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/leds.h>
  34 #include <linux/reboot.h>
  35
  36 #include <asm/cacheflush.h>
  37 #include <asm/idmap.h>
  38 #include <asm/processor.h>
  39 #include <asm/thread_notify.h>
  40 #include <asm/stacktrace.h>
  41 #include <asm/system_misc.h>
  42 #include <asm/mach/time.h>
  43 #include <asm/tls.h>
  44
  45 #ifdef CONFIG_CC_STACKPROTECTOR
  46 #include <linux/stackprotector.h>
  47 unsigned long __stack_chk_guard __read_mostly;
  48 EXPORT_SYMBOL(__stack_chk_guard);
  49 #endif
  50
  51 static const char *processor_modes[] __maybe_unused = {
  52   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  53   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  54   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
  55   "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  56 };
  57
  58 static const char *isa_modes[] __maybe_unused = {
  59   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  60 };
  61
  62 extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
  63 typedef void (*phys_reset_t)(unsigned long);
  64
  65 /*
  66  * A temporary stack to use for CPU reset. This is static so that we
  67  * don't clobber it with the identity mapping. When running with this
  68  * stack, any references to the current task *will not work* so you
  69  * should really do as little as possible before jumping to your reset
  70  * code.
  71  */
  72 static u64 soft_restart_stack[16];
  73
  74 static void __soft_restart(void *addr)
  75 {
  76         phys_reset_t phys_reset;
  77
  78         /* Take out a flat memory mapping. */
  79         setup_mm_for_reboot();
  80
  81         /* Clean and invalidate caches */
  82         flush_cache_all();
  83
  84         /* Turn off caching */
  85         cpu_proc_fin();
  86
  87         /* Push out any further dirty data, and ensure cache is empty */
  88         flush_cache_all();
  89
  90         /* Switch to the identity mapping. */
  91         phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
  92         phys_reset((unsigned long)addr);
  93
  94         /* Should never get here. */
  95         BUG();
  96 }
  97
  98 void soft_restart(unsigned long addr)
  99 {
 100         u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
 101
 102         /* Disable interrupts first */
 103         raw_local_irq_disable();
 104         local_fiq_disable();
 105
 106         /* Disable the L2 if we're the last man standing. */
 107         if (num_online_cpus() == 1)
 108                 outer_disable();
 109
 110         /* Change to the new stack and continue with the reset. */
 111         call_with_stack(__soft_restart, (void *)addr, (void *)stack);
 112
 113         /* Should never get here. */
 114         BUG();
 115 }
 116
 117 /*
 118  * Function pointers to optional machine specific functions
 119  */
 120 void (*pm_power_off)(void);
 121 EXPORT_SYMBOL(pm_power_off);
 122
 123 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
 124
 125 /*
 126  * This is our default idle handler.
 127  */
 128
 129 void (*arm_pm_idle)(void);
 130
 131 /*
 132  * Called from the core idle loop.
 133  */
 134
 135 void arch_cpu_idle(void)
 136 {
 137         if (arm_pm_idle)
 138                 arm_pm_idle();
 139         else
 140                 cpu_do_idle();
 141         local_irq_enable();
 142 }
 143
 144 void arch_cpu_idle_prepare(void)
 145 {
 146         local_fiq_enable();
 147 }
 148
 149 void arch_cpu_idle_enter(void)
 150 {
 151         ledtrig_cpu(CPU_LED_IDLE_START);
 152 #ifdef CONFIG_PL310_ERRATA_769419
 153         wmb();
 154 #endif
 155 }
 156
 157 void arch_cpu_idle_exit(void)
 158 {
 159         ledtrig_cpu(CPU_LED_IDLE_END);
 160 }
 161
 162 #ifdef CONFIG_HOTPLUG_CPU
 163 void arch_cpu_idle_dead(void)
 164 {
 165         cpu_die();
 166 }
 167 #endif
 168
 169 /*
 170  * Called by kexec, immediately prior to machine_kexec().
 171  *
 172  * This must completely disable all secondary CPUs; simply causing those CPUs
 173  * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
 174  * kexec'd kernel to use any and all RAM as it sees fit, without having to
 175  * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
 176  * functionality embodied in disable_nonboot_cpus() to achieve this.
 177  */
 178 void machine_shutdown(void)
 179 {
 180         disable_nonboot_cpus();
 181 }
 182
 183 /*
 184  * Halting simply requires that the secondary CPUs stop performing any
 185  * activity (executing tasks, handling interrupts). smp_send_stop()
 186  * achieves this.
 187  */
 188 void machine_halt(void)
 189 {
 190         local_irq_disable();
 191         smp_send_stop();
 192
 193         local_irq_disable();
 194         while (1);
 195 }
 196
 197 /*
 198  * Power-off simply requires that the secondary CPUs stop performing any
 199  * activity (executing tasks, handling interrupts). smp_send_stop()
 200  * achieves this. When the system power is turned off, it will take all CPUs
 201  * with it.
 202  */
 203 void machine_power_off(void)
 204 {
 205         local_irq_disable();
 206         smp_send_stop();
 207
 208         if (pm_power_off)
 209                 pm_power_off();
 210 }
 211
 212 /*
 213  * Restart requires that the secondary CPUs stop performing any activity
 214  * while the primary CPU resets the system. Systems with a single CPU can
 215  * use soft_restart() as their machine descriptor's .restart hook, since that
 216  * will cause the only available CPU to reset. Systems with multiple CPUs must
 217  * provide a HW restart implementation, to ensure that all CPUs reset at once.
 218  * This is required so that any code running after reset on the primary CPU
 219  * doesn't have to co-ordinate with other CPUs to ensure they aren't still
 220  * executing pre-reset code, and using RAM that the primary CPU's code wishes
 221  * to use. Implementing such co-ordination would be essentially impossible.
 222  */
 223 void machine_restart(char *cmd)
 224 {
 225         local_irq_disable();
 226         smp_send_stop();
 227
 228         if (arm_pm_restart)
 229                 arm_pm_restart(reboot_mode, cmd);
 230         else
 231                 do_kernel_restart(cmd);
 232
 233         /* Give a grace period for failure to restart of 1s */
 234         mdelay(1000);
 235
 236         /* Whoops - the platform was unable to reboot. Tell the user! */
 237         printk("Reboot failed -- System halted\n");
 238         local_irq_disable();
 239         while (1);
 240 }
 241
 242 void __show_regs(struct pt_regs *regs)
 243 {
 244         unsigned long flags;
 245         char buf[64];
 246
 247         show_regs_print_info(KERN_DEFAULT);
 248
 249         print_symbol("PC is at %s\n", instruction_pointer(regs));
 250         print_symbol("LR is at %s\n", regs->ARM_lr);
 251         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 252                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 253                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 254                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 255         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 256                 regs->ARM_r10, regs->ARM_r9,
 257                 regs->ARM_r8);
 258         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 259                 regs->ARM_r7, regs->ARM_r6,
 260                 regs->ARM_r5, regs->ARM_r4);
 261         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 262                 regs->ARM_r3, regs->ARM_r2,
 263                 regs->ARM_r1, regs->ARM_r0);
 264
 265         flags = regs->ARM_cpsr;
 266         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 267         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 268         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 269         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 270         buf[4] = '\0';
 271
 272 #ifndef CONFIG_CPU_V7M
 273         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 274                 buf, interrupts_enabled(regs) ? "n" : "ff",
 275                 fast_interrupts_enabled(regs) ? "n" : "ff",
 276                 processor_modes[processor_mode(regs)],
 277                 isa_modes[isa_mode(regs)],
 278                 get_fs() == get_ds() ? "kernel" : "user");
 279 #else
 280         printk("xPSR: %08lx\n", regs->ARM_cpsr);
 281 #endif
 282
 283 #ifdef CONFIG_CPU_CP15
 284         {
 285                 unsigned int ctrl;
 286
 287                 buf[0] = '\0';
 288 #ifdef CONFIG_CPU_CP15_MMU
 289                 {
 290                         unsigned int transbase, dac;
 291                         asm("mrc p15, 0, %0, c2, c0\n\t"
 292                             "mrc p15, 0, %1, c3, c0\n"
 293                             : "=r" (transbase), "=r" (dac));
 294                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 295                                 transbase, dac);
 296                 }
 297 #endif
 298                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 299
 300                 printk("Control: %08x%s\n", ctrl, buf);
 301         }
 302 #endif
 303 }
 304
 305 void show_regs(struct pt_regs * regs)
 306 {
 307         __show_regs(regs);
 308         dump_stack();
 309 }
 310
 311 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 312
 313 EXPORT_SYMBOL_GPL(thread_notify_head);
 314
 315 /*
 316  * Free current thread data structures etc..
 317  */
 318 void exit_thread(void)
 319 {
 320         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 321 }
 322
 323 void flush_thread(void)
 324 {
 325         struct thread_info *thread = current_thread_info();
 326         struct task_struct *tsk = current;
 327
 328         flush_ptrace_hw_breakpoint(tsk);
 329
 330         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 331         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 332         memset(&thread->fpstate, 0, sizeof(union fp_state));
 333
 334         flush_tls();
 335
 336         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 337 }
 338
 339 void release_thread(struct task_struct *dead_task)
 340 {
 341 }
 342
 343 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 344
 345 int
 346 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 347             unsigned long stk_sz, struct task_struct *p)
 348 {
 349         struct thread_info *thread = task_thread_info(p);
 350         struct pt_regs *childregs = task_pt_regs(p);
 351
 352         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 353
 354         if (likely(!(p->flags & PF_KTHREAD))) {
 355                 *childregs = *current_pt_regs();
 356                 childregs->ARM_r0 = 0;
 357                 if (stack_start)
 358                         childregs->ARM_sp = stack_start;
 359         } else {
 360                 memset(childregs, 0, sizeof(struct pt_regs));
 361                 thread->cpu_context.r4 = stk_sz;
 362                 thread->cpu_context.r5 = stack_start;
 363                 childregs->ARM_cpsr = SVC_MODE;
 364         }
 365         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 366         thread->cpu_context.sp = (unsigned long)childregs;
 367
 368         clear_ptrace_hw_breakpoint(p);
 369
 370         if (clone_flags & CLONE_SETTLS)
 371                 thread->tp_value[0] = childregs->ARM_r3;
 372         thread->tp_value[1] = get_tpuser();
 373
 374         thread_notify(THREAD_NOTIFY_COPY, thread);
 375
 376         return 0;
 377 }
 378
 379 /*
 380  * Fill in the task's elfregs structure for a core dump.
 381  */
 382 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 383 {
 384         elf_core_copy_regs(elfregs, task_pt_regs(t));
 385         return 1;
 386 }
 387
 388 /*
 389  * fill in the fpe structure for a core dump...
 390  */
 391 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 392 {
 393         struct thread_info *thread = current_thread_info();
 394         int used_math = thread->used_cp[1] | thread->used_cp[2];
 395
 396         if (used_math)
 397                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 398
 399         return used_math != 0;
 400 }
 401 EXPORT_SYMBOL(dump_fpu);
 402
 403 unsigned long get_wchan(struct task_struct *p)
 404 {
 405         struct stackframe frame;
 406         unsigned long stack_page;
 407         int count = 0;
 408         if (!p || p == current || p->state == TASK_RUNNING)
 409                 return 0;
 410
 411         frame.fp = thread_saved_fp(p);
 412         frame.sp = thread_saved_sp(p);
 413         frame.lr = 0;                   /* recovered from the stack */
 414         frame.pc = thread_saved_pc(p);
 415         stack_page = (unsigned long)task_stack_page(p);
 416         do {
 417                 if (frame.sp < stack_page ||
 418                     frame.sp >= stack_page + THREAD_SIZE ||
 419                     unwind_frame(&frame) < 0)
 420                         return 0;
 421                 if (!in_sched_functions(frame.pc))
 422                         return frame.pc;
 423         } while (count ++ < 16);
 424         return 0;
 425 }
 426
 427 unsigned long arch_randomize_brk(struct mm_struct *mm)
 428 {
 429         unsigned long range_end = mm->brk + 0x02000000;
 430         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 431 }
 432
 433 #ifdef CONFIG_MMU
 434 #ifdef CONFIG_KUSER_HELPERS
 435 /*
 436  * The vectors page is always readable from user space for the
 437  * atomic helpers. Insert it into the gate_vma so that it is visible
 438  * through ptrace and /proc/<pid>/mem.
 439  */
 440 static struct vm_area_struct gate_vma = {
 441         .vm_start       = 0xffff0000,
 442         .vm_end         = 0xffff0000 + PAGE_SIZE,
 443         .vm_flags       = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
 444 };
 445
 446 static int __init gate_vma_init(void)
 447 {
 448         gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
 449         return 0;
 450 }
 451 arch_initcall(gate_vma_init);
 452
 453 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 454 {
 455         return &gate_vma;
 456 }
 457
 458 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 459 {
 460         return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
 461 }
 462
 463 int in_gate_area_no_mm(unsigned long addr)
 464 {
 465         return in_gate_area(NULL, addr);
 466 }
 467 #define is_gate_vma(vma)        ((vma) == &gate_vma)
 468 #else
 469 #define is_gate_vma(vma)        0
 470 #endif
 471
 472 const char *arch_vma_name(struct vm_area_struct *vma)
 473 {
 474         return is_gate_vma(vma) ? "[vectors]" : NULL;
 475 }
 476
 477 /* If possible, provide a placement hint at a random offset from the
 478  * stack for the signal page.
 479  */
 480 static unsigned long sigpage_addr(const struct mm_struct *mm,
 481                                   unsigned int npages)
 482 {
 483         unsigned long offset;
 484         unsigned long first;
 485         unsigned long last;
 486         unsigned long addr;
 487         unsigned int slots;
 488
 489         first = PAGE_ALIGN(mm->start_stack);
 490
 491         last = TASK_SIZE - (npages << PAGE_SHIFT);
 492
 493         /* No room after stack? */
 494         if (first > last)
 495                 return 0;
 496
 497         /* Just enough room? */
 498         if (first == last)
 499                 return first;
 500
 501         slots = ((last - first) >> PAGE_SHIFT) + 1;
 502
 503         offset = get_random_int() % slots;
 504
 505         addr = first + (offset << PAGE_SHIFT);
 506
 507         return addr;
 508 }
 509
 510 static struct page *signal_page;
 511 extern struct page *get_signal_page(void);
 512
 513 static const struct vm_special_mapping sigpage_mapping = {
 514         .name = "[sigpage]",
 515         .pages = &signal_page,
 516 };
 517
 518 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 519 {
 520         struct mm_struct *mm = current->mm;
 521         struct vm_area_struct *vma;
 522         unsigned long addr;
 523         unsigned long hint;
 524         int ret = 0;
 525
 526         if (!signal_page)
 527                 signal_page = get_signal_page();
 528         if (!signal_page)
 529                 return -ENOMEM;
 530
 531         down_write(&mm->mmap_sem);
 532         hint = sigpage_addr(mm, 1);
 533         addr = get_unmapped_area(NULL, hint, PAGE_SIZE, 0, 0);
 534         if (IS_ERR_VALUE(addr)) {
 535                 ret = addr;
 536                 goto up_fail;
 537         }
 538
 539         vma = _install_special_mapping(mm, addr, PAGE_SIZE,
 540                 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
 541                 &sigpage_mapping);
 542
 543         if (IS_ERR(vma)) {
 544                 ret = PTR_ERR(vma);
 545                 goto up_fail;
 546         }
 547
 548         mm->context.sigpage = addr;
 549
 550  up_fail:
 551         up_write(&mm->mmap_sem);
 552         return ret;
 553 }
 554 #endif