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_alloc_free(struct pt_regs *regs) 96 { 97 int i; 98 99 /* check for r0 - r12 only */ 100 for (i = 0; i < 13; i++) { 101 pr_alert("Register r%d information:", i); 102 mem_dump_obj((void *)regs->uregs[i]); 103 } 104 } 105 106 void __show_regs(struct pt_regs *regs) 107 { 108 unsigned long flags; 109 char buf[64]; 110 #ifndef CONFIG_CPU_V7M 111 unsigned int domain, fs; 112 #ifdef CONFIG_CPU_SW_DOMAIN_PAN 113 /* 114 * Get the domain register for the parent context. In user 115 * mode, we don't save the DACR, so lets use what it should 116 * be. For other modes, we place it after the pt_regs struct. 117 */ 118 if (user_mode(regs)) { 119 domain = DACR_UACCESS_ENABLE; 120 fs = get_fs(); 121 } else { 122 domain = to_svc_pt_regs(regs)->dacr; 123 fs = to_svc_pt_regs(regs)->addr_limit; 124 } 125 #else 126 domain = get_domain(); 127 fs = get_fs(); 128 #endif 129 #endif 130 131 show_regs_print_info(KERN_DEFAULT); 132 133 printk("PC is at %pS\n", (void *)instruction_pointer(regs)); 134 printk("LR is at %pS\n", (void *)regs->ARM_lr); 135 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n", 136 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr); 137 printk("sp : %08lx ip : %08lx fp : %08lx\n", 138 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 139 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 140 regs->ARM_r10, regs->ARM_r9, 141 regs->ARM_r8); 142 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 143 regs->ARM_r7, regs->ARM_r6, 144 regs->ARM_r5, regs->ARM_r4); 145 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 146 regs->ARM_r3, regs->ARM_r2, 147 regs->ARM_r1, regs->ARM_r0); 148 149 flags = regs->ARM_cpsr; 150 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 151 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 152 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 153 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 154 buf[4] = '\0'; 155 156 #ifndef CONFIG_CPU_V7M 157 { 158 const char *segment; 159 160 if ((domain & domain_mask(DOMAIN_USER)) == 161 domain_val(DOMAIN_USER, DOMAIN_NOACCESS)) 162 segment = "none"; 163 else if (fs == KERNEL_DS) 164 segment = "kernel"; 165 else 166 segment = "user"; 167 168 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 169 buf, interrupts_enabled(regs) ? "n" : "ff", 170 fast_interrupts_enabled(regs) ? "n" : "ff", 171 processor_modes[processor_mode(regs)], 172 isa_modes[isa_mode(regs)], segment); 173 } 174 #else 175 printk("xPSR: %08lx\n", regs->ARM_cpsr); 176 #endif 177 178 #ifdef CONFIG_CPU_CP15 179 { 180 unsigned int ctrl; 181 182 buf[0] = '\0'; 183 #ifdef CONFIG_CPU_CP15_MMU 184 { 185 unsigned int transbase; 186 asm("mrc p15, 0, %0, c2, c0\n\t" 187 : "=r" (transbase)); 188 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 189 transbase, domain); 190 } 191 #endif 192 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 193 194 printk("Control: %08x%s\n", ctrl, buf); 195 } 196 #endif 197 } 198 199 void show_regs(struct pt_regs * regs) 200 { 201 __show_regs(regs); 202 dump_stack(); 203 } 204 205 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 206 207 EXPORT_SYMBOL_GPL(thread_notify_head); 208 209 /* 210 * Free current thread data structures etc.. 211 */ 212 void exit_thread(struct task_struct *tsk) 213 { 214 thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk)); 215 } 216 217 void flush_thread(void) 218 { 219 struct thread_info *thread = current_thread_info(); 220 struct task_struct *tsk = current; 221 222 flush_ptrace_hw_breakpoint(tsk); 223 224 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 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 void release_thread(struct task_struct *dead_task) 234 { 235 } 236 237 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 238 239 int copy_thread(unsigned long clone_flags, unsigned long stack_start, 240 unsigned long stk_sz, struct task_struct *p, unsigned long tls) 241 { 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(!(p->flags & (PF_KTHREAD | PF_IO_WORKER)))) { 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 = stk_sz; 265 thread->cpu_context.r5 = stack_start; 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 #ifdef CONFIG_STACKPROTECTOR_PER_TASK 280 thread->stack_canary = p->stack_canary; 281 #endif 282 283 return 0; 284 } 285 286 unsigned long get_wchan(struct task_struct *p) 287 { 288 struct stackframe frame; 289 unsigned long stack_page; 290 int count = 0; 291 if (!p || p == current || p->state == TASK_RUNNING) 292 return 0; 293 294 frame.fp = thread_saved_fp(p); 295 frame.sp = thread_saved_sp(p); 296 frame.lr = 0; /* recovered from the stack */ 297 frame.pc = thread_saved_pc(p); 298 stack_page = (unsigned long)task_stack_page(p); 299 do { 300 if (frame.sp < stack_page || 301 frame.sp >= stack_page + THREAD_SIZE || 302 unwind_frame(&frame) < 0) 303 return 0; 304 if (!in_sched_functions(frame.pc)) 305 return frame.pc; 306 } while (count ++ < 16); 307 return 0; 308 } 309 310 #ifdef CONFIG_MMU 311 #ifdef CONFIG_KUSER_HELPERS 312 /* 313 * The vectors page is always readable from user space for the 314 * atomic helpers. Insert it into the gate_vma so that it is visible 315 * through ptrace and /proc/<pid>/mem. 316 */ 317 static struct vm_area_struct gate_vma; 318 319 static int __init gate_vma_init(void) 320 { 321 vma_init(&gate_vma, NULL); 322 gate_vma.vm_page_prot = PAGE_READONLY_EXEC; 323 gate_vma.vm_start = 0xffff0000; 324 gate_vma.vm_end = 0xffff0000 + PAGE_SIZE; 325 gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC; 326 return 0; 327 } 328 arch_initcall(gate_vma_init); 329 330 struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 331 { 332 return &gate_vma; 333 } 334 335 int in_gate_area(struct mm_struct *mm, unsigned long addr) 336 { 337 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end); 338 } 339 340 int in_gate_area_no_mm(unsigned long addr) 341 { 342 return in_gate_area(NULL, addr); 343 } 344 #define is_gate_vma(vma) ((vma) == &gate_vma) 345 #else 346 #define is_gate_vma(vma) 0 347 #endif 348 349 const char *arch_vma_name(struct vm_area_struct *vma) 350 { 351 return is_gate_vma(vma) ? "[vectors]" : NULL; 352 } 353 354 /* If possible, provide a placement hint at a random offset from the 355 * stack for the sigpage and vdso pages. 356 */ 357 static unsigned long sigpage_addr(const struct mm_struct *mm, 358 unsigned int npages) 359 { 360 unsigned long offset; 361 unsigned long first; 362 unsigned long last; 363 unsigned long addr; 364 unsigned int slots; 365 366 first = PAGE_ALIGN(mm->start_stack); 367 368 last = TASK_SIZE - (npages << PAGE_SHIFT); 369 370 /* No room after stack? */ 371 if (first > last) 372 return 0; 373 374 /* Just enough room? */ 375 if (first == last) 376 return first; 377 378 slots = ((last - first) >> PAGE_SHIFT) + 1; 379 380 offset = get_random_int() % slots; 381 382 addr = first + (offset << PAGE_SHIFT); 383 384 return addr; 385 } 386 387 static struct page *signal_page; 388 extern struct page *get_signal_page(void); 389 390 static int sigpage_mremap(const struct vm_special_mapping *sm, 391 struct vm_area_struct *new_vma) 392 { 393 current->mm->context.sigpage = new_vma->vm_start; 394 return 0; 395 } 396 397 static const struct vm_special_mapping sigpage_mapping = { 398 .name = "[sigpage]", 399 .pages = &signal_page, 400 .mremap = sigpage_mremap, 401 }; 402 403 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 404 { 405 struct mm_struct *mm = current->mm; 406 struct vm_area_struct *vma; 407 unsigned long npages; 408 unsigned long addr; 409 unsigned long hint; 410 int ret = 0; 411 412 if (!signal_page) 413 signal_page = get_signal_page(); 414 if (!signal_page) 415 return -ENOMEM; 416 417 npages = 1; /* for sigpage */ 418 npages += vdso_total_pages; 419 420 if (mmap_write_lock_killable(mm)) 421 return -EINTR; 422 hint = sigpage_addr(mm, npages); 423 addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0); 424 if (IS_ERR_VALUE(addr)) { 425 ret = addr; 426 goto up_fail; 427 } 428 429 vma = _install_special_mapping(mm, addr, PAGE_SIZE, 430 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, 431 &sigpage_mapping); 432 433 if (IS_ERR(vma)) { 434 ret = PTR_ERR(vma); 435 goto up_fail; 436 } 437 438 mm->context.sigpage = addr; 439 440 /* Unlike the sigpage, failure to install the vdso is unlikely 441 * to be fatal to the process, so no error check needed 442 * here. 443 */ 444 arm_install_vdso(mm, addr + PAGE_SIZE); 445 446 up_fail: 447 mmap_write_unlock(mm); 448 return ret; 449 } 450 #endif 451