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_CURRENT_POINTER_IN_TPIDRURO) || defined(CONFIG_SMP) 40 DEFINE_PER_CPU(struct task_struct *, __entry_task); 41 #endif 42 43 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK) 44 #include <linux/stackprotector.h> 45 unsigned long __stack_chk_guard __read_mostly; 46 EXPORT_SYMBOL(__stack_chk_guard); 47 #endif 48 49 #ifndef CONFIG_CURRENT_POINTER_IN_TPIDRURO 50 asmlinkage struct task_struct *__current; 51 EXPORT_SYMBOL(__current); 52 #endif 53 54 static const char *processor_modes[] __maybe_unused = { 55 "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" , 56 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26", 57 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" , 58 "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32" 59 }; 60 61 static const char *isa_modes[] __maybe_unused = { 62 "ARM" , "Thumb" , "Jazelle", "ThumbEE" 63 }; 64 65 /* 66 * This is our default idle handler. 67 */ 68 69 void (*arm_pm_idle)(void); 70 71 /* 72 * Called from the core idle loop. 73 */ 74 75 void arch_cpu_idle(void) 76 { 77 if (arm_pm_idle) 78 arm_pm_idle(); 79 else 80 cpu_do_idle(); 81 } 82 83 void arch_cpu_idle_prepare(void) 84 { 85 local_fiq_enable(); 86 } 87 88 void arch_cpu_idle_enter(void) 89 { 90 ledtrig_cpu(CPU_LED_IDLE_START); 91 #ifdef CONFIG_PL310_ERRATA_769419 92 wmb(); 93 #endif 94 } 95 96 void arch_cpu_idle_exit(void) 97 { 98 ledtrig_cpu(CPU_LED_IDLE_END); 99 } 100 101 void __show_regs_alloc_free(struct pt_regs *regs) 102 { 103 int i; 104 105 /* check for r0 - r12 only */ 106 for (i = 0; i < 13; i++) { 107 pr_alert("Register r%d information:", i); 108 mem_dump_obj((void *)regs->uregs[i]); 109 } 110 } 111 112 void __show_regs(struct pt_regs *regs) 113 { 114 unsigned long flags; 115 char buf[64]; 116 #ifndef CONFIG_CPU_V7M 117 unsigned int domain; 118 #ifdef CONFIG_CPU_SW_DOMAIN_PAN 119 /* 120 * Get the domain register for the parent context. In user 121 * mode, we don't save the DACR, so lets use what it should 122 * be. For other modes, we place it after the pt_regs struct. 123 */ 124 if (user_mode(regs)) { 125 domain = DACR_UACCESS_ENABLE; 126 } else { 127 domain = to_svc_pt_regs(regs)->dacr; 128 } 129 #else 130 domain = get_domain(); 131 #endif 132 #endif 133 134 show_regs_print_info(KERN_DEFAULT); 135 136 printk("PC is at %pS\n", (void *)instruction_pointer(regs)); 137 printk("LR is at %pS\n", (void *)regs->ARM_lr); 138 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n", 139 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr); 140 printk("sp : %08lx ip : %08lx fp : %08lx\n", 141 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 142 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 143 regs->ARM_r10, regs->ARM_r9, 144 regs->ARM_r8); 145 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 146 regs->ARM_r7, regs->ARM_r6, 147 regs->ARM_r5, regs->ARM_r4); 148 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 149 regs->ARM_r3, regs->ARM_r2, 150 regs->ARM_r1, regs->ARM_r0); 151 152 flags = regs->ARM_cpsr; 153 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 154 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 155 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 156 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 157 buf[4] = '\0'; 158 159 #ifndef CONFIG_CPU_V7M 160 { 161 const char *segment; 162 163 if ((domain & domain_mask(DOMAIN_USER)) == 164 domain_val(DOMAIN_USER, DOMAIN_NOACCESS)) 165 segment = "none"; 166 else 167 segment = "user"; 168 169 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 170 buf, interrupts_enabled(regs) ? "n" : "ff", 171 fast_interrupts_enabled(regs) ? "n" : "ff", 172 processor_modes[processor_mode(regs)], 173 isa_modes[isa_mode(regs)], segment); 174 } 175 #else 176 printk("xPSR: %08lx\n", regs->ARM_cpsr); 177 #endif 178 179 #ifdef CONFIG_CPU_CP15 180 { 181 unsigned int ctrl; 182 183 buf[0] = '\0'; 184 #ifdef CONFIG_CPU_CP15_MMU 185 { 186 unsigned int transbase; 187 asm("mrc p15, 0, %0, c2, c0\n\t" 188 : "=r" (transbase)); 189 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 190 transbase, domain); 191 } 192 #endif 193 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 194 195 printk("Control: %08x%s\n", ctrl, buf); 196 } 197 #endif 198 } 199 200 void show_regs(struct pt_regs * regs) 201 { 202 __show_regs(regs); 203 dump_backtrace(regs, NULL, KERN_DEFAULT); 204 } 205 206 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 207 208 EXPORT_SYMBOL_GPL(thread_notify_head); 209 210 /* 211 * Free current thread data structures etc.. 212 */ 213 void exit_thread(struct task_struct *tsk) 214 { 215 thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk)); 216 } 217 218 void flush_thread(void) 219 { 220 struct thread_info *thread = current_thread_info(); 221 struct task_struct *tsk = current; 222 223 flush_ptrace_hw_breakpoint(tsk); 224 225 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 226 memset(&thread->fpstate, 0, sizeof(union fp_state)); 227 228 flush_tls(); 229 230 thread_notify(THREAD_NOTIFY_FLUSH, thread); 231 } 232 233 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 234 235 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 236 { 237 unsigned long clone_flags = args->flags; 238 unsigned long stack_start = args->stack; 239 unsigned long tls = args->tls; 240 struct thread_info *thread = task_thread_info(p); 241 struct pt_regs *childregs = task_pt_regs(p); 242 243 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 244 245 #ifdef CONFIG_CPU_USE_DOMAINS 246 /* 247 * Copy the initial value of the domain access control register 248 * from the current thread: thread->addr_limit will have been 249 * copied from the current thread via setup_thread_stack() in 250 * kernel/fork.c 251 */ 252 thread->cpu_domain = get_domain(); 253 #endif 254 255 if (likely(!args->fn)) { 256 *childregs = *current_pt_regs(); 257 childregs->ARM_r0 = 0; 258 if (stack_start) 259 childregs->ARM_sp = stack_start; 260 } else { 261 memset(childregs, 0, sizeof(struct pt_regs)); 262 thread->cpu_context.r4 = (unsigned long)args->fn_arg; 263 thread->cpu_context.r5 = (unsigned long)args->fn; 264 childregs->ARM_cpsr = SVC_MODE; 265 } 266 thread->cpu_context.pc = (unsigned long)ret_from_fork; 267 thread->cpu_context.sp = (unsigned long)childregs; 268 269 clear_ptrace_hw_breakpoint(p); 270 271 if (clone_flags & CLONE_SETTLS) 272 thread->tp_value[0] = tls; 273 thread->tp_value[1] = get_tpuser(); 274 275 thread_notify(THREAD_NOTIFY_COPY, thread); 276 277 return 0; 278 } 279 280 unsigned long __get_wchan(struct task_struct *p) 281 { 282 struct stackframe frame; 283 unsigned long stack_page; 284 int count = 0; 285 286 frame.fp = thread_saved_fp(p); 287 frame.sp = thread_saved_sp(p); 288 frame.lr = 0; /* recovered from the stack */ 289 frame.pc = thread_saved_pc(p); 290 stack_page = (unsigned long)task_stack_page(p); 291 do { 292 if (frame.sp < stack_page || 293 frame.sp >= stack_page + THREAD_SIZE || 294 unwind_frame(&frame) < 0) 295 return 0; 296 if (!in_sched_functions(frame.pc)) 297 return frame.pc; 298 } while (count ++ < 16); 299 return 0; 300 } 301 302 #ifdef CONFIG_MMU 303 #ifdef CONFIG_KUSER_HELPERS 304 /* 305 * The vectors page is always readable from user space for the 306 * atomic helpers. Insert it into the gate_vma so that it is visible 307 * through ptrace and /proc/<pid>/mem. 308 */ 309 static struct vm_area_struct gate_vma; 310 311 static int __init gate_vma_init(void) 312 { 313 vma_init(&gate_vma, NULL); 314 gate_vma.vm_page_prot = PAGE_READONLY_EXEC; 315 gate_vma.vm_start = 0xffff0000; 316 gate_vma.vm_end = 0xffff0000 + PAGE_SIZE; 317 vm_flags_init(&gate_vma, VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC); 318 return 0; 319 } 320 arch_initcall(gate_vma_init); 321 322 struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 323 { 324 return &gate_vma; 325 } 326 327 int in_gate_area(struct mm_struct *mm, unsigned long addr) 328 { 329 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end); 330 } 331 332 int in_gate_area_no_mm(unsigned long addr) 333 { 334 return in_gate_area(NULL, addr); 335 } 336 #define is_gate_vma(vma) ((vma) == &gate_vma) 337 #else 338 #define is_gate_vma(vma) 0 339 #endif 340 341 const char *arch_vma_name(struct vm_area_struct *vma) 342 { 343 return is_gate_vma(vma) ? "[vectors]" : NULL; 344 } 345 346 /* If possible, provide a placement hint at a random offset from the 347 * stack for the sigpage and vdso pages. 348 */ 349 static unsigned long sigpage_addr(const struct mm_struct *mm, 350 unsigned int npages) 351 { 352 unsigned long offset; 353 unsigned long first; 354 unsigned long last; 355 unsigned long addr; 356 unsigned int slots; 357 358 first = PAGE_ALIGN(mm->start_stack); 359 360 last = TASK_SIZE - (npages << PAGE_SHIFT); 361 362 /* No room after stack? */ 363 if (first > last) 364 return 0; 365 366 /* Just enough room? */ 367 if (first == last) 368 return first; 369 370 slots = ((last - first) >> PAGE_SHIFT) + 1; 371 372 offset = get_random_u32_below(slots); 373 374 addr = first + (offset << PAGE_SHIFT); 375 376 return addr; 377 } 378 379 static struct page *signal_page; 380 extern struct page *get_signal_page(void); 381 382 static int sigpage_mremap(const struct vm_special_mapping *sm, 383 struct vm_area_struct *new_vma) 384 { 385 current->mm->context.sigpage = new_vma->vm_start; 386 return 0; 387 } 388 389 static const struct vm_special_mapping sigpage_mapping = { 390 .name = "[sigpage]", 391 .pages = &signal_page, 392 .mremap = sigpage_mremap, 393 }; 394 395 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 396 { 397 struct mm_struct *mm = current->mm; 398 struct vm_area_struct *vma; 399 unsigned long npages; 400 unsigned long addr; 401 unsigned long hint; 402 int ret = 0; 403 404 if (!signal_page) 405 signal_page = get_signal_page(); 406 if (!signal_page) 407 return -ENOMEM; 408 409 npages = 1; /* for sigpage */ 410 npages += vdso_total_pages; 411 412 if (mmap_write_lock_killable(mm)) 413 return -EINTR; 414 hint = sigpage_addr(mm, npages); 415 addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0); 416 if (IS_ERR_VALUE(addr)) { 417 ret = addr; 418 goto up_fail; 419 } 420 421 vma = _install_special_mapping(mm, addr, PAGE_SIZE, 422 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, 423 &sigpage_mapping); 424 425 if (IS_ERR(vma)) { 426 ret = PTR_ERR(vma); 427 goto up_fail; 428 } 429 430 mm->context.sigpage = addr; 431 432 /* Unlike the sigpage, failure to install the vdso is unlikely 433 * to be fatal to the process, so no error check needed 434 * here. 435 */ 436 arm_install_vdso(mm, addr + PAGE_SIZE); 437 438 up_fail: 439 mmap_write_unlock(mm); 440 return ret; 441 } 442 #endif 443