT_SYMBOL_GPL(used_vectors);
  69
  70 asmlinkage int system_call(void);
  71
  72 /* Do we ignore FPU interrupts ? */
  73 char ignore_fpu_irq;
  74
  75 /*
  76  * The IDT has to be page-aligned to simplify the Pentium
  77  * F0 0F bug workaround.. We have a special link segment
  78  * for this.
  79  */
  80 gate_desc idt_table[256]
  81         __attribute__((__section__(".data.idt"))) = { { { { 0, 0 } } }, };
  82
  83 int panic_on_unrecovered_nmi;
  84 int kstack_depth_to_print = 24;
  85 static unsigned int code_bytes = 64;
  86 static int ignore_nmis;
  87 static int die_counter;
  88
  89 static inline void conditional_sti(struct pt_regs *regs)
  90 {
  91         if (regs->flags & X86_EFLAGS_IF)
  92                 local_irq_enable();
  93 }
  94
  95 void printk_address(unsigned long address, int reliable)
  96 {
  97 #ifdef CONFIG_KALLSYMS
  98         unsigned long offset = 0;
  99         unsigned long symsize;
 100         const char *symname;
 101         char *modname;
 102         char *delim = ":";
 103         char namebuf[KSYM_NAME_LEN];
 104         char reliab[4] = "";
 105
 106         symname = kallsyms_lookup(address, &symsize, &offset,
 107                                         &modname, namebuf);
 108         if (!symname) {
 109                 printk(" [<%08lx>]\n", address);
 110                 return;
 111         }
 112         if (!reliable)
 113                 strcpy(reliab, "? ");
 114
 115         if (!modname)
 116                 modname = delim = "";
 117         printk(" [<%08lx>] %s%s%s%s%s+0x%lx/0x%lx\n",
 118                 address, reliab, delim, modname, delim, symname, offset, symsize);
 119 #else
 120         printk(" [<%08lx>]\n", address);
 121 #endif
 122 }
 123
 124 static inline int valid_stack_ptr(struct thread_info *tinfo,
 125                         void *p, unsigned int size)
 126 {
 127         void *t = tinfo;
 128         return  p > t && p <= t + THREAD_SIZE - size;
 129 }
 130
 131 /* The form of the top of the frame on the stack */
 132 struct stack_frame {
 133         struct stack_frame *next_frame;
 134         unsigned long return_address;
 135 };
 136
 137 static inline unsigned long
 138 print_context_stack(struct thread_info *tinfo,
 139                 unsigned long *stack, unsigned long bp,
 140                 const struct stacktrace_ops *ops, void *data)
 141 {
 142         struct stack_frame *frame = (struct stack_frame *)bp;
 143
 144         while (valid_stack_ptr(tinfo, stack, sizeof(*stack))) {
 145                 unsigned long addr;
 146
 147                 addr = *stack;
 148                 if (__kernel_text_address(addr)) {
 149                         if ((unsigned long) stack == bp + 4) {
 150                                 ops->address(data, addr, 1);
 151                                 frame = frame->next_frame;
 152                                 bp = (unsigned long) frame;
 153                         } else {
 154                                 ops->address(data, addr, bp == 0);
 155                         }
 156                 }
 157                 stack++;
 158         }
 159         return bp;
 160 }
 161
 162 void dump_trace(struct task_struct *task, struct pt_regs *regs,
 163                 unsigned long *stack, unsigned long bp,
 164                 const struct stacktrace_ops *ops, void *data)
 165 {
 166         if (!task)
 167                 task = current;
 168
 169         if (!stack) {
 170                 unsigned long dummy;
 171                 stack = &dummy;
 172                 if (task != current)
 173                         stack = (unsigned long *)task->thread.sp;
 174         }
 175
 176 #ifdef CONFIG_FRAME_POINTER
 177         if (!bp) {
 178                 if (task == current) {
 179                         /* Grab bp right from our regs */
 180                         asm("movl %%ebp, %0" : "=r" (bp) :);
 181                 } else {
 182                         /* bp is the last reg pushed by switch_to */
 183                         bp = *(unsigned long *) task->thread.sp;
 184                 }
 185         }
 186 #endif
 187
 188         for (;;) {
 189                 struct thread_info *context;
 190
 191                 context = (struct thread_info *)
 192                         ((unsigned long)stack & (~(THREAD_SIZE - 1)));
 193                 bp = print_context_stack(context, stack, bp, ops, data);
 194                 /*
 195                  * Should be after the line below, but somewhere
 196                  * in early boot context comes out corrupted and we
 197                  * can't reference it:
 198                  */
 199                 if (ops->stack(data, "IRQ") < 0)
 200                         break;
 201                 stack = (unsigned long *)context->previous_esp;
 202                 if (!stack)
 203                         break;
 204                 touch_nmi_watchdog();
 205         }
 206 }
 207 EXPORT_SYMBOL(dump_trace);
 208
 209 static void
 210 print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
 211 {
 212         printk(data);
 213         print_symbol(msg, symbol);
 214         printk("\n");
 215 }
 216
 217 static void print_trace_warning(void *data, char *msg)
 218 {
 219         printk("%s%s\n", (char *)data, msg);
 220 }
 221
 222 static int print_trace_stack(void *data, char *name)
 223 {
 224         return 0;
 225 }
 226
 227 /*
 228  * Print one address/symbol entries per line.
 229  */
 230 static void print_trace_address(void *data, unsigned long addr, int reliable)
 231 {
 232         printk("%s [<%08lx>] ", (char *)data, addr);
 233         if (!reliable)
 234                 printk("? ");
 235         print_symbol("%s\n", addr);
 236         touch_nmi_watchdog();
 237 }
 238
 239 static const struct stacktrace_ops print_trace_ops = {
 240         .warning = print_trace_warning,
 241         .warning_symbol = print_trace_warning_symbol,
 242         .stack = print_trace_stack,
 243         .address = print_trace_address,
 244 };
 245
 246 static void
 247 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 248                 unsigned long *stack, unsigned long bp, char *log_lvl)
 249 {
 250         dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
 251         printk("%s =======================\n", log_lvl);
 252 }
 253
 254 void show_trace(struct task_struct *task, struct pt_regs *regs,
 255                 unsigned long *stack, unsigned long bp)
 256 {
 257         show_trace_log_lvl(task, regs, stack, bp, "");
 258 }
 259
 260 static void
 261 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 262                    unsigned long *sp, unsigned long bp, char *log_lvl)
 263 {
 264         unsigned long *stack;
 265         int i;
 266
 267         if (sp == NULL) {
 268                 if (task)
 269                         sp = (unsigned long *)task->thread.sp;
 270                 else
 271                         sp = (unsigned long *)&sp;
 272         }
 273
 274         stack = sp;
 275         for (i = 0; i < kstack_depth_to_print; i++) {
 276                 if (kstack_end(stack))
 277                         break;
 278                 if (i && ((i % 8) == 0))
 279                         printk("\n%s       ", log_lvl);
 280                 printk("%08lx ", *stack++);
 281         }
 282         printk("\n%sCall Trace:\n", log_lvl);
 283
 284         show_trace_log_lvl(task, regs, sp, bp, log_lvl);
 285 }
 286
 287 void show_stack(struct task_struct *task, unsigned long *sp)
 288 {
 289         printk("       ");
 290         show_stack_log_lvl(task, NULL, sp, 0, "");
 291 }
 292
 293 /*
 294  * The architecture-independent dump_stack generator
 295  */
 296 void dump_stack(void)
 297 {
 298         unsigned long bp = 0;
 299         unsigned long stack;
 300
 301 #ifdef CONFIG_FRAME_POINTER
 302         if (!bp)
 303                 asm("movl %%ebp, %0" : "=r" (bp):);
 304 #endif
 305
 306         printk("Pid: %d, comm: %.20s %s %s %.*s\n",
 307                 current->pid, current->comm, print_tainted(),
 308                 init_utsname()->release,
 309                 (int)strcspn(init_utsname()->version, " "),
 310                 init_utsname()->version);
 311
 312         show_trace(current, NULL, &stack, bp);
 313 }
 314
 315 EXPORT_SYMBOL(dump_stack);
 316
 317 void show_registers(struct pt_regs *regs)
 318 {
 319         int i;
 320
 321         print_modules();
 322         __show_registers(regs, 0);
 323
 324         printk(KERN_EMERG "Process %.*s (pid: %d, ti=%p task=%p task.ti=%p)",
 325                 TASK_COMM_LEN, current->comm, task_pid_nr(current),
 326                 current_thread_info(), current, task_thread_info(current));
 327         /*
 328          * When in-kernel, we also print out the stack and code at the
 329          * time of the fault..
 330          */
 331         if (!user_mode_vm(regs)) {
 332                 unsigned int code_prologue = code_bytes * 43 / 64;
 333                 unsigned int code_len = code_bytes;
 334                 unsigned char c;
 335                 u8 *ip;
 336
 337                 printk("\n" KERN_EMERG "Stack: ");
 338                 show_stack_log_lvl(NULL, regs, &regs->sp, 0, KERN_EMERG);
 339
 340                 printk(KERN_EMERG "Code: ");
 341
 342                 ip = (u8 *)regs->ip - code_prologue;
 343                 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
 344                         /* try starting at EIP */
 345                         ip = (u8 *)regs->ip;
 346                         code_len = code_len - code_prologue + 1;
 347                 }
 348                 for (i = 0; i < code_len; i++, ip++) {
 349                         if (ip < (u8 *)PAGE_OFFSET ||
 350                                         probe_kernel_address(ip, c)) {
 351                                 printk(" Bad EIP value.");
 352                                 break;
 353                         }
 354                         if (ip == (u8 *)regs->ip)
 355                                 printk("<%02x> ", c);
 356                         else
 357                                 printk("%02x ", c);
 358                 }
 359         }
 360         printk("\n");
 361 }
 362
 363 int is_valid_bugaddr(unsigned long ip)
 364 {
 365         unsigned short ud2;
 366
 367         if (ip < PAGE_OFFSET)
 368                 return 0;
 369         if (probe_kernel_address((unsigned short *)ip, ud2))
 370                 return 0;
 371
 372         return ud2 == 0x0b0f;
 373 }
 374
 375 static raw_spinlock_t die_lock = __RAW_SPIN_LOCK_UNLOCKED;
 376 static int die_owner = -1;
 377 static unsigned int die_nest_count;
 378
 379 unsigned __kprobes long oops_begin(void)
 380 {
 381         unsigned long flags;
 382
 383         oops_enter();
 384
 385         if (die_owner != raw_smp_processor_id()) {
 386                 console_verbose();
 387                 raw_local_irq_save(flags);
 388                 __raw_spin_lock(&die_lock);
 389                 die_owner = smp_processor_id();
 390                 die_nest_count = 0;
 391                 bust_spinlocks(1);
 392         } else {
 393                 raw_local_irq_save(flags);
 394         }
 395         die_nest_count++;
 396         return flags;
 397 }
 398
 399 void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 400 {
 401         bust_spinlocks(0);
 402         die_owner = -1;
 403         add_taint(TAINT_DIE);
 404         __raw_spin_unlock(&die_lock);
 405         raw_local_irq_restore(flags);
 406
 407         if (!regs)
 408                 return;
 409
 410         if (kexec_should_crash(current))
 411                 crash_kexec(regs);
 412
 413         if (in_interrupt())
 414                 panic("Fatal exception in interrupt");
 415
 416         if (panic_on_oops)
 417                 panic("Fatal exception");
 418
 419         oops_exit();
 420         do_exit(signr);
 421 }
 422
 423 int __kprobes __die(const char *str, struct pt_regs *regs, long err)
 424 {
 425         unsigned short ss;
 426         unsigned long sp;
 427
 428         printk(KERN_EMERG "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
 429 #ifdef CONFIG_PREEMPT
 430         printk("PREEMPT ");
 431 #endif
 432 #ifdef CONFIG_SMP
 433         printk("SMP ");
 434 #endif
 435 #ifdef CONFIG_DEBUG_PAGEALLOC
 436         printk("DEBUG_PAGEALLOC");
 437 #endif
 438         printk("\n");
 439         if (notify_die(DIE_OOPS, str, regs, err,
 440                         current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
 441                 return 1;
 442
 443         show_registers(regs);
 444         /* Executive summary in case the oops scrolled away */
 445         sp = (unsigned long) (&regs->sp);
 446         savesegment(ss, ss);
 447         if (user_mode(regs)) {
 448                 sp = regs->sp;
 449                 ss = regs->ss & 0xffff;
 450         }
 451         printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
 452         print_symbol("%s", regs->ip);
 453         printk(" SS:ESP %04x:%08lx\n", ss, sp);
 454         return 0;
 455 }
 456
 457 /*
 458  * This is gone through when something in the kernel has done something bad
 459  * and is about to be terminated:
 460  */
 461 void die(const char *str, struct pt_regs *regs, long err)
 462 {
 463         unsigned long flags = oops_begin();
 464
 465         if (die_nest_count < 3) {
 466                 report_bug(regs->ip, regs);
 467
 468                 if (__die(str, regs, err))
 469                         regs = NULL;
 470         } else {
 471                 printk(KERN_EMERG "Recursive die() failure, output suppressed\n");
 472         }
 473
 474         oops_end(flags, regs, SIGSEGV);
 475 }
 476
 477 static inline void
 478 die_if_kernel(const char *str, struct pt_regs *regs, long err)
 479 {
 480         if (!user_mode_vm(regs))
 481                 die(str, regs, err);
 482 }
 483
 484 static void __kprobes
 485 do_trap(int trapnr, int signr, char *str, int vm86, struct pt_regs *regs,
 486         long error_code, siginfo_t *info)
 487 {
 488         struct task_struct *tsk = current;
 489
 490         if (regs->flags & X86_VM_MASK) {
 491                 if (vm86)
 492                         goto vm86_trap;
 493                 goto trap_signal;
 494         }
 495
 496         if (!user_mode(regs))
 497                 goto kernel_trap;
 498
 499 trap_signal:
 500         /*
 501          * We want error_code and trap_no set for userspace faults and
 502          * kernelspace faults which result in die(), but not
 503          * kernelspace faults which are fixed up.  die() gives the
 504          * process no chance to handle the signal and notice the
 505          * kernel fault information, so that won't result in polluting
 506          * the information about previously queued, but not yet
 507          * delivered, faults.  See also do_general_protection below.
 508          */
 509         tsk->thread.error_code = error_code;
 510         tsk->thread.trap_no = trapnr;
 511
 512         if (info)
 513                 force_sig_info(signr, info, tsk);
 514         else
 515                 force_sig(signr, tsk);
 516         return;
 517
 518 kernel_trap:
 519         if (!fixup_exception(regs)) {
 520                 tsk->thread.error_code = error_code;
 521                 tsk->thread.trap_no = trapnr;
 522                 die(str, regs, error_code);
 523         }
 524         return;
 525
 526 vm86_trap:
 527         if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
 528                                                 error_code, trapnr))
 529                 goto trap_signal;
 530         return;
 531 }
 532
 533 #define DO_TRAP(trapnr, signr, str, name)                               \
 534 void do_##name(struct pt_regs *regs, long error_code)                   \
 535 {                                                                       \
 536         trace_hardirqs_fixup();                                         \
 537         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 538                                                         == NOTIFY_STOP) \
 539                 return;                                                 \
 540         do_trap(trapnr, signr, str, 0, regs, error_code, NULL);         \
 541 }
 542
 543 #define DO_TRAP_INFO(trapnr, signr, str, name, sicode, siaddr, irq)     \
 544 void do_##name(struct pt_regs *regs, long error_code)                   \
 545 {                                                                       \
 546         siginfo_t info;                                                 \
 547         if (irq)                                                        \
 548                 local_irq_enable();                                     \
 549         info.si_signo = signr;                                          \
 550         info.si_errno = 0;                                              \
 551         info.si_code = sicode;                                          \
 552         info.si_addr = (void __user *)siaddr;                           \
 553         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 554                                                         == NOTIFY_STOP) \
 555                 return;                                                 \
 556         do_trap(trapnr, signr, str, 0, regs, error_code, &info);        \
 557 }
 558
 559 #define DO_VM86_TRAP(trapnr, signr, str, name)                          \
 560 void do_##name(struct pt_regs *regs, long error_code)                   \
 561 {                                                                       \
 562         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 563                                                         == NOTIFY_STOP) \
 564                 return;                                                 \
 565         do_trap(trapnr, signr, str, 1, regs, error_code, NULL);         \
 566 }
 567
 568 #define DO_VM86_TRAP_INFO(trapnr, signr, str, name, sicode, siaddr)     \
 569 void do_##name(struct pt_regs *regs, long error_code)                   \
 570 {                                                                       \
 571         siginfo_t info;                                                 \
 572         info.si_signo = signr;                                          \
 573         info.si_errno = 0;                                              \
 574         info.si_code = sicode;                                          \
 575         info.si_addr = (void __user *)siaddr;                           \
 576         trace_hardirqs_fixup();                                         \
 577         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 578                                                         == NOTIFY_STOP) \
 579                 return;                                                 \
 580         do_trap(trapnr, signr, str, 1, regs, error_code, &info);        \
 581 }
 582
 583 #define DO_ERROR(trapnr, signr, str, name)                              \
 584 void do_##name(struct pt_regs *regs, long error_code)                   \
 585 {                                                                       \
 586         trace_hardirqs_fixup();                                         \
 587         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 588                                                         == NOTIFY_STOP) \
 589                 return;                                                 \
 590         conditional_sti(regs);                                          \
 591         do_trap(trapnr, signr, str, 0, regs, error_code, NULL);         \
 592 }
 593
 594 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr, irq)    \
 595 void do_##name(struct pt_regs *regs, long error_code)                   \
 596 {                                                                       \
 597         siginfo_t info;                                                 \
 598         if (irq)                                                        \
 599                 local_irq_enable();                                     \
 600         info.si_signo = signr;                                          \
 601         info.si_errno = 0;                                              \
 602         info.si_code = sicode;                                          \
 603         info.si_addr = (void __user *)siaddr;                           \
 604         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 605                                                         == NOTIFY_STOP) \
 606                 return;                                                 \
 607         conditional_sti(regs);                                          \
 608         do_trap(trapnr, signr, str, 0, regs, error_code, &info);        \
 609 }
 610
 611 #define DO_VM86_ERROR(trapnr, signr, str, name)                         \
 612 void do_##name(struct pt_regs *regs, long error_code)                   \
 613 {                                                                       \
 614         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 615                                                         == NOTIFY_STOP) \
 616                 return;                                                 \
 617         conditional_sti(regs);                                          \
 618         do_trap(trapnr, signr, str, 1, regs, error_code, NULL);         \
 619 }
 620
 621 #define DO_VM86_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr)    \
 622 void do_##name(struct pt_regs *regs, long error_code)                   \
 623 {                                                                       \
 624         siginfo_t info;                                                 \
 625         info.si_signo = signr;                                          \
 626         info.si_errno = 0;                                              \
 627         info.si_code = sicode;                                          \
 628         info.si_addr = (void __user *)siaddr;                           \
 629         trace_hardirqs_fixup();                                         \
 630         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 631                                                         == NOTIFY_STOP) \
 632                 return;                                                 \
 633         conditional_sti(regs);                                          \
 634         do_trap(trapnr, signr, str, 1, regs, error_code, &info);        \
 635 }
 636
 637 DO_VM86_ERROR_INFO(0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->ip)
 638 DO_VM86_ERROR(4, SIGSEGV, "overflow", overflow)
 639 DO_VM86_ERROR(5, SIGSEGV, "bounds", bounds)
 640 DO_ERROR_INFO(6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->ip, 0)
 641 DO_ERROR(9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
 642 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
 643 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
 644 DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
 645 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0, 0)
 646 DO_TRAP_INFO(32, SIGILL, "iret exception", iret_error, ILL_BADSTK, 0, 1)
 647
 648 void __kprobes
 649 do_general_protection(struct pt_regs *regs, long error_code)
 650 {
 651         struct task_struct *tsk;
 652         struct thread_struct *thread;
 653         struct tss_struct *tss;
 654         int cpu;
 655
 656         conditional_sti(regs);
 657
 658         cpu = get_cpu();
 659         tss = &per_cpu(init_tss, cpu);
 660         thread = &current->thread;
 661
 662         /*
 663          * Perform the lazy TSS's I/O bitmap copy. If the TSS has an
 664          * invalid offset set (the LAZY one) and the faulting thread has
 665          * a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS
 666          * and we set the offset field correctly. Then we let the CPU to
 667          * restart the faulting instruction.
 668          */
 669         if (tss->x86_tss.io_bitmap_base == INVALID_IO_BITMAP_OFFSET_LAZY &&
 670             thread->io_bitmap_ptr) {
 671                 memcpy(tss->io_bitmap, thread->io_bitmap_ptr,
 672                        thread->io_bitmap_max);
 673                 /*
 674                  * If the previously set map was extending to higher ports
 675                  * than the current one, pad extra space with 0xff (no access).
 676                  */
 677                 if (thread->io_bitmap_max < tss->io_bitmap_max) {
 678                         memset((char *) tss->io_bitmap +
 679                                 thread->io_bitmap_max, 0xff,
 680                                 tss->io_bitmap_max - thread->io_bitmap_max);
 681                 }
 682                 tss->io_bitmap_max = thread->io_bitmap_max;
 683                 tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
 684                 tss->io_bitmap_owner = thread;
 685                 put_cpu();
 686
 687                 return;
 688         }
 689         put_cpu();
 690
 691         if (regs->flags & X86_VM_MASK)
 692                 goto gp_in_vm86;
 693
 694         tsk = current;
 695         if (!user_mode(regs))
 696                 goto gp_in_kernel;
 697
 698         tsk->thread.error_code = error_code;
 699         tsk->thread.trap_no = 13;
 700
 701         if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
 702                         printk_ratelimit()) {
 703                 printk(KERN_INFO
 704                         "%s[%d] general protection ip:%lx sp:%lx error:%lx",
 705                         tsk->comm, task_pid_nr(tsk),
 706                         regs->ip, regs->sp, error_code);
 707                 print_vma_addr(" in ", regs->ip);
 708                 printk("\n");
 709         }
 710
 711         force_sig(SIGSEGV, tsk);
 712         return;
 713
 714 gp_in_vm86:
 715         local_irq_enable();
 716         handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
 717         return;
 718
 719 gp_in_kernel:
 720         if (fixup_exception(regs))
 721                 return;
 722
 723         tsk->thread.error_code = error_code;
 724         tsk->thread.trap_no = 13;
 725         if (notify_die(DIE_GPF, "general protection fault", regs,
 726                                 error_code, 13, SIGSEGV) == NOTIFY_STOP)
 727                 return;
 728         die("general protection fault", regs, error_code);
 729 }
 730
 731 static notrace __kprobes void
 732 mem_parity_error(unsigned char reason, struct pt_regs *regs)
 733 {
 734         printk(KERN_EMERG
 735                 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
 736                         reason, smp_processor_id());
 737
 738         printk(KERN_EMERG
 739                 "You have some hardware problem, likely on the PCI bus.\n");
 740
 741 #if defined(CONFIG_EDAC)
 742         if (edac_handler_set()) {
 743                 edac_atomic_assert_error();
 744                 return;
 745         }
 746 #endif
 747
 748         if (panic_on_unrecovered_nmi)
 749                 panic("NMI: Not continuing");
 750
 751         printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
 752
 753         /* Clear and disable the memory parity error line. */
 754         clear_mem_error(reason);
 755 }
 756
 757 static notrace __kprobes void
 758 io_check_error(unsigned char reason, struct pt_regs *regs)
 759 {
 760         unsigned long i;
 761
 762         printk(KERN_EMERG "NMI: IOCK error (debug interrupt?)\n");
 763         show_registers(regs);
 764
 765         /* Re-enable the IOCK line, wait for a few seconds */
 766         reason = (reason & 0xf) | 8;
 767         outb(reason, 0x61);
 768
 769         i = 2000;
 770         while (--i)
 771                 udelay(1000);
 772
 773         reason &= ~8;
 774         outb(reason, 0x61);
 775 }
 776
 777 static notrace __kprobes void
 778 unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
 779 {
 780         if (notify_die(DIE_NMIUNKNOWN, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
 781                 return;
 782 #ifdef CONFIG_MCA
 783         /*
 784          * Might actually be able to figure out what the guilty party
 785          * is:
 786          */
 787         if (MCA_bus) {
 788                 mca_handle_nmi();
 789                 return;
 790         }
 791 #endif
 792         printk(KERN_EMERG
 793                 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
 794                         reason, smp_processor_id());
 795
 796         printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
 797         if (panic_on_unrecovered_nmi)
 798                 panic("NMI: Not continuing");
 799
 800         printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
 801 }
 802
 803 static DEFINE_SPINLOCK(nmi_print_lock);
 804
 805 void notrace __kprobes die_nmi(char *str, struct pt_regs *regs, int do_panic)
 806 {
 807         if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP)
 808                 return;
 809
 810         spin_lock(&nmi_print_lock);
 811         /*
 812         * We are in trouble anyway, lets at least try
 813         * to get a message out:
 814         */
 815         bust_spinlocks(1);
 816         printk(KERN_EMERG "%s", str);
 817         printk(" on CPU%d, ip %08lx, registers:\n",
 818                 smp_processor_id(), regs->ip);
 819         show_registers(regs);
 820         if (do_panic)
 821                 panic("Non maskable interrupt");
 822         console_silent();
 823         spin_unlock(&nmi_print_lock);
 824         bust_spinlocks(0);
 825
 826         /*
 827          * If we are in kernel we are probably nested up pretty bad
 828          * and might aswell get out now while we still can:
 829          */
 830         if (!user_mode_vm(regs)) {
 831                 current->thread.trap_no = 2;
 832                 crash_kexec(regs);
 833         }
 834
 835         do_exit(SIGSEGV);
 836 }
 837
 838 static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
 839 {
 840         unsigned char reason = 0;
 841         int cpu;
 842
 843         cpu = smp_processor_id();
 844
 845         /* Only the BSP gets external NMIs from the system. */
 846         if (!cpu)
 847                 reason = get_nmi_reason();
 848
 849         if (!(reason & 0xc0)) {
 850                 if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
 851                                                                 == NOTIFY_STOP)
 852                         return;
 853 #ifdef CONFIG_X86_LOCAL_APIC
 854                 /*
 855                  * Ok, so this is none of the documented NMI sources,
 856                  * so it must be the NMI watchdog.
 857                  */
 858                 if (nmi_watchdog_tick(regs, reason))
 859                         return;
 860                 if (!do_nmi_callback(regs, cpu))
 861                         unknown_nmi_error(reason, regs);
 862 #else
 863                 unknown_nmi_error(reason, regs);
 864 #endif
 865
 866                 return;
 867         }
 868         if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
 869                 return;
 870
 871         /* AK: following checks seem to be broken on modern chipsets. FIXME */
 872         if (reason & 0x80)
 873                 mem_parity_error(reason, regs);
 874         if (reason & 0x40)
 875                 io_check_error(reason, regs);
 876         /*
 877          * Reassert NMI in case it became active meanwhile
 878          * as it's edge-triggered:
 879          */
 880         reassert_nmi();
 881 }
 882
 883 notrace __kprobes void do_nmi(struct pt_regs *regs, long error_code)
 884 {
 885         int cpu;
 886
 887         nmi_enter();
 888
 889         cpu = smp_processor_id();
 890
 891         ++nmi_count(cpu);
 892
 893         if (!ignore_nmis)
 894                 default_do_nmi(regs);
 895
 896         nmi_exit();
 897 }
 898
 899 void stop_nmi(void)
 900 {
 901         acpi_nmi_disable();
 902         ignore_nmis++;
 903 }
 904
 905 void restart_nmi(void)
 906 {
 907         ignore_nmis--;
 908         acpi_nmi_enable();
 909 }
 910
 911 void __kprobes do_int3(struct pt_regs *regs, long error_code)
 912 {
 913 #ifdef CONFIG_KPROBES
 914         trace_hardirqs_fixup();
 915
 916         if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
 917                         == NOTIFY_STOP)
 918                 return;
 919         /*
 920          * This is an interrupt gate, because kprobes wants interrupts
 921          * disabled. Normal trap handlers don't.
 922          */
 923         conditional_sti(regs);
 924 #else
 925         if (notify_die(DIE_TRAP, "int3", regs, error_code, 3, SIGTRAP)
 926                         == NOTIFY_STOP)
 927                 return;
 928 #endif
 929
 930         do_trap(3, SIGTRAP, "int3", 1, regs, error_code, NULL);
 931 }
 932
 933 /*
 934  * Our handling of the processor debug registers is non-trivial.
 935  * We do not clear them on entry and exit from the kernel. Therefore
 936  * it is possible to get a watchpoint trap here from inside the kernel.
 937  * However, the code in ./ptrace.c has ensured that the user can
 938  * only set watchpoints on userspace addresses. Therefore the in-kernel
 939  * watchpoint trap can only occur in code which is reading/writing
 940  * from user space. Such code must not hold kernel locks (since it
 941  * can equally take a page fault), therefore it is safe to call
 942  * force_sig_info even though that claims and releases locks.
 943  *
 944  * Code in ./signal.c ensures that the debug control register
 945  * is restored before we deliver any signal, and therefore that
 946  * user code runs with the correct debug control register even though
 947  * we clear it here.
 948  *
 949  * Being careful here means that we don't have to be as careful in a
 950  * lot of more complicated places (task switching can be a bit lazy
 951  * about restoring all the debug state, and ptrace doesn't have to
 952  * find every occurrence of the TF bit that could be saved away even
 953  * by user code)
 954  */
 955 void __kprobes do_debug(struct pt_regs *regs, long error_code)
 956 {
 957         struct task_struct *tsk = current;
 958         unsigned int condition;
 959         int si_code;
 960
 961         trace_hardirqs_fixup();
 962
 963         get_debugreg(condition, 6);
 964
 965         /*
 966          * The processor cleared BTF, so don't mark that we need it set.
 967          */
 968         clear_tsk_thread_flag(tsk, TIF_DEBUGCTLMSR);
 969         tsk->thread.debugctlmsr = 0;
 970
 971         if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
 972                                                 SIGTRAP) == NOTIFY_STOP)
 973                 return;
 974         /* It's safe to allow irq's after DR6 has been saved */
 975         if (regs->flags & X86_EFLAGS_IF)
 976                 local_irq_enable();
 977
 978         /* Mask out spurious debug traps due to lazy DR7 setting */
 979         if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
 980                 if (!tsk->thread.debugreg7)
 981                         goto clear_dr7;
 982         }
 983
 984         if (regs->flags & X86_VM_MASK)
 985                 goto debug_vm86;
 986
 987         /* Save debug status register where ptrace can see it */
 988         tsk->thread.debugreg6 = condition;
 989
 990         /*
 991          * Single-stepping through TF: make sure we ignore any events in
 992          * kernel space (but re-enable TF when returning to user mode).
 993          */
 994         if (condition & DR_STEP) {
 995                 /*
 996                  * We already checked v86 mode above, so we can
 997                  * check for kernel mode by just checking the CPL
 998                  * of CS.
 999                  */
1000                 if (!user_mode(regs))
1001                         goto clear_TF_reenable;
1002         }
1003
1004         si_code = get_si_code((unsigned long)condition);
1005         /* Ok, finally something we can handle */
1006         send_sigtrap(tsk, regs, error_code, si_code);
1007
1008         /*
1009          * Disable additional traps. They'll be re-enabled when
1010          * the signal is delivered.
1011          */
1012 clear_dr7:
1013         set_debugreg(0, 7);
1014         return;
1015
1016 debug_vm86:
1017         handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1);
1018         return;
1019
1020 clear_TF_reenable:
1021         set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
1022         regs->flags &= ~X86_EFLAGS_TF;
1023         return;
1024 }
1025
1026 /*
1027  * Note that we play around with the 'TS' bit in an attempt to get
1028  * the correct behaviour even in the presence of the asynchronous
1029  * IRQ13 behaviour
1030  */
1031 void math_error(void __user *ip)
1032 {
1033         struct task_struct *task;
1034         siginfo_t info;
1035         unsigned short cwd, swd;
1036
1037         /*
1038          * Save the info for the exception handler and clear the error.
1039          */
1040         task = current;
1041         save_init_fpu(task);
1042         task->thread.trap_no = 16;
1043         task->thread.error_code = 0;
1044         info.si_signo = SIGFPE;
1045         info.si_errno = 0;
1046         info.si_code = __SI_FAULT;
1047         info.si_addr = ip;
1048         /*
1049          * (~cwd & swd) will mask out exceptions that are not set to unmasked
1050          * status.  0x3f is the exception bits in these regs, 0x200 is the
1051          * C1 reg you need in case of a stack fault, 0x040 is the stack
1052          * fault bit.  We should only be taking one exception at a time,
1053          * so if this combination doesn't produce any single exception,
1054          * then we have a bad program that isn't synchronizing its FPU usage
1055          * and it will suffer the consequences since we won't be able to
1056          * fully reproduce the context of the exception
1057          */
1058         cwd = get_fpu_cwd(task);
1059         swd = get_fpu_swd(task);
1060         switch (swd & ~cwd & 0x3f) {
1061         case 0x000: /* No unmasked exception */
1062                 return;
1063         default: /* Multiple exceptions */
1064                 break;
1065         case 0x001: /* Invalid Op */
1066                 /*
1067                  * swd & 0x240 == 0x040: Stack Underflow
1068                  * swd & 0x240 == 0x240: Stack Overflow
1069                  * User must clear the SF bit (0x40) if set
1070                  */
1071                 info.si_code = FPE_FLTINV;
1072                 break;
1073         case 0x002: /* Denormalize */
1074         case 0x010: /* Underflow */
1075                 info.si_code = FPE_FLTUND;
1076                 break;
1077         case 0x004: /* Zero Divide */
1078                 info.si_code = FPE_FLTDIV;
1079                 break;
1080         case 0x008: /* Overflow */
1081                 info.si_code = FPE_FLTOVF;
1082                 break;
1083         case 0x020: /* Precision */
1084                 info.si_code = FPE_FLTRES;
1085                 break;
1086         }
1087         force_sig_info(SIGFPE, &info, task);
1088 }
1089
1090 void do_coprocessor_error(struct pt_regs *regs, long error_code)
1091 {
1092         conditional_sti(regs);
1093         ignore_fpu_irq = 1;
1094         math_error((void __user *)regs->ip);
1095 }
1096
1097 static void simd_math_error(void __user *ip)
1098 {
1099         struct task_struct *task;
1100         siginfo_t info;
1101         unsigned short mxcsr;
1102
1103         /*
1104          * Save the info for the exception handler and clear the error.
1105          */
1106         task = current;
1107         save_init_fpu(task);
1108         task->thread.trap_no = 19;
1109         task->thread.error_code = 0;
1110         info.si_signo = SIGFPE;
1111         info.si_errno = 0;
1112         info.si_code = __SI_FAULT;
1113         info.si_addr = ip;
1114         /*
1115          * The SIMD FPU exceptions are handled a little differently, as there
1116          * is only a single status/control register.  Thus, to determine which
1117          * unmasked exception was caught we must mask the exception mask bits
1118          * at 0x1f80, and then use these to mask the exception bits at 0x3f.
1119          */
1120         mxcsr = get_fpu_mxcsr(task);
1121         switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) {
1122         case 0x000:
1123         default:
1124                 break;
1125         case 0x001: /* Invalid Op */
1126                 info.si_code = FPE_FLTINV;
1127                 break;
1128         case 0x002: /* Denormalize */
1129         case 0x010: /* Underflow */
1130                 info.si_code = FPE_FLTUND;
1131                 break;
1132         case 0x004: /* Zero Divide */
1133                 info.si_code = FPE_FLTDIV;
1134                 break;
1135         case 0x008: /* Overflow */
1136                 info.si_code = FPE_FLTOVF;
1137                 break;
1138         case 0x020: /* Precision */
1139                 info.si_code = FPE_FLTRES;
1140                 break;
1141         }
1142         force_sig_info(SIGFPE, &info, task);
1143 }
1144
1145 void do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
1146 {
1147         conditional_sti(regs);
1148
1149         if (cpu_has_xmm) {
1150                 /* Handle SIMD FPU exceptions on PIII+ processors. */
1151                 ignore_fpu_irq = 1;
1152                 simd_math_error((void __user *)regs->ip);
1153                 return;
1154         }
1155         /*
1156          * Handle strange cache flush from user space exception
1157          * in all other cases.  This is undocumented behaviour.
1158          */
1159         if (regs->flags & X86_VM_MASK) {
1160                 handle_vm86_fault((struct kernel_vm86_regs *)regs, error_code);
1161                 return;
1162         }
1163         current->thread.trap_no = 19;
1164         current->thread.error_code = error_code;
1165         die_if_kernel("cache flush denied", regs, error_code);
1166         force_sig(SIGSEGV, current);
1167 }
1168
1169 void do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
1170 {
1171         conditional_sti(regs);
1172 #if 0
1173         /* No need to warn about this any longer. */
1174         printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
1175 #endif
1176 }
1177
1178 unsigned long patch_espfix_desc(unsigned long uesp, unsigned long kesp)
1179 {
1180         struct desc_struct *gdt = get_cpu_gdt_table(smp_processor_id());
1181         unsigned long base = (kesp - uesp) & -THREAD_SIZE;
1182         unsigned long new_kesp = kesp - base;
1183         unsigned long lim_pages = (new_kesp | (THREAD_SIZE - 1)) >> PAGE_SHIFT;
1184         __u64 desc = *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS];
1185
1186         /* Set up base for espfix segment */
1187         desc &= 0x00f0ff0000000000ULL;
1188         desc |= ((((__u64)base) << 16) & 0x000000ffffff0000ULL) |
1189                 ((((__u64)base) << 32) & 0xff00000000000000ULL) |
1190                 ((((__u64)lim_pages) << 32) & 0x000f000000000000ULL) |
1191                 (lim_pages & 0xffff);
1192         *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS] = desc;
1193
1194         return new_kesp;
1195 }
1196
1197 /*
1198  * 'math_state_restore()' saves the current math information in the
1199  * old math state array, and gets the new ones from the current task
1200  *
1201  * Careful.. There are problems with IBM-designed IRQ13 behaviour.
1202  * Don't touch unless you *really* know how it works.
1203  *
1204  * Must be called with kernel preemption disabled (in this case,
1205  * local interrupts are disabled at the call-site in entry.S).
1206  */
1207 asmlinkage void math_state_restore(void)
1208 {
1209         struct thread_info *thread = current_thread_info();
1210         struct task_struct *tsk = thread->task;
1211
1212         if (!tsk_used_math(tsk)) {
1213                 local_irq_enable();
1214                 /*
1215                  * does a slab alloc which can sleep
1216                  */
1217                 if (init_fpu(tsk)) {
1218                         /*
1219                          * ran out of memory!
1220                          */
1221                         do_group_exit(SIGKILL);
1222                         return;
1223                 }
1224                 local_irq_disable();
1225         }
1226
1227         clts();                         /* Allow maths ops (or we recurse) */
1228         restore_fpu(tsk);
1229         thread->status |= TS_USEDFPU;   /* So we fnsave on switch_to() */
1230         tsk->fpu_counter++;
1231 }
1232 EXPORT_SYMBOL_GPL(math_state_restore);
1233
1234 #ifndef CONFIG_MATH_EMULATION
1235
1236 asmlinkage void math_emulate(long arg)
1237 {
1238         printk(KERN_EMERG
1239                 "math-emulation not enabled and no coprocessor found.\n");
1240         printk(KERN_EMERG "killing %s.\n", current->comm);
1241         force_sig(SIGFPE, current);
1242         schedule();
1243 }
1244
1245 #endif /* CONFIG_MATH_EMULATION */
1246
1247 void __kprobes do_device_not_available(struct pt_regs *regs, long error)
1248 {
1249         if (read_cr0() & X86_CR0_EM) {
1250                 conditional_sti(regs);
1251                 math_emulate(0);
1252         } else {
1253                 math_state_restore(); /* interrupts still off */
1254                 conditional_sti(regs);
1255         }
1256 }
1257
1258 #ifdef CONFIG_X86_MCE
1259 void __kprobes do_machine_check(struct pt_regs *regs, long error)
1260 {
1261         conditional_sti(regs);
1262         machine_check_vector(regs, error);
1263 }
1264 #endif
1265
1266 void __init trap_init(void)
1267 {
1268         int i;
1269
1270 #ifdef CONFIG_EISA
1271         void __iomem *p = early_ioremap(0x0FFFD9, 4);
1272
1273         if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
1274                 EISA_bus = 1;
1275         early_iounmap(p, 4);
1276 #endif
1277
1278         set_intr_gate(0, &divide_error);
1279         set_intr_gate(1, &debug);
1280         set_intr_gate(2, &nmi);
1281         set_system_intr_gate(3, &int3); /* int3 can be called from all */
1282         set_system_intr_gate(4, &overflow); /* int4 can be called from all */
1283         set_intr_gate(5, &bounds);
1284         set_intr_gate(6, &invalid_op);
1285         set_intr_gate(7, &device_not_available);
1286         set_task_gate(8, GDT_ENTRY_DOUBLEFAULT_TSS);
1287         set_intr_gate(9, &coprocessor_segment_overrun);
1288         set_intr_gate(10, &invalid_TSS);
1289         set_intr_gate(11, &segment_not_present);
1290         set_intr_gate(12, &stack_segment);
1291         set_intr_gate(13, &general_protection);
1292         set_intr_gate(14, &page_fault);
1293         set_intr_gate(15, &spurious_interrupt_bug);
1294         set_intr_gate(16, &coprocessor_error);
1295         set_intr_gate(17, &alignment_check);
1296 #ifdef CONFIG_X86_MCE
1297         set_intr_gate(18, &machine_check);
1298 #endif
1299         set_intr_gate(19, &simd_coprocessor_error);
1300
1301         if (cpu_has_fxsr) {
1302                 printk(KERN_INFO "Enabling fast FPU save and restore... ");
1303                 set_in_cr4(X86_CR4_OSFXSR);
1304                 printk("done.\n");
1305         }
1306         if (cpu_has_xmm) {
1307                 printk(KERN_INFO
1308                         "Enabling unmasked SIMD FPU exception support... ");
1309                 set_in_cr4(X86_CR4_OSXMMEXCPT);
1310                 printk("done.\n");
1311         }
1312
1313         set_system_gate(SYSCALL_VECTOR, &system_call);
1314
1315         /* Reserve all the builtin and the syscall vector: */
1316         for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
1317                 set_bit(i, used_vectors);
1318
1319         set_bit(SYSCALL_VECTOR, used_vectors);
1320
1321         /*
1322          * Should be a barrier for any external CPU state:
1323          */
1324         cpu_init();
1325
1326         trap_init_hook();
1327 }
1328
1329 static int __init kstack_setup(char *s)
1330 {
1331         kstack_depth_to_print = simple_strtoul(s, NULL, 0);
1332
1333         return 1;
1334 }
1335 __setup("kstack=", kstack_setup);
1336
1337 static int __init code_bytes_setup(char *s)
1338 {
1339         code_bytes = simple_strtoul(s, NULL, 0);
1340         if (code_bytes > 8192)
1341                 code_bytes = 8192;
1342
1343         return 1;
1344 }
1345 __setup("code_bytes=", code_bytes_setup);