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