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