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/export.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 #include <linux/hw_breakpoint.h>
  33 #include <linux/cpuidle.h>
  34
  35 #include <asm/cacheflush.h>
  36 #include <asm/leds.h>
  37 #include <asm/processor.h>
  38 #include <asm/system.h>
  39 #include <asm/thread_notify.h>
  40 #include <asm/stacktrace.h>
  41 #include <asm/mach/time.h>
  42
  43 #ifdef CONFIG_CC_STACKPROTECTOR
  44 #include <linux/stackprotector.h>
  45 unsigned long __stack_chk_guard __read_mostly;
  46 EXPORT_SYMBOL(__stack_chk_guard);
  47 #endif
  48
  49 static const char *processor_modes[] = {
  50   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  51   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  52   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
  53   "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  54 };
  55
  56 static const char *isa_modes[] = {
  57   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  58 };
  59
  60 extern void setup_mm_for_reboot(char mode);
  61
  62 static volatile int hlt_counter;
  63
  64 #include <mach/system.h>
  65
  66 void disable_hlt(void)
  67 {
  68         hlt_counter++;
  69 }
  70
  71 EXPORT_SYMBOL(disable_hlt);
  72
  73 void enable_hlt(void)
  74 {
  75         hlt_counter--;
  76 }
  77
  78 EXPORT_SYMBOL(enable_hlt);
  79
  80 static int __init nohlt_setup(char *__unused)
  81 {
  82         hlt_counter = 1;
  83         return 1;
  84 }
  85
  86 static int __init hlt_setup(char *__unused)
  87 {
  88         hlt_counter = 0;
  89         return 1;
  90 }
  91
  92 __setup("nohlt", nohlt_setup);
  93 __setup("hlt", hlt_setup);
  94
  95 void arm_machine_restart(char mode, const char *cmd)
  96 {
  97         /* Disable interrupts first */
  98         local_irq_disable();
  99         local_fiq_disable();
 100
 101         /*
 102          * Tell the mm system that we are going to reboot -
 103          * we may need it to insert some 1:1 mappings so that
 104          * soft boot works.
 105          */
 106         setup_mm_for_reboot(mode);
 107
 108         /* Clean and invalidate caches */
 109         flush_cache_all();
 110
 111         /* Turn off caching */
 112         cpu_proc_fin();
 113
 114         /* Push out any further dirty data, and ensure cache is empty */
 115         flush_cache_all();
 116
 117         /*
 118          * Now call the architecture specific reboot code.
 119          */
 120         arch_reset(mode, cmd);
 121
 122         /*
 123          * Whoops - the architecture was unable to reboot.
 124          * Tell the user!
 125          */
 126         mdelay(1000);
 127         printk("Reboot failed -- System halted\n");
 128         local_irq_disable();
 129         while (1);
 130 }
 131
 132 /*
 133  * Function pointers to optional machine specific functions
 134  */
 135 void (*pm_power_off)(void);
 136 EXPORT_SYMBOL(pm_power_off);
 137
 138 void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart;
 139 EXPORT_SYMBOL_GPL(arm_pm_restart);
 140
 141 static void do_nothing(void *unused)
 142 {
 143 }
 144
 145 /*
 146  * cpu_idle_wait - Used to ensure that all the CPUs discard old value of
 147  * pm_idle and update to new pm_idle value. Required while changing pm_idle
 148  * handler on SMP systems.
 149  *
 150  * Caller must have changed pm_idle to the new value before the call. Old
 151  * pm_idle value will not be used by any CPU after the return of this function.
 152  */
 153 void cpu_idle_wait(void)
 154 {
 155         smp_mb();
 156         /* kick all the CPUs so that they exit out of pm_idle */
 157         smp_call_function(do_nothing, NULL, 1);
 158 }
 159 EXPORT_SYMBOL_GPL(cpu_idle_wait);
 160
 161 /*
 162  * This is our default idle handler.  We need to disable
 163  * interrupts here to ensure we don't miss a wakeup call.
 164  */
 165 static void default_idle(void)
 166 {
 167         if (!need_resched())
 168                 arch_idle();
 169         local_irq_enable();
 170 }
 171
 172 void (*pm_idle)(void) = default_idle;
 173 EXPORT_SYMBOL(pm_idle);
 174
 175 /*
 176  * The idle thread, has rather strange semantics for calling pm_idle,
 177  * but this is what x86 does and we need to do the same, so that
 178  * things like cpuidle get called in the same way.  The only difference
 179  * is that we always respect 'hlt_counter' to prevent low power idle.
 180  */
 181 void cpu_idle(void)
 182 {
 183         local_fiq_enable();
 184
 185         /* endless idle loop with no priority at all */
 186         while (1) {
 187                 tick_nohz_stop_sched_tick(1);
 188                 leds_event(led_idle_start);
 189                 while (!need_resched()) {
 190 #ifdef CONFIG_HOTPLUG_CPU
 191                         if (cpu_is_offline(smp_processor_id()))
 192                                 cpu_die();
 193 #endif
 194
 195                         local_irq_disable();
 196 #ifdef CONFIG_PL310_ERRATA_769419
 197                         wmb();
 198 #endif
 199                         if (hlt_counter) {
 200                                 local_irq_enable();
 201                                 cpu_relax();
 202                         } else {
 203                                 stop_critical_timings();
 204                                 if (cpuidle_idle_call())
 205                                         pm_idle();
 206                                 start_critical_timings();
 207                                 /*
 208                                  * This will eventually be removed - pm_idle
 209                                  * functions should always return with IRQs
 210                                  * enabled.
 211                                  */
 212                                 WARN_ON(irqs_disabled());
 213                                 local_irq_enable();
 214                         }
 215                 }
 216                 leds_event(led_idle_end);
 217                 tick_nohz_restart_sched_tick();
 218                 preempt_enable_no_resched();
 219                 schedule();
 220                 preempt_disable();
 221         }
 222 }
 223
 224 static char reboot_mode = 'h';
 225
 226 int __init reboot_setup(char *str)
 227 {
 228         reboot_mode = str[0];
 229         return 1;
 230 }
 231
 232 __setup("reboot=", reboot_setup);
 233
 234 void machine_shutdown(void)
 235 {
 236 #ifdef CONFIG_SMP
 237         smp_send_stop();
 238 #endif
 239 }
 240
 241 void machine_halt(void)
 242 {
 243         machine_shutdown();
 244         local_irq_disable();
 245         while (1);
 246 }
 247
 248 void machine_power_off(void)
 249 {
 250         machine_shutdown();
 251         if (pm_power_off)
 252                 pm_power_off();
 253 }
 254
 255 void machine_restart(char *cmd)
 256 {
 257         machine_shutdown();
 258         arm_pm_restart(reboot_mode, cmd);
 259 }
 260
 261 void __show_regs(struct pt_regs *regs)
 262 {
 263         unsigned long flags;
 264         char buf[64];
 265
 266         printk("CPU: %d    %s  (%s %.*s)\n",
 267                 raw_smp_processor_id(), print_tainted(),
 268                 init_utsname()->release,
 269                 (int)strcspn(init_utsname()->version, " "),
 270                 init_utsname()->version);
 271         print_symbol("PC is at %s\n", instruction_pointer(regs));
 272         print_symbol("LR is at %s\n", regs->ARM_lr);
 273         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 274                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 275                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 276                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 277         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 278                 regs->ARM_r10, regs->ARM_r9,
 279                 regs->ARM_r8);
 280         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 281                 regs->ARM_r7, regs->ARM_r6,
 282                 regs->ARM_r5, regs->ARM_r4);
 283         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 284                 regs->ARM_r3, regs->ARM_r2,
 285                 regs->ARM_r1, regs->ARM_r0);
 286
 287         flags = regs->ARM_cpsr;
 288         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 289         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 290         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 291         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 292         buf[4] = '\0';
 293
 294         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 295                 buf, interrupts_enabled(regs) ? "n" : "ff",
 296                 fast_interrupts_enabled(regs) ? "n" : "ff",
 297                 processor_modes[processor_mode(regs)],
 298                 isa_modes[isa_mode(regs)],
 299                 get_fs() == get_ds() ? "kernel" : "user");
 300 #ifdef CONFIG_CPU_CP15
 301         {
 302                 unsigned int ctrl;
 303
 304                 buf[0] = '\0';
 305 #ifdef CONFIG_CPU_CP15_MMU
 306                 {
 307                         unsigned int transbase, dac;
 308                         asm("mrc p15, 0, %0, c2, c0\n\t"
 309                             "mrc p15, 0, %1, c3, c0\n"
 310                             : "=r" (transbase), "=r" (dac));
 311                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 312                                 transbase, dac);
 313                 }
 314 #endif
 315                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 316
 317                 printk("Control: %08x%s\n", ctrl, buf);
 318         }
 319 #endif
 320 }
 321
 322 void show_regs(struct pt_regs * regs)
 323 {
 324         printk("\n");
 325         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
 326         __show_regs(regs);
 327         dump_stack();
 328 }
 329
 330 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 331
 332 EXPORT_SYMBOL_GPL(thread_notify_head);
 333
 334 /*
 335  * Free current thread data structures etc..
 336  */
 337 void exit_thread(void)
 338 {
 339         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 340 }
 341
 342 void flush_thread(void)
 343 {
 344         struct thread_info *thread = current_thread_info();
 345         struct task_struct *tsk = current;
 346
 347         flush_ptrace_hw_breakpoint(tsk);
 348
 349         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 350         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 351         memset(&thread->fpstate, 0, sizeof(union fp_state));
 352
 353         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 354 }
 355
 356 void release_thread(struct task_struct *dead_task)
 357 {
 358 }
 359
 360 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 361
 362 int
 363 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 364             unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
 365 {
 366         struct thread_info *thread = task_thread_info(p);
 367         struct pt_regs *childregs = task_pt_regs(p);
 368
 369         *childregs = *regs;
 370         childregs->ARM_r0 = 0;
 371         childregs->ARM_sp = stack_start;
 372
 373         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 374         thread->cpu_context.sp = (unsigned long)childregs;
 375         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 376
 377         clear_ptrace_hw_breakpoint(p);
 378
 379         if (clone_flags & CLONE_SETTLS)
 380                 thread->tp_value = regs->ARM_r3;
 381
 382         thread_notify(THREAD_NOTIFY_COPY, thread);
 383
 384         return 0;
 385 }
 386
 387 /*
 388  * Fill in the task's elfregs structure for a core dump.
 389  */
 390 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 391 {
 392         elf_core_copy_regs(elfregs, task_pt_regs(t));
 393         return 1;
 394 }
 395
 396 /*
 397  * fill in the fpe structure for a core dump...
 398  */
 399 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 400 {
 401         struct thread_info *thread = current_thread_info();
 402         int used_math = thread->used_cp[1] | thread->used_cp[2];
 403
 404         if (used_math)
 405                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 406
 407         return used_math != 0;
 408 }
 409 EXPORT_SYMBOL(dump_fpu);
 410
 411 /*
 412  * Shuffle the argument into the correct register before calling the
 413  * thread function.  r4 is the thread argument, r5 is the pointer to
 414  * the thread function, and r6 points to the exit function.
 415  */
 416 extern void kernel_thread_helper(void);
 417 asm(    ".pushsection .text\n"
 418 "       .align\n"
 419 "       .type   kernel_thread_helper, #function\n"
 420 "kernel_thread_helper:\n"
 421 #ifdef CONFIG_TRACE_IRQFLAGS
 422 "       bl      trace_hardirqs_on\n"
 423 #endif
 424 "       msr     cpsr_c, r7\n"
 425 "       mov     r0, r4\n"
 426 "       mov     lr, r6\n"
 427 "       mov     pc, r5\n"
 428 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
 429 "       .popsection");
 430
 431 #ifdef CONFIG_ARM_UNWIND
 432 extern void kernel_thread_exit(long code);
 433 asm(    ".pushsection .text\n"
 434 "       .align\n"
 435 "       .type   kernel_thread_exit, #function\n"
 436 "kernel_thread_exit:\n"
 437 "       .fnstart\n"
 438 "       .cantunwind\n"
 439 "       bl      do_exit\n"
 440 "       nop\n"
 441 "       .fnend\n"
 442 "       .size   kernel_thread_exit, . - kernel_thread_exit\n"
 443 "       .popsection");
 444 #else
 445 #define kernel_thread_exit      do_exit
 446 #endif
 447
 448 /*
 449  * Create a kernel thread.
 450  */
 451 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 452 {
 453         struct pt_regs regs;
 454
 455         memset(&regs, 0, sizeof(regs));
 456
 457         regs.ARM_r4 = (unsigned long)arg;
 458         regs.ARM_r5 = (unsigned long)fn;
 459         regs.ARM_r6 = (unsigned long)kernel_thread_exit;
 460         regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
 461         regs.ARM_pc = (unsigned long)kernel_thread_helper;
 462         regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT;
 463
 464         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
 465 }
 466 EXPORT_SYMBOL(kernel_thread);
 467
 468 unsigned long get_wchan(struct task_struct *p)
 469 {
 470         struct stackframe frame;
 471         unsigned long stack_page;
 472         int count = 0;
 473         if (!p || p == current || p->state == TASK_RUNNING)
 474                 return 0;
 475
 476         frame.fp = thread_saved_fp(p);
 477         frame.sp = thread_saved_sp(p);
 478         frame.lr = 0;                   /* recovered from the stack */
 479         frame.pc = thread_saved_pc(p);
 480         stack_page = (unsigned long)task_stack_page(p);
 481         do {
 482                 if (frame.sp < stack_page ||
 483                     frame.sp >= stack_page + THREAD_SIZE ||
 484                     unwind_frame(&frame) < 0)
 485                         return 0;
 486                 if (!in_sched_functions(frame.pc))
 487                         return frame.pc;
 488         } while (count ++ < 16);
 489         return 0;
 490 }
 491
 492 unsigned long arch_randomize_brk(struct mm_struct *mm)
 493 {
 494         unsigned long range_end = mm->brk + 0x02000000;
 495         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 496 }
 497
 498 #ifdef CONFIG_MMU
 499 /*
 500  * The vectors page is always readable from user space for the
 501  * atomic helpers and the signal restart code.  Let's declare a mapping
 502  * for it so it is visible through ptrace and /proc/<pid>/mem.
 503  */
 504
 505 int vectors_user_mapping(void)
 506 {
 507         struct mm_struct *mm = current->mm;
 508         return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
 509                                        VM_READ | VM_EXEC |
 510                                        VM_MAYREAD | VM_MAYEXEC |
 511                                        VM_ALWAYSDUMP | VM_RESERVED,
 512                                        NULL);
 513 }
 514
 515 const char *arch_vma_name(struct vm_area_struct *vma)
 516 {
 517         return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;
 518 }
 519 #endif