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/user.h>
  20 #include <linux/delay.h>
  21 #include <linux/reboot.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/kallsyms.h>
  24 #include <linux/init.h>
  25 #include <linux/cpu.h>
  26 #include <linux/elfcore.h>
  27 #include <linux/pm.h>
  28 #include <linux/tick.h>
  29 #include <linux/utsname.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/random.h>
  32
  33 #include <asm/cacheflush.h>
  34 #include <asm/leds.h>
  35 #include <asm/processor.h>
  36 #include <asm/system.h>
  37 #include <asm/thread_notify.h>
  38 #include <asm/stacktrace.h>
  39 #include <asm/mach/time.h>
  40
  41 #ifdef CONFIG_CC_STACKPROTECTOR
  42 #include <linux/stackprotector.h>
  43 unsigned long __stack_chk_guard __read_mostly;
  44 EXPORT_SYMBOL(__stack_chk_guard);
  45 #endif
  46
  47 static const char *processor_modes[] = {
  48   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  49   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  50   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
  51   "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  52 };
  53
  54 static const char *isa_modes[] = {
  55   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  56 };
  57
  58 extern void setup_mm_for_reboot(char mode);
  59
  60 static volatile int hlt_counter;
  61
  62 #include <mach/system.h>
  63
  64 void disable_hlt(void)
  65 {
  66         hlt_counter++;
  67 }
  68
  69 EXPORT_SYMBOL(disable_hlt);
  70
  71 void enable_hlt(void)
  72 {
  73         hlt_counter--;
  74 }
  75
  76 EXPORT_SYMBOL(enable_hlt);
  77
  78 static int __init nohlt_setup(char *__unused)
  79 {
  80         hlt_counter = 1;
  81         return 1;
  82 }
  83
  84 static int __init hlt_setup(char *__unused)
  85 {
  86         hlt_counter = 0;
  87         return 1;
  88 }
  89
  90 __setup("nohlt", nohlt_setup);
  91 __setup("hlt", hlt_setup);
  92
  93 void arm_machine_restart(char mode, const char *cmd)
  94 {
  95         /* Disable interrupts first */
  96         local_irq_disable();
  97         local_fiq_disable();
  98
  99         /*
 100          * Tell the mm system that we are going to reboot -
 101          * we may need it to insert some 1:1 mappings so that
 102          * soft boot works.
 103          */
 104         setup_mm_for_reboot(mode);
 105
 106         /* Clean and invalidate caches */
 107         flush_cache_all();
 108
 109         /* Turn off caching */
 110         cpu_proc_fin();
 111
 112         /* Push out any further dirty data, and ensure cache is empty */
 113         flush_cache_all();
 114
 115         /*
 116          * Now call the architecture specific reboot code.
 117          */
 118         arch_reset(mode, cmd);
 119
 120         /*
 121          * Whoops - the architecture was unable to reboot.
 122          * Tell the user!
 123          */
 124         mdelay(1000);
 125         printk("Reboot failed -- System halted\n");
 126         while (1);
 127 }
 128
 129 /*
 130  * Function pointers to optional machine specific functions
 131  */
 132 void (*pm_power_off)(void);
 133 EXPORT_SYMBOL(pm_power_off);
 134
 135 void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart;
 136 EXPORT_SYMBOL_GPL(arm_pm_restart);
 137
 138
 139 /*
 140  * This is our default idle handler.  We need to disable
 141  * interrupts here to ensure we don't miss a wakeup call.
 142  */
 143 static void default_idle(void)
 144 {
 145         if (!need_resched())
 146                 arch_idle();
 147         local_irq_enable();
 148 }
 149
 150 void (*pm_idle)(void) = default_idle;
 151 EXPORT_SYMBOL(pm_idle);
 152
 153 /*
 154  * The idle thread, has rather strange semantics for calling pm_idle,
 155  * but this is what x86 does and we need to do the same, so that
 156  * things like cpuidle get called in the same way.  The only difference
 157  * is that we always respect 'hlt_counter' to prevent low power idle.
 158  */
 159 void cpu_idle(void)
 160 {
 161         local_fiq_enable();
 162
 163         /* endless idle loop with no priority at all */
 164         while (1) {
 165                 tick_nohz_stop_sched_tick(1);
 166                 leds_event(led_idle_start);
 167                 while (!need_resched()) {
 168 #ifdef CONFIG_HOTPLUG_CPU
 169                         if (cpu_is_offline(smp_processor_id()))
 170                                 cpu_die();
 171 #endif
 172
 173                         local_irq_disable();
 174                         if (hlt_counter) {
 175                                 local_irq_enable();
 176                                 cpu_relax();
 177                         } else {
 178                                 stop_critical_timings();
 179                                 pm_idle();
 180                                 start_critical_timings();
 181                                 /*
 182                                  * This will eventually be removed - pm_idle
 183                                  * functions should always return with IRQs
 184                                  * enabled.
 185                                  */
 186                                 WARN_ON(irqs_disabled());
 187                                 local_irq_enable();
 188                         }
 189                 }
 190                 leds_event(led_idle_end);
 191                 tick_nohz_restart_sched_tick();
 192                 preempt_enable_no_resched();
 193                 schedule();
 194                 preempt_disable();
 195         }
 196 }
 197
 198 static char reboot_mode = 'h';
 199
 200 int __init reboot_setup(char *str)
 201 {
 202         reboot_mode = str[0];
 203         return 1;
 204 }
 205
 206 __setup("reboot=", reboot_setup);
 207
 208 void machine_shutdown(void)
 209 {
 210 #ifdef CONFIG_SMP
 211         smp_send_stop();
 212 #endif
 213 }
 214
 215 void machine_halt(void)
 216 {
 217         machine_shutdown();
 218         while (1);
 219 }
 220
 221 void machine_power_off(void)
 222 {
 223         machine_shutdown();
 224         if (pm_power_off)
 225                 pm_power_off();
 226 }
 227
 228 void machine_restart(char *cmd)
 229 {
 230         machine_shutdown();
 231         arm_pm_restart(reboot_mode, cmd);
 232 }
 233
 234 void __show_regs(struct pt_regs *regs)
 235 {
 236         unsigned long flags;
 237         char buf[64];
 238
 239         printk("CPU: %d    %s  (%s %.*s)\n",
 240                 raw_smp_processor_id(), print_tainted(),
 241                 init_utsname()->release,
 242                 (int)strcspn(init_utsname()->version, " "),
 243                 init_utsname()->version);
 244         print_symbol("PC is at %s\n", instruction_pointer(regs));
 245         print_symbol("LR is at %s\n", regs->ARM_lr);
 246         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 247                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 248                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 249                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 250         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 251                 regs->ARM_r10, regs->ARM_r9,
 252                 regs->ARM_r8);
 253         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 254                 regs->ARM_r7, regs->ARM_r6,
 255                 regs->ARM_r5, regs->ARM_r4);
 256         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 257                 regs->ARM_r3, regs->ARM_r2,
 258                 regs->ARM_r1, regs->ARM_r0);
 259
 260         flags = regs->ARM_cpsr;
 261         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 262         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 263         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 264         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 265         buf[4] = '\0';
 266
 267         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 268                 buf, interrupts_enabled(regs) ? "n" : "ff",
 269                 fast_interrupts_enabled(regs) ? "n" : "ff",
 270                 processor_modes[processor_mode(regs)],
 271                 isa_modes[isa_mode(regs)],
 272                 get_fs() == get_ds() ? "kernel" : "user");
 273 #ifdef CONFIG_CPU_CP15
 274         {
 275                 unsigned int ctrl;
 276
 277                 buf[0] = '\0';
 278 #ifdef CONFIG_CPU_CP15_MMU
 279                 {
 280                         unsigned int transbase, dac;
 281                         asm("mrc p15, 0, %0, c2, c0\n\t"
 282                             "mrc p15, 0, %1, c3, c0\n"
 283                             : "=r" (transbase), "=r" (dac));
 284                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 285                                 transbase, dac);
 286                 }
 287 #endif
 288                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 289
 290                 printk("Control: %08x%s\n", ctrl, buf);
 291         }
 292 #endif
 293 }
 294
 295 void show_regs(struct pt_regs * regs)
 296 {
 297         printk("\n");
 298         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 299         __show_regs(regs);
 300         __backtrace();
 301 }
 302
 303 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 304
 305 EXPORT_SYMBOL_GPL(thread_notify_head);
 306
 307 /*
 308  * Free current thread data structures etc..
 309  */
 310 void exit_thread(void)
 311 {
 312         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 313 }
 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         memset(&thread->fpstate, 0, sizeof(union fp_state));
 323
 324         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 325 }
 326
 327 void release_thread(struct task_struct *dead_task)
 328 {
 329 }
 330
 331 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 332
 333 int
 334 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 335             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 336 {
 337         struct thread_info *thread = task_thread_info(p);
 338         struct pt_regs *childregs = task_pt_regs(p);
 339
 340         *childregs = *regs;
 341         childregs->ARM_r0 = 0;
 342         childregs->ARM_sp = stack_start;
 343
 344         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 345         thread->cpu_context.sp = (unsigned long)childregs;
 346         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 347
 348         if (clone_flags & CLONE_SETTLS)
 349                 thread->tp_value = regs->ARM_r3;
 350
 351         return 0;
 352 }
 353
 354 /*
 355  * Fill in the task's elfregs structure for a core dump.
 356  */
 357 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 358 {
 359         elf_core_copy_regs(elfregs, task_pt_regs(t));
 360         return 1;
 361 }
 362
 363 /*
 364  * fill in the fpe structure for a core dump...
 365  */
 366 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 367 {
 368         struct thread_info *thread = current_thread_info();
 369         int used_math = thread->used_cp[1] | thread->used_cp[2];
 370
 371         if (used_math)
 372                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 373
 374         return used_math != 0;
 375 }
 376 EXPORT_SYMBOL(dump_fpu);
 377
 378 /*
 379  * Shuffle the argument into the correct register before calling the
 380  * thread function.  r4 is the thread argument, r5 is the pointer to
 381  * the thread function, and r6 points to the exit function.
 382  */
 383 extern void kernel_thread_helper(void);
 384 asm(    ".pushsection .text\n"
 385 "       .align\n"
 386 "       .type   kernel_thread_helper, #function\n"
 387 "kernel_thread_helper:\n"
 388 #ifdef CONFIG_TRACE_IRQFLAGS
 389 "       bl      trace_hardirqs_on\n"
 390 #endif
 391 "       msr     cpsr_c, r7\n"
 392 "       mov     r0, r4\n"
 393 "       mov     lr, r6\n"
 394 "       mov     pc, r5\n"
 395 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 396 "       .popsection");
 397
 398 #ifdef CONFIG_ARM_UNWIND
 399 extern void kernel_thread_exit(long code);
 400 asm(    ".pushsection .text\n"
 401 "       .align\n"
 402 "       .type   kernel_thread_exit, #function\n"
 403 "kernel_thread_exit:\n"
 404 "       .fnstart\n"
 405 "       .cantunwind\n"
 406 "       bl      do_exit\n"
 407 "       nop\n"
 408 "       .fnend\n"
 409 "       .size   kernel_thread_exit, . - kernel_thread_exit\n"
 410 "       .popsection");
 411 #else
 412 #define kernel_thread_exit      do_exit
 413 #endif
 414
 415 /*
 416  * Create a kernel thread.
 417  */
 418 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 419 {
 420         struct pt_regs regs;
 421
 422         memset(&regs, 0, sizeof(regs));
 423
 424         regs.ARM_r4 = (unsigned long)arg;
 425         regs.ARM_r5 = (unsigned long)fn;
 426         regs.ARM_r6 = (unsigned long)kernel_thread_exit;
 427         regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
 428         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 429         regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT;
 430
 431         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 432 }
 433 EXPORT_SYMBOL(kernel_thread);
 434
 435 unsigned long get_wchan(struct task_struct *p)
 436 {
 437         struct stackframe frame;
 438         int count = 0;
 439         if (!p || p == current || p->state == TASK_RUNNING)
 440                 return 0;
 441
 442         frame.fp = thread_saved_fp(p);
 443         frame.sp = thread_saved_sp(p);
 444         frame.lr = 0;                   /* recovered from the stack */
 445         frame.pc = thread_saved_pc(p);
 446         do {
 447                 int ret = unwind_frame(&frame);
 448                 if (ret < 0)
 449                         return 0;
 450                 if (!in_sched_functions(frame.pc))
 451                         return frame.pc;
 452         } while (count ++ < 16);
 453         return 0;
 454 }
 455
 456 unsigned long arch_randomize_brk(struct mm_struct *mm)
 457 {
 458         unsigned long range_end = mm->brk + 0x02000000;
 459         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 460 }
 461
 462 /*
 463  * The vectors page is always readable from user space for the
 464  * atomic helpers and the signal restart code.  Let's declare a mapping
 465  * for it so it is visible through ptrace and /proc/<pid>/mem.
 466  */
 467
 468 int vectors_user_mapping(void)
 469 {
 470         struct mm_struct *mm = current->mm;
 471         return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
 472                                        VM_READ | VM_EXEC |
 473                                        VM_MAYREAD | VM_MAYEXEC |
 474                                        VM_ALWAYSDUMP | VM_RESERVED,
 475                                        NULL);
 476 }
 477
 478 const char *arch_vma_name(struct vm_area_struct *vma)
 479 {
 480         return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;
 481 }