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 raw_local_irq_enable(); 82 } 83 84 void arch_cpu_idle_prepare(void) 85 { 86 local_fiq_enable(); 87 } 88 89 void arch_cpu_idle_enter(void) 90 { 91 ledtrig_cpu(CPU_LED_IDLE_START); 92 #ifdef CONFIG_PL310_ERRATA_769419 93 wmb(); 94 #endif 95 } 96 97 void arch_cpu_idle_exit(void) 98 { 99 ledtrig_cpu(CPU_LED_IDLE_END); 100 } 101 102 void __show_regs_alloc_free(struct pt_regs *regs) 103 { 104 int i; 105 106 /* check for r0 - r12 only */ 107 for (i = 0; i < 13; i++) { 108 pr_alert("Register r%d information:", i); 109 mem_dump_obj((void *)regs->uregs[i]); 110 } 111 } 112 113 void __show_regs(struct pt_regs *regs) 114 { 115 unsigned long flags; 116 char buf[64]; 117 #ifndef CONFIG_CPU_V7M 118 unsigned int domain; 119 #ifdef CONFIG_CPU_SW_DOMAIN_PAN 120 /* 121 * Get the domain register for the parent context. In user 122 * mode, we don't save the DACR, so lets use what it should 123 * be. For other modes, we place it after the pt_regs struct. 124 */ 125 if (user_mode(regs)) { 126 domain = DACR_UACCESS_ENABLE; 127 } else { 128 domain = to_svc_pt_regs(regs)->dacr; 129 } 130 #else 131 domain = get_domain(); 132 #endif 133 #endif 134 135 show_regs_print_info(KERN_DEFAULT); 136 137 printk("PC is at %pS\n", (void *)instruction_pointer(regs)); 138 printk("LR is at %pS\n", (void *)regs->ARM_lr); 139 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n", 140 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr); 141 printk("sp : %08lx ip : %08lx fp : %08lx\n", 142 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 143 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 144 regs->ARM_r10, regs->ARM_r9, 145 regs->ARM_r8); 146 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 147 regs->ARM_r7, regs->ARM_r6, 148 regs->ARM_r5, regs->ARM_r4); 149 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 150 regs->ARM_r3, regs->ARM_r2, 151 regs->ARM_r1, regs->ARM_r0); 152 153 flags = regs->ARM_cpsr; 154 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 155 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 156 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 157 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 158 buf[4] = '\0'; 159 160 #ifndef CONFIG_CPU_V7M 161 { 162 const char *segment; 163 164 if ((domain & domain_mask(DOMAIN_USER)) == 165 domain_val(DOMAIN_USER, DOMAIN_NOACCESS)) 166 segment = "none"; 167 else 168 segment = "user"; 169 170 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 171 buf, interrupts_enabled(regs) ? "n" : "ff", 172 fast_interrupts_enabled(regs) ? "n" : "ff", 173 processor_modes[processor_mode(regs)], 174 isa_modes[isa_mode(regs)], segment); 175 } 176 #else 177 printk("xPSR: %08lx\n", regs->ARM_cpsr); 178 #endif 179 180 #ifdef CONFIG_CPU_CP15 181 { 182 unsigned int ctrl; 183 184 buf[0] = '\0'; 185 #ifdef CONFIG_CPU_CP15_MMU 186 { 187 unsigned int transbase; 188 asm("mrc p15, 0, %0, c2, c0\n\t" 189 : "=r" (transbase)); 190 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 191 transbase, domain); 192 } 193 #endif 194 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 195 196 printk("Control: %08x%s\n", ctrl, buf); 197 } 198 #endif 199 } 200 201 void show_regs(struct pt_regs * regs) 202 { 203 __show_regs(regs); 204 dump_backtrace(regs, NULL, KERN_DEFAULT); 205 } 206 207 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 208 209 EXPORT_SYMBOL_GPL(thread_notify_head); 210 211 /* 212 * Free current thread data structures etc.. 213 */ 214 void exit_thread(struct task_struct *tsk) 215 { 216 thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk)); 217 } 218 219 void flush_thread(void) 220 { 221 struct thread_info *thread = current_thread_info(); 222 struct task_struct *tsk = current; 223 224 flush_ptrace_hw_breakpoint(tsk); 225 226 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 227 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 228 memset(&thread->fpstate, 0, sizeof(union fp_state)); 229 230 flush_tls(); 231 232 thread_notify(THREAD_NOTIFY_FLUSH, thread); 233 } 234 235 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 236 237 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 238 { 239 unsigned long clone_flags = args->flags; 240 unsigned long stack_start = args->stack; 241 unsigned long tls = args->tls; 242 struct thread_info *thread = task_thread_info(p); 243 struct pt_regs *childregs = task_pt_regs(p); 244 245 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 246 247 #ifdef CONFIG_CPU_USE_DOMAINS 248 /* 249 * Copy the initial value of the domain access control register 250 * from the current thread: thread->addr_limit will have been 251 * copied from the current thread via setup_thread_stack() in 252 * kernel/fork.c 253 */ 254 thread->cpu_domain = get_domain(); 255 #endif 256 257 if (likely(!args->fn)) { 258 *childregs = *current_pt_regs(); 259 childregs->ARM_r0 = 0; 260 if (stack_start) 261 childregs->ARM_sp = stack_start; 262 } else { 263 memset(childregs, 0, sizeof(struct pt_regs)); 264 thread->cpu_context.r4 = (unsigned long)args->fn_arg; 265 thread->cpu_context.r5 = (unsigned long)args->fn; 266 childregs->ARM_cpsr = SVC_MODE; 267 } 268 thread->cpu_context.pc = (unsigned long)ret_from_fork; 269 thread->cpu_context.sp = (unsigned long)childregs; 270 271 clear_ptrace_hw_breakpoint(p); 272 273 if (clone_flags & CLONE_SETTLS) 274 thread->tp_value[0] = tls; 275 thread->tp_value[1] = get_tpuser(); 276 277 thread_notify(THREAD_NOTIFY_COPY, thread); 278 279 return 0; 280 } 281 282 unsigned long __get_wchan(struct task_struct *p) 283 { 284 struct stackframe frame; 285 unsigned long stack_page; 286 int count = 0; 287 288 frame.fp = thread_saved_fp(p); 289 frame.sp = thread_saved_sp(p); 290 frame.lr = 0; /* recovered from the stack */ 291 frame.pc = thread_saved_pc(p); 292 stack_page = (unsigned long)task_stack_page(p); 293 do { 294 if (frame.sp < stack_page || 295 frame.sp >= stack_page + THREAD_SIZE || 296 unwind_frame(&frame) < 0) 297 return 0; 298 if (!in_sched_functions(frame.pc)) 299 return frame.pc; 300 } while (count ++ < 16); 301 return 0; 302 } 303 304 #ifdef CONFIG_MMU 305 #ifdef CONFIG_KUSER_HELPERS 306 /* 307 * The vectors page is always readable from user space for the 308 * atomic helpers. Insert it into the gate_vma so that it is visible 309 * through ptrace and /proc/<pid>/mem. 310 */ 311 static struct vm_area_struct gate_vma; 312 313 static int __init gate_vma_init(void) 314 { 315 vma_init(&gate_vma, NULL); 316 gate_vma.vm_page_prot = PAGE_READONLY_EXEC; 317 gate_vma.vm_start = 0xffff0000; 318 gate_vma.vm_end = 0xffff0000 + PAGE_SIZE; 319 gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC; 320 return 0; 321 } 322 arch_initcall(gate_vma_init); 323 324 struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 325 { 326 return &gate_vma; 327 } 328 329 int in_gate_area(struct mm_struct *mm, unsigned long addr) 330 { 331 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end); 332 } 333 334 int in_gate_area_no_mm(unsigned long addr) 335 { 336 return in_gate_area(NULL, addr); 337 } 338 #define is_gate_vma(vma) ((vma) == &gate_vma) 339 #else 340 #define is_gate_vma(vma) 0 341 #endif 342 343 const char *arch_vma_name(struct vm_area_struct *vma) 344 { 345 return is_gate_vma(vma) ? "[vectors]" : NULL; 346 } 347 348 /* If possible, provide a placement hint at a random offset from the 349 * stack for the sigpage and vdso pages. 350 */ 351 static unsigned long sigpage_addr(const struct mm_struct *mm, 352 unsigned int npages) 353 { 354 unsigned long offset; 355 unsigned long first; 356 unsigned long last; 357 unsigned long addr; 358 unsigned int slots; 359 360 first = PAGE_ALIGN(mm->start_stack); 361 362 last = TASK_SIZE - (npages << PAGE_SHIFT); 363 364 /* No room after stack? */ 365 if (first > last) 366 return 0; 367 368 /* Just enough room? */ 369 if (first == last) 370 return first; 371 372 slots = ((last - first) >> PAGE_SHIFT) + 1; 373 374 offset = prandom_u32_max(slots); 375 376 addr = first + (offset << PAGE_SHIFT); 377 378 return addr; 379 } 380 381 static struct page *signal_page; 382 extern struct page *get_signal_page(void); 383 384 static int sigpage_mremap(const struct vm_special_mapping *sm, 385 struct vm_area_struct *new_vma) 386 { 387 current->mm->context.sigpage = new_vma->vm_start; 388 return 0; 389 } 390 391 static const struct vm_special_mapping sigpage_mapping = { 392 .name = "[sigpage]", 393 .pages = &signal_page, 394 .mremap = sigpage_mremap, 395 }; 396 397 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 398 { 399 struct mm_struct *mm = current->mm; 400 struct vm_area_struct *vma; 401 unsigned long npages; 402 unsigned long addr; 403 unsigned long hint; 404 int ret = 0; 405 406 if (!signal_page) 407 signal_page = get_signal_page(); 408 if (!signal_page) 409 return -ENOMEM; 410 411 npages = 1; /* for sigpage */ 412 npages += vdso_total_pages; 413 414 if (mmap_write_lock_killable(mm)) 415 return -EINTR; 416 hint = sigpage_addr(mm, npages); 417 addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0); 418 if (IS_ERR_VALUE(addr)) { 419 ret = addr; 420 goto up_fail; 421 } 422 423 vma = _install_special_mapping(mm, addr, PAGE_SIZE, 424 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, 425 &sigpage_mapping); 426 427 if (IS_ERR(vma)) { 428 ret = PTR_ERR(vma); 429 goto up_fail; 430 } 431 432 mm->context.sigpage = addr; 433 434 /* Unlike the sigpage, failure to install the vdso is unlikely 435 * to be fatal to the process, so no error check needed 436 * here. 437 */ 438 arm_install_vdso(mm, addr + PAGE_SIZE); 439 440 up_fail: 441 mmap_write_unlock(mm); 442 return ret; 443 } 444 #endif 445