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 #include <linux/pm.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/uaccess.h>
  38 #include <asm/mach/time.h>
  39
  40 extern const char *processor_modes[];
  41 extern void setup_mm_for_reboot(char mode);
  42
  43 static volatile int hlt_counter;
  44
  45 #include <asm/arch/system.h>
  46
  47 void disable_hlt(void)
  48 {
  49         hlt_counter++;
  50 }
  51
  52 EXPORT_SYMBOL(disable_hlt);
  53
  54 void enable_hlt(void)
  55 {
  56         hlt_counter--;
  57 }
  58
  59 EXPORT_SYMBOL(enable_hlt);
  60
  61 static int __init nohlt_setup(char *__unused)
  62 {
  63         hlt_counter = 1;
  64         return 1;
  65 }
  66
  67 static int __init hlt_setup(char *__unused)
  68 {
  69         hlt_counter = 0;
  70         return 1;
  71 }
  72
  73 __setup("nohlt", nohlt_setup);
  74 __setup("hlt", hlt_setup);
  75
  76 void arm_machine_restart(char mode)
  77 {
  78         /*
  79          * Clean and disable cache, and turn off interrupts
  80          */
  81         cpu_proc_fin();
  82
  83         /*
  84          * Tell the mm system that we are going to reboot -
  85          * we may need it to insert some 1:1 mappings so that
  86          * soft boot works.
  87          */
  88         setup_mm_for_reboot(mode);
  89
  90         /*
  91          * Now call the architecture specific reboot code.
  92          */
  93         arch_reset(mode);
  94
  95         /*
  96          * Whoops - the architecture was unable to reboot.
  97          * Tell the user!
  98          */
  99         mdelay(1000);
 100         printk("Reboot failed -- System halted\n");
 101         while (1);
 102 }
 103
 104 /*
 105  * Function pointers to optional machine specific functions
 106  */
 107 void (*pm_idle)(void);
 108 EXPORT_SYMBOL(pm_idle);
 109
 110 void (*pm_power_off)(void);
 111 EXPORT_SYMBOL(pm_power_off);
 112
 113 void (*arm_pm_restart)(char str) = arm_machine_restart;
 114 EXPORT_SYMBOL_GPL(arm_pm_restart);
 115
 116
 117 /*
 118  * This is our default idle handler.  We need to disable
 119  * interrupts here to ensure we don't miss a wakeup call.
 120  */
 121 static void default_idle(void)
 122 {
 123         if (hlt_counter)
 124                 cpu_relax();
 125         else {
 126                 local_irq_disable();
 127                 if (!need_resched()) {
 128                         timer_dyn_reprogram();
 129                         arch_idle();
 130                 }
 131                 local_irq_enable();
 132         }
 133 }
 134
 135 /*
 136  * The idle thread.  We try to conserve power, while trying to keep
 137  * overall latency low.  The architecture specific idle is passed
 138  * a value to indicate the level of "idleness" of the system.
 139  */
 140 void cpu_idle(void)
 141 {
 142         local_fiq_enable();
 143
 144         /* endless idle loop with no priority at all */
 145         while (1) {
 146                 void (*idle)(void) = pm_idle;
 147
 148 #ifdef CONFIG_HOTPLUG_CPU
 149                 if (cpu_is_offline(smp_processor_id())) {
 150                         leds_event(led_idle_start);
 151                         cpu_die();
 152                 }
 153 #endif
 154
 155                 if (!idle)
 156                         idle = default_idle;
 157                 leds_event(led_idle_start);
 158                 while (!need_resched())
 159                         idle();
 160                 leds_event(led_idle_end);
 161                 preempt_enable_no_resched();
 162                 schedule();
 163                 preempt_disable();
 164         }
 165 }
 166
 167 static char reboot_mode = 'h';
 168
 169 int __init reboot_setup(char *str)
 170 {
 171         reboot_mode = str[0];
 172         return 1;
 173 }
 174
 175 __setup("reboot=", reboot_setup);
 176
 177 void machine_halt(void)
 178 {
 179 }
 180
 181
 182 void machine_power_off(void)
 183 {
 184         if (pm_power_off)
 185                 pm_power_off();
 186 }
 187
 188 void machine_restart(char * __unused)
 189 {
 190         arm_pm_restart(reboot_mode);
 191 }
 192
 193 void __show_regs(struct pt_regs *regs)
 194 {
 195         unsigned long flags = condition_codes(regs);
 196
 197         printk("CPU: %d\n", smp_processor_id());
 198         print_symbol("PC is at %s\n", instruction_pointer(regs));
 199         print_symbol("LR is at %s\n", regs->ARM_lr);
 200         printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
 201                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 202                 instruction_pointer(regs),
 203                 regs->ARM_lr, print_tainted(), regs->ARM_sp,
 204                 regs->ARM_ip, regs->ARM_fp);
 205         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 206                 regs->ARM_r10, regs->ARM_r9,
 207                 regs->ARM_r8);
 208         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 209                 regs->ARM_r7, regs->ARM_r6,
 210                 regs->ARM_r5, regs->ARM_r4);
 211         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 212                 regs->ARM_r3, regs->ARM_r2,
 213                 regs->ARM_r1, regs->ARM_r0);
 214         printk("Flags: %c%c%c%c",
 215                 flags & PSR_N_BIT ? 'N' : 'n',
 216                 flags & PSR_Z_BIT ? 'Z' : 'z',
 217                 flags & PSR_C_BIT ? 'C' : 'c',
 218                 flags & PSR_V_BIT ? 'V' : 'v');
 219         printk("  IRQs o%s  FIQs o%s  Mode %s%s  Segment %s\n",
 220                 interrupts_enabled(regs) ? "n" : "ff",
 221                 fast_interrupts_enabled(regs) ? "n" : "ff",
 222                 processor_modes[processor_mode(regs)],
 223                 thumb_mode(regs) ? " (T)" : "",
 224                 get_fs() == get_ds() ? "kernel" : "user");
 225         {
 226                 unsigned int ctrl, transbase, dac;
 227                   __asm__ (
 228                 "       mrc p15, 0, %0, c1, c0\n"
 229                 "       mrc p15, 0, %1, c2, c0\n"
 230                 "       mrc p15, 0, %2, c3, c0\n"
 231                 : "=r" (ctrl), "=r" (transbase), "=r" (dac));
 232                 printk("Control: %04X  Table: %08X  DAC: %08X\n",
 233                         ctrl, transbase, dac);
 234         }
 235 }
 236
 237 void show_regs(struct pt_regs * regs)
 238 {
 239         printk("\n");
 240         printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
 241         __show_regs(regs);
 242         __backtrace();
 243 }
 244
 245 void show_fpregs(struct user_fp *regs)
 246 {
 247         int i;
 248
 249         for (i = 0; i < 8; i++) {
 250                 unsigned long *p;
 251                 char type;
 252
 253                 p = (unsigned long *)(regs->fpregs + i);
 254
 255                 switch (regs->ftype[i]) {
 256                         case 1: type = 'f'; break;
 257                         case 2: type = 'd'; break;
 258                         case 3: type = 'e'; break;
 259                         default: type = '?'; break;
 260                 }
 261                 if (regs->init_flag)
 262                         type = '?';
 263
 264                 printk("  f%d(%c): %08lx %08lx %08lx%c",
 265                         i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
 266         }
 267
 268
 269         printk("FPSR: %08lx FPCR: %08lx\n",
 270                 (unsigned long)regs->fpsr,
 271                 (unsigned long)regs->fpcr);
 272 }
 273
 274 /*
 275  * Task structure and kernel stack allocation.
 276  */
 277 struct thread_info_list {
 278         unsigned long *head;
 279         unsigned int nr;
 280 };
 281
 282 static DEFINE_PER_CPU(struct thread_info_list, thread_info_list) = { NULL, 0 };
 283
 284 #define EXTRA_TASK_STRUCT       4
 285
 286 struct thread_info *alloc_thread_info(struct task_struct *task)
 287 {
 288         struct thread_info *thread = NULL;
 289
 290         if (EXTRA_TASK_STRUCT) {
 291                 struct thread_info_list *th = &get_cpu_var(thread_info_list);
 292                 unsigned long *p = th->head;
 293
 294                 if (p) {
 295                         th->head = (unsigned long *)p[0];
 296                         th->nr -= 1;
 297                 }
 298                 put_cpu_var(thread_info_list);
 299
 300                 thread = (struct thread_info *)p;
 301         }
 302
 303         if (!thread)
 304                 thread = (struct thread_info *)
 305                            __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
 306
 307 #ifdef CONFIG_DEBUG_STACK_USAGE
 308         /*
 309          * The stack must be cleared if you want SYSRQ-T to
 310          * give sensible stack usage information
 311          */
 312         if (thread)
 313                 memzero(thread, THREAD_SIZE);
 314 #endif
 315         return thread;
 316 }
 317
 318 void free_thread_info(struct thread_info *thread)
 319 {
 320         if (EXTRA_TASK_STRUCT) {
 321                 struct thread_info_list *th = &get_cpu_var(thread_info_list);
 322                 if (th->nr < EXTRA_TASK_STRUCT) {
 323                         unsigned long *p = (unsigned long *)thread;
 324                         p[0] = (unsigned long)th->head;
 325                         th->head = p;
 326                         th->nr += 1;
 327                         put_cpu_var(thread_info_list);
 328                         return;
 329                 }
 330                 put_cpu_var(thread_info_list);
 331         }
 332         free_pages((unsigned long)thread, THREAD_SIZE_ORDER);
 333 }
 334
 335 /*
 336  * Free current thread data structures etc..
 337  */
 338 void exit_thread(void)
 339 {
 340 }
 341
 342 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 343
 344 EXPORT_SYMBOL_GPL(thread_notify_head);
 345
 346 void flush_thread(void)
 347 {
 348         struct thread_info *thread = current_thread_info();
 349         struct task_struct *tsk = current;
 350
 351         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 352         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 353         memset(&thread->fpstate, 0, sizeof(union fp_state));
 354
 355         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 356 #if defined(CONFIG_IWMMXT)
 357         iwmmxt_task_release(thread);
 358 #endif
 359 }
 360
 361 void release_thread(struct task_struct *dead_task)
 362 {
 363         struct thread_info *thread = task_thread_info(dead_task);
 364
 365         thread_notify(THREAD_NOTIFY_RELEASE, thread);
 366 #if defined(CONFIG_IWMMXT)
 367         iwmmxt_task_release(thread);
 368 #endif
 369 }
 370
 371 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 372
 373 int
 374 copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
 375             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 376 {
 377         struct thread_info *thread = task_thread_info(p);
 378         struct pt_regs *childregs = task_pt_regs(p);
 379
 380         *childregs = *regs;
 381         childregs->ARM_r0 = 0;
 382         childregs->ARM_sp = stack_start;
 383
 384         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 385         thread->cpu_context.sp = (unsigned long)childregs;
 386         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 387
 388         if (clone_flags & CLONE_SETTLS)
 389                 thread->tp_value = regs->ARM_r3;
 390
 391         return 0;
 392 }
 393
 394 /*
 395  * fill in the fpe structure for a core dump...
 396  */
 397 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 398 {
 399         struct thread_info *thread = current_thread_info();
 400         int used_math = thread->used_cp[1] | thread->used_cp[2];
 401
 402         if (used_math)
 403                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 404
 405         return used_math != 0;
 406 }
 407 EXPORT_SYMBOL(dump_fpu);
 408
 409 /*
 410  * fill in the user structure for a core dump..
 411  */
 412 void dump_thread(struct pt_regs * regs, struct user * dump)
 413 {
 414         struct task_struct *tsk = current;
 415
 416         dump->magic = CMAGIC;
 417         dump->start_code = tsk->mm->start_code;
 418         dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);
 419
 420         dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
 421         dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
 422         dump->u_ssize = 0;
 423
 424         dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
 425         dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
 426         dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn.arm;
 427         dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn.arm;
 428         dump->u_debugreg[4] = tsk->thread.debug.nsaved;
 429
 430         if (dump->start_stack < 0x04000000)
 431                 dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;
 432
 433         dump->regs = *regs;
 434         dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
 435 }
 436 EXPORT_SYMBOL(dump_thread);
 437
 438 /*
 439  * Shuffle the argument into the correct register before calling the
 440  * thread function.  r1 is the thread argument, r2 is the pointer to
 441  * the thread function, and r3 points to the exit function.
 442  */
 443 extern void kernel_thread_helper(void);
 444 asm(    ".section .text\n"
 445 "       .align\n"
 446 "       .type   kernel_thread_helper, #function\n"
 447 "kernel_thread_helper:\n"
 448 "       mov     r0, r1\n"
 449 "       mov     lr, r3\n"
 450 "       mov     pc, r2\n"
 451 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 452 "       .previous");
 453
 454 /*
 455  * Create a kernel thread.
 456  */
 457 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 458 {
 459         struct pt_regs regs;
 460
 461         memset(&regs, 0, sizeof(regs));
 462
 463         regs.ARM_r1 = (unsigned long)arg;
 464         regs.ARM_r2 = (unsigned long)fn;
 465         regs.ARM_r3 = (unsigned long)do_exit;
 466         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 467         regs.ARM_cpsr = SVC_MODE;
 468
 469         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 470 }
 471 EXPORT_SYMBOL(kernel_thread);
 472
 473 unsigned long get_wchan(struct task_struct *p)
 474 {
 475         unsigned long fp, lr;
 476         unsigned long stack_start, stack_end;
 477         int count = 0;
 478         if (!p || p == current || p->state == TASK_RUNNING)
 479                 return 0;
 480
 481         stack_start = (unsigned long)end_of_stack(p);
 482         stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 483
 484         fp = thread_saved_fp(p);
 485         do {
 486                 if (fp < stack_start || fp > stack_end)
 487                         return 0;
 488                 lr = pc_pointer (((unsigned long *)fp)[-1]);
 489                 if (!in_sched_functions(lr))
 490                         return lr;
 491                 fp = *(unsigned long *) (fp - 12);
 492         } while (count ++ < 16);
 493         return 0;
 494 }