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