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