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/config.h>
  14 #include <linux/module.h>
  15 #include <linux/sched.h>
  16 #include <linux/kernel.h>
  17 #include <linux/mm.h>
  18 #include <linux/stddef.h>
  19 #include <linux/unistd.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/slab.h>
  22 #include <linux/user.h>
  23 #include <linux/a.out.h>
  24 #include <linux/delay.h>
  25 #include <linux/reboot.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/kallsyms.h>
  28 #include <linux/init.h>
  29 #include <linux/cpu.h>
  30 #include <linux/elfcore.h>
  31
  32 #include <asm/leds.h>
  33 #include <asm/processor.h>
  34 #include <asm/system.h>
  35 #include <asm/uaccess.h>
  36 #include <asm/mach/time.h>
  37
  38 extern const char *processor_modes[];
  39 extern void setup_mm_for_reboot(char mode);
  40
  41 static volatile int hlt_counter;
  42
  43 #include <asm/arch/system.h>
  44
  45 void disable_hlt(void)
  46 {
  47         hlt_counter++;
  48 }
  49
  50 EXPORT_SYMBOL(disable_hlt);
  51
  52 void enable_hlt(void)
  53 {
  54         hlt_counter--;
  55 }
  56
  57 EXPORT_SYMBOL(enable_hlt);
  58
  59 static int __init nohlt_setup(char *__unused)
  60 {
  61         hlt_counter = 1;
  62         return 1;
  63 }
  64
  65 static int __init hlt_setup(char *__unused)
  66 {
  67         hlt_counter = 0;
  68         return 1;
  69 }
  70
  71 __setup("nohlt", nohlt_setup);
  72 __setup("hlt", hlt_setup);
  73
  74 /*
  75  * The following aren't currently used.
  76  */
  77 void (*pm_idle)(void);
  78 EXPORT_SYMBOL(pm_idle);
  79
  80 void (*pm_power_off)(void);
  81 EXPORT_SYMBOL(pm_power_off);
  82
  83 /*
  84  * This is our default idle handler.  We need to disable
  85  * interrupts here to ensure we don't miss a wakeup call.
  86  */
  87 static void default_idle(void)
  88 {
  89         if (hlt_counter)
  90                 cpu_relax();
  91         else {
  92                 local_irq_disable();
  93                 if (!need_resched()) {
  94                         timer_dyn_reprogram();
  95                         arch_idle();
  96                 }
  97                 local_irq_enable();
  98         }
  99 }
 100
 101 /*
 102  * The idle thread.  We try to conserve power, while trying to keep
 103  * overall latency low.  The architecture specific idle is passed
 104  * a value to indicate the level of "idleness" of the system.
 105  */
 106 void cpu_idle(void)
 107 {
 108         local_fiq_enable();
 109
 110         /* endless idle loop with no priority at all */
 111         while (1) {
 112                 void (*idle)(void) = pm_idle;
 113
 114 #ifdef CONFIG_HOTPLUG_CPU
 115                 if (cpu_is_offline(smp_processor_id())) {
 116                         leds_event(led_idle_start);
 117                         cpu_die();
 118                 }
 119 #endif
 120
 121                 if (!idle)
 122                         idle = default_idle;
 123                 leds_event(led_idle_start);
 124                 while (!need_resched())
 125                         idle();
 126                 leds_event(led_idle_end);
 127                 preempt_enable_no_resched();
 128                 schedule();
 129                 preempt_disable();
 130         }
 131 }
 132
 133 static char reboot_mode = 'h';
 134
 135 int __init reboot_setup(char *str)
 136 {
 137         reboot_mode = str[0];
 138         return 1;
 139 }
 140
 141 __setup("reboot=", reboot_setup);
 142
 143 void machine_halt(void)
 144 {
 145 }
 146
 147
 148 void machine_power_off(void)
 149 {
 150         if (pm_power_off)
 151                 pm_power_off();
 152 }
 153
 154
 155 void machine_restart(char * __unused)
 156 {
 157         /*
 158          * Clean and disable cache, and turn off interrupts
 159          */
 160         cpu_proc_fin();
 161
 162         /*
 163          * Tell the mm system that we are going to reboot -
 164          * we may need it to insert some 1:1 mappings so that
 165          * soft boot works.
 166          */
 167         setup_mm_for_reboot(reboot_mode);
 168
 169         /*
 170          * Now call the architecture specific reboot code.
 171          */
 172         arch_reset(reboot_mode);
 173
 174         /*
 175          * Whoops - the architecture was unable to reboot.
 176          * Tell the user!
 177          */
 178         mdelay(1000);
 179         printk("Reboot failed -- System halted\n");
 180         while (1);
 181 }
 182
 183 void __show_regs(struct pt_regs *regs)
 184 {
 185         unsigned long flags = condition_codes(regs);
 186
 187         printk("CPU: %d\n", smp_processor_id());
 188         print_symbol("PC is at %s\n", instruction_pointer(regs));
 189         print_symbol("LR is at %s\n", regs->ARM_lr);
 190         printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
 191                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 192                 instruction_pointer(regs),
 193                 regs->ARM_lr, print_tainted(), regs->ARM_sp,
 194                 regs->ARM_ip, regs->ARM_fp);
 195         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 196                 regs->ARM_r10, regs->ARM_r9,
 197                 regs->ARM_r8);
 198         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 199                 regs->ARM_r7, regs->ARM_r6,
 200                 regs->ARM_r5, regs->ARM_r4);
 201         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 202                 regs->ARM_r3, regs->ARM_r2,
 203                 regs->ARM_r1, regs->ARM_r0);
 204         printk("Flags: %c%c%c%c",
 205                 flags & PSR_N_BIT ? 'N' : 'n',
 206                 flags & PSR_Z_BIT ? 'Z' : 'z',
 207                 flags & PSR_C_BIT ? 'C' : 'c',
 208                 flags & PSR_V_BIT ? 'V' : 'v');
 209         printk("  IRQs o%s  FIQs o%s  Mode %s%s  Segment %s\n",
 210                 interrupts_enabled(regs) ? "n" : "ff",
 211                 fast_interrupts_enabled(regs) ? "n" : "ff",
 212                 processor_modes[processor_mode(regs)],
 213                 thumb_mode(regs) ? " (T)" : "",
 214                 get_fs() == get_ds() ? "kernel" : "user");
 215         {
 216                 unsigned int ctrl, transbase, dac;
 217                   __asm__ (
 218                 "       mrc p15, 0, %0, c1, c0\n"
 219                 "       mrc p15, 0, %1, c2, c0\n"
 220                 "       mrc p15, 0, %2, c3, c0\n"
 221                 : "=r" (ctrl), "=r" (transbase), "=r" (dac));
 222                 printk("Control: %04X  Table: %08X  DAC: %08X\n",
 223                         ctrl, transbase, dac);
 224         }
 225 }
 226
 227 void show_regs(struct pt_regs * regs)
 228 {
 229         printk("\n");
 230         printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
 231         __show_regs(regs);
 232         __backtrace();
 233 }
 234
 235 void show_fpregs(struct user_fp *regs)
 236 {
 237         int i;
 238
 239         for (i = 0; i < 8; i++) {
 240                 unsigned long *p;
 241                 char type;
 242
 243                 p = (unsigned long *)(regs->fpregs + i);
 244
 245                 switch (regs->ftype[i]) {
 246                         case 1: type = 'f'; break;
 247                         case 2: type = 'd'; break;
 248                         case 3: type = 'e'; break;
 249                         default: type = '?'; break;
 250                 }
 251                 if (regs->init_flag)
 252                         type = '?';
 253
 254                 printk("  f%d(%c): %08lx %08lx %08lx%c",
 255                         i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
 256         }
 257
 258
 259         printk("FPSR: %08lx FPCR: %08lx\n",
 260                 (unsigned long)regs->fpsr,
 261                 (unsigned long)regs->fpcr);
 262 }
 263
 264 /*
 265  * Task structure and kernel stack allocation.
 266  */
 267 struct thread_info_list {
 268         unsigned long *head;
 269         unsigned int nr;
 270 };
 271
 272 static DEFINE_PER_CPU(struct thread_info_list, thread_info_list) = { NULL, 0 };
 273
 274 #define EXTRA_TASK_STRUCT       4
 275
 276 struct thread_info *alloc_thread_info(struct task_struct *task)
 277 {
 278         struct thread_info *thread = NULL;
 279
 280         if (EXTRA_TASK_STRUCT) {
 281                 struct thread_info_list *th = &get_cpu_var(thread_info_list);
 282                 unsigned long *p = th->head;
 283
 284                 if (p) {
 285                         th->head = (unsigned long *)p[0];
 286                         th->nr -= 1;
 287                 }
 288                 put_cpu_var(thread_info_list);
 289
 290                 thread = (struct thread_info *)p;
 291         }
 292
 293         if (!thread)
 294                 thread = (struct thread_info *)
 295                            __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
 296
 297 #ifdef CONFIG_DEBUG_STACK_USAGE
 298         /*
 299          * The stack must be cleared if you want SYSRQ-T to
 300          * give sensible stack usage information
 301          */
 302         if (thread)
 303                 memzero(thread, THREAD_SIZE);
 304 #endif
 305         return thread;
 306 }
 307
 308 void free_thread_info(struct thread_info *thread)
 309 {
 310         if (EXTRA_TASK_STRUCT) {
 311                 struct thread_info_list *th = &get_cpu_var(thread_info_list);
 312                 if (th->nr < EXTRA_TASK_STRUCT) {
 313                         unsigned long *p = (unsigned long *)thread;
 314                         p[0] = (unsigned long)th->head;
 315                         th->head = p;
 316                         th->nr += 1;
 317                         put_cpu_var(thread_info_list);
 318                         return;
 319                 }
 320                 put_cpu_var(thread_info_list);
 321         }
 322         free_pages((unsigned long)thread, THREAD_SIZE_ORDER);
 323 }
 324
 325 /*
 326  * Free current thread data structures etc..
 327  */
 328 void exit_thread(void)
 329 {
 330 }
 331
 332 static void default_fp_init(union fp_state *fp)
 333 {
 334         memset(fp, 0, sizeof(union fp_state));
 335 }
 336
 337 void (*fp_init)(union fp_state *) = default_fp_init;
 338 EXPORT_SYMBOL(fp_init);
 339
 340 void flush_thread(void)
 341 {
 342         struct thread_info *thread = current_thread_info();
 343         struct task_struct *tsk = current;
 344
 345         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 346         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 347 #if defined(CONFIG_IWMMXT)
 348         iwmmxt_task_release(thread);
 349 #endif
 350         fp_init(&thread->fpstate);
 351 #if defined(CONFIG_VFP)
 352         vfp_flush_thread(&thread->vfpstate);
 353 #endif
 354 }
 355
 356 void release_thread(struct task_struct *dead_task)
 357 {
 358 #if defined(CONFIG_VFP)
 359         vfp_release_thread(&task_thread_info(dead_task)->vfpstate);
 360 #endif
 361 #if defined(CONFIG_IWMMXT)
 362         iwmmxt_task_release(task_thread_info(dead_task));
 363 #endif
 364 }
 365
 366 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 367
 368 int
 369 copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
 370             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 371 {
 372         struct thread_info *thread = task_thread_info(p);
 373         struct pt_regs *childregs = task_pt_regs(p);
 374
 375         *childregs = *regs;
 376         childregs->ARM_r0 = 0;
 377         childregs->ARM_sp = stack_start;
 378
 379         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 380         thread->cpu_context.sp = (unsigned long)childregs;
 381         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 382
 383         if (clone_flags & CLONE_SETTLS)
 384                 thread->tp_value = regs->ARM_r3;
 385
 386         return 0;
 387 }
 388
 389 /*
 390  * fill in the fpe structure for a core dump...
 391  */
 392 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 393 {
 394         struct thread_info *thread = current_thread_info();
 395         int used_math = thread->used_cp[1] | thread->used_cp[2];
 396
 397         if (used_math)
 398                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 399
 400         return used_math != 0;
 401 }
 402 EXPORT_SYMBOL(dump_fpu);
 403
 404 /*
 405  * fill in the user structure for a core dump..
 406  */
 407 void dump_thread(struct pt_regs * regs, struct user * dump)
 408 {
 409         struct task_struct *tsk = current;
 410
 411         dump->magic = CMAGIC;
 412         dump->start_code = tsk->mm->start_code;
 413         dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);
 414
 415         dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
 416         dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
 417         dump->u_ssize = 0;
 418
 419         dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
 420         dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
 421         dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn.arm;
 422         dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn.arm;
 423         dump->u_debugreg[4] = tsk->thread.debug.nsaved;
 424
 425         if (dump->start_stack < 0x04000000)
 426                 dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;
 427
 428         dump->regs = *regs;
 429         dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
 430 }
 431 EXPORT_SYMBOL(dump_thread);
 432
 433 /*
 434  * Shuffle the argument into the correct register before calling the
 435  * thread function.  r1 is the thread argument, r2 is the pointer to
 436  * the thread function, and r3 points to the exit function.
 437  */
 438 extern void kernel_thread_helper(void);
 439 asm(    ".section .text\n"
 440 "       .align\n"
 441 "       .type   kernel_thread_helper, #function\n"
 442 "kernel_thread_helper:\n"
 443 "       mov     r0, r1\n"
 444 "       mov     lr, r3\n"
 445 "       mov     pc, r2\n"
 446 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 447 "       .previous");
 448
 449 /*
 450  * Create a kernel thread.
 451  */
 452 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 453 {
 454         struct pt_regs regs;
 455
 456         memset(&regs, 0, sizeof(regs));
 457
 458         regs.ARM_r1 = (unsigned long)arg;
 459         regs.ARM_r2 = (unsigned long)fn;
 460         regs.ARM_r3 = (unsigned long)do_exit;
 461         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 462         regs.ARM_cpsr = SVC_MODE;
 463
 464         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 465 }
 466 EXPORT_SYMBOL(kernel_thread);
 467
 468 unsigned long get_wchan(struct task_struct *p)
 469 {
 470         unsigned long fp, lr;
 471         unsigned long stack_start, stack_end;
 472         int count = 0;
 473         if (!p || p == current || p->state == TASK_RUNNING)
 474                 return 0;
 475
 476         stack_start = (unsigned long)end_of_stack(p);
 477         stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 478
 479         fp = thread_saved_fp(p);
 480         do {
 481                 if (fp < stack_start || fp > stack_end)
 482                         return 0;
 483                 lr = pc_pointer (((unsigned long *)fp)[-1]);
 484                 if (!in_sched_functions(lr))
 485                         return lr;
 486                 fp = *(unsigned long *) (fp - 12);
 487         } while (count ++ < 16);
 488         return 0;
 489 }