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/interrupt.h>
  21 #include <linux/kallsyms.h>
  22 #include <linux/init.h>
  23 #include <linux/elfcore.h>
  24 #include <linux/pm.h>
  25 #include <linux/tick.h>
  26 #include <linux/utsname.h>
  27 #include <linux/uaccess.h>
  28 #include <linux/random.h>
  29 #include <linux/hw_breakpoint.h>
  30 #include <linux/leds.h>
  31
  32 #include <asm/processor.h>
  33 #include <asm/thread_notify.h>
  34 #include <asm/stacktrace.h>
  35 #include <asm/system_misc.h>
  36 #include <asm/mach/time.h>
  37 #include <asm/tls.h>
  38 #include <asm/vdso.h>
  39
  40 #ifdef CONFIG_CC_STACKPROTECTOR
  41 #include <linux/stackprotector.h>
  42 unsigned long __stack_chk_guard __read_mostly;
  43 EXPORT_SYMBOL(__stack_chk_guard);
  44 #endif
  45
  46 static const char *processor_modes[] __maybe_unused = {
  47   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  48   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  49   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
  50   "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  51 };
  52
  53 static const char *isa_modes[] __maybe_unused = {
  54   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  55 };
  56
  57 /*
  58  * This is our default idle handler.
  59  */
  60
  61 void (*arm_pm_idle)(void);
  62
  63 /*
  64  * Called from the core idle loop.
  65  */
  66
  67 void arch_cpu_idle(void)
  68 {
  69         if (arm_pm_idle)
  70                 arm_pm_idle();
  71         else
  72                 cpu_do_idle();
  73         local_irq_enable();
  74 }
  75
  76 void arch_cpu_idle_prepare(void)
  77 {
  78         local_fiq_enable();
  79 }
  80
  81 void arch_cpu_idle_enter(void)
  82 {
  83         ledtrig_cpu(CPU_LED_IDLE_START);
  84 #ifdef CONFIG_PL310_ERRATA_769419
  85         wmb();
  86 #endif
  87 }
  88
  89 void arch_cpu_idle_exit(void)
  90 {
  91         ledtrig_cpu(CPU_LED_IDLE_END);
  92 }
  93
  94 void __show_regs(struct pt_regs *regs)
  95 {
  96         unsigned long flags;
  97         char buf[64];
  98 #ifndef CONFIG_CPU_V7M
  99         unsigned int domain, fs;
 100 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
 101         /*
 102          * Get the domain register for the parent context. In user
 103          * mode, we don't save the DACR, so lets use what it should
 104          * be. For other modes, we place it after the pt_regs struct.
 105          */
 106         if (user_mode(regs)) {
 107                 domain = DACR_UACCESS_ENABLE;
 108                 fs = get_fs();
 109         } else {
 110                 domain = to_svc_pt_regs(regs)->dacr;
 111                 fs = to_svc_pt_regs(regs)->addr_limit;
 112         }
 113 #else
 114         domain = get_domain();
 115         fs = get_fs();
 116 #endif
 117 #endif
 118
 119         show_regs_print_info(KERN_DEFAULT);
 120
 121         print_symbol("PC is at %s\n", instruction_pointer(regs));
 122         print_symbol("LR is at %s\n", regs->ARM_lr);
 123         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 124                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 125                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 126                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 127         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 128                 regs->ARM_r10, regs->ARM_r9,
 129                 regs->ARM_r8);
 130         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 131                 regs->ARM_r7, regs->ARM_r6,
 132                 regs->ARM_r5, regs->ARM_r4);
 133         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 134                 regs->ARM_r3, regs->ARM_r2,
 135                 regs->ARM_r1, regs->ARM_r0);
 136
 137         flags = regs->ARM_cpsr;
 138         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 139         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 140         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 141         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 142         buf[4] = '\0';
 143
 144 #ifndef CONFIG_CPU_V7M
 145         {
 146                 const char *segment;
 147
 148                 if ((domain & domain_mask(DOMAIN_USER)) ==
 149                     domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
 150                         segment = "none";
 151                 else if (fs == get_ds())
 152                         segment = "kernel";
 153                 else
 154                         segment = "user";
 155
 156                 printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 157                         buf, interrupts_enabled(regs) ? "n" : "ff",
 158                         fast_interrupts_enabled(regs) ? "n" : "ff",
 159                         processor_modes[processor_mode(regs)],
 160                         isa_modes[isa_mode(regs)], segment);
 161         }
 162 #else
 163         printk("xPSR: %08lx\n", regs->ARM_cpsr);
 164 #endif
 165
 166 #ifdef CONFIG_CPU_CP15
 167         {
 168                 unsigned int ctrl;
 169
 170                 buf[0] = '\0';
 171 #ifdef CONFIG_CPU_CP15_MMU
 172                 {
 173                         unsigned int transbase;
 174                         asm("mrc p15, 0, %0, c2, c0\n\t"
 175                             : "=r" (transbase));
 176                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 177                                 transbase, domain);
 178                 }
 179 #endif
 180                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 181
 182                 printk("Control: %08x%s\n", ctrl, buf);
 183         }
 184 #endif
 185 }
 186
 187 void show_regs(struct pt_regs * regs)
 188 {
 189         __show_regs(regs);
 190         dump_stack();
 191 }
 192
 193 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 194
 195 EXPORT_SYMBOL_GPL(thread_notify_head);
 196
 197 /*
 198  * Free current thread data structures etc..
 199  */
 200 void exit_thread(struct task_struct *tsk)
 201 {
 202         thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
 203 }
 204
 205 void flush_thread(void)
 206 {
 207         struct thread_info *thread = current_thread_info();
 208         struct task_struct *tsk = current;
 209
 210         flush_ptrace_hw_breakpoint(tsk);
 211
 212         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 213         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 214         memset(&thread->fpstate, 0, sizeof(union fp_state));
 215
 216         flush_tls();
 217
 218         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 219 }
 220
 221 void release_thread(struct task_struct *dead_task)
 222 {
 223 }
 224
 225 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 226
 227 int
 228 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 229             unsigned long stk_sz, struct task_struct *p)
 230 {
 231         struct thread_info *thread = task_thread_info(p);
 232         struct pt_regs *childregs = task_pt_regs(p);
 233
 234         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 235
 236 #ifdef CONFIG_CPU_USE_DOMAINS
 237         /*
 238          * Copy the initial value of the domain access control register
 239          * from the current thread: thread->addr_limit will have been
 240          * copied from the current thread via setup_thread_stack() in
 241          * kernel/fork.c
 242          */
 243         thread->cpu_domain = get_domain();
 244 #endif
 245
 246         if (likely(!(p->flags & PF_KTHREAD))) {
 247                 *childregs = *current_pt_regs();
 248                 childregs->ARM_r0 = 0;
 249                 if (stack_start)
 250                         childregs->ARM_sp = stack_start;
 251         } else {
 252                 memset(childregs, 0, sizeof(struct pt_regs));
 253                 thread->cpu_context.r4 = stk_sz;
 254                 thread->cpu_context.r5 = stack_start;
 255                 childregs->ARM_cpsr = SVC_MODE;
 256         }
 257         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 258         thread->cpu_context.sp = (unsigned long)childregs;
 259
 260         clear_ptrace_hw_breakpoint(p);
 261
 262         if (clone_flags & CLONE_SETTLS)
 263                 thread->tp_value[0] = childregs->ARM_r3;
 264         thread->tp_value[1] = get_tpuser();
 265
 266         thread_notify(THREAD_NOTIFY_COPY, thread);
 267
 268         return 0;
 269 }
 270
 271 /*
 272  * Fill in the task's elfregs structure for a core dump.
 273  */
 274 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 275 {
 276         elf_core_copy_regs(elfregs, task_pt_regs(t));
 277         return 1;
 278 }
 279
 280 /*
 281  * fill in the fpe structure for a core dump...
 282  */
 283 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 284 {
 285         struct thread_info *thread = current_thread_info();
 286         int used_math = thread->used_cp[1] | thread->used_cp[2];
 287
 288         if (used_math)
 289                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 290
 291         return used_math != 0;
 292 }
 293 EXPORT_SYMBOL(dump_fpu);
 294
 295 unsigned long get_wchan(struct task_struct *p)
 296 {
 297         struct stackframe frame;
 298         unsigned long stack_page;
 299         int count = 0;
 300         if (!p || p == current || p->state == TASK_RUNNING)
 301                 return 0;
 302
 303         frame.fp = thread_saved_fp(p);
 304         frame.sp = thread_saved_sp(p);
 305         frame.lr = 0;                   /* recovered from the stack */
 306         frame.pc = thread_saved_pc(p);
 307         stack_page = (unsigned long)task_stack_page(p);
 308         do {
 309                 if (frame.sp < stack_page ||
 310                     frame.sp >= stack_page + THREAD_SIZE ||
 311                     unwind_frame(&frame) < 0)
 312                         return 0;
 313                 if (!in_sched_functions(frame.pc))
 314                         return frame.pc;
 315         } while (count ++ < 16);
 316         return 0;
 317 }
 318
 319 unsigned long arch_randomize_brk(struct mm_struct *mm)
 320 {
 321         return randomize_page(mm->brk, 0x02000000);
 322 }
 323
 324 #ifdef CONFIG_MMU
 325 #ifdef CONFIG_KUSER_HELPERS
 326 /*
 327  * The vectors page is always readable from user space for the
 328  * atomic helpers. Insert it into the gate_vma so that it is visible
 329  * through ptrace and /proc/<pid>/mem.
 330  */
 331 static struct vm_area_struct gate_vma = {
 332         .vm_start       = 0xffff0000,
 333         .vm_end         = 0xffff0000 + PAGE_SIZE,
 334         .vm_flags       = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
 335 };
 336
 337 static int __init gate_vma_init(void)
 338 {
 339         gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
 340         return 0;
 341 }
 342 arch_initcall(gate_vma_init);
 343
 344 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 345 {
 346         return &gate_vma;
 347 }
 348
 349 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 350 {
 351         return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
 352 }
 353
 354 int in_gate_area_no_mm(unsigned long addr)
 355 {
 356         return in_gate_area(NULL, addr);
 357 }
 358 #define is_gate_vma(vma)        ((vma) == &gate_vma)
 359 #else
 360 #define is_gate_vma(vma)        0
 361 #endif
 362
 363 const char *arch_vma_name(struct vm_area_struct *vma)
 364 {
 365         return is_gate_vma(vma) ? "[vectors]" : NULL;
 366 }
 367
 368 /* If possible, provide a placement hint at a random offset from the
 369  * stack for the sigpage and vdso pages.
 370  */
 371 static unsigned long sigpage_addr(const struct mm_struct *mm,
 372                                   unsigned int npages)
 373 {
 374         unsigned long offset;
 375         unsigned long first;
 376         unsigned long last;
 377         unsigned long addr;
 378         unsigned int slots;
 379
 380         first = PAGE_ALIGN(mm->start_stack);
 381
 382         last = TASK_SIZE - (npages << PAGE_SHIFT);
 383
 384         /* No room after stack? */
 385         if (first > last)
 386                 return 0;
 387
 388         /* Just enough room? */
 389         if (first == last)
 390                 return first;
 391
 392         slots = ((last - first) >> PAGE_SHIFT) + 1;
 393
 394         offset = get_random_int() % slots;
 395
 396         addr = first + (offset << PAGE_SHIFT);
 397
 398         return addr;
 399 }
 400
 401 static struct page *signal_page;
 402 extern struct page *get_signal_page(void);
 403
 404 static const struct vm_special_mapping sigpage_mapping = {
 405         .name = "[sigpage]",
 406         .pages = &signal_page,
 407 };
 408
 409 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 410 {
 411         struct mm_struct *mm = current->mm;
 412         struct vm_area_struct *vma;
 413         unsigned long npages;
 414         unsigned long addr;
 415         unsigned long hint;
 416         int ret = 0;
 417
 418         if (!signal_page)
 419                 signal_page = get_signal_page();
 420         if (!signal_page)
 421                 return -ENOMEM;
 422
 423         npages = 1; /* for sigpage */
 424         npages += vdso_total_pages;
 425
 426         if (down_write_killable(&mm->mmap_sem))
 427                 return -EINTR;
 428         hint = sigpage_addr(mm, npages);
 429         addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
 430         if (IS_ERR_VALUE(addr)) {
 431                 ret = addr;
 432                 goto up_fail;
 433         }
 434
 435         vma = _install_special_mapping(mm, addr, PAGE_SIZE,
 436                 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
 437                 &sigpage_mapping);
 438
 439         if (IS_ERR(vma)) {
 440                 ret = PTR_ERR(vma);
 441                 goto up_fail;
 442         }
 443
 444         mm->context.sigpage = addr;
 445
 446         /* Unlike the sigpage, failure to install the vdso is unlikely
 447          * to be fatal to the process, so no error check needed
 448          * here.
 449          */
 450         arm_install_vdso(mm, addr + PAGE_SIZE);
 451
 452  up_fail:
 453         up_write(&mm->mmap_sem);
 454         return ret;
 455 }
 456 #endif