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
 140 /*
 141  * This is our default idle handler.  We need to disable
 142  * interrupts here to ensure we don't miss a wakeup call.
 143  */
 144 static void default_idle(void)
 145 {
 146         if (!need_resched())
 147                 arch_idle();
 148         local_irq_enable();
 149 }
 150
 151 void (*pm_idle)(void) = default_idle;
 152 EXPORT_SYMBOL(pm_idle);
 153
 154 /*
 155  * The idle thread, has rather strange semantics for calling pm_idle,
 156  * but this is what x86 does and we need to do the same, so that
 157  * things like cpuidle get called in the same way.  The only difference
 158  * is that we always respect 'hlt_counter' to prevent low power idle.
 159  */
 160 void cpu_idle(void)
 161 {
 162         local_fiq_enable();
 163
 164         /* endless idle loop with no priority at all */
 165         while (1) {
 166                 tick_nohz_stop_sched_tick(1);
 167                 leds_event(led_idle_start);
 168                 while (!need_resched()) {
 169 #ifdef CONFIG_HOTPLUG_CPU
 170                         if (cpu_is_offline(smp_processor_id()))
 171                                 cpu_die();
 172 #endif
 173
 174                         local_irq_disable();
 175                         if (hlt_counter) {
 176                                 local_irq_enable();
 177                                 cpu_relax();
 178                         } else {
 179                                 stop_critical_timings();
 180                                 pm_idle();
 181                                 start_critical_timings();
 182                                 /*
 183                                  * This will eventually be removed - pm_idle
 184                                  * functions should always return with IRQs
 185                                  * enabled.
 186                                  */
 187                                 WARN_ON(irqs_disabled());
 188                                 local_irq_enable();
 189                         }
 190                 }
 191                 leds_event(led_idle_end);
 192                 tick_nohz_restart_sched_tick();
 193                 preempt_enable_no_resched();
 194                 schedule();
 195                 preempt_disable();
 196         }
 197 }
 198
 199 static char reboot_mode = 'h';
 200
 201 int __init reboot_setup(char *str)
 202 {
 203         reboot_mode = str[0];
 204         return 1;
 205 }
 206
 207 __setup("reboot=", reboot_setup);
 208
 209 void machine_shutdown(void)
 210 {
 211 #ifdef CONFIG_SMP
 212         smp_send_stop();
 213 #endif
 214 }
 215
 216 void machine_halt(void)
 217 {
 218         machine_shutdown();
 219         while (1);
 220 }
 221
 222 void machine_power_off(void)
 223 {
 224         machine_shutdown();
 225         if (pm_power_off)
 226                 pm_power_off();
 227 }
 228
 229 void machine_restart(char *cmd)
 230 {
 231         machine_shutdown();
 232         arm_pm_restart(reboot_mode, cmd);
 233 }
 234
 235 void __show_regs(struct pt_regs *regs)
 236 {
 237         unsigned long flags;
 238         char buf[64];
 239
 240         printk("CPU: %d    %s  (%s %.*s)\n",
 241                 raw_smp_processor_id(), print_tainted(),
 242                 init_utsname()->release,
 243                 (int)strcspn(init_utsname()->version, " "),
 244                 init_utsname()->version);
 245         print_symbol("PC is at %s\n", instruction_pointer(regs));
 246         print_symbol("LR is at %s\n", regs->ARM_lr);
 247         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 248                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 249                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 250                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 251         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 252                 regs->ARM_r10, regs->ARM_r9,
 253                 regs->ARM_r8);
 254         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 255                 regs->ARM_r7, regs->ARM_r6,
 256                 regs->ARM_r5, regs->ARM_r4);
 257         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 258                 regs->ARM_r3, regs->ARM_r2,
 259                 regs->ARM_r1, regs->ARM_r0);
 260
 261         flags = regs->ARM_cpsr;
 262         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 263         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 264         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 265         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 266         buf[4] = '\0';
 267
 268         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 269                 buf, interrupts_enabled(regs) ? "n" : "ff",
 270                 fast_interrupts_enabled(regs) ? "n" : "ff",
 271                 processor_modes[processor_mode(regs)],
 272                 isa_modes[isa_mode(regs)],
 273                 get_fs() == get_ds() ? "kernel" : "user");
 274 #ifdef CONFIG_CPU_CP15
 275         {
 276                 unsigned int ctrl;
 277
 278                 buf[0] = '\0';
 279 #ifdef CONFIG_CPU_CP15_MMU
 280                 {
 281                         unsigned int transbase, dac;
 282                         asm("mrc p15, 0, %0, c2, c0\n\t"
 283                             "mrc p15, 0, %1, c3, c0\n"
 284                             : "=r" (transbase), "=r" (dac));
 285                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 286                                 transbase, dac);
 287                 }
 288 #endif
 289                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 290
 291                 printk("Control: %08x%s\n", ctrl, buf);
 292         }
 293 #endif
 294 }
 295
 296 void show_regs(struct pt_regs * regs)
 297 {
 298         printk("\n");
 299         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 300         __show_regs(regs);
 301         __backtrace();
 302 }
 303
 304 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 305
 306 EXPORT_SYMBOL_GPL(thread_notify_head);
 307
 308 /*
 309  * Free current thread data structures etc..
 310  */
 311 void exit_thread(void)
 312 {
 313         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 314 }
 315
 316 void flush_thread(void)
 317 {
 318         struct thread_info *thread = current_thread_info();
 319         struct task_struct *tsk = current;
 320
 321         flush_ptrace_hw_breakpoint(tsk);
 322
 323         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 324         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 325         memset(&thread->fpstate, 0, sizeof(union fp_state));
 326
 327         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 328 }
 329
 330 void release_thread(struct task_struct *dead_task)
 331 {
 332 }
 333
 334 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 335
 336 int
 337 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 338             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 339 {
 340         struct thread_info *thread = task_thread_info(p);
 341         struct pt_regs *childregs = task_pt_regs(p);
 342
 343         *childregs = *regs;
 344         childregs->ARM_r0 = 0;
 345         childregs->ARM_sp = stack_start;
 346
 347         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 348         thread->cpu_context.sp = (unsigned long)childregs;
 349         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 350
 351         clear_ptrace_hw_breakpoint(p);
 352
 353         if (clone_flags & CLONE_SETTLS)
 354                 thread->tp_value = regs->ARM_r3;
 355
 356         return 0;
 357 }
 358
 359 /*
 360  * Fill in the task's elfregs structure for a core dump.
 361  */
 362 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 363 {
 364         elf_core_copy_regs(elfregs, task_pt_regs(t));
 365         return 1;
 366 }
 367
 368 /*
 369  * fill in the fpe structure for a core dump...
 370  */
 371 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 372 {
 373         struct thread_info *thread = current_thread_info();
 374         int used_math = thread->used_cp[1] | thread->used_cp[2];
 375
 376         if (used_math)
 377                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 378
 379         return used_math != 0;
 380 }
 381 EXPORT_SYMBOL(dump_fpu);
 382
 383 /*
 384  * Shuffle the argument into the correct register before calling the
 385  * thread function.  r4 is the thread argument, r5 is the pointer to
 386  * the thread function, and r6 points to the exit function.
 387  */
 388 extern void kernel_thread_helper(void);
 389 asm(    ".pushsection .text\n"
 390 "       .align\n"
 391 "       .type   kernel_thread_helper, #function\n"
 392 "kernel_thread_helper:\n"
 393 #ifdef CONFIG_TRACE_IRQFLAGS
 394 "       bl      trace_hardirqs_on\n"
 395 #endif
 396 "       msr     cpsr_c, r7\n"
 397 "       mov     r0, r4\n"
 398 "       mov     lr, r6\n"
 399 "       mov     pc, r5\n"
 400 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 401 "       .popsection");
 402
 403 #ifdef CONFIG_ARM_UNWIND
 404 extern void kernel_thread_exit(long code);
 405 asm(    ".pushsection .text\n"
 406 "       .align\n"
 407 "       .type   kernel_thread_exit, #function\n"
 408 "kernel_thread_exit:\n"
 409 "       .fnstart\n"
 410 "       .cantunwind\n"
 411 "       bl      do_exit\n"
 412 "       nop\n"
 413 "       .fnend\n"
 414 "       .size   kernel_thread_exit, . - kernel_thread_exit\n"
 415 "       .popsection");
 416 #else
 417 #define kernel_thread_exit      do_exit
 418 #endif
 419
 420 /*
 421  * Create a kernel thread.
 422  */
 423 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 424 {
 425         struct pt_regs regs;
 426
 427         memset(&regs, 0, sizeof(regs));
 428
 429         regs.ARM_r4 = (unsigned long)arg;
 430         regs.ARM_r5 = (unsigned long)fn;
 431         regs.ARM_r6 = (unsigned long)kernel_thread_exit;
 432         regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
 433         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 434         regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT;
 435
 436         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 437 }
 438 EXPORT_SYMBOL(kernel_thread);
 439
 440 unsigned long get_wchan(struct task_struct *p)
 441 {
 442         struct stackframe frame;
 443         int count = 0;
 444         if (!p || p == current || p->state == TASK_RUNNING)
 445                 return 0;
 446
 447         frame.fp = thread_saved_fp(p);
 448         frame.sp = thread_saved_sp(p);
 449         frame.lr = 0;                   /* recovered from the stack */
 450         frame.pc = thread_saved_pc(p);
 451         do {
 452                 int ret = unwind_frame(&frame);
 453                 if (ret < 0)
 454                         return 0;
 455                 if (!in_sched_functions(frame.pc))
 456                         return frame.pc;
 457         } while (count ++ < 16);
 458         return 0;
 459 }
 460
 461 unsigned long arch_randomize_brk(struct mm_struct *mm)
 462 {
 463         unsigned long range_end = mm->brk + 0x02000000;
 464         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 465 }