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