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