arch/arm/kernel/process.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/arch/arm/kernel/process.c
   4  *
   5  *  Copyright (C) 1996-2000 Russell King - Converted to ARM.
   6  *  Original Copyright (C) 1995  Linus Torvalds
   7  */
   8 #include <linux/export.h>
   9 #include <linux/sched.h>
  10 #include <linux/sched/debug.h>
  11 #include <linux/sched/task.h>
  12 #include <linux/sched/task_stack.h>
  13 #include <linux/kernel.h>
  14 #include <linux/mm.h>
  15 #include <linux/stddef.h>
  16 #include <linux/unistd.h>
  17 #include <linux/user.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/init.h>
  20 #include <linux/elfcore.h>
  21 #include <linux/pm.h>
  22 #include <linux/tick.h>
  23 #include <linux/utsname.h>
  24 #include <linux/uaccess.h>
  25 #include <linux/random.h>
  26 #include <linux/hw_breakpoint.h>
  27 #include <linux/leds.h>
  28
  29 #include <asm/processor.h>
  30 #include <asm/thread_notify.h>
  31 #include <asm/stacktrace.h>
  32 #include <asm/system_misc.h>
  33 #include <asm/mach/time.h>
  34 #include <asm/tls.h>
  35 #include <asm/vdso.h>
  36
  37 #include "signal.h"
  38
  39 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
  40 #include <linux/stackprotector.h>
  41 unsigned long __stack_chk_guard __read_mostly;
  42 EXPORT_SYMBOL(__stack_chk_guard);
  43 #endif
  44
  45 static const char *processor_modes[] __maybe_unused = {
  46   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
  47   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
  48   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
  49   "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
  50 };
  51
  52 static const char *isa_modes[] __maybe_unused = {
  53   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
  54 };
  55
  56 /*
  57  * This is our default idle handler.
  58  */
  59
  60 void (*arm_pm_idle)(void);
  61
  62 /*
  63  * Called from the core idle loop.
  64  */
  65
  66 void arch_cpu_idle(void)
  67 {
  68         if (arm_pm_idle)
  69                 arm_pm_idle();
  70         else
  71                 cpu_do_idle();
  72         raw_local_irq_enable();
  73 }
  74
  75 void arch_cpu_idle_prepare(void)
  76 {
  77         local_fiq_enable();
  78 }
  79
  80 void arch_cpu_idle_enter(void)
  81 {
  82         ledtrig_cpu(CPU_LED_IDLE_START);
  83 #ifdef CONFIG_PL310_ERRATA_769419
  84         wmb();
  85 #endif
  86 }
  87
  88 void arch_cpu_idle_exit(void)
  89 {
  90         ledtrig_cpu(CPU_LED_IDLE_END);
  91 }
  92
  93 void __show_regs_alloc_free(struct pt_regs *regs)
  94 {
  95         int i;
  96
  97         /* check for r0 - r12 only */
  98         for (i = 0; i < 13; i++) {
  99                 pr_alert("Register r%d information:", i);
 100                 mem_dump_obj((void *)regs->uregs[i]);
 101         }
 102 }
 103
 104 void __show_regs(struct pt_regs *regs)
 105 {
 106         unsigned long flags;
 107         char buf[64];
 108 #ifndef CONFIG_CPU_V7M
 109         unsigned int domain;
 110 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
 111         /*
 112          * Get the domain register for the parent context. In user
 113          * mode, we don't save the DACR, so lets use what it should
 114          * be. For other modes, we place it after the pt_regs struct.
 115          */
 116         if (user_mode(regs)) {
 117                 domain = DACR_UACCESS_ENABLE;
 118         } else {
 119                 domain = to_svc_pt_regs(regs)->dacr;
 120         }
 121 #else
 122         domain = get_domain();
 123 #endif
 124 #endif
 125
 126         show_regs_print_info(KERN_DEFAULT);
 127
 128         printk("PC is at %pS\n", (void *)instruction_pointer(regs));
 129         printk("LR is at %pS\n", (void *)regs->ARM_lr);
 130         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n",
 131                regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
 132         printk("sp : %08lx  ip : %08lx  fp : %08lx\n",
 133                regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
 134         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
 135                 regs->ARM_r10, regs->ARM_r9,
 136                 regs->ARM_r8);
 137         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
 138                 regs->ARM_r7, regs->ARM_r6,
 139                 regs->ARM_r5, regs->ARM_r4);
 140         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
 141                 regs->ARM_r3, regs->ARM_r2,
 142                 regs->ARM_r1, regs->ARM_r0);
 143
 144         flags = regs->ARM_cpsr;
 145         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
 146         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
 147         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
 148         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
 149         buf[4] = '\0';
 150
 151 #ifndef CONFIG_CPU_V7M
 152         {
 153                 const char *segment;
 154
 155                 if ((domain & domain_mask(DOMAIN_USER)) ==
 156                     domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
 157                         segment = "none";
 158                 else
 159                         segment = "user";
 160
 161                 printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
 162                         buf, interrupts_enabled(regs) ? "n" : "ff",
 163                         fast_interrupts_enabled(regs) ? "n" : "ff",
 164                         processor_modes[processor_mode(regs)],
 165                         isa_modes[isa_mode(regs)], segment);
 166         }
 167 #else
 168         printk("xPSR: %08lx\n", regs->ARM_cpsr);
 169 #endif
 170
 171 #ifdef CONFIG_CPU_CP15
 172         {
 173                 unsigned int ctrl;
 174
 175                 buf[0] = '\0';
 176 #ifdef CONFIG_CPU_CP15_MMU
 177                 {
 178                         unsigned int transbase;
 179                         asm("mrc p15, 0, %0, c2, c0\n\t"
 180                             : "=r" (transbase));
 181                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
 182                                 transbase, domain);
 183                 }
 184 #endif
 185                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
 186
 187                 printk("Control: %08x%s\n", ctrl, buf);
 188         }
 189 #endif
 190 }
 191
 192 void show_regs(struct pt_regs * regs)
 193 {
 194         __show_regs(regs);
 195         dump_stack();
 196 }
 197
 198 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
 199
 200 EXPORT_SYMBOL_GPL(thread_notify_head);
 201
 202 /*
 203  * Free current thread data structures etc..
 204  */
 205 void exit_thread(struct task_struct *tsk)
 206 {
 207         thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
 208 }
 209
 210 void flush_thread(void)
 211 {
 212         struct thread_info *thread = current_thread_info();
 213         struct task_struct *tsk = current;
 214
 215         flush_ptrace_hw_breakpoint(tsk);
 216
 217         memset(thread->used_cp, 0, sizeof(thread->used_cp));
 218         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 219         memset(&thread->fpstate, 0, sizeof(union fp_state));
 220
 221         flush_tls();
 222
 223         thread_notify(THREAD_NOTIFY_FLUSH, thread);
 224 }
 225
 226 void release_thread(struct task_struct *dead_task)
 227 {
 228 }
 229
 230 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 231
 232 int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 233                 unsigned long stk_sz, struct task_struct *p, unsigned long tls)
 234 {
 235         struct thread_info *thread = task_thread_info(p);
 236         struct pt_regs *childregs = task_pt_regs(p);
 237
 238         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
 239
 240 #ifdef CONFIG_CPU_USE_DOMAINS
 241         /*
 242          * Copy the initial value of the domain access control register
 243          * from the current thread: thread->addr_limit will have been
 244          * copied from the current thread via setup_thread_stack() in
 245          * kernel/fork.c
 246          */
 247         thread->cpu_domain = get_domain();
 248 #endif
 249
 250         if (likely(!(p->flags & (PF_KTHREAD | PF_IO_WORKER)))) {
 251                 *childregs = *current_pt_regs();
 252                 childregs->ARM_r0 = 0;
 253                 if (stack_start)
 254                         childregs->ARM_sp = stack_start;
 255         } else {
 256                 memset(childregs, 0, sizeof(struct pt_regs));
 257                 thread->cpu_context.r4 = stk_sz;
 258                 thread->cpu_context.r5 = stack_start;
 259                 childregs->ARM_cpsr = SVC_MODE;
 260         }
 261         thread->cpu_context.pc = (unsigned long)ret_from_fork;
 262         thread->cpu_context.sp = (unsigned long)childregs;
 263
 264         clear_ptrace_hw_breakpoint(p);
 265
 266         if (clone_flags & CLONE_SETTLS)
 267                 thread->tp_value[0] = tls;
 268         thread->tp_value[1] = get_tpuser();
 269
 270         thread_notify(THREAD_NOTIFY_COPY, thread);
 271
 272 #ifdef CONFIG_STACKPROTECTOR_PER_TASK
 273         thread->stack_canary = p->stack_canary;
 274 #endif
 275
 276         return 0;
 277 }
 278
 279 unsigned long get_wchan(struct task_struct *p)
 280 {
 281         struct stackframe frame;
 282         unsigned long stack_page;
 283         int count = 0;
 284         if (!p || p == current || task_is_running(p))
 285                 return 0;
 286
 287         frame.fp = thread_saved_fp(p);
 288         frame.sp = thread_saved_sp(p);
 289         frame.lr = 0;                   /* recovered from the stack */
 290         frame.pc = thread_saved_pc(p);
 291         stack_page = (unsigned long)task_stack_page(p);
 292         do {
 293                 if (frame.sp < stack_page ||
 294                     frame.sp >= stack_page + THREAD_SIZE ||
 295                     unwind_frame(&frame) < 0)
 296                         return 0;
 297                 if (!in_sched_functions(frame.pc))
 298                         return frame.pc;
 299         } while (count ++ < 16);
 300         return 0;
 301 }
 302
 303 #ifdef CONFIG_MMU
 304 #ifdef CONFIG_KUSER_HELPERS
 305 /*
 306  * The vectors page is always readable from user space for the
 307  * atomic helpers. Insert it into the gate_vma so that it is visible
 308  * through ptrace and /proc/<pid>/mem.
 309  */
 310 static struct vm_area_struct gate_vma;
 311
 312 static int __init gate_vma_init(void)
 313 {
 314         vma_init(&gate_vma, NULL);
 315         gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
 316         gate_vma.vm_start = 0xffff0000;
 317         gate_vma.vm_end = 0xffff0000 + PAGE_SIZE;
 318         gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC;
 319         return 0;
 320 }
 321 arch_initcall(gate_vma_init);
 322
 323 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 324 {
 325         return &gate_vma;
 326 }
 327
 328 int in_gate_area(struct mm_struct *mm, unsigned long addr)
 329 {
 330         return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
 331 }
 332
 333 int in_gate_area_no_mm(unsigned long addr)
 334 {
 335         return in_gate_area(NULL, addr);
 336 }
 337 #define is_gate_vma(vma)        ((vma) == &gate_vma)
 338 #else
 339 #define is_gate_vma(vma)        0
 340 #endif
 341
 342 const char *arch_vma_name(struct vm_area_struct *vma)
 343 {
 344         return is_gate_vma(vma) ? "[vectors]" : NULL;
 345 }
 346
 347 /* If possible, provide a placement hint at a random offset from the
 348  * stack for the sigpage and vdso pages.
 349  */
 350 static unsigned long sigpage_addr(const struct mm_struct *mm,
 351                                   unsigned int npages)
 352 {
 353         unsigned long offset;
 354         unsigned long first;
 355         unsigned long last;
 356         unsigned long addr;
 357         unsigned int slots;
 358
 359         first = PAGE_ALIGN(mm->start_stack);
 360
 361         last = TASK_SIZE - (npages << PAGE_SHIFT);
 362
 363         /* No room after stack? */
 364         if (first > last)
 365                 return 0;
 366
 367         /* Just enough room? */
 368         if (first == last)
 369                 return first;
 370
 371         slots = ((last - first) >> PAGE_SHIFT) + 1;
 372
 373         offset = get_random_int() % slots;
 374
 375         addr = first + (offset << PAGE_SHIFT);
 376
 377         return addr;
 378 }
 379
 380 static struct page *signal_page;
 381 extern struct page *get_signal_page(void);
 382
 383 static int sigpage_mremap(const struct vm_special_mapping *sm,
 384                 struct vm_area_struct *new_vma)
 385 {
 386         current->mm->context.sigpage = new_vma->vm_start;
 387         return 0;
 388 }
 389
 390 static const struct vm_special_mapping sigpage_mapping = {
 391         .name = "[sigpage]",
 392         .pages = &signal_page,
 393         .mremap = sigpage_mremap,
 394 };
 395
 396 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 397 {
 398         struct mm_struct *mm = current->mm;
 399         struct vm_area_struct *vma;
 400         unsigned long npages;
 401         unsigned long addr;
 402         unsigned long hint;
 403         int ret = 0;
 404
 405         if (!signal_page)
 406                 signal_page = get_signal_page();
 407         if (!signal_page)
 408                 return -ENOMEM;
 409
 410         npages = 1; /* for sigpage */
 411         npages += vdso_total_pages;
 412
 413         if (mmap_write_lock_killable(mm))
 414                 return -EINTR;
 415         hint = sigpage_addr(mm, npages);
 416         addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
 417         if (IS_ERR_VALUE(addr)) {
 418                 ret = addr;
 419                 goto up_fail;
 420         }
 421
 422         vma = _install_special_mapping(mm, addr, PAGE_SIZE,
 423                 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
 424                 &sigpage_mapping);
 425
 426         if (IS_ERR(vma)) {
 427                 ret = PTR_ERR(vma);
 428                 goto up_fail;
 429         }
 430
 431         mm->context.sigpage = addr;
 432
 433         /* Unlike the sigpage, failure to install the vdso is unlikely
 434          * to be fatal to the process, so no error check needed
 435          * here.
 436          */
 437         arm_install_vdso(mm, addr + PAGE_SIZE);
 438
 439  up_fail:
 440         mmap_write_unlock(mm);
 441         return ret;
 442 }
 443 #endif