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 #ifdef CONFIG_HOTPLUG_CPU
  95 void arch_cpu_idle_dead(void)
  96 {
  97         cpu_die();
  98 }
  99 #endif
 100
 101 void __show_regs(struct pt_regs *regs)
 102 {
 103         unsigned long flags;
 104         char buf[64];
 105
 106         show_regs_print_info(KERN_DEFAULT);
 107
 108         print_symbol("PC is at %s\n", instruction_pointer(regs));
 109         print_symbol("LR is at %s\n", regs->ARM_lr);
 110         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
 111                "sp : %08lx  ip : %08lx  fp : %08lx\n",
 112                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
 113                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 114         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 115                 regs->ARM_r10, regs->ARM_r9,
 116                 regs->ARM_r8);
 117         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 118                 regs->ARM_r7, regs->ARM_r6,
 119                 regs->ARM_r5, regs->ARM_r4);
 120         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 121                 regs->ARM_r3, regs->ARM_r2,
 122                 regs->ARM_r1, regs->ARM_r0);
 123
 124         flags = regs->ARM_cpsr;
 125         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 126         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 127         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 128         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 129         buf[4] = '\0';
 130
 131 #ifndef CONFIG_CPU_V7M
 132         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 133                 buf, interrupts_enabled(regs) ? "n" : "ff",
 134                 fast_interrupts_enabled(regs) ? "n" : "ff",
 135                 processor_modes[processor_mode(regs)],
 136                 isa_modes[isa_mode(regs)],
 137                 get_fs() == get_ds() ? "kernel" : "user");
 138 #else
 139         printk("xPSR: %08lx\n", regs->ARM_cpsr);
 140 #endif
 141
 142 #ifdef CONFIG_CPU_CP15
 143         {
 144                 unsigned int ctrl;
 145
 146                 buf[0] = '\0';
 147 #ifdef CONFIG_CPU_CP15_MMU
 148                 {
 149                         unsigned int transbase, dac;
 150                         asm("mrc p15, 0, %0, c2, c0\n\t"
 151                             "mrc p15, 0, %1, c3, c0\n"
 152                             : "=r" (transbase), "=r" (dac));
 153                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 154                                 transbase, dac);
 155                 }
 156 #endif
 157                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 158
 159                 printk("Control: %08x%s\n", ctrl, buf);
 160         }
 161 #endif
 162 }
 163
 164 void show_regs(struct pt_regs * regs)
 165 {
 166         __show_regs(regs);
 167         dump_stack();
 168 }
 169
 170 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 171
 172 EXPORT_SYMBOL_GPL(thread_notify_head);
 173
 174 /*
 175  * Free current thread data structures etc..
 176  */
 177 void exit_thread(void)
 178 {
 179         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
 180 }
 181
 182 void flush_thread(void)
 183 {
 184         struct thread_info *thread = current_thread_info();
 185         struct task_struct *tsk = current;
 186
 187         flush_ptrace_hw_breakpoint(tsk);
 188
 189         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 190         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 191         memset(&thread->fpstate, 0, sizeof(union fp_state));
 192
 193         flush_tls();
 194
 195         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 196 }
 197
 198 void release_thread(struct task_struct *dead_task)
 199 {
 200 }
 201
 202 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 203
 204 int
 205 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 206             unsigned long stk_sz, struct task_struct *p)
 207 {
 208         struct thread_info *thread = task_thread_info(p);
 209         struct pt_regs *childregs = task_pt_regs(p);
 210
 211         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 212
 213         if (likely(!(p->flags & PF_KTHREAD))) {
 214                 *childregs = *current_pt_regs();
 215                 childregs->ARM_r0 = 0;
 216                 if (stack_start)
 217                         childregs->ARM_sp = stack_start;
 218         } else {
 219                 memset(childregs, 0, sizeof(struct pt_regs));
 220                 thread->cpu_context.r4 = stk_sz;
 221                 thread->cpu_context.r5 = stack_start;
 222                 childregs->ARM_cpsr = SVC_MODE;
 223         }
 224         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 225         thread->cpu_context.sp = (unsigned long)childregs;
 226
 227         clear_ptrace_hw_breakpoint(p);
 228
 229         if (clone_flags & CLONE_SETTLS)
 230                 thread->tp_value[0] = childregs->ARM_r3;
 231         thread->tp_value[1] = get_tpuser();
 232
 233         thread_notify(THREAD_NOTIFY_COPY, thread);
 234
 235         return 0;
 236 }
 237
 238 /*
 239  * Fill in the task's elfregs structure for a core dump.
 240  */
 241 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 242 {
 243         elf_core_copy_regs(elfregs, task_pt_regs(t));
 244         return 1;
 245 }
 246
 247 /*
 248  * fill in the fpe structure for a core dump...
 249  */
 250 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 251 {
 252         struct thread_info *thread = current_thread_info();
 253         int used_math = thread->used_cp[1] | thread->used_cp[2];
 254
 255         if (used_math)
 256                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 257
 258         return used_math != 0;
 259 }
 260 EXPORT_SYMBOL(dump_fpu);
 261
 262 unsigned long get_wchan(struct task_struct *p)
 263 {
 264         struct stackframe frame;
 265         unsigned long stack_page;
 266         int count = 0;
 267         if (!p || p == current || p->state == TASK_RUNNING)
 268                 return 0;
 269
 270         frame.fp = thread_saved_fp(p);
 271         frame.sp = thread_saved_sp(p);
 272         frame.lr = 0;                   /* recovered from the stack */
 273         frame.pc = thread_saved_pc(p);
 274         stack_page = (unsigned long)task_stack_page(p);
 275         do {
 276                 if (frame.sp < stack_page ||
 277                     frame.sp >= stack_page + THREAD_SIZE ||
 278                     unwind_frame(&frame) < 0)
 279                         return 0;
 280                 if (!in_sched_functions(frame.pc))
 281                         return frame.pc;
 282         } while (count ++ < 16);
 283         return 0;
 284 }
 285
 286 unsigned long arch_randomize_brk(struct mm_struct *mm)
 287 {
 288         unsigned long range_end = mm->brk + 0x02000000;
 289         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 290 }
 291
 292 #ifdef CONFIG_MMU
 293 #ifdef CONFIG_KUSER_HELPERS
 294 /*
 295  * The vectors page is always readable from user space for the
 296  * atomic helpers. Insert it into the gate_vma so that it is visible
 297  * through ptrace and /proc/<pid>/mem.
 298  */
 299 static struct vm_area_struct gate_vma = {
 300         .vm_start       = 0xffff0000,
 301         .vm_end         = 0xffff0000 + PAGE_SIZE,
 302         .vm_flags       = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
 303 };
 304
 305 static int __init gate_vma_init(void)
 306 {
 307         gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
 308         return 0;
 309 }
 310 arch_initcall(gate_vma_init);
 311
 312 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 313 {
 314         return &gate_vma;
 315 }
 316
 317 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 318 {
 319         return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
 320 }
 321
 322 int in_gate_area_no_mm(unsigned long addr)
 323 {
 324         return in_gate_area(NULL, addr);
 325 }
 326 #define is_gate_vma(vma)        ((vma) == &gate_vma)
 327 #else
 328 #define is_gate_vma(vma)        0
 329 #endif
 330
 331 const char *arch_vma_name(struct vm_area_struct *vma)
 332 {
 333         return is_gate_vma(vma) ? "[vectors]" : NULL;
 334 }
 335
 336 /* If possible, provide a placement hint at a random offset from the
 337  * stack for the sigpage and vdso pages.
 338  */
 339 static unsigned long sigpage_addr(const struct mm_struct *mm,
 340                                   unsigned int npages)
 341 {
 342         unsigned long offset;
 343         unsigned long first;
 344         unsigned long last;
 345         unsigned long addr;
 346         unsigned int slots;
 347
 348         first = PAGE_ALIGN(mm->start_stack);
 349
 350         last = TASK_SIZE - (npages << PAGE_SHIFT);
 351
 352         /* No room after stack? */
 353         if (first > last)
 354                 return 0;
 355
 356         /* Just enough room? */
 357         if (first == last)
 358                 return first;
 359
 360         slots = ((last - first) >> PAGE_SHIFT) + 1;
 361
 362         offset = get_random_int() % slots;
 363
 364         addr = first + (offset << PAGE_SHIFT);
 365
 366         return addr;
 367 }
 368
 369 static struct page *signal_page;
 370 extern struct page *get_signal_page(void);
 371
 372 static const struct vm_special_mapping sigpage_mapping = {
 373         .name = "[sigpage]",
 374         .pages = &signal_page,
 375 };
 376
 377 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 378 {
 379         struct mm_struct *mm = current->mm;
 380         struct vm_area_struct *vma;
 381         unsigned long npages;
 382         unsigned long addr;
 383         unsigned long hint;
 384         int ret = 0;
 385
 386         if (!signal_page)
 387                 signal_page = get_signal_page();
 388         if (!signal_page)
 389                 return -ENOMEM;
 390
 391         npages = 1; /* for sigpage */
 392         npages += vdso_total_pages;
 393
 394         down_write(&mm->mmap_sem);
 395         hint = sigpage_addr(mm, npages);
 396         addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
 397         if (IS_ERR_VALUE(addr)) {
 398                 ret = addr;
 399                 goto up_fail;
 400         }
 401
 402         vma = _install_special_mapping(mm, addr, PAGE_SIZE,
 403                 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
 404                 &sigpage_mapping);
 405
 406         if (IS_ERR(vma)) {
 407                 ret = PTR_ERR(vma);
 408                 goto up_fail;
 409         }
 410
 411         mm->context.sigpage = addr;
 412
 413         /* Unlike the sigpage, failure to install the vdso is unlikely
 414          * to be fatal to the process, so no error check needed
 415          * here.
 416          */
 417         arm_install_vdso(mm, addr + PAGE_SIZE);
 418
 419  up_fail:
 420         up_write(&mm->mmap_sem);
 421         return ret;
 422 }
 423 #endif