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 static unsigned long *thread_info_head;
 268 static unsigned int nr_thread_info;
 269
 270 #define EXTRA_TASK_STRUCT       4
 271
 272 struct thread_info *alloc_thread_info(struct task_struct *task)
 273 {
 274         struct thread_info *thread = NULL;
 275
 276         if (EXTRA_TASK_STRUCT) {
 277                 unsigned long *p = thread_info_head;
 278
 279                 if (p) {
 280                         thread_info_head = (unsigned long *)p[0];
 281                         nr_thread_info -= 1;
 282                 }
 283                 thread = (struct thread_info *)p;
 284         }
 285
 286         if (!thread)
 287                 thread = (struct thread_info *)
 288                            __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
 289
 290 #ifdef CONFIG_DEBUG_STACK_USAGE
 291         /*
 292          * The stack must be cleared if you want SYSRQ-T to
 293          * give sensible stack usage information
 294          */
 295         if (thread)
 296                 memzero(thread, THREAD_SIZE);
 297 #endif
 298         return thread;
 299 }
 300
 301 void free_thread_info(struct thread_info *thread)
 302 {
 303         if (EXTRA_TASK_STRUCT && nr_thread_info < EXTRA_TASK_STRUCT) {
 304                 unsigned long *p = (unsigned long *)thread;
 305                 p[0] = (unsigned long)thread_info_head;
 306                 thread_info_head = p;
 307                 nr_thread_info += 1;
 308         } else
 309                 free_pages((unsigned long)thread, THREAD_SIZE_ORDER);
 310 }
 311
 312 /*
 313  * Free current thread data structures etc..
 314  */
 315 void exit_thread(void)
 316 {
 317 }
 318
 319 static void default_fp_init(union fp_state *fp)
 320 {
 321         memset(fp, 0, sizeof(union fp_state));
 322 }
 323
 324 void (*fp_init)(union fp_state *) = default_fp_init;
 325 EXPORT_SYMBOL(fp_init);
 326
 327 void flush_thread(void)
 328 {
 329         struct thread_info *thread = current_thread_info();
 330         struct task_struct *tsk = current;
 331
 332         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 333         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 334 #if defined(CONFIG_IWMMXT)
 335         iwmmxt_task_release(thread);
 336 #endif
 337         fp_init(&thread->fpstate);
 338 #if defined(CONFIG_VFP)
 339         vfp_flush_thread(&thread->vfpstate);
 340 #endif
 341 }
 342
 343 void release_thread(struct task_struct *dead_task)
 344 {
 345 #if defined(CONFIG_VFP)
 346         vfp_release_thread(&task_thread_info(dead_task)->vfpstate);
 347 #endif
 348 #if defined(CONFIG_IWMMXT)
 349         iwmmxt_task_release(task_thread_info(dead_task));
 350 #endif
 351 }
 352
 353 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 354
 355 int
 356 copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
 357             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 358 {
 359         struct thread_info *thread = task_thread_info(p);
 360         struct pt_regs *childregs = task_pt_regs(p);
 361
 362         *childregs = *regs;
 363         childregs->ARM_r0 = 0;
 364         childregs->ARM_sp = stack_start;
 365
 366         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 367         thread->cpu_context.sp = (unsigned long)childregs;
 368         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 369
 370         if (clone_flags & CLONE_SETTLS)
 371                 thread->tp_value = regs->ARM_r3;
 372
 373         return 0;
 374 }
 375
 376 /*
 377  * fill in the fpe structure for a core dump...
 378  */
 379 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 380 {
 381         struct thread_info *thread = current_thread_info();
 382         int used_math = thread->used_cp[1] | thread->used_cp[2];
 383
 384         if (used_math)
 385                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 386
 387         return used_math != 0;
 388 }
 389 EXPORT_SYMBOL(dump_fpu);
 390
 391 /*
 392  * fill in the user structure for a core dump..
 393  */
 394 void dump_thread(struct pt_regs * regs, struct user * dump)
 395 {
 396         struct task_struct *tsk = current;
 397
 398         dump->magic = CMAGIC;
 399         dump->start_code = tsk->mm->start_code;
 400         dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);
 401
 402         dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
 403         dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
 404         dump->u_ssize = 0;
 405
 406         dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
 407         dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
 408         dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn.arm;
 409         dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn.arm;
 410         dump->u_debugreg[4] = tsk->thread.debug.nsaved;
 411
 412         if (dump->start_stack < 0x04000000)
 413                 dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;
 414
 415         dump->regs = *regs;
 416         dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
 417 }
 418 EXPORT_SYMBOL(dump_thread);
 419
 420 /*
 421  * Shuffle the argument into the correct register before calling the
 422  * thread function.  r1 is the thread argument, r2 is the pointer to
 423  * the thread function, and r3 points to the exit function.
 424  */
 425 extern void kernel_thread_helper(void);
 426 asm(    ".section .text\n"
 427 "       .align\n"
 428 "       .type   kernel_thread_helper, #function\n"
 429 "kernel_thread_helper:\n"
 430 "       mov     r0, r1\n"
 431 "       mov     lr, r3\n"
 432 "       mov     pc, r2\n"
 433 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 434 "       .previous");
 435
 436 /*
 437  * Create a kernel thread.
 438  */
 439 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 440 {
 441         struct pt_regs regs;
 442
 443         memset(&regs, 0, sizeof(regs));
 444
 445         regs.ARM_r1 = (unsigned long)arg;
 446         regs.ARM_r2 = (unsigned long)fn;
 447         regs.ARM_r3 = (unsigned long)do_exit;
 448         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 449         regs.ARM_cpsr = SVC_MODE;
 450
 451         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 452 }
 453 EXPORT_SYMBOL(kernel_thread);
 454
 455 unsigned long get_wchan(struct task_struct *p)
 456 {
 457         unsigned long fp, lr;
 458         unsigned long stack_start, stack_end;
 459         int count = 0;
 460         if (!p || p == current || p->state == TASK_RUNNING)
 461                 return 0;
 462
 463         stack_start = (unsigned long)end_of_stack(p);
 464         stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 465
 466         fp = thread_saved_fp(p);
 467         do {
 468                 if (fp < stack_start || fp > stack_end)
 469                         return 0;
 470                 lr = pc_pointer (((unsigned long *)fp)[-1]);
 471                 if (!in_sched_functions(lr))
 472                         return lr;
 473                 fp = *(unsigned long *) (fp - 12);
 474         } while (count ++ < 16);
 475         return 0;
 476 }
 477 EXPORT_SYMBOL(get_wchan);