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/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/delay.h> 21 #include <linux/reboot.h> 22 #include <linux/interrupt.h> 23 #include <linux/kallsyms.h> 24 #include <linux/init.h> 25 #include <linux/cpu.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 #include <linux/reboot.h> 35 36 #include <asm/cacheflush.h> 37 #include <asm/idmap.h> 38 #include <asm/processor.h> 39 #include <asm/thread_notify.h> 40 #include <asm/stacktrace.h> 41 #include <asm/system_misc.h> 42 #include <asm/mach/time.h> 43 #include <asm/tls.h> 44 45 #ifdef CONFIG_CC_STACKPROTECTOR 46 #include <linux/stackprotector.h> 47 unsigned long __stack_chk_guard __read_mostly; 48 EXPORT_SYMBOL(__stack_chk_guard); 49 #endif 50 51 static const char *processor_modes[] __maybe_unused = { 52 "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" , 53 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26", 54 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" , 55 "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32" 56 }; 57 58 static const char *isa_modes[] __maybe_unused = { 59 "ARM" , "Thumb" , "Jazelle", "ThumbEE" 60 }; 61 62 extern void call_with_stack(void (*fn)(void *), void *arg, void *sp); 63 typedef void (*phys_reset_t)(unsigned long); 64 65 /* 66 * A temporary stack to use for CPU reset. This is static so that we 67 * don't clobber it with the identity mapping. When running with this 68 * stack, any references to the current task *will not work* so you 69 * should really do as little as possible before jumping to your reset 70 * code. 71 */ 72 static u64 soft_restart_stack[16]; 73 74 static void __soft_restart(void *addr) 75 { 76 phys_reset_t phys_reset; 77 78 /* Take out a flat memory mapping. */ 79 setup_mm_for_reboot(); 80 81 /* Clean and invalidate caches */ 82 flush_cache_all(); 83 84 /* Turn off caching */ 85 cpu_proc_fin(); 86 87 /* Push out any further dirty data, and ensure cache is empty */ 88 flush_cache_all(); 89 90 /* Switch to the identity mapping. */ 91 phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset); 92 phys_reset((unsigned long)addr); 93 94 /* Should never get here. */ 95 BUG(); 96 } 97 98 void soft_restart(unsigned long addr) 99 { 100 u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack); 101 102 /* Disable interrupts first */ 103 raw_local_irq_disable(); 104 local_fiq_disable(); 105 106 /* Disable the L2 if we're the last man standing. */ 107 if (num_online_cpus() == 1) 108 outer_disable(); 109 110 /* Change to the new stack and continue with the reset. */ 111 call_with_stack(__soft_restart, (void *)addr, (void *)stack); 112 113 /* Should never get here. */ 114 BUG(); 115 } 116 117 static void null_restart(enum reboot_mode reboot_mode, const char *cmd) 118 { 119 } 120 121 /* 122 * Function pointers to optional machine specific functions 123 */ 124 void (*pm_power_off)(void); 125 EXPORT_SYMBOL(pm_power_off); 126 127 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd) = null_restart; 128 EXPORT_SYMBOL_GPL(arm_pm_restart); 129 130 /* 131 * This is our default idle handler. 132 */ 133 134 void (*arm_pm_idle)(void); 135 136 /* 137 * Called from the core idle loop. 138 */ 139 140 void arch_cpu_idle(void) 141 { 142 if (arm_pm_idle) 143 arm_pm_idle(); 144 else 145 cpu_do_idle(); 146 local_irq_enable(); 147 } 148 149 void arch_cpu_idle_prepare(void) 150 { 151 local_fiq_enable(); 152 } 153 154 void arch_cpu_idle_enter(void) 155 { 156 ledtrig_cpu(CPU_LED_IDLE_START); 157 #ifdef CONFIG_PL310_ERRATA_769419 158 wmb(); 159 #endif 160 } 161 162 void arch_cpu_idle_exit(void) 163 { 164 ledtrig_cpu(CPU_LED_IDLE_END); 165 } 166 167 #ifdef CONFIG_HOTPLUG_CPU 168 void arch_cpu_idle_dead(void) 169 { 170 cpu_die(); 171 } 172 #endif 173 174 /* 175 * Called by kexec, immediately prior to machine_kexec(). 176 * 177 * This must completely disable all secondary CPUs; simply causing those CPUs 178 * to execute e.g. a RAM-based pin loop is not sufficient. This allows the 179 * kexec'd kernel to use any and all RAM as it sees fit, without having to 180 * avoid any code or data used by any SW CPU pin loop. The CPU hotplug 181 * functionality embodied in disable_nonboot_cpus() to achieve this. 182 */ 183 void machine_shutdown(void) 184 { 185 disable_nonboot_cpus(); 186 } 187 188 /* 189 * Halting simply requires that the secondary CPUs stop performing any 190 * activity (executing tasks, handling interrupts). smp_send_stop() 191 * achieves this. 192 */ 193 void machine_halt(void) 194 { 195 local_irq_disable(); 196 smp_send_stop(); 197 198 local_irq_disable(); 199 while (1); 200 } 201 202 /* 203 * Power-off simply requires that the secondary CPUs stop performing any 204 * activity (executing tasks, handling interrupts). smp_send_stop() 205 * achieves this. When the system power is turned off, it will take all CPUs 206 * with it. 207 */ 208 void machine_power_off(void) 209 { 210 local_irq_disable(); 211 smp_send_stop(); 212 213 if (pm_power_off) 214 pm_power_off(); 215 } 216 217 /* 218 * Restart requires that the secondary CPUs stop performing any activity 219 * while the primary CPU resets the system. Systems with a single CPU can 220 * use soft_restart() as their machine descriptor's .restart hook, since that 221 * will cause the only available CPU to reset. Systems with multiple CPUs must 222 * provide a HW restart implementation, to ensure that all CPUs reset at once. 223 * This is required so that any code running after reset on the primary CPU 224 * doesn't have to co-ordinate with other CPUs to ensure they aren't still 225 * executing pre-reset code, and using RAM that the primary CPU's code wishes 226 * to use. Implementing such co-ordination would be essentially impossible. 227 */ 228 void machine_restart(char *cmd) 229 { 230 local_irq_disable(); 231 smp_send_stop(); 232 233 arm_pm_restart(reboot_mode, cmd); 234 235 /* Give a grace period for failure to restart of 1s */ 236 mdelay(1000); 237 238 /* Whoops - the platform was unable to reboot. Tell the user! */ 239 printk("Reboot failed -- System halted\n"); 240 local_irq_disable(); 241 while (1); 242 } 243 244 void __show_regs(struct pt_regs *regs) 245 { 246 unsigned long flags; 247 char buf[64]; 248 249 show_regs_print_info(KERN_DEFAULT); 250 251 print_symbol("PC is at %s\n", instruction_pointer(regs)); 252 print_symbol("LR is at %s\n", regs->ARM_lr); 253 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n" 254 "sp : %08lx ip : %08lx fp : %08lx\n", 255 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr, 256 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 257 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 258 regs->ARM_r10, regs->ARM_r9, 259 regs->ARM_r8); 260 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 261 regs->ARM_r7, regs->ARM_r6, 262 regs->ARM_r5, regs->ARM_r4); 263 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 264 regs->ARM_r3, regs->ARM_r2, 265 regs->ARM_r1, regs->ARM_r0); 266 267 flags = regs->ARM_cpsr; 268 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 269 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 270 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 271 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 272 buf[4] = '\0'; 273 274 #ifndef CONFIG_CPU_V7M 275 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 276 buf, interrupts_enabled(regs) ? "n" : "ff", 277 fast_interrupts_enabled(regs) ? "n" : "ff", 278 processor_modes[processor_mode(regs)], 279 isa_modes[isa_mode(regs)], 280 get_fs() == get_ds() ? "kernel" : "user"); 281 #else 282 printk("xPSR: %08lx\n", regs->ARM_cpsr); 283 #endif 284 285 #ifdef CONFIG_CPU_CP15 286 { 287 unsigned int ctrl; 288 289 buf[0] = '\0'; 290 #ifdef CONFIG_CPU_CP15_MMU 291 { 292 unsigned int transbase, dac; 293 asm("mrc p15, 0, %0, c2, c0\n\t" 294 "mrc p15, 0, %1, c3, c0\n" 295 : "=r" (transbase), "=r" (dac)); 296 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 297 transbase, dac); 298 } 299 #endif 300 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 301 302 printk("Control: %08x%s\n", ctrl, buf); 303 } 304 #endif 305 } 306 307 void show_regs(struct pt_regs * regs) 308 { 309 printk("\n"); 310 __show_regs(regs); 311 dump_stack(); 312 } 313 314 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 315 316 EXPORT_SYMBOL_GPL(thread_notify_head); 317 318 /* 319 * Free current thread data structures etc.. 320 */ 321 void exit_thread(void) 322 { 323 thread_notify(THREAD_NOTIFY_EXIT, current_thread_info()); 324 } 325 326 void flush_thread(void) 327 { 328 struct thread_info *thread = current_thread_info(); 329 struct task_struct *tsk = current; 330 331 flush_ptrace_hw_breakpoint(tsk); 332 333 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 334 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 335 memset(&thread->fpstate, 0, sizeof(union fp_state)); 336 337 thread_notify(THREAD_NOTIFY_FLUSH, thread); 338 } 339 340 void release_thread(struct task_struct *dead_task) 341 { 342 } 343 344 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 345 346 int 347 copy_thread(unsigned long clone_flags, unsigned long stack_start, 348 unsigned long stk_sz, struct task_struct *p) 349 { 350 struct thread_info *thread = task_thread_info(p); 351 struct pt_regs *childregs = task_pt_regs(p); 352 353 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 354 355 if (likely(!(p->flags & PF_KTHREAD))) { 356 *childregs = *current_pt_regs(); 357 childregs->ARM_r0 = 0; 358 if (stack_start) 359 childregs->ARM_sp = stack_start; 360 } else { 361 memset(childregs, 0, sizeof(struct pt_regs)); 362 thread->cpu_context.r4 = stk_sz; 363 thread->cpu_context.r5 = stack_start; 364 childregs->ARM_cpsr = SVC_MODE; 365 } 366 thread->cpu_context.pc = (unsigned long)ret_from_fork; 367 thread->cpu_context.sp = (unsigned long)childregs; 368 369 clear_ptrace_hw_breakpoint(p); 370 371 if (clone_flags & CLONE_SETTLS) 372 thread->tp_value[0] = childregs->ARM_r3; 373 thread->tp_value[1] = get_tpuser(); 374 375 thread_notify(THREAD_NOTIFY_COPY, thread); 376 377 return 0; 378 } 379 380 /* 381 * Fill in the task's elfregs structure for a core dump. 382 */ 383 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs) 384 { 385 elf_core_copy_regs(elfregs, task_pt_regs(t)); 386 return 1; 387 } 388 389 /* 390 * fill in the fpe structure for a core dump... 391 */ 392 int dump_fpu (struct pt_regs *regs, struct user_fp *fp) 393 { 394 struct thread_info *thread = current_thread_info(); 395 int used_math = thread->used_cp[1] | thread->used_cp[2]; 396 397 if (used_math) 398 memcpy(fp, &thread->fpstate.soft, sizeof (*fp)); 399 400 return used_math != 0; 401 } 402 EXPORT_SYMBOL(dump_fpu); 403 404 unsigned long get_wchan(struct task_struct *p) 405 { 406 struct stackframe frame; 407 unsigned long stack_page; 408 int count = 0; 409 if (!p || p == current || p->state == TASK_RUNNING) 410 return 0; 411 412 frame.fp = thread_saved_fp(p); 413 frame.sp = thread_saved_sp(p); 414 frame.lr = 0; /* recovered from the stack */ 415 frame.pc = thread_saved_pc(p); 416 stack_page = (unsigned long)task_stack_page(p); 417 do { 418 if (frame.sp < stack_page || 419 frame.sp >= stack_page + THREAD_SIZE || 420 unwind_frame(&frame) < 0) 421 return 0; 422 if (!in_sched_functions(frame.pc)) 423 return frame.pc; 424 } while (count ++ < 16); 425 return 0; 426 } 427 428 unsigned long arch_randomize_brk(struct mm_struct *mm) 429 { 430 unsigned long range_end = mm->brk + 0x02000000; 431 return randomize_range(mm->brk, range_end, 0) ? : mm->brk; 432 } 433 434 #ifdef CONFIG_MMU 435 #ifdef CONFIG_KUSER_HELPERS 436 /* 437 * The vectors page is always readable from user space for the 438 * atomic helpers. Insert it into the gate_vma so that it is visible 439 * through ptrace and /proc/<pid>/mem. 440 */ 441 static struct vm_area_struct gate_vma = { 442 .vm_start = 0xffff0000, 443 .vm_end = 0xffff0000 + PAGE_SIZE, 444 .vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC, 445 }; 446 447 static int __init gate_vma_init(void) 448 { 449 gate_vma.vm_page_prot = PAGE_READONLY_EXEC; 450 return 0; 451 } 452 arch_initcall(gate_vma_init); 453 454 struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 455 { 456 return &gate_vma; 457 } 458 459 int in_gate_area(struct mm_struct *mm, unsigned long addr) 460 { 461 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end); 462 } 463 464 int in_gate_area_no_mm(unsigned long addr) 465 { 466 return in_gate_area(NULL, addr); 467 } 468 #define is_gate_vma(vma) ((vma) == &gate_vma) 469 #else 470 #define is_gate_vma(vma) 0 471 #endif 472 473 const char *arch_vma_name(struct vm_area_struct *vma) 474 { 475 return is_gate_vma(vma) ? "[vectors]" : 476 (vma->vm_mm && vma->vm_start == vma->vm_mm->context.sigpage) ? 477 "[sigpage]" : NULL; 478 } 479 480 static struct page *signal_page; 481 extern struct page *get_signal_page(void); 482 483 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 484 { 485 struct mm_struct *mm = current->mm; 486 unsigned long addr; 487 int ret; 488 489 if (!signal_page) 490 signal_page = get_signal_page(); 491 if (!signal_page) 492 return -ENOMEM; 493 494 down_write(&mm->mmap_sem); 495 addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0); 496 if (IS_ERR_VALUE(addr)) { 497 ret = addr; 498 goto up_fail; 499 } 500 501 ret = install_special_mapping(mm, addr, PAGE_SIZE, 502 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, 503 &signal_page); 504 505 if (ret == 0) 506 mm->context.sigpage = addr; 507 508 up_fail: 509 up_write(&mm->mmap_sem); 510 return ret; 511 } 512 #endif 513