1 /* 2 * linux/arch/arm/kernel/process.c 3 * 4 * Copyright (C) 1996-2000 Russell King - Converted to ARM. 5 * Original Copyright (C) 1995 Linus Torvalds 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 #include <stdarg.h> 12 13 #include <linux/export.h> 14 #include <linux/sched.h> 15 #include <linux/sched/debug.h> 16 #include <linux/sched/task.h> 17 #include <linux/sched/task_stack.h> 18 #include <linux/kernel.h> 19 #include <linux/mm.h> 20 #include <linux/stddef.h> 21 #include <linux/unistd.h> 22 #include <linux/user.h> 23 #include <linux/interrupt.h> 24 #include <linux/init.h> 25 #include <linux/elfcore.h> 26 #include <linux/pm.h> 27 #include <linux/tick.h> 28 #include <linux/utsname.h> 29 #include <linux/uaccess.h> 30 #include <linux/random.h> 31 #include <linux/hw_breakpoint.h> 32 #include <linux/leds.h> 33 34 #include <asm/processor.h> 35 #include <asm/thread_notify.h> 36 #include <asm/stacktrace.h> 37 #include <asm/system_misc.h> 38 #include <asm/mach/time.h> 39 #include <asm/tls.h> 40 #include <asm/vdso.h> 41 42 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK) 43 #include <linux/stackprotector.h> 44 unsigned long __stack_chk_guard __read_mostly; 45 EXPORT_SYMBOL(__stack_chk_guard); 46 #endif 47 48 static const char *processor_modes[] __maybe_unused = { 49 "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" , 50 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26", 51 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" , 52 "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32" 53 }; 54 55 static const char *isa_modes[] __maybe_unused = { 56 "ARM" , "Thumb" , "Jazelle", "ThumbEE" 57 }; 58 59 /* 60 * This is our default idle handler. 61 */ 62 63 void (*arm_pm_idle)(void); 64 65 /* 66 * Called from the core idle loop. 67 */ 68 69 void arch_cpu_idle(void) 70 { 71 if (arm_pm_idle) 72 arm_pm_idle(); 73 else 74 cpu_do_idle(); 75 local_irq_enable(); 76 } 77 78 void arch_cpu_idle_prepare(void) 79 { 80 local_fiq_enable(); 81 } 82 83 void arch_cpu_idle_enter(void) 84 { 85 ledtrig_cpu(CPU_LED_IDLE_START); 86 #ifdef CONFIG_PL310_ERRATA_769419 87 wmb(); 88 #endif 89 } 90 91 void arch_cpu_idle_exit(void) 92 { 93 ledtrig_cpu(CPU_LED_IDLE_END); 94 } 95 96 void __show_regs(struct pt_regs *regs) 97 { 98 unsigned long flags; 99 char buf[64]; 100 #ifndef CONFIG_CPU_V7M 101 unsigned int domain, fs; 102 #ifdef CONFIG_CPU_SW_DOMAIN_PAN 103 /* 104 * Get the domain register for the parent context. In user 105 * mode, we don't save the DACR, so lets use what it should 106 * be. For other modes, we place it after the pt_regs struct. 107 */ 108 if (user_mode(regs)) { 109 domain = DACR_UACCESS_ENABLE; 110 fs = get_fs(); 111 } else { 112 domain = to_svc_pt_regs(regs)->dacr; 113 fs = to_svc_pt_regs(regs)->addr_limit; 114 } 115 #else 116 domain = get_domain(); 117 fs = get_fs(); 118 #endif 119 #endif 120 121 show_regs_print_info(KERN_DEFAULT); 122 123 printk("PC is at %pS\n", (void *)instruction_pointer(regs)); 124 printk("LR is at %pS\n", (void *)regs->ARM_lr); 125 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n", 126 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr); 127 printk("sp : %08lx ip : %08lx fp : %08lx\n", 128 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 129 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 130 regs->ARM_r10, regs->ARM_r9, 131 regs->ARM_r8); 132 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 133 regs->ARM_r7, regs->ARM_r6, 134 regs->ARM_r5, regs->ARM_r4); 135 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 136 regs->ARM_r3, regs->ARM_r2, 137 regs->ARM_r1, regs->ARM_r0); 138 139 flags = regs->ARM_cpsr; 140 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 141 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 142 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 143 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 144 buf[4] = '\0'; 145 146 #ifndef CONFIG_CPU_V7M 147 { 148 const char *segment; 149 150 if ((domain & domain_mask(DOMAIN_USER)) == 151 domain_val(DOMAIN_USER, DOMAIN_NOACCESS)) 152 segment = "none"; 153 else if (fs == get_ds()) 154 segment = "kernel"; 155 else 156 segment = "user"; 157 158 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 159 buf, interrupts_enabled(regs) ? "n" : "ff", 160 fast_interrupts_enabled(regs) ? "n" : "ff", 161 processor_modes[processor_mode(regs)], 162 isa_modes[isa_mode(regs)], segment); 163 } 164 #else 165 printk("xPSR: %08lx\n", regs->ARM_cpsr); 166 #endif 167 168 #ifdef CONFIG_CPU_CP15 169 { 170 unsigned int ctrl; 171 172 buf[0] = '\0'; 173 #ifdef CONFIG_CPU_CP15_MMU 174 { 175 unsigned int transbase; 176 asm("mrc p15, 0, %0, c2, c0\n\t" 177 : "=r" (transbase)); 178 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 179 transbase, domain); 180 } 181 #endif 182 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 183 184 printk("Control: %08x%s\n", ctrl, buf); 185 } 186 #endif 187 } 188 189 void show_regs(struct pt_regs * regs) 190 { 191 __show_regs(regs); 192 dump_stack(); 193 } 194 195 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 196 197 EXPORT_SYMBOL_GPL(thread_notify_head); 198 199 /* 200 * Free current thread data structures etc.. 201 */ 202 void exit_thread(struct task_struct *tsk) 203 { 204 thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk)); 205 } 206 207 void flush_thread(void) 208 { 209 struct thread_info *thread = current_thread_info(); 210 struct task_struct *tsk = current; 211 212 flush_ptrace_hw_breakpoint(tsk); 213 214 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 215 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 216 memset(&thread->fpstate, 0, sizeof(union fp_state)); 217 218 flush_tls(); 219 220 thread_notify(THREAD_NOTIFY_FLUSH, thread); 221 } 222 223 void release_thread(struct task_struct *dead_task) 224 { 225 } 226 227 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 228 229 int 230 copy_thread(unsigned long clone_flags, unsigned long stack_start, 231 unsigned long stk_sz, struct task_struct *p) 232 { 233 struct thread_info *thread = task_thread_info(p); 234 struct pt_regs *childregs = task_pt_regs(p); 235 236 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 237 238 #ifdef CONFIG_CPU_USE_DOMAINS 239 /* 240 * Copy the initial value of the domain access control register 241 * from the current thread: thread->addr_limit will have been 242 * copied from the current thread via setup_thread_stack() in 243 * kernel/fork.c 244 */ 245 thread->cpu_domain = get_domain(); 246 #endif 247 248 if (likely(!(p->flags & PF_KTHREAD))) { 249 *childregs = *current_pt_regs(); 250 childregs->ARM_r0 = 0; 251 if (stack_start) 252 childregs->ARM_sp = stack_start; 253 } else { 254 memset(childregs, 0, sizeof(struct pt_regs)); 255 thread->cpu_context.r4 = stk_sz; 256 thread->cpu_context.r5 = stack_start; 257 childregs->ARM_cpsr = SVC_MODE; 258 } 259 thread->cpu_context.pc = (unsigned long)ret_from_fork; 260 thread->cpu_context.sp = (unsigned long)childregs; 261 262 clear_ptrace_hw_breakpoint(p); 263 264 if (clone_flags & CLONE_SETTLS) 265 thread->tp_value[0] = childregs->ARM_r3; 266 thread->tp_value[1] = get_tpuser(); 267 268 thread_notify(THREAD_NOTIFY_COPY, thread); 269 270 #ifdef CONFIG_STACKPROTECTOR_PER_TASK 271 thread->stack_canary = p->stack_canary; 272 #endif 273 274 return 0; 275 } 276 277 /* 278 * Fill in the task's elfregs structure for a core dump. 279 */ 280 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs) 281 { 282 elf_core_copy_regs(elfregs, task_pt_regs(t)); 283 return 1; 284 } 285 286 /* 287 * fill in the fpe structure for a core dump... 288 */ 289 int dump_fpu (struct pt_regs *regs, struct user_fp *fp) 290 { 291 struct thread_info *thread = current_thread_info(); 292 int used_math = thread->used_cp[1] | thread->used_cp[2]; 293 294 if (used_math) 295 memcpy(fp, &thread->fpstate.soft, sizeof (*fp)); 296 297 return used_math != 0; 298 } 299 EXPORT_SYMBOL(dump_fpu); 300 301 unsigned long get_wchan(struct task_struct *p) 302 { 303 struct stackframe frame; 304 unsigned long stack_page; 305 int count = 0; 306 if (!p || p == current || p->state == TASK_RUNNING) 307 return 0; 308 309 frame.fp = thread_saved_fp(p); 310 frame.sp = thread_saved_sp(p); 311 frame.lr = 0; /* recovered from the stack */ 312 frame.pc = thread_saved_pc(p); 313 stack_page = (unsigned long)task_stack_page(p); 314 do { 315 if (frame.sp < stack_page || 316 frame.sp >= stack_page + THREAD_SIZE || 317 unwind_frame(&frame) < 0) 318 return 0; 319 if (!in_sched_functions(frame.pc)) 320 return frame.pc; 321 } while (count ++ < 16); 322 return 0; 323 } 324 325 unsigned long arch_randomize_brk(struct mm_struct *mm) 326 { 327 return randomize_page(mm->brk, 0x02000000); 328 } 329 330 #ifdef CONFIG_MMU 331 #ifdef CONFIG_KUSER_HELPERS 332 /* 333 * The vectors page is always readable from user space for the 334 * atomic helpers. Insert it into the gate_vma so that it is visible 335 * through ptrace and /proc/<pid>/mem. 336 */ 337 static struct vm_area_struct gate_vma; 338 339 static int __init gate_vma_init(void) 340 { 341 vma_init(&gate_vma, NULL); 342 gate_vma.vm_page_prot = PAGE_READONLY_EXEC; 343 gate_vma.vm_start = 0xffff0000; 344 gate_vma.vm_end = 0xffff0000 + PAGE_SIZE; 345 gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC; 346 return 0; 347 } 348 arch_initcall(gate_vma_init); 349 350 struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 351 { 352 return &gate_vma; 353 } 354 355 int in_gate_area(struct mm_struct *mm, unsigned long addr) 356 { 357 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end); 358 } 359 360 int in_gate_area_no_mm(unsigned long addr) 361 { 362 return in_gate_area(NULL, addr); 363 } 364 #define is_gate_vma(vma) ((vma) == &gate_vma) 365 #else 366 #define is_gate_vma(vma) 0 367 #endif 368 369 const char *arch_vma_name(struct vm_area_struct *vma) 370 { 371 return is_gate_vma(vma) ? "[vectors]" : NULL; 372 } 373 374 /* If possible, provide a placement hint at a random offset from the 375 * stack for the sigpage and vdso pages. 376 */ 377 static unsigned long sigpage_addr(const struct mm_struct *mm, 378 unsigned int npages) 379 { 380 unsigned long offset; 381 unsigned long first; 382 unsigned long last; 383 unsigned long addr; 384 unsigned int slots; 385 386 first = PAGE_ALIGN(mm->start_stack); 387 388 last = TASK_SIZE - (npages << PAGE_SHIFT); 389 390 /* No room after stack? */ 391 if (first > last) 392 return 0; 393 394 /* Just enough room? */ 395 if (first == last) 396 return first; 397 398 slots = ((last - first) >> PAGE_SHIFT) + 1; 399 400 offset = get_random_int() % slots; 401 402 addr = first + (offset << PAGE_SHIFT); 403 404 return addr; 405 } 406 407 static struct page *signal_page; 408 extern struct page *get_signal_page(void); 409 410 static int sigpage_mremap(const struct vm_special_mapping *sm, 411 struct vm_area_struct *new_vma) 412 { 413 current->mm->context.sigpage = new_vma->vm_start; 414 return 0; 415 } 416 417 static const struct vm_special_mapping sigpage_mapping = { 418 .name = "[sigpage]", 419 .pages = &signal_page, 420 .mremap = sigpage_mremap, 421 }; 422 423 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 424 { 425 struct mm_struct *mm = current->mm; 426 struct vm_area_struct *vma; 427 unsigned long npages; 428 unsigned long addr; 429 unsigned long hint; 430 int ret = 0; 431 432 if (!signal_page) 433 signal_page = get_signal_page(); 434 if (!signal_page) 435 return -ENOMEM; 436 437 npages = 1; /* for sigpage */ 438 npages += vdso_total_pages; 439 440 if (down_write_killable(&mm->mmap_sem)) 441 return -EINTR; 442 hint = sigpage_addr(mm, npages); 443 addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0); 444 if (IS_ERR_VALUE(addr)) { 445 ret = addr; 446 goto up_fail; 447 } 448 449 vma = _install_special_mapping(mm, addr, PAGE_SIZE, 450 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, 451 &sigpage_mapping); 452 453 if (IS_ERR(vma)) { 454 ret = PTR_ERR(vma); 455 goto up_fail; 456 } 457 458 mm->context.sigpage = addr; 459 460 /* Unlike the sigpage, failure to install the vdso is unlikely 461 * to be fatal to the process, so no error check needed 462 * here. 463 */ 464 arm_install_vdso(mm, addr + PAGE_SIZE); 465 466 up_fail: 467 up_write(&mm->mmap_sem); 468 return ret; 469 } 470 #endif 471