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 444