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" , "UK6_32" , "ABT_32" ,
  55   "UK8_32" , "UK9_32" , "UK10_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 static void null_restart(enum reboot_mode reboot_mode, const char *cmd)
 118 {
 119 }
 120
 121 /*
 122  * Function pointers to optional machine specific functions
 123  */
 124 void (*pm_power_off)(void);
 125 EXPORT_SYMBOL(pm_power_off);
 126
 127 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd) = null_restart;
 128 EXPORT_SYMBOL_GPL(arm_pm_restart);
 129
 130 /*
 131  * This is our default idle handler.
 132  */
 133
 134 void (*arm_pm_idle)(void);
 135
 136 /*
 137  * Called from the core idle loop.
 138  */
 139
 140 void arch_cpu_idle(void)
 141 {
 142         if (arm_pm_idle)
 143                 arm_pm_idle();
 144         else
 145                 cpu_do_idle();
 146         local_irq_enable();
 147 }
 148
 149 void arch_cpu_idle_prepare(void)
 150 {
 151         local_fiq_enable();
 152 }
 153
 154 void arch_cpu_idle_enter(void)
 155 {
 156         ledtrig_cpu(CPU_LED_IDLE_START);
 157 #ifdef CONFIG_PL310_ERRATA_769419
 158         wmb();
 159 #endif
 160 }
 161
 162 void arch_cpu_idle_exit(void)
 163 {
 164         ledtrig_cpu(CPU_LED_IDLE_END);
 165 }
 166
 167 #ifdef CONFIG_HOTPLUG_CPU
 168 void arch_cpu_idle_dead(void)
 169 {
 170         cpu_die();
 171 }
 172 #endif
 173
 174 /*
 175  * Called by kexec, immediately prior to machine_kexec().
 176  *
 177  * This must completely disable all secondary CPUs; simply causing those CPUs
 178  * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
 179  * kexec'd kernel to use any and all RAM as it sees fit, without having to
 180  * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
 181  * functionality embodied in disable_nonboot_cpus() to achieve this.
 182  */
 183 void machine_shutdown(void)
 184 {
 185         disable_nonboot_cpus();
 186 }
 187
 188 /*
 189  * Halting simply requires that the secondary CPUs stop performing any
 190  * activity (executing tasks, handling interrupts). smp_send_stop()
 191  * achieves this.
 192  */
 193 void machine_halt(void)
 194 {
 195         local_irq_disable();
 196         smp_send_stop();
 197
 198         local_irq_disable();
 199         while (1);
 200 }
 201
 202 /*
 203  * Power-off simply requires that the secondary CPUs stop performing any
 204  * activity (executing tasks, handling interrupts). smp_send_stop()
 205  * achieves this. When the system power is turned off, it will take all CPUs
 206  * with it.
 207  */
 208 void machine_power_off(void)
 209 {
 210         local_irq_disable();
 211         smp_send_stop();
 212
 213         if (pm_power_off)
 214                 pm_power_off();
 215 }
 216
 217 /*
 218  * Restart requires that the secondary CPUs stop performing any activity
 219  * while the primary CPU resets the system. Systems with a single CPU can
 220  * use soft_restart() as their machine descriptor's .restart hook, since that
 221  * will cause the only available CPU to reset. Systems with multiple CPUs must
 222  * provide a HW restart implementation, to ensure that all CPUs reset at once.
 223  * This is required so that any code running after reset on the primary CPU
 224  * doesn't have to co-ordinate with other CPUs to ensure they aren't still
 225  * executing pre-reset code, and using RAM that the primary CPU's code wishes
 226  * to use. Implementing such co-ordination would be essentially impossible.
 227  */
 228 void machine_restart(char *cmd)
 229 {
 230         local_irq_disable();
 231         smp_send_stop();
 232
 233         arm_pm_restart(reboot_mode, cmd);
 234
 235         /* Give a grace period for failure to restart of 1s */
 236         mdelay(1000);
 237
 238         /* Whoops - the platform was unable to reboot. Tell the user! */
 239         printk("Reboot failed -- System halted\n");
 240         local_irq_disable();
 241         while (1);
 242 }
 243
 244 void __show_regs(struct pt_regs *regs)
 245 {
 246         unsigned long flags;
 247         char buf[64];
 248
 249         show_regs_print_info(KERN_DEFAULT);
 250
 251         print_symbol("PC is at %s\n", instruction_pointer(regs));
 252         print_symbol("LR is at %s\n", regs->ARM_lr);
 253         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 254                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 255                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 256                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 257         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 258                 regs->ARM_r10, regs->ARM_r9,
 259                 regs->ARM_r8);
 260         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 261                 regs->ARM_r7, regs->ARM_r6,
 262                 regs->ARM_r5, regs->ARM_r4);
 263         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 264                 regs->ARM_r3, regs->ARM_r2,
 265                 regs->ARM_r1, regs->ARM_r0);
 266
 267         flags = regs->ARM_cpsr;
 268         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 269         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 270         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 271         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 272         buf[4] = '\0';
 273
 274 #ifndef CONFIG_CPU_V7M
 275         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 276                 buf, interrupts_enabled(regs) ? "n" : "ff",
 277                 fast_interrupts_enabled(regs) ? "n" : "ff",
 278                 processor_modes[processor_mode(regs)],
 279                 isa_modes[isa_mode(regs)],
 280                 get_fs() == get_ds() ? "kernel" : "user");
 281 #else
 282         printk("xPSR: %08lx\n", regs->ARM_cpsr);
 283 #endif
 284
 285 #ifdef CONFIG_CPU_CP15
 286         {
 287                 unsigned int ctrl;
 288
 289                 buf[0] = '\0';
 290 #ifdef CONFIG_CPU_CP15_MMU
 291                 {
 292                         unsigned int transbase, dac;
 293                         asm("mrc p15, 0, %0, c2, c0\n\t"
 294                             "mrc p15, 0, %1, c3, c0\n"
 295                             : "=r" (transbase), "=r" (dac));
 296                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 297                                 transbase, dac);
 298                 }
 299 #endif
 300                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 301
 302                 printk("Control: %08x%s\n", ctrl, buf);
 303         }
 304 #endif
 305 }
 306
 307 void show_regs(struct pt_regs * regs)
 308 {
 309         printk("\n");
 310         __show_regs(regs);
 311         dump_stack();
 312 }
 313
 314 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 315
 316 EXPORT_SYMBOL_GPL(thread_notify_head);
 317
 318 /*
 319  * Free current thread data structures etc..
 320  */
 321 void exit_thread(void)
 322 {
 323         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 324 }
 325
 326 void flush_thread(void)
 327 {
 328         struct thread_info *thread = current_thread_info();
 329         struct task_struct *tsk = current;
 330
 331         flush_ptrace_hw_breakpoint(tsk);
 332
 333         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 334         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 335         memset(&thread->fpstate, 0, sizeof(union fp_state));
 336
 337         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 338 }
 339
 340 void release_thread(struct task_struct *dead_task)
 341 {
 342 }
 343
 344 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 345
 346 int
 347 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 348             unsigned long stk_sz, struct task_struct *p)
 349 {
 350         struct thread_info *thread = task_thread_info(p);
 351         struct pt_regs *childregs = task_pt_regs(p);
 352
 353         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 354
 355         if (likely(!(p->flags & PF_KTHREAD))) {
 356                 *childregs = *current_pt_regs();
 357                 childregs->ARM_r0 = 0;
 358                 if (stack_start)
 359                         childregs->ARM_sp = stack_start;
 360         } else {
 361                 memset(childregs, 0, sizeof(struct pt_regs));
 362                 thread->cpu_context.r4 = stk_sz;
 363                 thread->cpu_context.r5 = stack_start;
 364                 childregs->ARM_cpsr = SVC_MODE;
 365         }
 366         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 367         thread->cpu_context.sp = (unsigned long)childregs;
 368
 369         clear_ptrace_hw_breakpoint(p);
 370
 371         if (clone_flags & CLONE_SETTLS)
 372                 thread->tp_value[0] = childregs->ARM_r3;
 373         thread->tp_value[1] = get_tpuser();
 374
 375         thread_notify(THREAD_NOTIFY_COPY, thread);
 376
 377         return 0;
 378 }
 379
 380 /*
 381  * Fill in the task's elfregs structure for a core dump.
 382  */
 383 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 384 {
 385         elf_core_copy_regs(elfregs, task_pt_regs(t));
 386         return 1;
 387 }
 388
 389 /*
 390  * fill in the fpe structure for a core dump...
 391  */
 392 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 393 {
 394         struct thread_info *thread = current_thread_info();
 395         int used_math = thread->used_cp[1] | thread->used_cp[2];
 396
 397         if (used_math)
 398                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 399
 400         return used_math != 0;
 401 }
 402 EXPORT_SYMBOL(dump_fpu);
 403
 404 unsigned long get_wchan(struct task_struct *p)
 405 {
 406         struct stackframe frame;
 407         unsigned long stack_page;
 408         int count = 0;
 409         if (!p || p == current || p->state == TASK_RUNNING)
 410                 return 0;
 411
 412         frame.fp = thread_saved_fp(p);
 413         frame.sp = thread_saved_sp(p);
 414         frame.lr = 0;                   /* recovered from the stack */
 415         frame.pc = thread_saved_pc(p);
 416         stack_page = (unsigned long)task_stack_page(p);
 417         do {
 418                 if (frame.sp < stack_page ||
 419                     frame.sp >= stack_page + THREAD_SIZE ||
 420                     unwind_frame(&frame) < 0)
 421                         return 0;
 422                 if (!in_sched_functions(frame.pc))
 423                         return frame.pc;
 424         } while (count ++ < 16);
 425         return 0;
 426 }
 427
 428 unsigned long arch_randomize_brk(struct mm_struct *mm)
 429 {
 430         unsigned long range_end = mm->brk + 0x02000000;
 431         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 432 }
 433
 434 #ifdef CONFIG_MMU
 435 #ifdef CONFIG_KUSER_HELPERS
 436 /*
 437  * The vectors page is always readable from user space for the
 438  * atomic helpers. Insert it into the gate_vma so that it is visible
 439  * through ptrace and /proc/<pid>/mem.
 440  */
 441 static struct vm_area_struct gate_vma = {
 442         .vm_start       = 0xffff0000,
 443         .vm_end         = 0xffff0000 + PAGE_SIZE,
 444         .vm_flags       = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
 445 };
 446
 447 static int __init gate_vma_init(void)
 448 {
 449         gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
 450         return 0;
 451 }
 452 arch_initcall(gate_vma_init);
 453
 454 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 455 {
 456         return &gate_vma;
 457 }
 458
 459 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 460 {
 461         return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
 462 }
 463
 464 int in_gate_area_no_mm(unsigned long addr)
 465 {
 466         return in_gate_area(NULL, addr);
 467 }
 468 #define is_gate_vma(vma)        ((vma) == &gate_vma)
 469 #else
 470 #define is_gate_vma(vma)        0
 471 #endif
 472
 473 const char *arch_vma_name(struct vm_area_struct *vma)
 474 {
 475         return is_gate_vma(vma) ? "[vectors]" :
 476                 (vma->vm_mm && vma->vm_start == vma->vm_mm->context.sigpage) ?
 477                  "[sigpage]" : NULL;
 478 }
 479
 480 static struct page *signal_page;
 481 extern struct page *get_signal_page(void);
 482
 483 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 484 {
 485         struct mm_struct *mm = current->mm;
 486         unsigned long addr;
 487         int ret;
 488
 489         if (!signal_page)
 490                 signal_page = get_signal_page();
 491         if (!signal_page)
 492                 return -ENOMEM;
 493
 494         down_write(&mm->mmap_sem);
 495         addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
 496         if (IS_ERR_VALUE(addr)) {
 497                 ret = addr;
 498                 goto up_fail;
 499         }
 500
 501         ret = install_special_mapping(mm, addr, PAGE_SIZE,
 502                 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
 503                 &signal_page);
 504
 505         if (ret == 0)
 506                 mm->context.sigpage = addr;
 507
 508  up_fail:
 509         up_write(&mm->mmap_sem);
 510         return ret;
 511 }
 512 #endif