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/slab.h>
  20 #include <linux/user.h>
  21 #include <linux/delay.h>
  22 #include <linux/reboot.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/kallsyms.h>
  25 #include <linux/init.h>
  26 #include <linux/cpu.h>
  27 #include <linux/elfcore.h>
  28 #include <linux/pm.h>
  29 #include <linux/tick.h>
  30 #include <linux/utsname.h>
  31 #include <linux/uaccess.h>
  32
  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         /*
  89          * Clean and disable cache, and turn off interrupts
  90          */
  91         cpu_proc_fin();
  92
  93         /*
  94          * Tell the mm system that we are going to reboot -
  95          * we may need it to insert some 1:1 mappings so that
  96          * soft boot works.
  97          */
  98         setup_mm_for_reboot(mode);
  99
 100         /*
 101          * Now call the architecture specific reboot code.
 102          */
 103         arch_reset(mode, cmd);
 104
 105         /*
 106          * Whoops - the architecture was unable to reboot.
 107          * Tell the user!
 108          */
 109         mdelay(1000);
 110         printk("Reboot failed -- System halted\n");
 111         while (1);
 112 }
 113
 114 /*
 115  * Function pointers to optional machine specific functions
 116  */
 117 void (*pm_power_off)(void);
 118 EXPORT_SYMBOL(pm_power_off);
 119
 120 void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart;
 121 EXPORT_SYMBOL_GPL(arm_pm_restart);
 122
 123
 124 /*
 125  * This is our default idle handler.  We need to disable
 126  * interrupts here to ensure we don't miss a wakeup call.
 127  */
 128 static void default_idle(void)
 129 {
 130         if (!need_resched())
 131                 arch_idle();
 132         local_irq_enable();
 133 }
 134
 135 void (*pm_idle)(void) = default_idle;
 136 EXPORT_SYMBOL(pm_idle);
 137
 138 /*
 139  * The idle thread, has rather strange semantics for calling pm_idle,
 140  * but this is what x86 does and we need to do the same, so that
 141  * things like cpuidle get called in the same way.  The only difference
 142  * is that we always respect 'hlt_counter' to prevent low power idle.
 143  */
 144 void cpu_idle(void)
 145 {
 146         local_fiq_enable();
 147
 148         /* endless idle loop with no priority at all */
 149         while (1) {
 150                 tick_nohz_stop_sched_tick(1);
 151                 leds_event(led_idle_start);
 152                 while (!need_resched()) {
 153 #ifdef CONFIG_HOTPLUG_CPU
 154                         if (cpu_is_offline(smp_processor_id()))
 155                                 cpu_die();
 156 #endif
 157
 158                         local_irq_disable();
 159                         if (hlt_counter) {
 160                                 local_irq_enable();
 161                                 cpu_relax();
 162                         } else {
 163                                 stop_critical_timings();
 164                                 pm_idle();
 165                                 start_critical_timings();
 166                                 /*
 167                                  * This will eventually be removed - pm_idle
 168                                  * functions should always return with IRQs
 169                                  * enabled.
 170                                  */
 171                                 WARN_ON(irqs_disabled());
 172                                 local_irq_enable();
 173                         }
 174                 }
 175                 leds_event(led_idle_end);
 176                 tick_nohz_restart_sched_tick();
 177                 preempt_enable_no_resched();
 178                 schedule();
 179                 preempt_disable();
 180         }
 181 }
 182
 183 static char reboot_mode = 'h';
 184
 185 int __init reboot_setup(char *str)
 186 {
 187         reboot_mode = str[0];
 188         return 1;
 189 }
 190
 191 __setup("reboot=", reboot_setup);
 192
 193 void machine_halt(void)
 194 {
 195 }
 196
 197
 198 void machine_power_off(void)
 199 {
 200         if (pm_power_off)
 201                 pm_power_off();
 202 }
 203
 204 void machine_restart(char *cmd)
 205 {
 206         arm_pm_restart(reboot_mode, cmd);
 207 }
 208
 209 void __show_regs(struct pt_regs *regs)
 210 {
 211         unsigned long flags;
 212         char buf[64];
 213
 214         printk("CPU: %d    %s  (%s %.*s)\n",
 215                 smp_processor_id(), print_tainted(), init_utsname()->release,
 216                 (int)strcspn(init_utsname()->version, " "),
 217                 init_utsname()->version);
 218         print_symbol("PC is at %s\n", instruction_pointer(regs));
 219         print_symbol("LR is at %s\n", regs->ARM_lr);
 220         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 221                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 222                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 223                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 224         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 225                 regs->ARM_r10, regs->ARM_r9,
 226                 regs->ARM_r8);
 227         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 228                 regs->ARM_r7, regs->ARM_r6,
 229                 regs->ARM_r5, regs->ARM_r4);
 230         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 231                 regs->ARM_r3, regs->ARM_r2,
 232                 regs->ARM_r1, regs->ARM_r0);
 233
 234         flags = regs->ARM_cpsr;
 235         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 236         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 237         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 238         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 239         buf[4] = '\0';
 240
 241         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 242                 buf, interrupts_enabled(regs) ? "n" : "ff",
 243                 fast_interrupts_enabled(regs) ? "n" : "ff",
 244                 processor_modes[processor_mode(regs)],
 245                 isa_modes[isa_mode(regs)],
 246                 get_fs() == get_ds() ? "kernel" : "user");
 247 #ifdef CONFIG_CPU_CP15
 248         {
 249                 unsigned int ctrl;
 250
 251                 buf[0] = '\0';
 252 #ifdef CONFIG_CPU_CP15_MMU
 253                 {
 254                         unsigned int transbase, dac;
 255                         asm("mrc p15, 0, %0, c2, c0\n\t"
 256                             "mrc p15, 0, %1, c3, c0\n"
 257                             : "=r" (transbase), "=r" (dac));
 258                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 259                                 transbase, dac);
 260                 }
 261 #endif
 262                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 263
 264                 printk("Control: %08x%s\n", ctrl, buf);
 265         }
 266 #endif
 267 }
 268
 269 void show_regs(struct pt_regs * regs)
 270 {
 271         printk("\n");
 272         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 273         __show_regs(regs);
 274         __backtrace();
 275 }
 276
 277 /*
 278  * Free current thread data structures etc..
 279  */
 280 void exit_thread(void)
 281 {
 282 }
 283
 284 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 285
 286 EXPORT_SYMBOL_GPL(thread_notify_head);
 287
 288 void flush_thread(void)
 289 {
 290         struct thread_info *thread = current_thread_info();
 291         struct task_struct *tsk = current;
 292
 293         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 294         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 295         memset(&thread->fpstate, 0, sizeof(union fp_state));
 296
 297         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 298 }
 299
 300 void release_thread(struct task_struct *dead_task)
 301 {
 302         struct thread_info *thread = task_thread_info(dead_task);
 303
 304         thread_notify(THREAD_NOTIFY_RELEASE, thread);
 305 }
 306
 307 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 308
 309 int
 310 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 311             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 312 {
 313         struct thread_info *thread = task_thread_info(p);
 314         struct pt_regs *childregs = task_pt_regs(p);
 315
 316         *childregs = *regs;
 317         childregs->ARM_r0 = 0;
 318         childregs->ARM_sp = stack_start;
 319
 320         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 321         thread->cpu_context.sp = (unsigned long)childregs;
 322         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 323
 324         if (clone_flags & CLONE_SETTLS)
 325                 thread->tp_value = regs->ARM_r3;
 326
 327         return 0;
 328 }
 329
 330 /*
 331  * fill in the fpe structure for a core dump...
 332  */
 333 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 334 {
 335         struct thread_info *thread = current_thread_info();
 336         int used_math = thread->used_cp[1] | thread->used_cp[2];
 337
 338         if (used_math)
 339                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 340
 341         return used_math != 0;
 342 }
 343 EXPORT_SYMBOL(dump_fpu);
 344
 345 /*
 346  * Shuffle the argument into the correct register before calling the
 347  * thread function.  r1 is the thread argument, r2 is the pointer to
 348  * the thread function, and r3 points to the exit function.
 349  */
 350 extern void kernel_thread_helper(void);
 351 asm(    ".section .text\n"
 352 "       .align\n"
 353 "       .type   kernel_thread_helper, #function\n"
 354 "kernel_thread_helper:\n"
 355 "       mov     r0, r1\n"
 356 "       mov     lr, r3\n"
 357 "       mov     pc, r2\n"
 358 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 359 "       .previous");
 360
 361 #ifdef CONFIG_ARM_UNWIND
 362 extern void kernel_thread_exit(long code);
 363 asm(    ".section .text\n"
 364 "       .align\n"
 365 "       .type   kernel_thread_exit, #function\n"
 366 "kernel_thread_exit:\n"
 367 "       .fnstart\n"
 368 "       .cantunwind\n"
 369 "       bl      do_exit\n"
 370 "       nop\n"
 371 "       .fnend\n"
 372 "       .size   kernel_thread_exit, . - kernel_thread_exit\n"
 373 "       .previous");
 374 #else
 375 #define kernel_thread_exit      do_exit
 376 #endif
 377
 378 /*
 379  * Create a kernel thread.
 380  */
 381 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 382 {
 383         struct pt_regs regs;
 384
 385         memset(&regs, 0, sizeof(regs));
 386
 387         regs.ARM_r1 = (unsigned long)arg;
 388         regs.ARM_r2 = (unsigned long)fn;
 389         regs.ARM_r3 = (unsigned long)kernel_thread_exit;
 390         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 391         regs.ARM_cpsr = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
 392
 393         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 394 }
 395 EXPORT_SYMBOL(kernel_thread);
 396
 397 unsigned long get_wchan(struct task_struct *p)
 398 {
 399         struct stackframe frame;
 400         int count = 0;
 401         if (!p || p == current || p->state == TASK_RUNNING)
 402                 return 0;
 403
 404         frame.fp = thread_saved_fp(p);
 405         frame.sp = thread_saved_sp(p);
 406         frame.lr = 0;                   /* recovered from the stack */
 407         frame.pc = thread_saved_pc(p);
 408         do {
 409                 int ret = unwind_frame(&frame);
 410                 if (ret < 0)
 411                         return 0;
 412                 if (!in_sched_functions(frame.pc))
 413                         return frame.pc;
 414         } while (count ++ < 16);
 415         return 0;
 416 }