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