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/leds.h>
  33 #include <asm/processor.h>
  34 #include <asm/system.h>
  35 #include <asm/thread_notify.h>
  36 #include <asm/stacktrace.h>
  37 #include <asm/mach/time.h>
  38
  39 static const char *processor_modes[] = {
  40   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  41   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  42   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
  43   "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  44 };
  45
  46 static const char *isa_modes[] = {
  47   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  48 };
  49
  50 extern void setup_mm_for_reboot(char mode);
  51
  52 static volatile int hlt_counter;
  53
  54 #include <mach/system.h>
  55
  56 void disable_hlt(void)
  57 {
  58         hlt_counter++;
  59 }
  60
  61 EXPORT_SYMBOL(disable_hlt);
  62
  63 void enable_hlt(void)
  64 {
  65         hlt_counter--;
  66 }
  67
  68 EXPORT_SYMBOL(enable_hlt);
  69
  70 static int __init nohlt_setup(char *__unused)
  71 {
  72         hlt_counter = 1;
  73         return 1;
  74 }
  75
  76 static int __init hlt_setup(char *__unused)
  77 {
  78         hlt_counter = 0;
  79         return 1;
  80 }
  81
  82 __setup("nohlt", nohlt_setup);
  83 __setup("hlt", hlt_setup);
  84
  85 void arm_machine_restart(char mode, const char *cmd)
  86 {
  87         /*
  88          * Clean and disable cache, and turn off interrupts
  89          */
  90         cpu_proc_fin();
  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         /*
 100          * Now call the architecture specific reboot code.
 101          */
 102         arch_reset(mode, cmd);
 103
 104         /*
 105          * Whoops - the architecture was unable to reboot.
 106          * Tell the user!
 107          */
 108         mdelay(1000);
 109         printk("Reboot failed -- System halted\n");
 110         while (1);
 111 }
 112
 113 /*
 114  * Function pointers to optional machine specific functions
 115  */
 116 void (*pm_power_off)(void);
 117 EXPORT_SYMBOL(pm_power_off);
 118
 119 void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart;
 120 EXPORT_SYMBOL_GPL(arm_pm_restart);
 121
 122
 123 /*
 124  * This is our default idle handler.  We need to disable
 125  * interrupts here to ensure we don't miss a wakeup call.
 126  */
 127 static void default_idle(void)
 128 {
 129         if (!need_resched())
 130                 arch_idle();
 131         local_irq_enable();
 132 }
 133
 134 void (*pm_idle)(void) = default_idle;
 135 EXPORT_SYMBOL(pm_idle);
 136
 137 /*
 138  * The idle thread, has rather strange semantics for calling pm_idle,
 139  * but this is what x86 does and we need to do the same, so that
 140  * things like cpuidle get called in the same way.  The only difference
 141  * is that we always respect 'hlt_counter' to prevent low power idle.
 142  */
 143 void cpu_idle(void)
 144 {
 145         local_fiq_enable();
 146
 147         /* endless idle loop with no priority at all */
 148         while (1) {
 149                 tick_nohz_stop_sched_tick(1);
 150                 leds_event(led_idle_start);
 151                 while (!need_resched()) {
 152 #ifdef CONFIG_HOTPLUG_CPU
 153                         if (cpu_is_offline(smp_processor_id()))
 154                                 cpu_die();
 155 #endif
 156
 157                         local_irq_disable();
 158                         if (hlt_counter) {
 159                                 local_irq_enable();
 160                                 cpu_relax();
 161                         } else {
 162                                 stop_critical_timings();
 163                                 pm_idle();
 164                                 start_critical_timings();
 165                                 /*
 166                                  * This will eventually be removed - pm_idle
 167                                  * functions should always return with IRQs
 168                                  * enabled.
 169                                  */
 170                                 WARN_ON(irqs_disabled());
 171                                 local_irq_enable();
 172                         }
 173                 }
 174                 leds_event(led_idle_end);
 175                 tick_nohz_restart_sched_tick();
 176                 preempt_enable_no_resched();
 177                 schedule();
 178                 preempt_disable();
 179         }
 180 }
 181
 182 static char reboot_mode = 'h';
 183
 184 int __init reboot_setup(char *str)
 185 {
 186         reboot_mode = str[0];
 187         return 1;
 188 }
 189
 190 __setup("reboot=", reboot_setup);
 191
 192 void machine_halt(void)
 193 {
 194 }
 195
 196
 197 void machine_power_off(void)
 198 {
 199         if (pm_power_off)
 200                 pm_power_off();
 201 }
 202
 203 void machine_restart(char *cmd)
 204 {
 205         arm_pm_restart(reboot_mode, cmd);
 206 }
 207
 208 void __show_regs(struct pt_regs *regs)
 209 {
 210         unsigned long flags;
 211         char buf[64];
 212
 213         printk("CPU: %d    %s  (%s %.*s)\n",
 214                 raw_smp_processor_id(), print_tainted(),
 215                 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 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 278
 279 EXPORT_SYMBOL_GPL(thread_notify_head);
 280
 281 /*
 282  * Free current thread data structures etc..
 283  */
 284 void exit_thread(void)
 285 {
 286         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 287 }
 288
 289 void flush_thread(void)
 290 {
 291         struct thread_info *thread = current_thread_info();
 292         struct task_struct *tsk = current;
 293
 294         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 295         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 296         memset(&thread->fpstate, 0, sizeof(union fp_state));
 297
 298         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 299 }
 300
 301 void release_thread(struct task_struct *dead_task)
 302 {
 303 }
 304
 305 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 306
 307 int
 308 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 309             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 310 {
 311         struct thread_info *thread = task_thread_info(p);
 312         struct pt_regs *childregs = task_pt_regs(p);
 313
 314         *childregs = *regs;
 315         childregs->ARM_r0 = 0;
 316         childregs->ARM_sp = stack_start;
 317
 318         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 319         thread->cpu_context.sp = (unsigned long)childregs;
 320         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 321
 322         if (clone_flags & CLONE_SETTLS)
 323                 thread->tp_value = regs->ARM_r3;
 324
 325         return 0;
 326 }
 327
 328 /*
 329  * Fill in the task's elfregs structure for a core dump.
 330  */
 331 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 332 {
 333         elf_core_copy_regs(elfregs, task_pt_regs(t));
 334         return 1;
 335 }
 336
 337 /*
 338  * fill in the fpe structure for a core dump...
 339  */
 340 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 341 {
 342         struct thread_info *thread = current_thread_info();
 343         int used_math = thread->used_cp[1] | thread->used_cp[2];
 344
 345         if (used_math)
 346                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 347
 348         return used_math != 0;
 349 }
 350 EXPORT_SYMBOL(dump_fpu);
 351
 352 /*
 353  * Shuffle the argument into the correct register before calling the
 354  * thread function.  r1 is the thread argument, r2 is the pointer to
 355  * the thread function, and r3 points to the exit function.
 356  */
 357 extern void kernel_thread_helper(void);
 358 asm(    ".section .text\n"
 359 "       .align\n"
 360 "       .type   kernel_thread_helper, #function\n"
 361 "kernel_thread_helper:\n"
 362 "       mov     r0, r1\n"
 363 "       mov     lr, r3\n"
 364 "       mov     pc, r2\n"
 365 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 366 "       .previous");
 367
 368 #ifdef CONFIG_ARM_UNWIND
 369 extern void kernel_thread_exit(long code);
 370 asm(    ".section .text\n"
 371 "       .align\n"
 372 "       .type   kernel_thread_exit, #function\n"
 373 "kernel_thread_exit:\n"
 374 "       .fnstart\n"
 375 "       .cantunwind\n"
 376 "       bl      do_exit\n"
 377 "       nop\n"
 378 "       .fnend\n"
 379 "       .size   kernel_thread_exit, . - kernel_thread_exit\n"
 380 "       .previous");
 381 #else
 382 #define kernel_thread_exit      do_exit
 383 #endif
 384
 385 /*
 386  * Create a kernel thread.
 387  */
 388 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 389 {
 390         struct pt_regs regs;
 391
 392         memset(&regs, 0, sizeof(regs));
 393
 394         regs.ARM_r1 = (unsigned long)arg;
 395         regs.ARM_r2 = (unsigned long)fn;
 396         regs.ARM_r3 = (unsigned long)kernel_thread_exit;
 397         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 398         regs.ARM_cpsr = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
 399
 400         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 401 }
 402 EXPORT_SYMBOL(kernel_thread);
 403
 404 unsigned long get_wchan(struct task_struct *p)
 405 {
 406         struct stackframe frame;
 407         int count = 0;
 408         if (!p || p == current || p->state == TASK_RUNNING)
 409                 return 0;
 410
 411         frame.fp = thread_saved_fp(p);
 412         frame.sp = thread_saved_sp(p);
 413         frame.lr = 0;                   /* recovered from the stack */
 414         frame.pc = thread_saved_pc(p);
 415         do {
 416                 int ret = unwind_frame(&frame);
 417                 if (ret < 0)
 418                         return 0;
 419                 if (!in_sched_functions(frame.pc))
 420                         return frame.pc;
 421         } while (count ++ < 16);
 422         return 0;
 423 }