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 #ifdef CONFIG_PL310_ERRATA_769419
 160                         wmb();
 161 #endif
 162                         if (hlt_counter) {
 163                                 local_irq_enable();
 164                                 cpu_relax();
 165                         } else {
 166                                 stop_critical_timings();
 167                                 pm_idle();
 168                                 start_critical_timings();
 169                                 /*
 170                                  * This will eventually be removed - pm_idle
 171                                  * functions should always return with IRQs
 172                                  * enabled.
 173                                  */
 174                                 WARN_ON(irqs_disabled());
 175                                 local_irq_enable();
 176                         }
 177                 }
 178                 leds_event(led_idle_end);
 179                 tick_nohz_restart_sched_tick();
 180                 preempt_enable_no_resched();
 181                 schedule();
 182                 preempt_disable();
 183         }
 184 }
 185
 186 static char reboot_mode = 'h';
 187
 188 int __init reboot_setup(char *str)
 189 {
 190         reboot_mode = str[0];
 191         return 1;
 192 }
 193
 194 __setup("reboot=", reboot_setup);
 195
 196 void machine_halt(void)
 197 {
 198 }
 199
 200
 201 void machine_power_off(void)
 202 {
 203         if (pm_power_off)
 204                 pm_power_off();
 205 }
 206
 207 void machine_restart(char *cmd)
 208 {
 209         arm_pm_restart(reboot_mode, cmd);
 210 }
 211
 212 void __show_regs(struct pt_regs *regs)
 213 {
 214         unsigned long flags;
 215         char buf[64];
 216
 217         printk("CPU: %d    %s  (%s %.*s)\n",
 218                 smp_processor_id(), print_tainted(), init_utsname()->release,
 219                 (int)strcspn(init_utsname()->version, " "),
 220                 init_utsname()->version);
 221         print_symbol("PC is at %s\n", instruction_pointer(regs));
 222         print_symbol("LR is at %s\n", regs->ARM_lr);
 223         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 224                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 225                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 226                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 227         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 228                 regs->ARM_r10, regs->ARM_r9,
 229                 regs->ARM_r8);
 230         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 231                 regs->ARM_r7, regs->ARM_r6,
 232                 regs->ARM_r5, regs->ARM_r4);
 233         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 234                 regs->ARM_r3, regs->ARM_r2,
 235                 regs->ARM_r1, regs->ARM_r0);
 236
 237         flags = regs->ARM_cpsr;
 238         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 239         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 240         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 241         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 242         buf[4] = '\0';
 243
 244         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 245                 buf, interrupts_enabled(regs) ? "n" : "ff",
 246                 fast_interrupts_enabled(regs) ? "n" : "ff",
 247                 processor_modes[processor_mode(regs)],
 248                 isa_modes[isa_mode(regs)],
 249                 get_fs() == get_ds() ? "kernel" : "user");
 250 #ifdef CONFIG_CPU_CP15
 251         {
 252                 unsigned int ctrl;
 253
 254                 buf[0] = '\0';
 255 #ifdef CONFIG_CPU_CP15_MMU
 256                 {
 257                         unsigned int transbase, dac;
 258                         asm("mrc p15, 0, %0, c2, c0\n\t"
 259                             "mrc p15, 0, %1, c3, c0\n"
 260                             : "=r" (transbase), "=r" (dac));
 261                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 262                                 transbase, dac);
 263                 }
 264 #endif
 265                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 266
 267                 printk("Control: %08x%s\n", ctrl, buf);
 268         }
 269 #endif
 270 }
 271
 272 void show_regs(struct pt_regs * regs)
 273 {
 274         printk("\n");
 275         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 276         __show_regs(regs);
 277         __backtrace();
 278 }
 279
 280 /*
 281  * Free current thread data structures etc..
 282  */
 283 void exit_thread(void)
 284 {
 285 }
 286
 287 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 288
 289 EXPORT_SYMBOL_GPL(thread_notify_head);
 290
 291 void flush_thread(void)
 292 {
 293         struct thread_info *thread = current_thread_info();
 294         struct task_struct *tsk = current;
 295
 296         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 297         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 298         memset(&thread->fpstate, 0, sizeof(union fp_state));
 299
 300         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 301 }
 302
 303 void release_thread(struct task_struct *dead_task)
 304 {
 305         struct thread_info *thread = task_thread_info(dead_task);
 306
 307         thread_notify(THREAD_NOTIFY_RELEASE, thread);
 308 }
 309
 310 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 311
 312 int
 313 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 314             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 315 {
 316         struct thread_info *thread = task_thread_info(p);
 317         struct pt_regs *childregs = task_pt_regs(p);
 318
 319         *childregs = *regs;
 320         childregs->ARM_r0 = 0;
 321         childregs->ARM_sp = stack_start;
 322
 323         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 324         thread->cpu_context.sp = (unsigned long)childregs;
 325         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 326
 327         if (clone_flags & CLONE_SETTLS)
 328                 thread->tp_value = regs->ARM_r3;
 329
 330         return 0;
 331 }
 332
 333 /*
 334  * Fill in the task's elfregs structure for a core dump.
 335  */
 336 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 337 {
 338         elf_core_copy_regs(elfregs, task_pt_regs(t));
 339         return 1;
 340 }
 341
 342 /*
 343  * fill in the fpe structure for a core dump...
 344  */
 345 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 346 {
 347         struct thread_info *thread = current_thread_info();
 348         int used_math = thread->used_cp[1] | thread->used_cp[2];
 349
 350         if (used_math)
 351                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 352
 353         return used_math != 0;
 354 }
 355 EXPORT_SYMBOL(dump_fpu);
 356
 357 /*
 358  * Shuffle the argument into the correct register before calling the
 359  * thread function.  r1 is the thread argument, r2 is the pointer to
 360  * the thread function, and r3 points to the exit function.
 361  */
 362 extern void kernel_thread_helper(void);
 363 asm(    ".section .text\n"
 364 "       .align\n"
 365 "       .type   kernel_thread_helper, #function\n"
 366 "kernel_thread_helper:\n"
 367 "       mov     r0, r1\n"
 368 "       mov     lr, r3\n"
 369 "       mov     pc, r2\n"
 370 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 371 "       .previous");
 372
 373 #ifdef CONFIG_ARM_UNWIND
 374 extern void kernel_thread_exit(long code);
 375 asm(    ".section .text\n"
 376 "       .align\n"
 377 "       .type   kernel_thread_exit, #function\n"
 378 "kernel_thread_exit:\n"
 379 "       .fnstart\n"
 380 "       .cantunwind\n"
 381 "       bl      do_exit\n"
 382 "       nop\n"
 383 "       .fnend\n"
 384 "       .size   kernel_thread_exit, . - kernel_thread_exit\n"
 385 "       .previous");
 386 #else
 387 #define kernel_thread_exit      do_exit
 388 #endif
 389
 390 /*
 391  * Create a kernel thread.
 392  */
 393 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 394 {
 395         struct pt_regs regs;
 396
 397         memset(&regs, 0, sizeof(regs));
 398
 399         regs.ARM_r1 = (unsigned long)arg;
 400         regs.ARM_r2 = (unsigned long)fn;
 401         regs.ARM_r3 = (unsigned long)kernel_thread_exit;
 402         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 403         regs.ARM_cpsr = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
 404
 405         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 406 }
 407 EXPORT_SYMBOL(kernel_thread);
 408
 409 unsigned long get_wchan(struct task_struct *p)
 410 {
 411         struct stackframe frame;
 412         int count = 0;
 413         if (!p || p == current || p->state == TASK_RUNNING)
 414                 return 0;
 415
 416         frame.fp = thread_saved_fp(p);
 417         frame.sp = thread_saved_sp(p);
 418         frame.lr = 0;                   /* recovered from the stack */
 419         frame.pc = thread_saved_pc(p);
 420         do {
 421                 int ret = unwind_frame(&frame);
 422                 if (ret < 0)
 423                         return 0;
 424                 if (!in_sched_functions(frame.pc))
 425                         return frame.pc;
 426         } while (count ++ < 16);
 427         return 0;
 428 }