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 <stdarg.h> 9 10 #include <linux/export.h> 11 #include <linux/sched.h> 12 #include <linux/sched/debug.h> 13 #include <linux/sched/task.h> 14 #include <linux/sched/task_stack.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/init.h> 22 #include <linux/elfcore.h> 23 #include <linux/pm.h> 24 #include <linux/tick.h> 25 #include <linux/utsname.h> 26 #include <linux/uaccess.h> 27 #include <linux/random.h> 28 #include <linux/hw_breakpoint.h> 29 #include <linux/leds.h> 30 31 #include <asm/processor.h> 32 #include <asm/thread_notify.h> 33 #include <asm/stacktrace.h> 34 #include <asm/system_misc.h> 35 #include <asm/mach/time.h> 36 #include <asm/tls.h> 37 #include <asm/vdso.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 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(struct pt_regs *regs) 94 { 95 unsigned long flags; 96 char buf[64]; 97 #ifndef CONFIG_CPU_V7M 98 unsigned int domain, fs; 99 #ifdef CONFIG_CPU_SW_DOMAIN_PAN 100 /* 101 * Get the domain register for the parent context. In user 102 * mode, we don't save the DACR, so lets use what it should 103 * be. For other modes, we place it after the pt_regs struct. 104 */ 105 if (user_mode(regs)) { 106 domain = DACR_UACCESS_ENABLE; 107 fs = get_fs(); 108 } else { 109 domain = to_svc_pt_regs(regs)->dacr; 110 fs = to_svc_pt_regs(regs)->addr_limit; 111 } 112 #else 113 domain = get_domain(); 114 fs = get_fs(); 115 #endif 116 #endif 117 118 show_regs_print_info(KERN_DEFAULT); 119 120 printk("PC is at %pS\n", (void *)instruction_pointer(regs)); 121 printk("LR is at %pS\n", (void *)regs->ARM_lr); 122 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n", 123 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr); 124 printk("sp : %08lx ip : %08lx fp : %08lx\n", 125 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 126 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 127 regs->ARM_r10, regs->ARM_r9, 128 regs->ARM_r8); 129 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 130 regs->ARM_r7, regs->ARM_r6, 131 regs->ARM_r5, regs->ARM_r4); 132 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 133 regs->ARM_r3, regs->ARM_r2, 134 regs->ARM_r1, regs->ARM_r0); 135 136 flags = regs->ARM_cpsr; 137 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 138 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 139 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 140 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 141 buf[4] = '\0'; 142 143 #ifndef CONFIG_CPU_V7M 144 { 145 const char *segment; 146 147 if ((domain & domain_mask(DOMAIN_USER)) == 148 domain_val(DOMAIN_USER, DOMAIN_NOACCESS)) 149 segment = "none"; 150 else if (fs == KERNEL_DS) 151 segment = "kernel"; 152 else 153 segment = "user"; 154 155 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 156 buf, interrupts_enabled(regs) ? "n" : "ff", 157 fast_interrupts_enabled(regs) ? "n" : "ff", 158 processor_modes[processor_mode(regs)], 159 isa_modes[isa_mode(regs)], segment); 160 } 161 #else 162 printk("xPSR: %08lx\n", regs->ARM_cpsr); 163 #endif 164 165 #ifdef CONFIG_CPU_CP15 166 { 167 unsigned int ctrl; 168 169 buf[0] = '\0'; 170 #ifdef CONFIG_CPU_CP15_MMU 171 { 172 unsigned int transbase; 173 asm("mrc p15, 0, %0, c2, c0\n\t" 174 : "=r" (transbase)); 175 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 176 transbase, domain); 177 } 178 #endif 179 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 180 181 printk("Control: %08x%s\n", ctrl, buf); 182 } 183 #endif 184 } 185 186 void show_regs(struct pt_regs * regs) 187 { 188 __show_regs(regs); 189 dump_stack(); 190 } 191 192 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 193 194 EXPORT_SYMBOL_GPL(thread_notify_head); 195 196 /* 197 * Free current thread data structures etc.. 198 */ 199 void exit_thread(struct task_struct *tsk) 200 { 201 thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk)); 202 } 203 204 void flush_thread(void) 205 { 206 struct thread_info *thread = current_thread_info(); 207 struct task_struct *tsk = current; 208 209 flush_ptrace_hw_breakpoint(tsk); 210 211 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 212 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 213 memset(&thread->fpstate, 0, sizeof(union fp_state)); 214 215 flush_tls(); 216 217 thread_notify(THREAD_NOTIFY_FLUSH, thread); 218 } 219 220 void release_thread(struct task_struct *dead_task) 221 { 222 } 223 224 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 225 226 int 227 copy_thread(unsigned long clone_flags, unsigned long stack_start, 228 unsigned long stk_sz, struct task_struct *p) 229 { 230 struct thread_info *thread = task_thread_info(p); 231 struct pt_regs *childregs = task_pt_regs(p); 232 233 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 234 235 #ifdef CONFIG_CPU_USE_DOMAINS 236 /* 237 * Copy the initial value of the domain access control register 238 * from the current thread: thread->addr_limit will have been 239 * copied from the current thread via setup_thread_stack() in 240 * kernel/fork.c 241 */ 242 thread->cpu_domain = get_domain(); 243 #endif 244 245 if (likely(!(p->flags & PF_KTHREAD))) { 246 *childregs = *current_pt_regs(); 247 childregs->ARM_r0 = 0; 248 if (stack_start) 249 childregs->ARM_sp = stack_start; 250 } else { 251 memset(childregs, 0, sizeof(struct pt_regs)); 252 thread->cpu_context.r4 = stk_sz; 253 thread->cpu_context.r5 = stack_start; 254 childregs->ARM_cpsr = SVC_MODE; 255 } 256 thread->cpu_context.pc = (unsigned long)ret_from_fork; 257 thread->cpu_context.sp = (unsigned long)childregs; 258 259 clear_ptrace_hw_breakpoint(p); 260 261 if (clone_flags & CLONE_SETTLS) 262 thread->tp_value[0] = childregs->ARM_r3; 263 thread->tp_value[1] = get_tpuser(); 264 265 thread_notify(THREAD_NOTIFY_COPY, thread); 266 267 #ifdef CONFIG_STACKPROTECTOR_PER_TASK 268 thread->stack_canary = p->stack_canary; 269 #endif 270 271 return 0; 272 } 273 274 /* 275 * Fill in the task's elfregs structure for a core dump. 276 */ 277 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs) 278 { 279 elf_core_copy_regs(elfregs, task_pt_regs(t)); 280 return 1; 281 } 282 283 /* 284 * fill in the fpe structure for a core dump... 285 */ 286 int dump_fpu (struct pt_regs *regs, struct user_fp *fp) 287 { 288 struct thread_info *thread = current_thread_info(); 289 int used_math = thread->used_cp[1] | thread->used_cp[2]; 290 291 if (used_math) 292 memcpy(fp, &thread->fpstate.soft, sizeof (*fp)); 293 294 return used_math != 0; 295 } 296 EXPORT_SYMBOL(dump_fpu); 297 298 unsigned long get_wchan(struct task_struct *p) 299 { 300 struct stackframe frame; 301 unsigned long stack_page; 302 int count = 0; 303 if (!p || p == current || p->state == TASK_RUNNING) 304 return 0; 305 306 frame.fp = thread_saved_fp(p); 307 frame.sp = thread_saved_sp(p); 308 frame.lr = 0; /* recovered from the stack */ 309 frame.pc = thread_saved_pc(p); 310 stack_page = (unsigned long)task_stack_page(p); 311 do { 312 if (frame.sp < stack_page || 313 frame.sp >= stack_page + THREAD_SIZE || 314 unwind_frame(&frame) < 0) 315 return 0; 316 if (!in_sched_functions(frame.pc)) 317 return frame.pc; 318 } while (count ++ < 16); 319 return 0; 320 } 321 322 #ifdef CONFIG_MMU 323 #ifdef CONFIG_KUSER_HELPERS 324 /* 325 * The vectors page is always readable from user space for the 326 * atomic helpers. Insert it into the gate_vma so that it is visible 327 * through ptrace and /proc/<pid>/mem. 328 */ 329 static struct vm_area_struct gate_vma; 330 331 static int __init gate_vma_init(void) 332 { 333 vma_init(&gate_vma, NULL); 334 gate_vma.vm_page_prot = PAGE_READONLY_EXEC; 335 gate_vma.vm_start = 0xffff0000; 336 gate_vma.vm_end = 0xffff0000 + PAGE_SIZE; 337 gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC; 338 return 0; 339 } 340 arch_initcall(gate_vma_init); 341 342 struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 343 { 344 return &gate_vma; 345 } 346 347 int in_gate_area(struct mm_struct *mm, unsigned long addr) 348 { 349 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end); 350 } 351 352 int in_gate_area_no_mm(unsigned long addr) 353 { 354 return in_gate_area(NULL, addr); 355 } 356 #define is_gate_vma(vma) ((vma) == &gate_vma) 357 #else 358 #define is_gate_vma(vma) 0 359 #endif 360 361 const char *arch_vma_name(struct vm_area_struct *vma) 362 { 363 return is_gate_vma(vma) ? "[vectors]" : NULL; 364 } 365 366 /* If possible, provide a placement hint at a random offset from the 367 * stack for the sigpage and vdso pages. 368 */ 369 static unsigned long sigpage_addr(const struct mm_struct *mm, 370 unsigned int npages) 371 { 372 unsigned long offset; 373 unsigned long first; 374 unsigned long last; 375 unsigned long addr; 376 unsigned int slots; 377 378 first = PAGE_ALIGN(mm->start_stack); 379 380 last = TASK_SIZE - (npages << PAGE_SHIFT); 381 382 /* No room after stack? */ 383 if (first > last) 384 return 0; 385 386 /* Just enough room? */ 387 if (first == last) 388 return first; 389 390 slots = ((last - first) >> PAGE_SHIFT) + 1; 391 392 offset = get_random_int() % slots; 393 394 addr = first + (offset << PAGE_SHIFT); 395 396 return addr; 397 } 398 399 static struct page *signal_page; 400 extern struct page *get_signal_page(void); 401 402 static int sigpage_mremap(const struct vm_special_mapping *sm, 403 struct vm_area_struct *new_vma) 404 { 405 current->mm->context.sigpage = new_vma->vm_start; 406 return 0; 407 } 408 409 static const struct vm_special_mapping sigpage_mapping = { 410 .name = "[sigpage]", 411 .pages = &signal_page, 412 .mremap = sigpage_mremap, 413 }; 414 415 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 416 { 417 struct mm_struct *mm = current->mm; 418 struct vm_area_struct *vma; 419 unsigned long npages; 420 unsigned long addr; 421 unsigned long hint; 422 int ret = 0; 423 424 if (!signal_page) 425 signal_page = get_signal_page(); 426 if (!signal_page) 427 return -ENOMEM; 428 429 npages = 1; /* for sigpage */ 430 npages += vdso_total_pages; 431 432 if (down_write_killable(&mm->mmap_sem)) 433 return -EINTR; 434 hint = sigpage_addr(mm, npages); 435 addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0); 436 if (IS_ERR_VALUE(addr)) { 437 ret = addr; 438 goto up_fail; 439 } 440 441 vma = _install_special_mapping(mm, addr, PAGE_SIZE, 442 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, 443 &sigpage_mapping); 444 445 if (IS_ERR(vma)) { 446 ret = PTR_ERR(vma); 447 goto up_fail; 448 } 449 450 mm->context.sigpage = addr; 451 452 /* Unlike the sigpage, failure to install the vdso is unlikely 453 * to be fatal to the process, so no error check needed 454 * here. 455 */ 456 arm_install_vdso(mm, addr + PAGE_SIZE); 457 458 up_fail: 459 up_write(&mm->mmap_sem); 460 return ret; 461 } 462 #endif 463