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/sched/debug.h>
  16 #include <linux/sched/task.h>
  17 #include <linux/sched/task_stack.h>
  18 #include <linux/kernel.h>
  19 #include <linux/mm.h>
  20 #include <linux/stddef.h>
  21 #include <linux/unistd.h>
  22 #include <linux/user.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/init.h>
  25 #include <linux/elfcore.h>
  26 #include <linux/pm.h>
  27 #include <linux/tick.h>
  28 #include <linux/utsname.h>
  29 #include <linux/uaccess.h>
  30 #include <linux/random.h>
  31 #include <linux/hw_breakpoint.h>
  32 #include <linux/leds.h>
  33
  34 #include <asm/processor.h>
  35 #include <asm/thread_notify.h>
  36 #include <asm/stacktrace.h>
  37 #include <asm/system_misc.h>
  38 #include <asm/mach/time.h>
  39 #include <asm/tls.h>
  40 #include <asm/vdso.h>
  41
  42 #ifdef CONFIG_CC_STACKPROTECTOR
  43 #include <linux/stackprotector.h>
  44 unsigned long __stack_chk_guard __read_mostly;
  45 EXPORT_SYMBOL(__stack_chk_guard);
  46 #endif
  47
  48 static const char *processor_modes[] __maybe_unused = {
  49   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  50   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  51   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
  52   "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  53 };
  54
  55 static const char *isa_modes[] __maybe_unused = {
  56   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  57 };
  58
  59 /*
  60  * This is our default idle handler.
  61  */
  62
  63 void (*arm_pm_idle)(void);
  64
  65 /*
  66  * Called from the core idle loop.
  67  */
  68
  69 void arch_cpu_idle(void)
  70 {
  71         if (arm_pm_idle)
  72                 arm_pm_idle();
  73         else
  74                 cpu_do_idle();
  75         local_irq_enable();
  76 }
  77
  78 void arch_cpu_idle_prepare(void)
  79 {
  80         local_fiq_enable();
  81 }
  82
  83 void arch_cpu_idle_enter(void)
  84 {
  85         ledtrig_cpu(CPU_LED_IDLE_START);
  86 #ifdef CONFIG_PL310_ERRATA_769419
  87         wmb();
  88 #endif
  89 }
  90
  91 void arch_cpu_idle_exit(void)
  92 {
  93         ledtrig_cpu(CPU_LED_IDLE_END);
  94 }
  95
  96 void __show_regs(struct pt_regs *regs)
  97 {
  98         unsigned long flags;
  99         char buf[64];
 100 #ifndef CONFIG_CPU_V7M
 101         unsigned int domain, fs;
 102 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
 103         /*
 104          * Get the domain register for the parent context. In user
 105          * mode, we don't save the DACR, so lets use what it should
 106          * be. For other modes, we place it after the pt_regs struct.
 107          */
 108         if (user_mode(regs)) {
 109                 domain = DACR_UACCESS_ENABLE;
 110                 fs = get_fs();
 111         } else {
 112                 domain = to_svc_pt_regs(regs)->dacr;
 113                 fs = to_svc_pt_regs(regs)->addr_limit;
 114         }
 115 #else
 116         domain = get_domain();
 117         fs = get_fs();
 118 #endif
 119 #endif
 120
 121         show_regs_print_info(KERN_DEFAULT);
 122
 123         printk("PC is at %pS\n", (void *)instruction_pointer(regs));
 124         printk("LR is at %pS\n", (void *)regs->ARM_lr);
 125         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n",
 126                regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
 127         printk("sp : %08lx  ip : %08lx  fp : %08lx\n",
 128                regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 129         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 130                 regs->ARM_r10, regs->ARM_r9,
 131                 regs->ARM_r8);
 132         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 133                 regs->ARM_r7, regs->ARM_r6,
 134                 regs->ARM_r5, regs->ARM_r4);
 135         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 136                 regs->ARM_r3, regs->ARM_r2,
 137                 regs->ARM_r1, regs->ARM_r0);
 138
 139         flags = regs->ARM_cpsr;
 140         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 141         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 142         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 143         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 144         buf[4] = '\0';
 145
 146 #ifndef CONFIG_CPU_V7M
 147         {
 148                 const char *segment;
 149
 150                 if ((domain & domain_mask(DOMAIN_USER)) ==
 151                     domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
 152                         segment = "none";
 153                 else if (fs == get_ds())
 154                         segment = "kernel";
 155                 else
 156                         segment = "user";
 157
 158                 printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 159                         buf, interrupts_enabled(regs) ? "n" : "ff",
 160                         fast_interrupts_enabled(regs) ? "n" : "ff",
 161                         processor_modes[processor_mode(regs)],
 162                         isa_modes[isa_mode(regs)], segment);
 163         }
 164 #else
 165         printk("xPSR: %08lx\n", regs->ARM_cpsr);
 166 #endif
 167
 168 #ifdef CONFIG_CPU_CP15
 169         {
 170                 unsigned int ctrl;
 171
 172                 buf[0] = '\0';
 173 #ifdef CONFIG_CPU_CP15_MMU
 174                 {
 175                         unsigned int transbase;
 176                         asm("mrc p15, 0, %0, c2, c0\n\t"
 177                             : "=r" (transbase));
 178                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 179                                 transbase, domain);
 180                 }
 181 #endif
 182                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 183
 184                 printk("Control: %08x%s\n", ctrl, buf);
 185         }
 186 #endif
 187 }
 188
 189 void show_regs(struct pt_regs * regs)
 190 {
 191         __show_regs(regs);
 192         dump_stack();
 193 }
 194
 195 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 196
 197 EXPORT_SYMBOL_GPL(thread_notify_head);
 198
 199 /*
 200  * Free current thread data structures etc..
 201  */
 202 void exit_thread(struct task_struct *tsk)
 203 {
 204         thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
 205 }
 206
 207 void flush_thread(void)
 208 {
 209         struct thread_info *thread = current_thread_info();
 210         struct task_struct *tsk = current;
 211
 212         flush_ptrace_hw_breakpoint(tsk);
 213
 214         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 215         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 216         memset(&thread->fpstate, 0, sizeof(union fp_state));
 217
 218         flush_tls();
 219
 220         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 221 }
 222
 223 void release_thread(struct task_struct *dead_task)
 224 {
 225 }
 226
 227 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 228
 229 int
 230 copy_thread(unsigned long clone_flags, unsigned long stack_start,
 231             unsigned long stk_sz, struct task_struct *p)
 232 {
 233         struct thread_info *thread = task_thread_info(p);
 234         struct pt_regs *childregs = task_pt_regs(p);
 235
 236         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 237
 238 #ifdef CONFIG_CPU_USE_DOMAINS
 239         /*
 240          * Copy the initial value of the domain access control register
 241          * from the current thread: thread->addr_limit will have been
 242          * copied from the current thread via setup_thread_stack() in
 243          * kernel/fork.c
 244          */
 245         thread->cpu_domain = get_domain();
 246 #endif
 247
 248         if (likely(!(p->flags & PF_KTHREAD))) {
 249                 *childregs = *current_pt_regs();
 250                 childregs->ARM_r0 = 0;
 251                 if (stack_start)
 252                         childregs->ARM_sp = stack_start;
 253         } else {
 254                 memset(childregs, 0, sizeof(struct pt_regs));
 255                 thread->cpu_context.r4 = stk_sz;
 256                 thread->cpu_context.r5 = stack_start;
 257                 childregs->ARM_cpsr = SVC_MODE;
 258         }
 259         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 260         thread->cpu_context.sp = (unsigned long)childregs;
 261
 262         clear_ptrace_hw_breakpoint(p);
 263
 264         if (clone_flags & CLONE_SETTLS)
 265                 thread->tp_value[0] = childregs->ARM_r3;
 266         thread->tp_value[1] = get_tpuser();
 267
 268         thread_notify(THREAD_NOTIFY_COPY, thread);
 269
 270         return 0;
 271 }
 272
 273 /*
 274  * Fill in the task's elfregs structure for a core dump.
 275  */
 276 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
 277 {
 278         elf_core_copy_regs(elfregs, task_pt_regs(t));
 279         return 1;
 280 }
 281
 282 /*
 283  * fill in the fpe structure for a core dump...
 284  */
 285 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 286 {
 287         struct thread_info *thread = current_thread_info();
 288         int used_math = thread->used_cp[1] | thread->used_cp[2];
 289
 290         if (used_math)
 291                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
 292
 293         return used_math != 0;
 294 }
 295 EXPORT_SYMBOL(dump_fpu);
 296
 297 unsigned long get_wchan(struct task_struct *p)
 298 {
 299         struct stackframe frame;
 300         unsigned long stack_page;
 301         int count = 0;
 302         if (!p || p == current || p->state == TASK_RUNNING)
 303                 return 0;
 304
 305         frame.fp = thread_saved_fp(p);
 306         frame.sp = thread_saved_sp(p);
 307         frame.lr = 0;                   /* recovered from the stack */
 308         frame.pc = thread_saved_pc(p);
 309         stack_page = (unsigned long)task_stack_page(p);
 310         do {
 311                 if (frame.sp < stack_page ||
 312                     frame.sp >= stack_page + THREAD_SIZE ||
 313                     unwind_frame(&frame) < 0)
 314                         return 0;
 315                 if (!in_sched_functions(frame.pc))
 316                         return frame.pc;
 317         } while (count ++ < 16);
 318         return 0;
 319 }
 320
 321 unsigned long arch_randomize_brk(struct mm_struct *mm)
 322 {
 323         return randomize_page(mm->brk, 0x02000000);
 324 }
 325
 326 #ifdef CONFIG_MMU
 327 #ifdef CONFIG_KUSER_HELPERS
 328 /*
 329  * The vectors page is always readable from user space for the
 330  * atomic helpers. Insert it into the gate_vma so that it is visible
 331  * through ptrace and /proc/<pid>/mem.
 332  */
 333 static struct vm_area_struct gate_vma = {
 334         .vm_start       = 0xffff0000,
 335         .vm_end         = 0xffff0000 + PAGE_SIZE,
 336         .vm_flags       = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
 337 };
 338
 339 static int __init gate_vma_init(void)
 340 {
 341         gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
 342         return 0;
 343 }
 344 arch_initcall(gate_vma_init);
 345
 346 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 347 {
 348         return &gate_vma;
 349 }
 350
 351 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 352 {
 353         return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
 354 }
 355
 356 int in_gate_area_no_mm(unsigned long addr)
 357 {
 358         return in_gate_area(NULL, addr);
 359 }
 360 #define is_gate_vma(vma)        ((vma) == &gate_vma)
 361 #else
 362 #define is_gate_vma(vma)        0
 363 #endif
 364
 365 const char *arch_vma_name(struct vm_area_struct *vma)
 366 {
 367         return is_gate_vma(vma) ? "[vectors]" : NULL;
 368 }
 369
 370 /* If possible, provide a placement hint at a random offset from the
 371  * stack for the sigpage and vdso pages.
 372  */
 373 static unsigned long sigpage_addr(const struct mm_struct *mm,
 374                                   unsigned int npages)
 375 {
 376         unsigned long offset;
 377         unsigned long first;
 378         unsigned long last;
 379         unsigned long addr;
 380         unsigned int slots;
 381
 382         first = PAGE_ALIGN(mm->start_stack);
 383
 384         last = TASK_SIZE - (npages << PAGE_SHIFT);
 385
 386         /* No room after stack? */
 387         if (first > last)
 388                 return 0;
 389
 390         /* Just enough room? */
 391         if (first == last)
 392                 return first;
 393
 394         slots = ((last - first) >> PAGE_SHIFT) + 1;
 395
 396         offset = get_random_int() % slots;
 397
 398         addr = first + (offset << PAGE_SHIFT);
 399
 400         return addr;
 401 }
 402
 403 static struct page *signal_page;
 404 extern struct page *get_signal_page(void);
 405
 406 static int sigpage_mremap(const struct vm_special_mapping *sm,
 407                 struct vm_area_struct *new_vma)
 408 {
 409         current->mm->context.sigpage = new_vma->vm_start;
 410         return 0;
 411 }
 412
 413 static const struct vm_special_mapping sigpage_mapping = {
 414         .name = "[sigpage]",
 415         .pages = &signal_page,
 416         .mremap = sigpage_mremap,
 417 };
 418
 419 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 420 {
 421         struct mm_struct *mm = current->mm;
 422         struct vm_area_struct *vma;
 423         unsigned long npages;
 424         unsigned long addr;
 425         unsigned long hint;
 426         int ret = 0;
 427
 428         if (!signal_page)
 429                 signal_page = get_signal_page();
 430         if (!signal_page)
 431                 return -ENOMEM;
 432
 433         npages = 1; /* for sigpage */
 434         npages += vdso_total_pages;
 435
 436         if (down_write_killable(&mm->mmap_sem))
 437                 return -EINTR;
 438         hint = sigpage_addr(mm, npages);
 439         addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
 440         if (IS_ERR_VALUE(addr)) {
 441                 ret = addr;
 442                 goto up_fail;
 443         }
 444
 445         vma = _install_special_mapping(mm, addr, PAGE_SIZE,
 446                 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
 447                 &sigpage_mapping);
 448
 449         if (IS_ERR(vma)) {
 450                 ret = PTR_ERR(vma);
 451                 goto up_fail;
 452         }
 453
 454         mm->context.sigpage = addr;
 455
 456         /* Unlike the sigpage, failure to install the vdso is unlikely
 457          * to be fatal to the process, so no error check needed
 458          * here.
 459          */
 460         arm_install_vdso(mm, addr + PAGE_SIZE);
 461
 462  up_fail:
 463         up_write(&mm->mmap_sem);
 464         return ret;
 465 }
 466 #endif