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/system.h>
  39 #include <asm/thread_notify.h>
  40 #include <asm/stacktrace.h>
  41 #include <asm/mach/time.h>
  42
  43 #ifdef CONFIG_CC_STACKPROTECTOR
  44 #include <linux/stackprotector.h>
  45 unsigned long __stack_chk_guard __read_mostly;
  46 EXPORT_SYMBOL(__stack_chk_guard);
  47 #endif
  48
  49 static const char *processor_modes[] = {
  50   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  51   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  52   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
  53   "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  54 };
  55
  56 static const char *isa_modes[] = {
  57   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  58 };
  59
  60 extern void setup_mm_for_reboot(void);
  61
  62 static volatile int hlt_counter;
  63
  64 #include <mach/system.h>
  65
  66 void disable_hlt(void)
  67 {
  68         hlt_counter++;
  69 }
  70
  71 EXPORT_SYMBOL(disable_hlt);
  72
  73 void enable_hlt(void)
  74 {
  75         hlt_counter--;
  76 }
  77
  78 EXPORT_SYMBOL(enable_hlt);
  79
  80 static int __init nohlt_setup(char *__unused)
  81 {
  82         hlt_counter = 1;
  83         return 1;
  84 }
  85
  86 static int __init hlt_setup(char *__unused)
  87 {
  88         hlt_counter = 0;
  89         return 1;
  90 }
  91
  92 __setup("nohlt", nohlt_setup);
  93 __setup("hlt", hlt_setup);
  94
  95 extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
  96 typedef void (*phys_reset_t)(unsigned long);
  97
  98 /*
  99  * A temporary stack to use for CPU reset. This is static so that we
 100  * don't clobber it with the identity mapping. When running with this
 101  * stack, any references to the current task *will not work* so you
 102  * should really do as little as possible before jumping to your reset
 103  * code.
 104  */
 105 static u64 soft_restart_stack[16];
 106
 107 static void __soft_restart(void *addr)
 108 {
 109         phys_reset_t phys_reset;
 110
 111         /* Take out a flat memory mapping. */
 112         setup_mm_for_reboot();
 113
 114         /* Clean and invalidate caches */
 115         flush_cache_all();
 116
 117         /* Turn off caching */
 118         cpu_proc_fin();
 119
 120         /* Push out any further dirty data, and ensure cache is empty */
 121         flush_cache_all();
 122
 123         /* Switch to the identity mapping. */
 124         phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
 125         phys_reset((unsigned long)addr);
 126
 127         /* Should never get here. */
 128         BUG();
 129 }
 130
 131 void soft_restart(unsigned long addr)
 132 {
 133         u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
 134
 135         /* Disable interrupts first */
 136         local_irq_disable();
 137         local_fiq_disable();
 138
 139         /* Disable the L2 if we're the last man standing. */
 140         if (num_online_cpus() == 1)
 141                 outer_disable();
 142
 143         /* Change to the new stack and continue with the reset. */
 144         call_with_stack(__soft_restart, (void *)addr, (void *)stack);
 145
 146         /* Should never get here. */
 147         BUG();
 148 }
 149
 150 static void null_restart(char mode, const char *cmd)
 151 {
 152 }
 153
 154 /*
 155  * Function pointers to optional machine specific functions
 156  */
 157 void (*pm_power_off)(void);
 158 EXPORT_SYMBOL(pm_power_off);
 159
 160 void (*arm_pm_restart)(char str, const char *cmd) = null_restart;
 161 EXPORT_SYMBOL_GPL(arm_pm_restart);
 162
 163 static void do_nothing(void *unused)
 164 {
 165 }
 166
 167 /*
 168  * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
 169  * pm_idle and update to new pm_idle value. Required while changing pm_idle
 170  * handler on SMP systems.
 171  *
 172  * Caller must have changed pm_idle to the new value before the call. Old
 173  * pm_idle value will not be used by any CPU after the return of this function.
 174  */
 175 void cpu_idle_wait(void)
 176 {
 177         smp_mb();
 178         /* kick all the CPUs so that they exit out of pm_idle */
 179         smp_call_function(do_nothing, NULL, 1);
 180 }
 181 EXPORT_SYMBOL_GPL(cpu_idle_wait);
 182
 183 /*
 184  * This is our default idle handler.  We need to disable
 185  * interrupts here to ensure we don't miss a wakeup call.
 186  */
 187 static void default_idle(void)
 188 {
 189         if (!need_resched())
 190                 arch_idle();
 191         local_irq_enable();
 192 }
 193
 194 void (*pm_idle)(void) = default_idle;
 195 EXPORT_SYMBOL(pm_idle);
 196
 197 /*
 198  * The idle thread, has rather strange semantics for calling pm_idle,
 199  * but this is what x86 does and we need to do the same, so that
 200  * things like cpuidle get called in the same way.  The only difference
 201  * is that we always respect 'hlt_counter' to prevent low power idle.
 202  */
 203 void cpu_idle(void)
 204 {
 205         local_fiq_enable();
 206
 207         /* endless idle loop with no priority at all */
 208         while (1) {
 209                 tick_nohz_idle_enter();
 210                 rcu_idle_enter();
 211                 leds_event(led_idle_start);
 212                 while (!need_resched()) {
 213 #ifdef CONFIG_HOTPLUG_CPU
 214                         if (cpu_is_offline(smp_processor_id()))
 215                                 cpu_die();
 216 #endif
 217
 218                         local_irq_disable();
 219 #ifdef CONFIG_PL310_ERRATA_769419
 220                         wmb();
 221 #endif
 222                         if (hlt_counter) {
 223                                 local_irq_enable();
 224                                 cpu_relax();
 225                         } else {
 226                                 stop_critical_timings();
 227                                 if (cpuidle_idle_call())
 228                                         pm_idle();
 229                                 start_critical_timings();
 230                                 /*
 231                                  * This will eventually be removed - pm_idle
 232                                  * functions should always return with IRQs
 233                                  * enabled.
 234                                  */
 235                                 WARN_ON(irqs_disabled());
 236                                 local_irq_enable();
 237                         }
 238                 }
 239                 leds_event(led_idle_end);
 240                 rcu_idle_exit();
 241                 tick_nohz_idle_exit();
 242                 preempt_enable_no_resched();
 243                 schedule();
 244                 preempt_disable();
 245         }
 246 }
 247
 248 static char reboot_mode = 'h';
 249
 250 int __init reboot_setup(char *str)
 251 {
 252         reboot_mode = str[0];
 253         return 1;
 254 }
 255
 256 __setup("reboot=", reboot_setup);
 257
 258 void machine_shutdown(void)
 259 {
 260 #ifdef CONFIG_SMP
 261         smp_send_stop();
 262 #endif
 263 }
 264
 265 void machine_halt(void)
 266 {
 267         machine_shutdown();
 268         while (1);
 269 }
 270
 271 void machine_power_off(void)
 272 {
 273         machine_shutdown();
 274         if (pm_power_off)
 275                 pm_power_off();
 276 }
 277
 278 void machine_restart(char *cmd)
 279 {
 280         machine_shutdown();
 281
 282         arm_pm_restart(reboot_mode, cmd);
 283
 284         /* Give a grace period for failure to restart of 1s */
 285         mdelay(1000);
 286
 287         /* Whoops - the platform was unable to reboot. Tell the user! */
 288         printk("Reboot failed -- System halted\n");
 289         while (1);
 290 }
 291
 292 void __show_regs(struct pt_regs *regs)
 293 {
 294         unsigned long flags;
 295         char buf[64];
 296
 297         printk("CPU: %d    %s  (%s %.*s)\n",
 298                 raw_smp_processor_id(), print_tainted(),
 299                 init_utsname()->release,
 300                 (int)strcspn(init_utsname()->version, " "),
 301                 init_utsname()->version);
 302         print_symbol("PC is at %s\n", instruction_pointer(regs));
 303         print_symbol("LR is at %s\n", regs->ARM_lr);
 304         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 305                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 306                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 307                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 308         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 309                 regs->ARM_r10, regs->ARM_r9,
 310                 regs->ARM_r8);
 311         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 312                 regs->ARM_r7, regs->ARM_r6,
 313                 regs->ARM_r5, regs->ARM_r4);
 314         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 315                 regs->ARM_r3, regs->ARM_r2,
 316                 regs->ARM_r1, regs->ARM_r0);
 317
 318         flags = regs->ARM_cpsr;
 319         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 320         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 321         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 322         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 323         buf[4] = '\0';
 324
 325         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 326                 buf, interrupts_enabled(regs) ? "n" : "ff",
 327                 fast_interrupts_enabled(regs) ? "n" : "ff",
 328                 processor_modes[processor_mode(regs)],
 329                 isa_modes[isa_mode(regs)],
 330                 get_fs() == get_ds() ? "kernel" : "user");
 331 #ifdef CONFIG_CPU_CP15
 332         {
 333                 unsigned int ctrl;
 334
 335                 buf[0] = '\0';
 336 #ifdef CONFIG_CPU_CP15_MMU
 337                 {
 338                         unsigned int transbase, dac;
 339                         asm("mrc p15, 0, %0, c2, c0\n\t"
 340                             "mrc p15, 0, %1, c3, c0\n"
 341                             : "=r" (transbase), "=r" (dac));
 342                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 343                                 transbase, dac);
 344                 }
 345 #endif
 346                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 347
 348                 printk("Control: %08x%s\n", ctrl, buf);
 349         }
 350 #endif
 351 }
 352
 353 void show_regs(struct pt_regs * regs)
 354 {
 355         printk("\n");
 356         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 357         __show_regs(regs);
 358         dump_stack();
 359 }
 360
 361 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 362
 363 EXPORT_SYMBOL_GPL(thread_notify_head);
 364
 365 /*
 366  * Free current thread data structures etc..
 367  */
 368 void exit_thread(void)
 369 {
 370         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 371 }
 372
 373 void flush_thread(void)
 374 {
 375         struct thread_info *thread = current_thread_info();
 376         struct task_struct *tsk = current;
 377
 378         flush_ptrace_hw_breakpoint(tsk);
 379
 380         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 381         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 382         memset(&thread->fpstate, 0, sizeof(union fp_state));
 383
 384         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 385 }
 386
 387 void release_thread(struct task_struct *dead_task)
 388 {
 389 }
 390
 391 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 392
 393 int
 394 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 395             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 396 {
 397         struct thread_info *thread = task_thread_info(p);
 398         struct pt_regs *childregs = task_pt_regs(p);
 399
 400         *childregs = *regs;
 401         childregs->ARM_r0 = 0;
 402         childregs->ARM_sp = stack_start;
 403
 404         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 405         thread->cpu_context.sp = (unsigned long)childregs;
 406         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 407
 408         clear_ptrace_hw_breakpoint(p);
 409
 410         if (clone_flags & CLONE_SETTLS)
 411                 thread->tp_value = regs->ARM_r3;
 412
 413         thread_notify(THREAD_NOTIFY_COPY, thread);
 414
 415         return 0;
 416 }
 417
 418 /*
 419  * Fill in the task's elfregs structure for a core dump.
 420  */
 421 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 422 {
 423         elf_core_copy_regs(elfregs, task_pt_regs(t));
 424         return 1;
 425 }
 426
 427 /*
 428  * fill in the fpe structure for a core dump...
 429  */
 430 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 431 {
 432         struct thread_info *thread = current_thread_info();
 433         int used_math = thread->used_cp[1] | thread->used_cp[2];
 434
 435         if (used_math)
 436                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 437
 438         return used_math != 0;
 439 }
 440 EXPORT_SYMBOL(dump_fpu);
 441
 442 /*
 443  * Shuffle the argument into the correct register before calling the
 444  * thread function.  r4 is the thread argument, r5 is the pointer to
 445  * the thread function, and r6 points to the exit function.
 446  */
 447 extern void kernel_thread_helper(void);
 448 asm(    ".pushsection .text\n"
 449 "       .align\n"
 450 "       .type   kernel_thread_helper, #function\n"
 451 "kernel_thread_helper:\n"
 452 #ifdef CONFIG_TRACE_IRQFLAGS
 453 "       bl      trace_hardirqs_on\n"
 454 #endif
 455 "       msr     cpsr_c, r7\n"
 456 "       mov     r0, r4\n"
 457 "       mov     lr, r6\n"
 458 "       mov     pc, r5\n"
 459 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 460 "       .popsection");
 461
 462 #ifdef CONFIG_ARM_UNWIND
 463 extern void kernel_thread_exit(long code);
 464 asm(    ".pushsection .text\n"
 465 "       .align\n"
 466 "       .type   kernel_thread_exit, #function\n"
 467 "kernel_thread_exit:\n"
 468 "       .fnstart\n"
 469 "       .cantunwind\n"
 470 "       bl      do_exit\n"
 471 "       nop\n"
 472 "       .fnend\n"
 473 "       .size   kernel_thread_exit, . - kernel_thread_exit\n"
 474 "       .popsection");
 475 #else
 476 #define kernel_thread_exit      do_exit
 477 #endif
 478
 479 /*
 480  * Create a kernel thread.
 481  */
 482 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 483 {
 484         struct pt_regs regs;
 485
 486         memset(&regs, 0, sizeof(regs));
 487
 488         regs.ARM_r4 = (unsigned long)arg;
 489         regs.ARM_r5 = (unsigned long)fn;
 490         regs.ARM_r6 = (unsigned long)kernel_thread_exit;
 491         regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
 492         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 493         regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT;
 494
 495         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 496 }
 497 EXPORT_SYMBOL(kernel_thread);
 498
 499 unsigned long get_wchan(struct task_struct *p)
 500 {
 501         struct stackframe frame;
 502         int count = 0;
 503         if (!p || p == current || p->state == TASK_RUNNING)
 504                 return 0;
 505
 506         frame.fp = thread_saved_fp(p);
 507         frame.sp = thread_saved_sp(p);
 508         frame.lr = 0;                   /* recovered from the stack */
 509         frame.pc = thread_saved_pc(p);
 510         do {
 511                 int ret = unwind_frame(&frame);
 512                 if (ret < 0)
 513                         return 0;
 514                 if (!in_sched_functions(frame.pc))
 515                         return frame.pc;
 516         } while (count ++ < 16);
 517         return 0;
 518 }
 519
 520 unsigned long arch_randomize_brk(struct mm_struct *mm)
 521 {
 522         unsigned long range_end = mm->brk + 0x02000000;
 523         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 524 }
 525
 526 #ifdef CONFIG_MMU
 527 /*
 528  * The vectors page is always readable from user space for the
 529  * atomic helpers and the signal restart code.  Let's declare a mapping
 530  * for it so it is visible through ptrace and /proc/<pid>/mem.
 531  */
 532
 533 int vectors_user_mapping(void)
 534 {
 535         struct mm_struct *mm = current->mm;
 536         return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
 537                                        VM_READ | VM_EXEC |
 538                                        VM_MAYREAD | VM_MAYEXEC |
 539                                        VM_ALWAYSDUMP | VM_RESERVED,
 540                                        NULL);
 541 }
 542
 543 const char *arch_vma_name(struct vm_area_struct *vma)
 544 {
 545         return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;
 546 }
 547 #endif