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/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)
  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);
 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_idle)(void);
 117 EXPORT_SYMBOL(pm_idle);
 118
 119 void (*pm_power_off)(void);
 120 EXPORT_SYMBOL(pm_power_off);
 121
 122 void (*arm_pm_restart)(char str) = arm_machine_restart;
 123 EXPORT_SYMBOL_GPL(arm_pm_restart);
 124
 125
 126 /*
 127  * This is our default idle handler.  We need to disable
 128  * interrupts here to ensure we don't miss a wakeup call.
 129  */
 130 static void default_idle(void)
 131 {
 132         if (hlt_counter)
 133                 cpu_relax();
 134         else {
 135                 local_irq_disable();
 136                 if (!need_resched())
 137                         arch_idle();
 138                 local_irq_enable();
 139         }
 140 }
 141
 142 /*
 143  * The idle thread.  We try to conserve power, while trying to keep
 144  * overall latency low.  The architecture specific idle is passed
 145  * a value to indicate the level of "idleness" of the system.
 146  */
 147 void cpu_idle(void)
 148 {
 149         local_fiq_enable();
 150
 151         /* endless idle loop with no priority at all */
 152         while (1) {
 153                 void (*idle)(void) = pm_idle;
 154
 155 #ifdef CONFIG_HOTPLUG_CPU
 156                 if (cpu_is_offline(smp_processor_id())) {
 157                         leds_event(led_idle_start);
 158                         cpu_die();
 159                 }
 160 #endif
 161
 162                 if (!idle)
 163                         idle = default_idle;
 164                 leds_event(led_idle_start);
 165                 tick_nohz_stop_sched_tick(1);
 166                 while (!need_resched())
 167                         idle();
 168                 leds_event(led_idle_end);
 169                 tick_nohz_restart_sched_tick();
 170                 preempt_enable_no_resched();
 171                 schedule();
 172                 preempt_disable();
 173         }
 174 }
 175
 176 static char reboot_mode = 'h';
 177
 178 int __init reboot_setup(char *str)
 179 {
 180         reboot_mode = str[0];
 181         return 1;
 182 }
 183
 184 __setup("reboot=", reboot_setup);
 185
 186 void machine_halt(void)
 187 {
 188 }
 189
 190
 191 void machine_power_off(void)
 192 {
 193         if (pm_power_off)
 194                 pm_power_off();
 195 }
 196
 197 void machine_restart(char * __unused)
 198 {
 199         arm_pm_restart(reboot_mode);
 200 }
 201
 202 void __show_regs(struct pt_regs *regs)
 203 {
 204         unsigned long flags;
 205         char buf[64];
 206
 207         printk("CPU: %d    %s  (%s %.*s)\n",
 208                 smp_processor_id(), print_tainted(), init_utsname()->release,
 209                 (int)strcspn(init_utsname()->version, " "),
 210                 init_utsname()->version);
 211         print_symbol("PC is at %s\n", instruction_pointer(regs));
 212         print_symbol("LR is at %s\n", regs->ARM_lr);
 213         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 214                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 215                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 216                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 217         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 218                 regs->ARM_r10, regs->ARM_r9,
 219                 regs->ARM_r8);
 220         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 221                 regs->ARM_r7, regs->ARM_r6,
 222                 regs->ARM_r5, regs->ARM_r4);
 223         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 224                 regs->ARM_r3, regs->ARM_r2,
 225                 regs->ARM_r1, regs->ARM_r0);
 226
 227         flags = regs->ARM_cpsr;
 228         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 229         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 230         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 231         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 232         buf[4] = '\0';
 233
 234         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 235                 buf, interrupts_enabled(regs) ? "n" : "ff",
 236                 fast_interrupts_enabled(regs) ? "n" : "ff",
 237                 processor_modes[processor_mode(regs)],
 238                 isa_modes[isa_mode(regs)],
 239                 get_fs() == get_ds() ? "kernel" : "user");
 240 #ifdef CONFIG_CPU_CP15
 241         {
 242                 unsigned int ctrl;
 243
 244                 buf[0] = '\0';
 245 #ifdef CONFIG_CPU_CP15_MMU
 246                 {
 247                         unsigned int transbase, dac;
 248                         asm("mrc p15, 0, %0, c2, c0\n\t"
 249                             "mrc p15, 0, %1, c3, c0\n"
 250                             : "=r" (transbase), "=r" (dac));
 251                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 252                                 transbase, dac);
 253                 }
 254 #endif
 255                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 256
 257                 printk("Control: %08x%s\n", ctrl, buf);
 258         }
 259 #endif
 260 }
 261
 262 void show_regs(struct pt_regs * regs)
 263 {
 264         printk("\n");
 265         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 266         __show_regs(regs);
 267         __backtrace();
 268 }
 269
 270 /*
 271  * Free current thread data structures etc..
 272  */
 273 void exit_thread(void)
 274 {
 275 }
 276
 277 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 278
 279 EXPORT_SYMBOL_GPL(thread_notify_head);
 280
 281 void flush_thread(void)
 282 {
 283         struct thread_info *thread = current_thread_info();
 284         struct task_struct *tsk = current;
 285
 286         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 287         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 288         memset(&thread->fpstate, 0, sizeof(union fp_state));
 289
 290         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 291 }
 292
 293 void release_thread(struct task_struct *dead_task)
 294 {
 295         struct thread_info *thread = task_thread_info(dead_task);
 296
 297         thread_notify(THREAD_NOTIFY_RELEASE, thread);
 298 }
 299
 300 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 301
 302 int
 303 copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
 304             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 305 {
 306         struct thread_info *thread = task_thread_info(p);
 307         struct pt_regs *childregs = task_pt_regs(p);
 308
 309         *childregs = *regs;
 310         childregs->ARM_r0 = 0;
 311         childregs->ARM_sp = stack_start;
 312
 313         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 314         thread->cpu_context.sp = (unsigned long)childregs;
 315         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 316
 317         if (clone_flags & CLONE_SETTLS)
 318                 thread->tp_value = regs->ARM_r3;
 319
 320         return 0;
 321 }
 322
 323 /*
 324  * fill in the fpe structure for a core dump...
 325  */
 326 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 327 {
 328         struct thread_info *thread = current_thread_info();
 329         int used_math = thread->used_cp[1] | thread->used_cp[2];
 330
 331         if (used_math)
 332                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 333
 334         return used_math != 0;
 335 }
 336 EXPORT_SYMBOL(dump_fpu);
 337
 338 /*
 339  * Shuffle the argument into the correct register before calling the
 340  * thread function.  r1 is the thread argument, r2 is the pointer to
 341  * the thread function, and r3 points to the exit function.
 342  */
 343 extern void kernel_thread_helper(void);
 344 asm(    ".section .text\n"
 345 "       .align\n"
 346 "       .type   kernel_thread_helper, #function\n"
 347 "kernel_thread_helper:\n"
 348 "       mov     r0, r1\n"
 349 "       mov     lr, r3\n"
 350 "       mov     pc, r2\n"
 351 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 352 "       .previous");
 353
 354 /*
 355  * Create a kernel thread.
 356  */
 357 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 358 {
 359         struct pt_regs regs;
 360
 361         memset(&regs, 0, sizeof(regs));
 362
 363         regs.ARM_r1 = (unsigned long)arg;
 364         regs.ARM_r2 = (unsigned long)fn;
 365         regs.ARM_r3 = (unsigned long)do_exit;
 366         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 367         regs.ARM_cpsr = SVC_MODE;
 368
 369         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 370 }
 371 EXPORT_SYMBOL(kernel_thread);
 372
 373 unsigned long get_wchan(struct task_struct *p)
 374 {
 375         unsigned long fp, lr;
 376         unsigned long stack_start, stack_end;
 377         int count = 0;
 378         if (!p || p == current || p->state == TASK_RUNNING)
 379                 return 0;
 380
 381         stack_start = (unsigned long)end_of_stack(p);
 382         stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 383
 384         fp = thread_saved_fp(p);
 385         do {
 386                 if (fp < stack_start || fp > stack_end)
 387                         return 0;
 388                 lr = ((unsigned long *)fp)[-1];
 389                 if (!in_sched_functions(lr))
 390                         return lr;
 391                 fp = *(unsigned long *) (fp - 12);
 392         } while (count ++ < 16);
 393         return 0;
 394 }