arch/arm/kernel/process.c

   1 /*
   2  *  linux/arch/arm/kernel/process.c
   3  *
   4  *  Copyright (C) 1996-2000 Russell King - Converted to ARM.
   5  *  Original Copyright (C) 1995  Linus Torvalds
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <stdarg.h>
  12
  13 #include <linux/export.h>
  14 #include <linux/sched.h>
  15 #include <linux/kernel.h>
  16 #include <linux/mm.h>
  17 #include <linux/stddef.h>
  18 #include <linux/unistd.h>
  19 #include <linux/user.h>
  20 #include <linux/delay.h>
  21 #include <linux/reboot.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/kallsyms.h>
  24 #include <linux/init.h>
  25 #include <linux/cpu.h>
  26 #include <linux/elfcore.h>
  27 #include <linux/pm.h>
  28 #include <linux/tick.h>
  29 #include <linux/utsname.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/random.h>
  32 #include <linux/hw_breakpoint.h>
  33 #include <linux/cpuidle.h>
  34
  35 #include <asm/cacheflush.h>
  36 #include <asm/leds.h>
  37 #include <asm/processor.h>
  38 #include <asm/thread_notify.h>
  39 #include <asm/stacktrace.h>
  40 #include <asm/mach/time.h>
  41
  42 #ifdef CONFIG_CC_STACKPROTECTOR
  43 #include <linux/stackprotector.h>
  44 unsigned long __stack_chk_guard __read_mostly;
  45 EXPORT_SYMBOL(__stack_chk_guard);
  46 #endif
  47
  48 static const char *processor_modes[] = {
  49   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  50   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  51   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
  52   "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  53 };
  54
  55 static const char *isa_modes[] = {
  56   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  57 };
  58
  59 extern void setup_mm_for_reboot(void);
  60
  61 static volatile int hlt_counter;
  62
  63 #include <mach/system.h>
  64
  65 void disable_hlt(void)
  66 {
  67         hlt_counter++;
  68 }
  69
  70 EXPORT_SYMBOL(disable_hlt);
  71
  72 void enable_hlt(void)
  73 {
  74         hlt_counter--;
  75 }
  76
  77 EXPORT_SYMBOL(enable_hlt);
  78
  79 static int __init nohlt_setup(char *__unused)
  80 {
  81         hlt_counter = 1;
  82         return 1;
  83 }
  84
  85 static int __init hlt_setup(char *__unused)
  86 {
  87         hlt_counter = 0;
  88         return 1;
  89 }
  90
  91 __setup("nohlt", nohlt_setup);
  92 __setup("hlt", hlt_setup);
  93
  94 extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
  95 typedef void (*phys_reset_t)(unsigned long);
  96
  97 /*
  98  * A temporary stack to use for CPU reset. This is static so that we
  99  * don't clobber it with the identity mapping. When running with this
 100  * stack, any references to the current task *will not work* so you
 101  * should really do as little as possible before jumping to your reset
 102  * code.
 103  */
 104 static u64 soft_restart_stack[16];
 105
 106 static void __soft_restart(void *addr)
 107 {
 108         phys_reset_t phys_reset;
 109
 110         /* Take out a flat memory mapping. */
 111         setup_mm_for_reboot();
 112
 113         /* Clean and invalidate caches */
 114         flush_cache_all();
 115
 116         /* Turn off caching */
 117         cpu_proc_fin();
 118
 119         /* Push out any further dirty data, and ensure cache is empty */
 120         flush_cache_all();
 121
 122         /* Switch to the identity mapping. */
 123         phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
 124         phys_reset((unsigned long)addr);
 125
 126         /* Should never get here. */
 127         BUG();
 128 }
 129
 130 void soft_restart(unsigned long addr)
 131 {
 132         u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
 133
 134         /* Disable interrupts first */
 135         local_irq_disable();
 136         local_fiq_disable();
 137
 138         /* Disable the L2 if we're the last man standing. */
 139         if (num_online_cpus() == 1)
 140                 outer_disable();
 141
 142         /* Change to the new stack and continue with the reset. */
 143         call_with_stack(__soft_restart, (void *)addr, (void *)stack);
 144
 145         /* Should never get here. */
 146         BUG();
 147 }
 148
 149 static void null_restart(char mode, const char *cmd)
 150 {
 151 }
 152
 153 /*
 154  * Function pointers to optional machine specific functions
 155  */
 156 void (*pm_power_off)(void);
 157 EXPORT_SYMBOL(pm_power_off);
 158
 159 void (*arm_pm_restart)(char str, const char *cmd) = null_restart;
 160 EXPORT_SYMBOL_GPL(arm_pm_restart);
 161
 162 static void do_nothing(void *unused)
 163 {
 164 }
 165
 166 /*
 167  * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
 168  * pm_idle and update to new pm_idle value. Required while changing pm_idle
 169  * handler on SMP systems.
 170  *
 171  * Caller must have changed pm_idle to the new value before the call. Old
 172  * pm_idle value will not be used by any CPU after the return of this function.
 173  */
 174 void cpu_idle_wait(void)
 175 {
 176         smp_mb();
 177         /* kick all the CPUs so that they exit out of pm_idle */
 178         smp_call_function(do_nothing, NULL, 1);
 179 }
 180 EXPORT_SYMBOL_GPL(cpu_idle_wait);
 181
 182 /*
 183  * This is our default idle handler.  We need to disable
 184  * interrupts here to ensure we don't miss a wakeup call.
 185  */
 186 static void default_idle(void)
 187 {
 188         if (!need_resched())
 189                 arch_idle();
 190         local_irq_enable();
 191 }
 192
 193 void (*pm_idle)(void) = default_idle;
 194 EXPORT_SYMBOL(pm_idle);
 195
 196 /*
 197  * The idle thread, has rather strange semantics for calling pm_idle,
 198  * but this is what x86 does and we need to do the same, so that
 199  * things like cpuidle get called in the same way.  The only difference
 200  * is that we always respect 'hlt_counter' to prevent low power idle.
 201  */
 202 void cpu_idle(void)
 203 {
 204         local_fiq_enable();
 205
 206         /* endless idle loop with no priority at all */
 207         while (1) {
 208                 tick_nohz_idle_enter();
 209                 rcu_idle_enter();
 210                 leds_event(led_idle_start);
 211                 while (!need_resched()) {
 212 #ifdef CONFIG_HOTPLUG_CPU
 213                         if (cpu_is_offline(smp_processor_id()))
 214                                 cpu_die();
 215 #endif
 216
 217                         local_irq_disable();
 218 #ifdef CONFIG_PL310_ERRATA_769419
 219                         wmb();
 220 #endif
 221                         if (hlt_counter) {
 222                                 local_irq_enable();
 223                                 cpu_relax();
 224                         } else {
 225                                 stop_critical_timings();
 226                                 if (cpuidle_idle_call())
 227                                         pm_idle();
 228                                 start_critical_timings();
 229                                 /*
 230                                  * This will eventually be removed - pm_idle
 231                                  * functions should always return with IRQs
 232                                  * enabled.
 233                                  */
 234                                 WARN_ON(irqs_disabled());
 235                                 local_irq_enable();
 236                         }
 237                 }
 238                 leds_event(led_idle_end);
 239                 rcu_idle_exit();
 240                 tick_nohz_idle_exit();
 241                 schedule_preempt_disabled();
 242         }
 243 }
 244
 245 static char reboot_mode = 'h';
 246
 247 int __init reboot_setup(char *str)
 248 {
 249         reboot_mode = str[0];
 250         return 1;
 251 }
 252
 253 __setup("reboot=", reboot_setup);
 254
 255 void machine_shutdown(void)
 256 {
 257 #ifdef CONFIG_SMP
 258         smp_send_stop();
 259 #endif
 260 }
 261
 262 void machine_halt(void)
 263 {
 264         machine_shutdown();
 265         while (1);
 266 }
 267
 268 void machine_power_off(void)
 269 {
 270         machine_shutdown();
 271         if (pm_power_off)
 272                 pm_power_off();
 273 }
 274
 275 void machine_restart(char *cmd)
 276 {
 277         machine_shutdown();
 278
 279         arm_pm_restart(reboot_mode, cmd);
 280
 281         /* Give a grace period for failure to restart of 1s */
 282         mdelay(1000);
 283
 284         /* Whoops - the platform was unable to reboot. Tell the user! */
 285         printk("Reboot failed -- System halted\n");
 286         while (1);
 287 }
 288
 289 void __show_regs(struct pt_regs *regs)
 290 {
 291         unsigned long flags;
 292         char buf[64];
 293
 294         printk("CPU: %d    %s  (%s %.*s)\n",
 295                 raw_smp_processor_id(), print_tainted(),
 296                 init_utsname()->release,
 297                 (int)strcspn(init_utsname()->version, " "),
 298                 init_utsname()->version);
 299         print_symbol("PC is at %s\n", instruction_pointer(regs));
 300         print_symbol("LR is at %s\n", regs->ARM_lr);
 301         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 302                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 303                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 304                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 305         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 306                 regs->ARM_r10, regs->ARM_r9,
 307                 regs->ARM_r8);
 308         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 309                 regs->ARM_r7, regs->ARM_r6,
 310                 regs->ARM_r5, regs->ARM_r4);
 311         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 312                 regs->ARM_r3, regs->ARM_r2,
 313                 regs->ARM_r1, regs->ARM_r0);
 314
 315         flags = regs->ARM_cpsr;
 316         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 317         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 318         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 319         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 320         buf[4] = '\0';
 321
 322         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 323                 buf, interrupts_enabled(regs) ? "n" : "ff",
 324                 fast_interrupts_enabled(regs) ? "n" : "ff",
 325                 processor_modes[processor_mode(regs)],
 326                 isa_modes[isa_mode(regs)],
 327                 get_fs() == get_ds() ? "kernel" : "user");
 328 #ifdef CONFIG_CPU_CP15
 329         {
 330                 unsigned int ctrl;
 331
 332                 buf[0] = '\0';
 333 #ifdef CONFIG_CPU_CP15_MMU
 334                 {
 335                         unsigned int transbase, dac;
 336                         asm("mrc p15, 0, %0, c2, c0\n\t"
 337                             "mrc p15, 0, %1, c3, c0\n"
 338                             : "=r" (transbase), "=r" (dac));
 339                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 340                                 transbase, dac);
 341                 }
 342 #endif
 343                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 344
 345                 printk("Control: %08x%s\n", ctrl, buf);
 346         }
 347 #endif
 348 }
 349
 350 void show_regs(struct pt_regs * regs)
 351 {
 352         printk("\n");
 353         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 354         __show_regs(regs);
 355         dump_stack();
 356 }
 357
 358 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 359
 360 EXPORT_SYMBOL_GPL(thread_notify_head);
 361
 362 /*
 363  * Free current thread data structures etc..
 364  */
 365 void exit_thread(void)
 366 {
 367         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 368 }
 369
 370 void flush_thread(void)
 371 {
 372         struct thread_info *thread = current_thread_info();
 373         struct task_struct *tsk = current;
 374
 375         flush_ptrace_hw_breakpoint(tsk);
 376
 377         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 378         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 379         memset(&thread->fpstate, 0, sizeof(union fp_state));
 380
 381         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 382 }
 383
 384 void release_thread(struct task_struct *dead_task)
 385 {
 386 }
 387
 388 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 389
 390 int
 391 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 392             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 393 {
 394         struct thread_info *thread = task_thread_info(p);
 395         struct pt_regs *childregs = task_pt_regs(p);
 396
 397         *childregs = *regs;
 398         childregs->ARM_r0 = 0;
 399         childregs->ARM_sp = stack_start;
 400
 401         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 402         thread->cpu_context.sp = (unsigned long)childregs;
 403         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 404
 405         clear_ptrace_hw_breakpoint(p);
 406
 407         if (clone_flags & CLONE_SETTLS)
 408                 thread->tp_value = regs->ARM_r3;
 409
 410         thread_notify(THREAD_NOTIFY_COPY, thread);
 411
 412         return 0;
 413 }
 414
 415 /*
 416  * Fill in the task's elfregs structure for a core dump.
 417  */
 418 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 419 {
 420         elf_core_copy_regs(elfregs, task_pt_regs(t));
 421         return 1;
 422 }
 423
 424 /*
 425  * fill in the fpe structure for a core dump...
 426  */
 427 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 428 {
 429         struct thread_info *thread = current_thread_info();
 430         int used_math = thread->used_cp[1] | thread->used_cp[2];
 431
 432         if (used_math)
 433                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 434
 435         return used_math != 0;
 436 }
 437 EXPORT_SYMBOL(dump_fpu);
 438
 439 /*
 440  * Shuffle the argument into the correct register before calling the
 441  * thread function.  r4 is the thread argument, r5 is the pointer to
 442  * the thread function, and r6 points to the exit function.
 443  */
 444 extern void kernel_thread_helper(void);
 445 asm(    ".pushsection .text\n"
 446 "       .align\n"
 447 "       .type   kernel_thread_helper, #function\n"
 448 "kernel_thread_helper:\n"
 449 #ifdef CONFIG_TRACE_IRQFLAGS
 450 "       bl      trace_hardirqs_on\n"
 451 #endif
 452 "       msr     cpsr_c, r7\n"
 453 "       mov     r0, r4\n"
 454 "       mov     lr, r6\n"
 455 "       mov     pc, r5\n"
 456 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 457 "       .popsection");
 458
 459 #ifdef CONFIG_ARM_UNWIND
 460 extern void kernel_thread_exit(long code);
 461 asm(    ".pushsection .text\n"
 462 "       .align\n"
 463 "       .type   kernel_thread_exit, #function\n"
 464 "kernel_thread_exit:\n"
 465 "       .fnstart\n"
 466 "       .cantunwind\n"
 467 "       bl      do_exit\n"
 468 "       nop\n"
 469 "       .fnend\n"
 470 "       .size   kernel_thread_exit, . - kernel_thread_exit\n"
 471 "       .popsection");
 472 #else
 473 #define kernel_thread_exit      do_exit
 474 #endif
 475
 476 /*
 477  * Create a kernel thread.
 478  */
 479 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 480 {
 481         struct pt_regs regs;
 482
 483         memset(&regs, 0, sizeof(regs));
 484
 485         regs.ARM_r4 = (unsigned long)arg;
 486         regs.ARM_r5 = (unsigned long)fn;
 487         regs.ARM_r6 = (unsigned long)kernel_thread_exit;
 488         regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
 489         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 490         regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT;
 491
 492         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 493 }
 494 EXPORT_SYMBOL(kernel_thread);
 495
 496 unsigned long get_wchan(struct task_struct *p)
 497 {
 498         struct stackframe frame;
 499         int count = 0;
 500         if (!p || p == current || p->state == TASK_RUNNING)
 501                 return 0;
 502
 503         frame.fp = thread_saved_fp(p);
 504         frame.sp = thread_saved_sp(p);
 505         frame.lr = 0;                   /* recovered from the stack */
 506         frame.pc = thread_saved_pc(p);
 507         do {
 508                 int ret = unwind_frame(&frame);
 509                 if (ret < 0)
 510                         return 0;
 511                 if (!in_sched_functions(frame.pc))
 512                         return frame.pc;
 513         } while (count ++ < 16);
 514         return 0;
 515 }
 516
 517 unsigned long arch_randomize_brk(struct mm_struct *mm)
 518 {
 519         unsigned long range_end = mm->brk + 0x02000000;
 520         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 521 }
 522
 523 #ifdef CONFIG_MMU
 524 /*
 525  * The vectors page is always readable from user space for the
 526  * atomic helpers and the signal restart code.  Let's declare a mapping
 527  * for it so it is visible through ptrace and /proc/<pid>/mem.
 528  */
 529
 530 int vectors_user_mapping(void)
 531 {
 532         struct mm_struct *mm = current->mm;
 533         return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
 534                                        VM_READ | VM_EXEC |
 535                                        VM_MAYREAD | VM_MAYEXEC |
 536                                        VM_ALWAYSDUMP | VM_RESERVED,
 537                                        NULL);
 538 }
 539
 540 const char *arch_vma_name(struct vm_area_struct *vma)
 541 {
 542         return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;
 543 }
 544 #endif