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