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;
 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         else
 109                 domain = *(unsigned int *)(regs + 1);
 110 #else
 111         domain = get_domain();
 112 #endif
 113 #endif
 114
 115         show_regs_print_info(KERN_DEFAULT);
 116
 117         print_symbol("PC is at %s\n", instruction_pointer(regs));
 118         print_symbol("LR is at %s\n", regs->ARM_lr);
 119         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 120                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 121                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 122                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 123         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 124                 regs->ARM_r10, regs->ARM_r9,
 125                 regs->ARM_r8);
 126         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 127                 regs->ARM_r7, regs->ARM_r6,
 128                 regs->ARM_r5, regs->ARM_r4);
 129         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 130                 regs->ARM_r3, regs->ARM_r2,
 131                 regs->ARM_r1, regs->ARM_r0);
 132
 133         flags = regs->ARM_cpsr;
 134         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 135         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 136         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 137         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 138         buf[4] = '\0';
 139
 140 #ifndef CONFIG_CPU_V7M
 141         {
 142                 const char *segment;
 143
 144                 if ((domain & domain_mask(DOMAIN_USER)) ==
 145                     domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
 146                         segment = "none";
 147                 else if (get_fs() == get_ds())
 148                         segment = "kernel";
 149                 else
 150                         segment = "user";
 151
 152                 printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 153                         buf, interrupts_enabled(regs) ? "n" : "ff",
 154                         fast_interrupts_enabled(regs) ? "n" : "ff",
 155                         processor_modes[processor_mode(regs)],
 156                         isa_modes[isa_mode(regs)], segment);
 157         }
 158 #else
 159         printk("xPSR: %08lx\n", regs->ARM_cpsr);
 160 #endif
 161
 162 #ifdef CONFIG_CPU_CP15
 163         {
 164                 unsigned int ctrl;
 165
 166                 buf[0] = '\0';
 167 #ifdef CONFIG_CPU_CP15_MMU
 168                 {
 169                         unsigned int transbase;
 170                         asm("mrc p15, 0, %0, c2, c0\n\t"
 171                             : "=r" (transbase));
 172                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 173                                 transbase, domain);
 174                 }
 175 #endif
 176                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 177
 178                 printk("Control: %08x%s\n", ctrl, buf);
 179         }
 180 #endif
 181 }
 182
 183 void show_regs(struct pt_regs * regs)
 184 {
 185         __show_regs(regs);
 186         dump_stack();
 187 }
 188
 189 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 190
 191 EXPORT_SYMBOL_GPL(thread_notify_head);
 192
 193 /*
 194  * Free current thread data structures etc..
 195  */
 196 void exit_thread(void)
 197 {
 198         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 199 }
 200
 201 void flush_thread(void)
 202 {
 203         struct thread_info *thread = current_thread_info();
 204         struct task_struct *tsk = current;
 205
 206         flush_ptrace_hw_breakpoint(tsk);
 207
 208         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 209         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 210         memset(&thread->fpstate, 0, sizeof(union fp_state));
 211
 212         flush_tls();
 213
 214         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 215 }
 216
 217 void release_thread(struct task_struct *dead_task)
 218 {
 219 }
 220
 221 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 222
 223 int
 224 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 225             unsigned long stk_sz, struct task_struct *p)
 226 {
 227         struct thread_info *thread = task_thread_info(p);
 228         struct pt_regs *childregs = task_pt_regs(p);
 229
 230         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 231
 232 #ifdef CONFIG_CPU_USE_DOMAINS
 233         /*
 234          * Copy the initial value of the domain access control register
 235          * from the current thread: thread->addr_limit will have been
 236          * copied from the current thread via setup_thread_stack() in
 237          * kernel/fork.c
 238          */
 239         thread->cpu_domain = get_domain();
 240 #endif
 241
 242         if (likely(!(p->flags & PF_KTHREAD))) {
 243                 *childregs = *current_pt_regs();
 244                 childregs->ARM_r0 = 0;
 245                 if (stack_start)
 246                         childregs->ARM_sp = stack_start;
 247         } else {
 248                 memset(childregs, 0, sizeof(struct pt_regs));
 249                 thread->cpu_context.r4 = stk_sz;
 250                 thread->cpu_context.r5 = stack_start;
 251                 childregs->ARM_cpsr = SVC_MODE;
 252         }
 253         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 254         thread->cpu_context.sp = (unsigned long)childregs;
 255
 256         clear_ptrace_hw_breakpoint(p);
 257
 258         if (clone_flags & CLONE_SETTLS)
 259                 thread->tp_value[0] = childregs->ARM_r3;
 260         thread->tp_value[1] = get_tpuser();
 261
 262         thread_notify(THREAD_NOTIFY_COPY, thread);
 263
 264         return 0;
 265 }
 266
 267 /*
 268  * Fill in the task's elfregs structure for a core dump.
 269  */
 270 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 271 {
 272         elf_core_copy_regs(elfregs, task_pt_regs(t));
 273         return 1;
 274 }
 275
 276 /*
 277  * fill in the fpe structure for a core dump...
 278  */
 279 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 280 {
 281         struct thread_info *thread = current_thread_info();
 282         int used_math = thread->used_cp[1] | thread->used_cp[2];
 283
 284         if (used_math)
 285                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 286
 287         return used_math != 0;
 288 }
 289 EXPORT_SYMBOL(dump_fpu);
 290
 291 unsigned long get_wchan(struct task_struct *p)
 292 {
 293         struct stackframe frame;
 294         unsigned long stack_page;
 295         int count = 0;
 296         if (!p || p == current || p->state == TASK_RUNNING)
 297                 return 0;
 298
 299         frame.fp = thread_saved_fp(p);
 300         frame.sp = thread_saved_sp(p);
 301         frame.lr = 0;                   /* recovered from the stack */
 302         frame.pc = thread_saved_pc(p);
 303         stack_page = (unsigned long)task_stack_page(p);
 304         do {
 305                 if (frame.sp < stack_page ||
 306                     frame.sp >= stack_page + THREAD_SIZE ||
 307                     unwind_frame(&frame) < 0)
 308                         return 0;
 309                 if (!in_sched_functions(frame.pc))
 310                         return frame.pc;
 311         } while (count ++ < 16);
 312         return 0;
 313 }
 314
 315 unsigned long arch_randomize_brk(struct mm_struct *mm)
 316 {
 317         unsigned long range_end = mm->brk + 0x02000000;
 318         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 319 }
 320
 321 #ifdef CONFIG_MMU
 322 #ifdef CONFIG_KUSER_HELPERS
 323 /*
 324  * The vectors page is always readable from user space for the
 325  * atomic helpers. Insert it into the gate_vma so that it is visible
 326  * through ptrace and /proc/<pid>/mem.
 327  */
 328 static struct vm_area_struct gate_vma = {
 329         .vm_start       = 0xffff0000,
 330         .vm_end         = 0xffff0000 + PAGE_SIZE,
 331         .vm_flags       = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
 332 };
 333
 334 static int __init gate_vma_init(void)
 335 {
 336         gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
 337         return 0;
 338 }
 339 arch_initcall(gate_vma_init);
 340
 341 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 342 {
 343         return &gate_vma;
 344 }
 345
 346 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 347 {
 348         return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
 349 }
 350
 351 int in_gate_area_no_mm(unsigned long addr)
 352 {
 353         return in_gate_area(NULL, addr);
 354 }
 355 #define is_gate_vma(vma)        ((vma) == &gate_vma)
 356 #else
 357 #define is_gate_vma(vma)        0
 358 #endif
 359
 360 const char *arch_vma_name(struct vm_area_struct *vma)
 361 {
 362         return is_gate_vma(vma) ? "[vectors]" : NULL;
 363 }
 364
 365 /* If possible, provide a placement hint at a random offset from the
 366  * stack for the sigpage and vdso pages.
 367  */
 368 static unsigned long sigpage_addr(const struct mm_struct *mm,
 369                                   unsigned int npages)
 370 {
 371         unsigned long offset;
 372         unsigned long first;
 373         unsigned long last;
 374         unsigned long addr;
 375         unsigned int slots;
 376
 377         first = PAGE_ALIGN(mm->start_stack);
 378
 379         last = TASK_SIZE - (npages << PAGE_SHIFT);
 380
 381         /* No room after stack? */
 382         if (first > last)
 383                 return 0;
 384
 385         /* Just enough room? */
 386         if (first == last)
 387                 return first;
 388
 389         slots = ((last - first) >> PAGE_SHIFT) + 1;
 390
 391         offset = get_random_int() % slots;
 392
 393         addr = first + (offset << PAGE_SHIFT);
 394
 395         return addr;
 396 }
 397
 398 static struct page *signal_page;
 399 extern struct page *get_signal_page(void);
 400
 401 static const struct vm_special_mapping sigpage_mapping = {
 402         .name = "[sigpage]",
 403         .pages = &signal_page,
 404 };
 405
 406 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 407 {
 408         struct mm_struct *mm = current->mm;
 409         struct vm_area_struct *vma;
 410         unsigned long npages;
 411         unsigned long addr;
 412         unsigned long hint;
 413         int ret = 0;
 414
 415         if (!signal_page)
 416                 signal_page = get_signal_page();
 417         if (!signal_page)
 418                 return -ENOMEM;
 419
 420         npages = 1; /* for sigpage */
 421         npages += vdso_total_pages;
 422
 423         down_write(&mm->mmap_sem);
 424         hint = sigpage_addr(mm, npages);
 425         addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
 426         if (IS_ERR_VALUE(addr)) {
 427                 ret = addr;
 428                 goto up_fail;
 429         }
 430
 431         vma = _install_special_mapping(mm, addr, PAGE_SIZE,
 432                 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
 433                 &sigpage_mapping);
 434
 435         if (IS_ERR(vma)) {
 436                 ret = PTR_ERR(vma);
 437                 goto up_fail;
 438         }
 439
 440         mm->context.sigpage = addr;
 441
 442         /* Unlike the sigpage, failure to install the vdso is unlikely
 443          * to be fatal to the process, so no error check needed
 444          * here.
 445          */
 446         arm_install_vdso(mm, addr + PAGE_SIZE);
 447
 448  up_fail:
 449         up_write(&mm->mmap_sem);
 450         return ret;
 451 }
 452 #endif