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