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/delay.h>
  22 #include <linux/reboot.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/kallsyms.h>
  25 #include <linux/init.h>
  26 #include <linux/cpu.h>
  27 #include <linux/elfcore.h>
  28 #include <linux/pm.h>
  29 #include <linux/tick.h>
  30 #include <linux/utsname.h>
  31 #include <linux/uaccess.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/stacktrace.h>
  38 #include <asm/mach/time.h>
  39
  40 static const char *processor_modes[] = {
  41   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  42   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  43   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
  44   "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  45 };
  46
  47 static const char *isa_modes[] = {
  48   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  49 };
  50
  51 extern void setup_mm_for_reboot(char mode);
  52
  53 static volatile int hlt_counter;
  54
  55 #include <mach/system.h>
  56
  57 void disable_hlt(void)
  58 {
  59         hlt_counter++;
  60 }
  61
  62 EXPORT_SYMBOL(disable_hlt);
  63
  64 void enable_hlt(void)
  65 {
  66         hlt_counter--;
  67 }
  68
  69 EXPORT_SYMBOL(enable_hlt);
  70
  71 static int __init nohlt_setup(char *__unused)
  72 {
  73         hlt_counter = 1;
  74         return 1;
  75 }
  76
  77 static int __init hlt_setup(char *__unused)
  78 {
  79         hlt_counter = 0;
  80         return 1;
  81 }
  82
  83 __setup("nohlt", nohlt_setup);
  84 __setup("hlt", hlt_setup);
  85
  86 void arm_machine_restart(char mode, const char *cmd)
  87 {
  88         /*
  89          * Clean and disable cache, and turn off interrupts
  90          */
  91         cpu_proc_fin();
  92
  93         /*
  94          * Tell the mm system that we are going to reboot -
  95          * we may need it to insert some 1:1 mappings so that
  96          * soft boot works.
  97          */
  98         setup_mm_for_reboot(mode);
  99
 100         /*
 101          * Now call the architecture specific reboot code.
 102          */
 103         arch_reset(mode, cmd);
 104
 105         /*
 106          * Whoops - the architecture was unable to reboot.
 107          * Tell the user!
 108          */
 109         mdelay(1000);
 110         printk("Reboot failed -- System halted\n");
 111         while (1);
 112 }
 113
 114 /*
 115  * Function pointers to optional machine specific functions
 116  */
 117 void (*pm_power_off)(void);
 118 EXPORT_SYMBOL(pm_power_off);
 119
 120 void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart;
 121 EXPORT_SYMBOL_GPL(arm_pm_restart);
 122
 123
 124 /*
 125  * This is our default idle handler.  We need to disable
 126  * interrupts here to ensure we don't miss a wakeup call.
 127  */
 128 static void default_idle(void)
 129 {
 130         if (!need_resched())
 131                 arch_idle();
 132         local_irq_enable();
 133 }
 134
 135 void (*pm_idle)(void) = default_idle;
 136 EXPORT_SYMBOL(pm_idle);
 137
 138 /*
 139  * The idle thread, has rather strange semantics for calling pm_idle,
 140  * but this is what x86 does and we need to do the same, so that
 141  * things like cpuidle get called in the same way.  The only difference
 142  * is that we always respect 'hlt_counter' to prevent low power idle.
 143  */
 144 void cpu_idle(void)
 145 {
 146         local_fiq_enable();
 147
 148         /* endless idle loop with no priority at all */
 149         while (1) {
 150                 tick_nohz_stop_sched_tick(1);
 151                 leds_event(led_idle_start);
 152                 while (!need_resched()) {
 153 #ifdef CONFIG_HOTPLUG_CPU
 154                         if (cpu_is_offline(smp_processor_id()))
 155                                 cpu_die();
 156 #endif
 157
 158                         local_irq_disable();
 159                         if (hlt_counter) {
 160                                 local_irq_enable();
 161                                 cpu_relax();
 162                         } else {
 163                                 stop_critical_timings();
 164                                 pm_idle();
 165                                 start_critical_timings();
 166                                 /*
 167                                  * This will eventually be removed - pm_idle
 168                                  * functions should always return with IRQs
 169                                  * enabled.
 170                                  */
 171                                 WARN_ON(irqs_disabled());
 172                                 local_irq_enable();
 173                         }
 174                 }
 175                 leds_event(led_idle_end);
 176                 tick_nohz_restart_sched_tick();
 177                 preempt_enable_no_resched();
 178                 schedule();
 179                 preempt_disable();
 180         }
 181 }
 182
 183 static char reboot_mode = 'h';
 184
 185 int __init reboot_setup(char *str)
 186 {
 187         reboot_mode = str[0];
 188         return 1;
 189 }
 190
 191 __setup("reboot=", reboot_setup);
 192
 193 void machine_halt(void)
 194 {
 195 }
 196
 197
 198 void machine_power_off(void)
 199 {
 200         if (pm_power_off)
 201                 pm_power_off();
 202 }
 203
 204 void machine_restart(char *cmd)
 205 {
 206         arm_pm_restart(reboot_mode, cmd);
 207 }
 208
 209 /*
 210  * dump a block of kernel memory from around the given address
 211  */
 212 static void show_data(unsigned long addr, int nbytes, const char *name)
 213 {
 214         int     i, j;
 215         int     nlines;
 216         u32     *p;
 217
 218         /*
 219          * don't attempt to dump non-kernel addresses or
 220          * values that are probably just small negative numbers
 221          */
 222         if (addr < PAGE_OFFSET || addr > -256UL)
 223                 return;
 224
 225         printk("\n%s: %#lx:\n", name, addr);
 226
 227         /*
 228          * round address down to a 32 bit boundary
 229          * and always dump a multiple of 32 bytes
 230          */
 231         p = (u32 *)(addr & ~(sizeof(u32) - 1));
 232         nbytes += (addr & (sizeof(u32) - 1));
 233         nlines = (nbytes + 31) / 32;
 234
 235
 236         for (i = 0; i < nlines; i++) {
 237                 /*
 238                  * just display low 16 bits of address to keep
 239                  * each line of the dump < 80 characters
 240                  */
 241                 printk("%04lx ", (unsigned long)p & 0xffff);
 242                 for (j = 0; j < 8; j++) {
 243                         u32     data;
 244                         if (probe_kernel_address(p, data)) {
 245                                 printk(" ********");
 246                         } else {
 247                                 printk(" %08x", data);
 248                         }
 249                         ++p;
 250                 }
 251                 printk("\n");
 252         }
 253 }
 254
 255 static void show_extra_register_data(struct pt_regs *regs, int nbytes)
 256 {
 257         mm_segment_t fs;
 258
 259         fs = get_fs();
 260         set_fs(KERNEL_DS);
 261         show_data(regs->ARM_pc - nbytes, nbytes * 2, "PC");
 262         show_data(regs->ARM_lr - nbytes, nbytes * 2, "LR");
 263         show_data(regs->ARM_sp - nbytes, nbytes * 2, "SP");
 264         show_data(regs->ARM_ip - nbytes, nbytes * 2, "IP");
 265         show_data(regs->ARM_fp - nbytes, nbytes * 2, "FP");
 266         show_data(regs->ARM_r0 - nbytes, nbytes * 2, "R0");
 267         show_data(regs->ARM_r1 - nbytes, nbytes * 2, "R1");
 268         show_data(regs->ARM_r2 - nbytes, nbytes * 2, "R2");
 269         show_data(regs->ARM_r3 - nbytes, nbytes * 2, "R3");
 270         show_data(regs->ARM_r4 - nbytes, nbytes * 2, "R4");
 271         show_data(regs->ARM_r5 - nbytes, nbytes * 2, "R5");
 272         show_data(regs->ARM_r6 - nbytes, nbytes * 2, "R6");
 273         show_data(regs->ARM_r7 - nbytes, nbytes * 2, "R7");
 274         show_data(regs->ARM_r8 - nbytes, nbytes * 2, "R8");
 275         show_data(regs->ARM_r9 - nbytes, nbytes * 2, "R9");
 276         show_data(regs->ARM_r10 - nbytes, nbytes * 2, "R10");
 277         set_fs(fs);
 278 }
 279
 280 void __show_regs(struct pt_regs *regs)
 281 {
 282         unsigned long flags;
 283         char buf[64];
 284
 285         printk("CPU: %d    %s  (%s %.*s)\n",
 286                 smp_processor_id(), print_tainted(), init_utsname()->release,
 287                 (int)strcspn(init_utsname()->version, " "),
 288                 init_utsname()->version);
 289         print_symbol("PC is at %s\n", instruction_pointer(regs));
 290         print_symbol("LR is at %s\n", regs->ARM_lr);
 291         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 292                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 293                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 294                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 295         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 296                 regs->ARM_r10, regs->ARM_r9,
 297                 regs->ARM_r8);
 298         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 299                 regs->ARM_r7, regs->ARM_r6,
 300                 regs->ARM_r5, regs->ARM_r4);
 301         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 302                 regs->ARM_r3, regs->ARM_r2,
 303                 regs->ARM_r1, regs->ARM_r0);
 304
 305         flags = regs->ARM_cpsr;
 306         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 307         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 308         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 309         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 310         buf[4] = '\0';
 311
 312         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 313                 buf, interrupts_enabled(regs) ? "n" : "ff",
 314                 fast_interrupts_enabled(regs) ? "n" : "ff",
 315                 processor_modes[processor_mode(regs)],
 316                 isa_modes[isa_mode(regs)],
 317                 get_fs() == get_ds() ? "kernel" : "user");
 318 #ifdef CONFIG_CPU_CP15
 319         {
 320                 unsigned int ctrl;
 321
 322                 buf[0] = '\0';
 323 #ifdef CONFIG_CPU_CP15_MMU
 324                 {
 325                         unsigned int transbase, dac;
 326                         asm("mrc p15, 0, %0, c2, c0\n\t"
 327                             "mrc p15, 0, %1, c3, c0\n"
 328                             : "=r" (transbase), "=r" (dac));
 329                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 330                                 transbase, dac);
 331                 }
 332 #endif
 333                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 334
 335                 printk("Control: %08x%s\n", ctrl, buf);
 336         }
 337 #endif
 338
 339         show_extra_register_data(regs, 128);
 340 }
 341
 342 void show_regs(struct pt_regs * regs)
 343 {
 344         printk("\n");
 345         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 346         __show_regs(regs);
 347         __backtrace();
 348 }
 349
 350 /*
 351  * Free current thread data structures etc..
 352  */
 353 void exit_thread(void)
 354 {
 355 }
 356
 357 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 358
 359 EXPORT_SYMBOL_GPL(thread_notify_head);
 360
 361 void flush_thread(void)
 362 {
 363         struct thread_info *thread = current_thread_info();
 364         struct task_struct *tsk = current;
 365
 366         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 367         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 368         memset(&thread->fpstate, 0, sizeof(union fp_state));
 369
 370         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 371 }
 372
 373 void release_thread(struct task_struct *dead_task)
 374 {
 375         struct thread_info *thread = task_thread_info(dead_task);
 376
 377         thread_notify(THREAD_NOTIFY_RELEASE, thread);
 378 }
 379
 380 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 381
 382 int
 383 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 384             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 385 {
 386         struct thread_info *thread = task_thread_info(p);
 387         struct pt_regs *childregs = task_pt_regs(p);
 388
 389         *childregs = *regs;
 390         childregs->ARM_r0 = 0;
 391         childregs->ARM_sp = stack_start;
 392
 393         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 394         thread->cpu_context.sp = (unsigned long)childregs;
 395         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 396
 397         if (clone_flags & CLONE_SETTLS)
 398                 thread->tp_value = regs->ARM_r3;
 399
 400         return 0;
 401 }
 402
 403 /*
 404  * Fill in the task's elfregs structure for a core dump.
 405  */
 406 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 407 {
 408         elf_core_copy_regs(elfregs, task_pt_regs(t));
 409         return 1;
 410 }
 411
 412 /*
 413  * fill in the fpe structure for a core dump...
 414  */
 415 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 416 {
 417         struct thread_info *thread = current_thread_info();
 418         int used_math = thread->used_cp[1] | thread->used_cp[2];
 419
 420         if (used_math)
 421                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 422
 423         return used_math != 0;
 424 }
 425 EXPORT_SYMBOL(dump_fpu);
 426
 427 /*
 428  * Shuffle the argument into the correct register before calling the
 429  * thread function.  r1 is the thread argument, r2 is the pointer to
 430  * the thread function, and r3 points to the exit function.
 431  */
 432 extern void kernel_thread_helper(void);
 433 asm(    ".section .text\n"
 434 "       .align\n"
 435 "       .type   kernel_thread_helper, #function\n"
 436 "kernel_thread_helper:\n"
 437 "       mov     r0, r1\n"
 438 "       mov     lr, r3\n"
 439 "       mov     pc, r2\n"
 440 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 441 "       .previous");
 442
 443 #ifdef CONFIG_ARM_UNWIND
 444 extern void kernel_thread_exit(long code);
 445 asm(    ".section .text\n"
 446 "       .align\n"
 447 "       .type   kernel_thread_exit, #function\n"
 448 "kernel_thread_exit:\n"
 449 "       .fnstart\n"
 450 "       .cantunwind\n"
 451 "       bl      do_exit\n"
 452 "       nop\n"
 453 "       .fnend\n"
 454 "       .size   kernel_thread_exit, . - kernel_thread_exit\n"
 455 "       .previous");
 456 #else
 457 #define kernel_thread_exit      do_exit
 458 #endif
 459
 460 /*
 461  * Create a kernel thread.
 462  */
 463 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 464 {
 465         struct pt_regs regs;
 466
 467         memset(&regs, 0, sizeof(regs));
 468
 469         regs.ARM_r1 = (unsigned long)arg;
 470         regs.ARM_r2 = (unsigned long)fn;
 471         regs.ARM_r3 = (unsigned long)kernel_thread_exit;
 472         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 473         regs.ARM_cpsr = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
 474
 475         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 476 }
 477 EXPORT_SYMBOL(kernel_thread);
 478
 479 unsigned long get_wchan(struct task_struct *p)
 480 {
 481         struct stackframe frame;
 482         int count = 0;
 483         if (!p || p == current || p->state == TASK_RUNNING)
 484                 return 0;
 485
 486         frame.fp = thread_saved_fp(p);
 487         frame.sp = thread_saved_sp(p);
 488         frame.lr = 0;                   /* recovered from the stack */
 489         frame.pc = thread_saved_pc(p);
 490         do {
 491                 int ret = unwind_frame(&frame);
 492                 if (ret < 0)
 493                         return 0;
 494                 if (!in_sched_functions(frame.pc))
 495                         return frame.pc;
 496         } while (count ++ < 16);
 497         return 0;
 498 }