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/module.h>
  14 #include <linux/sched.h>
  15 #include <linux/kernel.h>
  16 #include <linux/mm.h>
  17 #include <linux/stddef.h>
  18 #include <linux/unistd.h>
  19 #include <linux/slab.h>
  20 #include <linux/user.h>
  21 #include <linux/a.out.h>
  22 #include <linux/delay.h>
  23 #include <linux/reboot.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/kallsyms.h>
  26 #include <linux/init.h>
  27 #include <linux/cpu.h>
  28 #include <linux/elfcore.h>
  29 #include <linux/pm.h>
  30 #include <linux/tick.h>
  31
  32 #include <asm/leds.h>
  33 #include <asm/processor.h>
  34 #include <asm/system.h>
  35 #include <asm/thread_notify.h>
  36 #include <asm/uaccess.h>
  37 #include <asm/mach/time.h>
  38
  39 static const char *processor_modes[] = {
  40   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  41   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  42   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
  43   "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  44 };
  45
  46 extern void setup_mm_for_reboot(char mode);
  47
  48 static volatile int hlt_counter;
  49
  50 #include <asm/arch/system.h>
  51
  52 void disable_hlt(void)
  53 {
  54         hlt_counter++;
  55 }
  56
  57 EXPORT_SYMBOL(disable_hlt);
  58
  59 void enable_hlt(void)
  60 {
  61         hlt_counter--;
  62 }
  63
  64 EXPORT_SYMBOL(enable_hlt);
  65
  66 static int __init nohlt_setup(char *__unused)
  67 {
  68         hlt_counter = 1;
  69         return 1;
  70 }
  71
  72 static int __init hlt_setup(char *__unused)
  73 {
  74         hlt_counter = 0;
  75         return 1;
  76 }
  77
  78 __setup("nohlt", nohlt_setup);
  79 __setup("hlt", hlt_setup);
  80
  81 void arm_machine_restart(char mode)
  82 {
  83         /*
  84          * Clean and disable cache, and turn off interrupts
  85          */
  86         cpu_proc_fin();
  87
  88         /*
  89          * Tell the mm system that we are going to reboot -
  90          * we may need it to insert some 1:1 mappings so that
  91          * soft boot works.
  92          */
  93         setup_mm_for_reboot(mode);
  94
  95         /*
  96          * Now call the architecture specific reboot code.
  97          */
  98         arch_reset(mode);
  99
 100         /*
 101          * Whoops - the architecture was unable to reboot.
 102          * Tell the user!
 103          */
 104         mdelay(1000);
 105         printk("Reboot failed -- System halted\n");
 106         while (1);
 107 }
 108
 109 /*
 110  * Function pointers to optional machine specific functions
 111  */
 112 void (*pm_idle)(void);
 113 EXPORT_SYMBOL(pm_idle);
 114
 115 void (*pm_power_off)(void);
 116 EXPORT_SYMBOL(pm_power_off);
 117
 118 void (*arm_pm_restart)(char str) = arm_machine_restart;
 119 EXPORT_SYMBOL_GPL(arm_pm_restart);
 120
 121
 122 /*
 123  * This is our default idle handler.  We need to disable
 124  * interrupts here to ensure we don't miss a wakeup call.
 125  */
 126 static void default_idle(void)
 127 {
 128         if (hlt_counter)
 129                 cpu_relax();
 130         else {
 131                 local_irq_disable();
 132                 if (!need_resched()) {
 133                         timer_dyn_reprogram();
 134                         arch_idle();
 135                 }
 136                 local_irq_enable();
 137         }
 138 }
 139
 140 /*
 141  * The idle thread.  We try to conserve power, while trying to keep
 142  * overall latency low.  The architecture specific idle is passed
 143  * a value to indicate the level of "idleness" of the system.
 144  */
 145 void cpu_idle(void)
 146 {
 147         local_fiq_enable();
 148
 149         /* endless idle loop with no priority at all */
 150         while (1) {
 151                 void (*idle)(void) = pm_idle;
 152
 153 #ifdef CONFIG_HOTPLUG_CPU
 154                 if (cpu_is_offline(smp_processor_id())) {
 155                         leds_event(led_idle_start);
 156                         cpu_die();
 157                 }
 158 #endif
 159
 160                 if (!idle)
 161                         idle = default_idle;
 162                 leds_event(led_idle_start);
 163                 tick_nohz_stop_sched_tick();
 164                 while (!need_resched())
 165                         idle();
 166                 leds_event(led_idle_end);
 167                 tick_nohz_restart_sched_tick();
 168                 preempt_enable_no_resched();
 169                 schedule();
 170                 preempt_disable();
 171         }
 172 }
 173
 174 static char reboot_mode = 'h';
 175
 176 int __init reboot_setup(char *str)
 177 {
 178         reboot_mode = str[0];
 179         return 1;
 180 }
 181
 182 __setup("reboot=", reboot_setup);
 183
 184 void machine_halt(void)
 185 {
 186 }
 187
 188
 189 void machine_power_off(void)
 190 {
 191         if (pm_power_off)
 192                 pm_power_off();
 193 }
 194
 195 void machine_restart(char * __unused)
 196 {
 197         arm_pm_restart(reboot_mode);
 198 }
 199
 200 void __show_regs(struct pt_regs *regs)
 201 {
 202         unsigned long flags = condition_codes(regs);
 203
 204         printk("CPU: %d\n", smp_processor_id());
 205         print_symbol("PC is at %s\n", instruction_pointer(regs));
 206         print_symbol("LR is at %s\n", regs->ARM_lr);
 207         printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
 208                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 209                 instruction_pointer(regs),
 210                 regs->ARM_lr, print_tainted(), regs->ARM_sp,
 211                 regs->ARM_ip, regs->ARM_fp);
 212         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 213                 regs->ARM_r10, regs->ARM_r9,
 214                 regs->ARM_r8);
 215         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 216                 regs->ARM_r7, regs->ARM_r6,
 217                 regs->ARM_r5, regs->ARM_r4);
 218         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 219                 regs->ARM_r3, regs->ARM_r2,
 220                 regs->ARM_r1, regs->ARM_r0);
 221         printk("Flags: %c%c%c%c",
 222                 flags & PSR_N_BIT ? 'N' : 'n',
 223                 flags & PSR_Z_BIT ? 'Z' : 'z',
 224                 flags & PSR_C_BIT ? 'C' : 'c',
 225                 flags & PSR_V_BIT ? 'V' : 'v');
 226         printk("  IRQs o%s  FIQs o%s  Mode %s%s  Segment %s\n",
 227                 interrupts_enabled(regs) ? "n" : "ff",
 228                 fast_interrupts_enabled(regs) ? "n" : "ff",
 229                 processor_modes[processor_mode(regs)],
 230                 thumb_mode(regs) ? " (T)" : "",
 231                 get_fs() == get_ds() ? "kernel" : "user");
 232 #if CONFIG_CPU_CP15
 233         {
 234                 unsigned int ctrl;
 235                   __asm__ (
 236                 "       mrc p15, 0, %0, c1, c0\n"
 237                 : "=r" (ctrl));
 238                 printk("Control: %04X\n", ctrl);
 239         }
 240 #ifdef CONFIG_CPU_CP15_MMU
 241         {
 242                 unsigned int transbase, dac;
 243                   __asm__ (
 244                 "       mrc p15, 0, %0, c2, c0\n"
 245                 "       mrc p15, 0, %1, c3, c0\n"
 246                 : "=r" (transbase), "=r" (dac));
 247                 printk("Table: %08X  DAC: %08X\n",
 248                         transbase, dac);
 249         }
 250 #endif
 251 #endif
 252 }
 253
 254 void show_regs(struct pt_regs * regs)
 255 {
 256         printk("\n");
 257         printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
 258         __show_regs(regs);
 259         __backtrace();
 260 }
 261
 262 void show_fpregs(struct user_fp *regs)
 263 {
 264         int i;
 265
 266         for (i = 0; i < 8; i++) {
 267                 unsigned long *p;
 268                 char type;
 269
 270                 p = (unsigned long *)(regs->fpregs + i);
 271
 272                 switch (regs->ftype[i]) {
 273                         case 1: type = 'f'; break;
 274                         case 2: type = 'd'; break;
 275                         case 3: type = 'e'; break;
 276                         default: type = '?'; break;
 277                 }
 278                 if (regs->init_flag)
 279                         type = '?';
 280
 281                 printk("  f%d(%c): %08lx %08lx %08lx%c",
 282                         i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
 283         }
 284
 285
 286         printk("FPSR: %08lx FPCR: %08lx\n",
 287                 (unsigned long)regs->fpsr,
 288                 (unsigned long)regs->fpcr);
 289 }
 290
 291 /*
 292  * Free current thread data structures etc..
 293  */
 294 void exit_thread(void)
 295 {
 296 }
 297
 298 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 299
 300 EXPORT_SYMBOL_GPL(thread_notify_head);
 301
 302 void flush_thread(void)
 303 {
 304         struct thread_info *thread = current_thread_info();
 305         struct task_struct *tsk = current;
 306
 307         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 308         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 309         memset(&thread->fpstate, 0, sizeof(union fp_state));
 310
 311         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 312 }
 313
 314 void release_thread(struct task_struct *dead_task)
 315 {
 316         struct thread_info *thread = task_thread_info(dead_task);
 317
 318         thread_notify(THREAD_NOTIFY_RELEASE, thread);
 319 }
 320
 321 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 322
 323 int
 324 copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
 325             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 326 {
 327         struct thread_info *thread = task_thread_info(p);
 328         struct pt_regs *childregs = task_pt_regs(p);
 329
 330         *childregs = *regs;
 331         childregs->ARM_r0 = 0;
 332         childregs->ARM_sp = stack_start;
 333
 334         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 335         thread->cpu_context.sp = (unsigned long)childregs;
 336         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 337
 338         if (clone_flags & CLONE_SETTLS)
 339                 thread->tp_value = regs->ARM_r3;
 340
 341         return 0;
 342 }
 343
 344 /*
 345  * fill in the fpe structure for a core dump...
 346  */
 347 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 348 {
 349         struct thread_info *thread = current_thread_info();
 350         int used_math = thread->used_cp[1] | thread->used_cp[2];
 351
 352         if (used_math)
 353                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 354
 355         return used_math != 0;
 356 }
 357 EXPORT_SYMBOL(dump_fpu);
 358
 359 /*
 360  * fill in the user structure for a core dump..
 361  */
 362 void dump_thread(struct pt_regs * regs, struct user * dump)
 363 {
 364         struct task_struct *tsk = current;
 365
 366         dump->magic = CMAGIC;
 367         dump->start_code = tsk->mm->start_code;
 368         dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);
 369
 370         dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
 371         dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
 372         dump->u_ssize = 0;
 373
 374         dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
 375         dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
 376         dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn.arm;
 377         dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn.arm;
 378         dump->u_debugreg[4] = tsk->thread.debug.nsaved;
 379
 380         if (dump->start_stack < 0x04000000)
 381                 dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;
 382
 383         dump->regs = *regs;
 384         dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
 385 }
 386 EXPORT_SYMBOL(dump_thread);
 387
 388 /*
 389  * Shuffle the argument into the correct register before calling the
 390  * thread function.  r1 is the thread argument, r2 is the pointer to
 391  * the thread function, and r3 points to the exit function.
 392  */
 393 extern void kernel_thread_helper(void);
 394 asm(    ".section .text\n"
 395 "       .align\n"
 396 "       .type   kernel_thread_helper, #function\n"
 397 "kernel_thread_helper:\n"
 398 "       mov     r0, r1\n"
 399 "       mov     lr, r3\n"
 400 "       mov     pc, r2\n"
 401 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 402 "       .previous");
 403
 404 /*
 405  * Create a kernel thread.
 406  */
 407 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 408 {
 409         struct pt_regs regs;
 410
 411         memset(&regs, 0, sizeof(regs));
 412
 413         regs.ARM_r1 = (unsigned long)arg;
 414         regs.ARM_r2 = (unsigned long)fn;
 415         regs.ARM_r3 = (unsigned long)do_exit;
 416         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 417         regs.ARM_cpsr = SVC_MODE;
 418
 419         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 420 }
 421 EXPORT_SYMBOL(kernel_thread);
 422
 423 unsigned long get_wchan(struct task_struct *p)
 424 {
 425         unsigned long fp, lr;
 426         unsigned long stack_start, stack_end;
 427         int count = 0;
 428         if (!p || p == current || p->state == TASK_RUNNING)
 429                 return 0;
 430
 431         stack_start = (unsigned long)end_of_stack(p);
 432         stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 433
 434         fp = thread_saved_fp(p);
 435         do {
 436                 if (fp < stack_start || fp > stack_end)
 437                         return 0;
 438                 lr = pc_pointer (((unsigned long *)fp)[-1]);
 439                 if (!in_sched_functions(lr))
 440                         return lr;
 441                 fp = *(unsigned long *) (fp - 12);
 442         } while (count ++ < 16);
 443         return 0;
 444 }