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, fs; 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 fs = get_fs(); 119 } else { 120 domain = to_svc_pt_regs(regs)->dacr; 121 fs = to_svc_pt_regs(regs)->addr_limit; 122 } 123 #else 124 domain = get_domain(); 125 fs = get_fs(); 126 #endif 127 #endif 128 129 show_regs_print_info(KERN_DEFAULT); 130 131 printk("PC is at %pS\n", (void *)instruction_pointer(regs)); 132 printk("LR is at %pS\n", (void *)regs->ARM_lr); 133 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n", 134 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr); 135 printk("sp : %08lx ip : %08lx fp : %08lx\n", 136 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 137 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 138 regs->ARM_r10, regs->ARM_r9, 139 regs->ARM_r8); 140 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 141 regs->ARM_r7, regs->ARM_r6, 142 regs->ARM_r5, regs->ARM_r4); 143 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 144 regs->ARM_r3, regs->ARM_r2, 145 regs->ARM_r1, regs->ARM_r0); 146 147 flags = regs->ARM_cpsr; 148 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 149 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 150 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 151 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 152 buf[4] = '\0'; 153 154 #ifndef CONFIG_CPU_V7M 155 { 156 const char *segment; 157 158 if ((domain & domain_mask(DOMAIN_USER)) == 159 domain_val(DOMAIN_USER, DOMAIN_NOACCESS)) 160 segment = "none"; 161 else if (fs == KERNEL_DS) 162 segment = "kernel"; 163 else 164 segment = "user"; 165 166 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 167 buf, interrupts_enabled(regs) ? "n" : "ff", 168 fast_interrupts_enabled(regs) ? "n" : "ff", 169 processor_modes[processor_mode(regs)], 170 isa_modes[isa_mode(regs)], segment); 171 } 172 #else 173 printk("xPSR: %08lx\n", regs->ARM_cpsr); 174 #endif 175 176 #ifdef CONFIG_CPU_CP15 177 { 178 unsigned int ctrl; 179 180 buf[0] = '\0'; 181 #ifdef CONFIG_CPU_CP15_MMU 182 { 183 unsigned int transbase; 184 asm("mrc p15, 0, %0, c2, c0\n\t" 185 : "=r" (transbase)); 186 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 187 transbase, domain); 188 } 189 #endif 190 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 191 192 printk("Control: %08x%s\n", ctrl, buf); 193 } 194 #endif 195 } 196 197 void show_regs(struct pt_regs * regs) 198 { 199 __show_regs(regs); 200 dump_stack(); 201 } 202 203 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 204 205 EXPORT_SYMBOL_GPL(thread_notify_head); 206 207 /* 208 * Free current thread data structures etc.. 209 */ 210 void exit_thread(struct task_struct *tsk) 211 { 212 thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk)); 213 } 214 215 void flush_thread(void) 216 { 217 struct thread_info *thread = current_thread_info(); 218 struct task_struct *tsk = current; 219 220 flush_ptrace_hw_breakpoint(tsk); 221 222 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 223 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 224 memset(&thread->fpstate, 0, sizeof(union fp_state)); 225 226 flush_tls(); 227 228 thread_notify(THREAD_NOTIFY_FLUSH, thread); 229 } 230 231 void release_thread(struct task_struct *dead_task) 232 { 233 } 234 235 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 236 237 int copy_thread(unsigned long clone_flags, unsigned long stack_start, 238 unsigned long stk_sz, struct task_struct *p, unsigned long tls) 239 { 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(!(p->flags & (PF_KTHREAD | PF_IO_WORKER)))) { 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 = stk_sz; 263 thread->cpu_context.r5 = stack_start; 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 #ifdef CONFIG_STACKPROTECTOR_PER_TASK 278 thread->stack_canary = p->stack_canary; 279 #endif 280 281 return 0; 282 } 283 284 unsigned long get_wchan(struct task_struct *p) 285 { 286 struct stackframe frame; 287 unsigned long stack_page; 288 int count = 0; 289 if (!p || p == current || task_is_running(p)) 290 return 0; 291 292 frame.fp = thread_saved_fp(p); 293 frame.sp = thread_saved_sp(p); 294 frame.lr = 0; /* recovered from the stack */ 295 frame.pc = thread_saved_pc(p); 296 stack_page = (unsigned long)task_stack_page(p); 297 do { 298 if (frame.sp < stack_page || 299 frame.sp >= stack_page + THREAD_SIZE || 300 unwind_frame(&frame) < 0) 301 return 0; 302 if (!in_sched_functions(frame.pc)) 303 return frame.pc; 304 } while (count ++ < 16); 305 return 0; 306 } 307 308 #ifdef CONFIG_MMU 309 #ifdef CONFIG_KUSER_HELPERS 310 /* 311 * The vectors page is always readable from user space for the 312 * atomic helpers. Insert it into the gate_vma so that it is visible 313 * through ptrace and /proc/<pid>/mem. 314 */ 315 static struct vm_area_struct gate_vma; 316 317 static int __init gate_vma_init(void) 318 { 319 vma_init(&gate_vma, NULL); 320 gate_vma.vm_page_prot = PAGE_READONLY_EXEC; 321 gate_vma.vm_start = 0xffff0000; 322 gate_vma.vm_end = 0xffff0000 + PAGE_SIZE; 323 gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC; 324 return 0; 325 } 326 arch_initcall(gate_vma_init); 327 328 struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 329 { 330 return &gate_vma; 331 } 332 333 int in_gate_area(struct mm_struct *mm, unsigned long addr) 334 { 335 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end); 336 } 337 338 int in_gate_area_no_mm(unsigned long addr) 339 { 340 return in_gate_area(NULL, addr); 341 } 342 #define is_gate_vma(vma) ((vma) == &gate_vma) 343 #else 344 #define is_gate_vma(vma) 0 345 #endif 346 347 const char *arch_vma_name(struct vm_area_struct *vma) 348 { 349 return is_gate_vma(vma) ? "[vectors]" : NULL; 350 } 351 352 /* If possible, provide a placement hint at a random offset from the 353 * stack for the sigpage and vdso pages. 354 */ 355 static unsigned long sigpage_addr(const struct mm_struct *mm, 356 unsigned int npages) 357 { 358 unsigned long offset; 359 unsigned long first; 360 unsigned long last; 361 unsigned long addr; 362 unsigned int slots; 363 364 first = PAGE_ALIGN(mm->start_stack); 365 366 last = TASK_SIZE - (npages << PAGE_SHIFT); 367 368 /* No room after stack? */ 369 if (first > last) 370 return 0; 371 372 /* Just enough room? */ 373 if (first == last) 374 return first; 375 376 slots = ((last - first) >> PAGE_SHIFT) + 1; 377 378 offset = get_random_int() % slots; 379 380 addr = first + (offset << PAGE_SHIFT); 381 382 return addr; 383 } 384 385 static struct page *signal_page; 386 extern struct page *get_signal_page(void); 387 388 static int sigpage_mremap(const struct vm_special_mapping *sm, 389 struct vm_area_struct *new_vma) 390 { 391 current->mm->context.sigpage = new_vma->vm_start; 392 return 0; 393 } 394 395 static const struct vm_special_mapping sigpage_mapping = { 396 .name = "[sigpage]", 397 .pages = &signal_page, 398 .mremap = sigpage_mremap, 399 }; 400 401 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 402 { 403 struct mm_struct *mm = current->mm; 404 struct vm_area_struct *vma; 405 unsigned long npages; 406 unsigned long addr; 407 unsigned long hint; 408 int ret = 0; 409 410 if (!signal_page) 411 signal_page = get_signal_page(); 412 if (!signal_page) 413 return -ENOMEM; 414 415 npages = 1; /* for sigpage */ 416 npages += vdso_total_pages; 417 418 if (mmap_write_lock_killable(mm)) 419 return -EINTR; 420 hint = sigpage_addr(mm, npages); 421 addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0); 422 if (IS_ERR_VALUE(addr)) { 423 ret = addr; 424 goto up_fail; 425 } 426 427 vma = _install_special_mapping(mm, addr, PAGE_SIZE, 428 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, 429 &sigpage_mapping); 430 431 if (IS_ERR(vma)) { 432 ret = PTR_ERR(vma); 433 goto up_fail; 434 } 435 436 mm->context.sigpage = addr; 437 438 /* Unlike the sigpage, failure to install the vdso is unlikely 439 * to be fatal to the process, so no error check needed 440 * here. 441 */ 442 arm_install_vdso(mm, addr + PAGE_SIZE); 443 444 up_fail: 445 mmap_write_unlock(mm); 446 return ret; 447 } 448 #endif 449