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/module.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
  34 #include <asm/cacheflush.h>
  35 #include <asm/leds.h>
  36 #include <asm/processor.h>
  37 #include <asm/system.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(char mode);
  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 void arm_machine_restart(char mode, const char *cmd)
  95 {
  96         /* Disable interrupts first */
  97         local_irq_disable();
  98         local_fiq_disable();
  99
 100         /*
 101          * Tell the mm system that we are going to reboot -
 102          * we may need it to insert some 1:1 mappings so that
 103          * soft boot works.
 104          */
 105         setup_mm_for_reboot(mode);
 106
 107         /* Clean and invalidate caches */
 108         flush_cache_all();
 109
 110         /* Turn off caching */
 111         cpu_proc_fin();
 112
 113         /* Push out any further dirty data, and ensure cache is empty */
 114         flush_cache_all();
 115
 116         /*
 117          * Now call the architecture specific reboot code.
 118          */
 119         arch_reset(mode, cmd);
 120
 121         /*
 122          * Whoops - the architecture was unable to reboot.
 123          * Tell the user!
 124          */
 125         mdelay(1000);
 126         printk("Reboot failed -- System halted\n");
 127         while (1);
 128 }
 129
 130 /*
 131  * Function pointers to optional machine specific functions
 132  */
 133 void (*pm_power_off)(void);
 134 EXPORT_SYMBOL(pm_power_off);
 135
 136 void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart;
 137 EXPORT_SYMBOL_GPL(arm_pm_restart);
 138
 139 static void do_nothing(void *unused)
 140 {
 141 }
 142
 143 /*
 144  * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
 145  * pm_idle and update to new pm_idle value. Required while changing pm_idle
 146  * handler on SMP systems.
 147  *
 148  * Caller must have changed pm_idle to the new value before the call. Old
 149  * pm_idle value will not be used by any CPU after the return of this function.
 150  */
 151 void cpu_idle_wait(void)
 152 {
 153         smp_mb();
 154         /* kick all the CPUs so that they exit out of pm_idle */
 155         smp_call_function(do_nothing, NULL, 1);
 156 }
 157 EXPORT_SYMBOL_GPL(cpu_idle_wait);
 158
 159 /*
 160  * This is our default idle handler.  We need to disable
 161  * interrupts here to ensure we don't miss a wakeup call.
 162  */
 163 static void default_idle(void)
 164 {
 165         if (!need_resched())
 166                 arch_idle();
 167         local_irq_enable();
 168 }
 169
 170 void (*pm_idle)(void) = default_idle;
 171 EXPORT_SYMBOL(pm_idle);
 172
 173 /*
 174  * The idle thread, has rather strange semantics for calling pm_idle,
 175  * but this is what x86 does and we need to do the same, so that
 176  * things like cpuidle get called in the same way.  The only difference
 177  * is that we always respect 'hlt_counter' to prevent low power idle.
 178  */
 179 void cpu_idle(void)
 180 {
 181         local_fiq_enable();
 182
 183         /* endless idle loop with no priority at all */
 184         while (1) {
 185                 tick_nohz_stop_sched_tick(1);
 186                 leds_event(led_idle_start);
 187                 while (!need_resched()) {
 188 #ifdef CONFIG_HOTPLUG_CPU
 189                         if (cpu_is_offline(smp_processor_id()))
 190                                 cpu_die();
 191 #endif
 192
 193                         local_irq_disable();
 194                         if (hlt_counter) {
 195                                 local_irq_enable();
 196                                 cpu_relax();
 197                         } else {
 198                                 stop_critical_timings();
 199                                 pm_idle();
 200                                 start_critical_timings();
 201                                 /*
 202                                  * This will eventually be removed - pm_idle
 203                                  * functions should always return with IRQs
 204                                  * enabled.
 205                                  */
 206                                 WARN_ON(irqs_disabled());
 207                                 local_irq_enable();
 208                         }
 209                 }
 210                 leds_event(led_idle_end);
 211                 tick_nohz_restart_sched_tick();
 212                 preempt_enable_no_resched();
 213                 schedule();
 214                 preempt_disable();
 215         }
 216 }
 217
 218 static char reboot_mode = 'h';
 219
 220 int __init reboot_setup(char *str)
 221 {
 222         reboot_mode = str[0];
 223         return 1;
 224 }
 225
 226 __setup("reboot=", reboot_setup);
 227
 228 void machine_shutdown(void)
 229 {
 230 #ifdef CONFIG_SMP
 231         smp_send_stop();
 232 #endif
 233 }
 234
 235 void machine_halt(void)
 236 {
 237         machine_shutdown();
 238         while (1);
 239 }
 240
 241 void machine_power_off(void)
 242 {
 243         machine_shutdown();
 244         if (pm_power_off)
 245                 pm_power_off();
 246 }
 247
 248 void machine_restart(char *cmd)
 249 {
 250         machine_shutdown();
 251         arm_pm_restart(reboot_mode, cmd);
 252 }
 253
 254 void __show_regs(struct pt_regs *regs)
 255 {
 256         unsigned long flags;
 257         char buf[64];
 258
 259         printk("CPU: %d    %s  (%s %.*s)\n",
 260                 raw_smp_processor_id(), print_tainted(),
 261                 init_utsname()->release,
 262                 (int)strcspn(init_utsname()->version, " "),
 263                 init_utsname()->version);
 264         print_symbol("PC is at %s\n", instruction_pointer(regs));
 265         print_symbol("LR is at %s\n", regs->ARM_lr);
 266         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 267                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 268                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 269                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 270         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 271                 regs->ARM_r10, regs->ARM_r9,
 272                 regs->ARM_r8);
 273         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 274                 regs->ARM_r7, regs->ARM_r6,
 275                 regs->ARM_r5, regs->ARM_r4);
 276         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 277                 regs->ARM_r3, regs->ARM_r2,
 278                 regs->ARM_r1, regs->ARM_r0);
 279
 280         flags = regs->ARM_cpsr;
 281         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 282         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 283         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 284         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 285         buf[4] = '\0';
 286
 287         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 288                 buf, interrupts_enabled(regs) ? "n" : "ff",
 289                 fast_interrupts_enabled(regs) ? "n" : "ff",
 290                 processor_modes[processor_mode(regs)],
 291                 isa_modes[isa_mode(regs)],
 292                 get_fs() == get_ds() ? "kernel" : "user");
 293 #ifdef CONFIG_CPU_CP15
 294         {
 295                 unsigned int ctrl;
 296
 297                 buf[0] = '\0';
 298 #ifdef CONFIG_CPU_CP15_MMU
 299                 {
 300                         unsigned int transbase, dac;
 301                         asm("mrc p15, 0, %0, c2, c0\n\t"
 302                             "mrc p15, 0, %1, c3, c0\n"
 303                             : "=r" (transbase), "=r" (dac));
 304                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 305                                 transbase, dac);
 306                 }
 307 #endif
 308                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 309
 310                 printk("Control: %08x%s\n", ctrl, buf);
 311         }
 312 #endif
 313 }
 314
 315 void show_regs(struct pt_regs * regs)
 316 {
 317         printk("\n");
 318         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 319         __show_regs(regs);
 320         __backtrace();
 321 }
 322
 323 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 324
 325 EXPORT_SYMBOL_GPL(thread_notify_head);
 326
 327 /*
 328  * Free current thread data structures etc..
 329  */
 330 void exit_thread(void)
 331 {
 332         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 333 }
 334
 335 void flush_thread(void)
 336 {
 337         struct thread_info *thread = current_thread_info();
 338         struct task_struct *tsk = current;
 339
 340         flush_ptrace_hw_breakpoint(tsk);
 341
 342         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 343         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 344         memset(&thread->fpstate, 0, sizeof(union fp_state));
 345
 346         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 347 }
 348
 349 void release_thread(struct task_struct *dead_task)
 350 {
 351 }
 352
 353 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 354
 355 int
 356 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 357             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 358 {
 359         struct thread_info *thread = task_thread_info(p);
 360         struct pt_regs *childregs = task_pt_regs(p);
 361
 362         *childregs = *regs;
 363         childregs->ARM_r0 = 0;
 364         childregs->ARM_sp = stack_start;
 365
 366         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 367         thread->cpu_context.sp = (unsigned long)childregs;
 368         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 369
 370         clear_ptrace_hw_breakpoint(p);
 371
 372         if (clone_flags & CLONE_SETTLS)
 373                 thread->tp_value = regs->ARM_r3;
 374
 375         thread_notify(THREAD_NOTIFY_COPY, thread);
 376
 377         return 0;
 378 }
 379
 380 /*
 381  * Fill in the task's elfregs structure for a core dump.
 382  */
 383 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 384 {
 385         elf_core_copy_regs(elfregs, task_pt_regs(t));
 386         return 1;
 387 }
 388
 389 /*
 390  * fill in the fpe structure for a core dump...
 391  */
 392 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 393 {
 394         struct thread_info *thread = current_thread_info();
 395         int used_math = thread->used_cp[1] | thread->used_cp[2];
 396
 397         if (used_math)
 398                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 399
 400         return used_math != 0;
 401 }
 402 EXPORT_SYMBOL(dump_fpu);
 403
 404 /*
 405  * Shuffle the argument into the correct register before calling the
 406  * thread function.  r4 is the thread argument, r5 is the pointer to
 407  * the thread function, and r6 points to the exit function.
 408  */
 409 extern void kernel_thread_helper(void);
 410 asm(    ".pushsection .text\n"
 411 "       .align\n"
 412 "       .type   kernel_thread_helper, #function\n"
 413 "kernel_thread_helper:\n"
 414 #ifdef CONFIG_TRACE_IRQFLAGS
 415 "       bl      trace_hardirqs_on\n"
 416 #endif
 417 "       msr     cpsr_c, r7\n"
 418 "       mov     r0, r4\n"
 419 "       mov     lr, r6\n"
 420 "       mov     pc, r5\n"
 421 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 422 "       .popsection");
 423
 424 #ifdef CONFIG_ARM_UNWIND
 425 extern void kernel_thread_exit(long code);
 426 asm(    ".pushsection .text\n"
 427 "       .align\n"
 428 "       .type   kernel_thread_exit, #function\n"
 429 "kernel_thread_exit:\n"
 430 "       .fnstart\n"
 431 "       .cantunwind\n"
 432 "       bl      do_exit\n"
 433 "       nop\n"
 434 "       .fnend\n"
 435 "       .size   kernel_thread_exit, . - kernel_thread_exit\n"
 436 "       .popsection");
 437 #else
 438 #define kernel_thread_exit      do_exit
 439 #endif
 440
 441 /*
 442  * Create a kernel thread.
 443  */
 444 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 445 {
 446         struct pt_regs regs;
 447
 448         memset(&regs, 0, sizeof(regs));
 449
 450         regs.ARM_r4 = (unsigned long)arg;
 451         regs.ARM_r5 = (unsigned long)fn;
 452         regs.ARM_r6 = (unsigned long)kernel_thread_exit;
 453         regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
 454         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 455         regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT;
 456
 457         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 458 }
 459 EXPORT_SYMBOL(kernel_thread);
 460
 461 unsigned long get_wchan(struct task_struct *p)
 462 {
 463         struct stackframe frame;
 464         int count = 0;
 465         if (!p || p == current || p->state == TASK_RUNNING)
 466                 return 0;
 467
 468         frame.fp = thread_saved_fp(p);
 469         frame.sp = thread_saved_sp(p);
 470         frame.lr = 0;                   /* recovered from the stack */
 471         frame.pc = thread_saved_pc(p);
 472         do {
 473                 int ret = unwind_frame(&frame);
 474                 if (ret < 0)
 475                         return 0;
 476                 if (!in_sched_functions(frame.pc))
 477                         return frame.pc;
 478         } while (count ++ < 16);
 479         return 0;
 480 }
 481
 482 unsigned long arch_randomize_brk(struct mm_struct *mm)
 483 {
 484         unsigned long range_end = mm->brk + 0x02000000;
 485         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 486 }
 487
 488 #ifdef CONFIG_MMU
 489 /*
 490  * The vectors page is always readable from user space for the
 491  * atomic helpers and the signal restart code.  Let's declare a mapping
 492  * for it so it is visible through ptrace and /proc/<pid>/mem.
 493  */
 494
 495 int vectors_user_mapping(void)
 496 {
 497         struct mm_struct *mm = current->mm;
 498         return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
 499                                        VM_READ | VM_EXEC |
 500                                        VM_MAYREAD | VM_MAYEXEC |
 501                                        VM_ALWAYSDUMP | VM_RESERVED,
 502                                        NULL);
 503 }
 504
 505 const char *arch_vma_name(struct vm_area_struct *vma)
 506 {
 507         return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;
 508 }
 509 #endif