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 #ifdef CONFIG_CURRENT_POINTER_IN_TPIDRURO 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 static const char *processor_modes[] __maybe_unused = { 50 "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" , 51 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26", 52 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" , 53 "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32" 54 }; 55 56 static const char *isa_modes[] __maybe_unused = { 57 "ARM" , "Thumb" , "Jazelle", "ThumbEE" 58 }; 59 60 /* 61 * This is our default idle handler. 62 */ 63 64 void (*arm_pm_idle)(void); 65 66 /* 67 * Called from the core idle loop. 68 */ 69 70 void arch_cpu_idle(void) 71 { 72 if (arm_pm_idle) 73 arm_pm_idle(); 74 else 75 cpu_do_idle(); 76 raw_local_irq_enable(); 77 } 78 79 void arch_cpu_idle_prepare(void) 80 { 81 local_fiq_enable(); 82 } 83 84 void arch_cpu_idle_enter(void) 85 { 86 ledtrig_cpu(CPU_LED_IDLE_START); 87 #ifdef CONFIG_PL310_ERRATA_769419 88 wmb(); 89 #endif 90 } 91 92 void arch_cpu_idle_exit(void) 93 { 94 ledtrig_cpu(CPU_LED_IDLE_END); 95 } 96 97 void __show_regs_alloc_free(struct pt_regs *regs) 98 { 99 int i; 100 101 /* check for r0 - r12 only */ 102 for (i = 0; i < 13; i++) { 103 pr_alert("Register r%d information:", i); 104 mem_dump_obj((void *)regs->uregs[i]); 105 } 106 } 107 108 void __show_regs(struct pt_regs *regs) 109 { 110 unsigned long flags; 111 char buf[64]; 112 #ifndef CONFIG_CPU_V7M 113 unsigned int domain; 114 #ifdef CONFIG_CPU_SW_DOMAIN_PAN 115 /* 116 * Get the domain register for the parent context. In user 117 * mode, we don't save the DACR, so lets use what it should 118 * be. For other modes, we place it after the pt_regs struct. 119 */ 120 if (user_mode(regs)) { 121 domain = DACR_UACCESS_ENABLE; 122 } else { 123 domain = to_svc_pt_regs(regs)->dacr; 124 } 125 #else 126 domain = get_domain(); 127 #endif 128 #endif 129 130 show_regs_print_info(KERN_DEFAULT); 131 132 printk("PC is at %pS\n", (void *)instruction_pointer(regs)); 133 printk("LR is at %pS\n", (void *)regs->ARM_lr); 134 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n", 135 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr); 136 printk("sp : %08lx ip : %08lx fp : %08lx\n", 137 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 138 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 139 regs->ARM_r10, regs->ARM_r9, 140 regs->ARM_r8); 141 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 142 regs->ARM_r7, regs->ARM_r6, 143 regs->ARM_r5, regs->ARM_r4); 144 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 145 regs->ARM_r3, regs->ARM_r2, 146 regs->ARM_r1, regs->ARM_r0); 147 148 flags = regs->ARM_cpsr; 149 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 150 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 151 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 152 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 153 buf[4] = '\0'; 154 155 #ifndef CONFIG_CPU_V7M 156 { 157 const char *segment; 158 159 if ((domain & domain_mask(DOMAIN_USER)) == 160 domain_val(DOMAIN_USER, DOMAIN_NOACCESS)) 161 segment = "none"; 162 else 163 segment = "user"; 164 165 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 166 buf, interrupts_enabled(regs) ? "n" : "ff", 167 fast_interrupts_enabled(regs) ? "n" : "ff", 168 processor_modes[processor_mode(regs)], 169 isa_modes[isa_mode(regs)], segment); 170 } 171 #else 172 printk("xPSR: %08lx\n", regs->ARM_cpsr); 173 #endif 174 175 #ifdef CONFIG_CPU_CP15 176 { 177 unsigned int ctrl; 178 179 buf[0] = '\0'; 180 #ifdef CONFIG_CPU_CP15_MMU 181 { 182 unsigned int transbase; 183 asm("mrc p15, 0, %0, c2, c0\n\t" 184 : "=r" (transbase)); 185 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 186 transbase, domain); 187 } 188 #endif 189 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 190 191 printk("Control: %08x%s\n", ctrl, buf); 192 } 193 #endif 194 } 195 196 void show_regs(struct pt_regs * regs) 197 { 198 __show_regs(regs); 199 dump_stack(); 200 } 201 202 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 203 204 EXPORT_SYMBOL_GPL(thread_notify_head); 205 206 /* 207 * Free current thread data structures etc.. 208 */ 209 void exit_thread(struct task_struct *tsk) 210 { 211 thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk)); 212 } 213 214 void flush_thread(void) 215 { 216 struct thread_info *thread = current_thread_info(); 217 struct task_struct *tsk = current; 218 219 flush_ptrace_hw_breakpoint(tsk); 220 221 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 222 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 223 memset(&thread->fpstate, 0, sizeof(union fp_state)); 224 225 flush_tls(); 226 227 thread_notify(THREAD_NOTIFY_FLUSH, thread); 228 } 229 230 void release_thread(struct task_struct *dead_task) 231 { 232 } 233 234 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 235 236 int copy_thread(unsigned long clone_flags, unsigned long stack_start, 237 unsigned long stk_sz, struct task_struct *p, unsigned long tls) 238 { 239 struct thread_info *thread = task_thread_info(p); 240 struct pt_regs *childregs = task_pt_regs(p); 241 242 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 243 244 #ifdef CONFIG_CPU_USE_DOMAINS 245 /* 246 * Copy the initial value of the domain access control register 247 * from the current thread: thread->addr_limit will have been 248 * copied from the current thread via setup_thread_stack() in 249 * kernel/fork.c 250 */ 251 thread->cpu_domain = get_domain(); 252 #endif 253 254 if (likely(!(p->flags & (PF_KTHREAD | PF_IO_WORKER)))) { 255 *childregs = *current_pt_regs(); 256 childregs->ARM_r0 = 0; 257 if (stack_start) 258 childregs->ARM_sp = stack_start; 259 } else { 260 memset(childregs, 0, sizeof(struct pt_regs)); 261 thread->cpu_context.r4 = stk_sz; 262 thread->cpu_context.r5 = stack_start; 263 childregs->ARM_cpsr = SVC_MODE; 264 } 265 thread->cpu_context.pc = (unsigned long)ret_from_fork; 266 thread->cpu_context.sp = (unsigned long)childregs; 267 268 clear_ptrace_hw_breakpoint(p); 269 270 if (clone_flags & CLONE_SETTLS) 271 thread->tp_value[0] = tls; 272 thread->tp_value[1] = get_tpuser(); 273 274 thread_notify(THREAD_NOTIFY_COPY, thread); 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; 284 285 frame.fp = thread_saved_fp(p); 286 frame.sp = thread_saved_sp(p); 287 frame.lr = 0; /* recovered from the stack */ 288 frame.pc = thread_saved_pc(p); 289 stack_page = (unsigned long)task_stack_page(p); 290 do { 291 if (frame.sp < stack_page || 292 frame.sp >= stack_page + THREAD_SIZE || 293 unwind_frame(&frame) < 0) 294 return 0; 295 if (!in_sched_functions(frame.pc)) 296 return frame.pc; 297 } while (count ++ < 16); 298 return 0; 299 } 300 301 #ifdef CONFIG_MMU 302 #ifdef CONFIG_KUSER_HELPERS 303 /* 304 * The vectors page is always readable from user space for the 305 * atomic helpers. Insert it into the gate_vma so that it is visible 306 * through ptrace and /proc/<pid>/mem. 307 */ 308 static struct vm_area_struct gate_vma; 309 310 static int __init gate_vma_init(void) 311 { 312 vma_init(&gate_vma, NULL); 313 gate_vma.vm_page_prot = PAGE_READONLY_EXEC; 314 gate_vma.vm_start = 0xffff0000; 315 gate_vma.vm_end = 0xffff0000 + PAGE_SIZE; 316 gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC; 317 return 0; 318 } 319 arch_initcall(gate_vma_init); 320 321 struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 322 { 323 return &gate_vma; 324 } 325 326 int in_gate_area(struct mm_struct *mm, unsigned long addr) 327 { 328 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end); 329 } 330 331 int in_gate_area_no_mm(unsigned long addr) 332 { 333 return in_gate_area(NULL, addr); 334 } 335 #define is_gate_vma(vma) ((vma) == &gate_vma) 336 #else 337 #define is_gate_vma(vma) 0 338 #endif 339 340 const char *arch_vma_name(struct vm_area_struct *vma) 341 { 342 return is_gate_vma(vma) ? "[vectors]" : NULL; 343 } 344 345 /* If possible, provide a placement hint at a random offset from the 346 * stack for the sigpage and vdso pages. 347 */ 348 static unsigned long sigpage_addr(const struct mm_struct *mm, 349 unsigned int npages) 350 { 351 unsigned long offset; 352 unsigned long first; 353 unsigned long last; 354 unsigned long addr; 355 unsigned int slots; 356 357 first = PAGE_ALIGN(mm->start_stack); 358 359 last = TASK_SIZE - (npages << PAGE_SHIFT); 360 361 /* No room after stack? */ 362 if (first > last) 363 return 0; 364 365 /* Just enough room? */ 366 if (first == last) 367 return first; 368 369 slots = ((last - first) >> PAGE_SHIFT) + 1; 370 371 offset = get_random_int() % slots; 372 373 addr = first + (offset << PAGE_SHIFT); 374 375 return addr; 376 } 377 378 static struct page *signal_page; 379 extern struct page *get_signal_page(void); 380 381 static int sigpage_mremap(const struct vm_special_mapping *sm, 382 struct vm_area_struct *new_vma) 383 { 384 current->mm->context.sigpage = new_vma->vm_start; 385 return 0; 386 } 387 388 static const struct vm_special_mapping sigpage_mapping = { 389 .name = "[sigpage]", 390 .pages = &signal_page, 391 .mremap = sigpage_mremap, 392 }; 393 394 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 395 { 396 struct mm_struct *mm = current->mm; 397 struct vm_area_struct *vma; 398 unsigned long npages; 399 unsigned long addr; 400 unsigned long hint; 401 int ret = 0; 402 403 if (!signal_page) 404 signal_page = get_signal_page(); 405 if (!signal_page) 406 return -ENOMEM; 407 408 npages = 1; /* for sigpage */ 409 npages += vdso_total_pages; 410 411 if (mmap_write_lock_killable(mm)) 412 return -EINTR; 413 hint = sigpage_addr(mm, npages); 414 addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0); 415 if (IS_ERR_VALUE(addr)) { 416 ret = addr; 417 goto up_fail; 418 } 419 420 vma = _install_special_mapping(mm, addr, PAGE_SIZE, 421 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, 422 &sigpage_mapping); 423 424 if (IS_ERR(vma)) { 425 ret = PTR_ERR(vma); 426 goto up_fail; 427 } 428 429 mm->context.sigpage = addr; 430 431 /* Unlike the sigpage, failure to install the vdso is unlikely 432 * to be fatal to the process, so no error check needed 433 * here. 434 */ 435 arm_install_vdso(mm, addr + PAGE_SIZE); 436 437 up_fail: 438 mmap_write_unlock(mm); 439 return ret; 440 } 441 #endif 442