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