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/cpuidle.h> 34 35 #include <asm/cacheflush.h> 36 #include <asm/leds.h> 37 #include <asm/processor.h> 38 #include <asm/system.h> 39 #include <asm/thread_notify.h> 40 #include <asm/stacktrace.h> 41 #include <asm/mach/time.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[] = { 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" , "UK6_32" , "ABT_32" , 53 "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32" 54 }; 55 56 static const char *isa_modes[] = { 57 "ARM" , "Thumb" , "Jazelle", "ThumbEE" 58 }; 59 60 extern void setup_mm_for_reboot(void); 61 62 static volatile int hlt_counter; 63 64 #include <mach/system.h> 65 66 void disable_hlt(void) 67 { 68 hlt_counter++; 69 } 70 71 EXPORT_SYMBOL(disable_hlt); 72 73 void enable_hlt(void) 74 { 75 hlt_counter--; 76 } 77 78 EXPORT_SYMBOL(enable_hlt); 79 80 static int __init nohlt_setup(char *__unused) 81 { 82 hlt_counter = 1; 83 return 1; 84 } 85 86 static int __init hlt_setup(char *__unused) 87 { 88 hlt_counter = 0; 89 return 1; 90 } 91 92 __setup("nohlt", nohlt_setup); 93 __setup("hlt", hlt_setup); 94 95 extern void call_with_stack(void (*fn)(void *), void *arg, void *sp); 96 typedef void (*phys_reset_t)(unsigned long); 97 98 /* 99 * A temporary stack to use for CPU reset. This is static so that we 100 * don't clobber it with the identity mapping. When running with this 101 * stack, any references to the current task *will not work* so you 102 * should really do as little as possible before jumping to your reset 103 * code. 104 */ 105 static u64 soft_restart_stack[16]; 106 107 static void __soft_restart(void *addr) 108 { 109 phys_reset_t phys_reset; 110 111 /* Take out a flat memory mapping. */ 112 setup_mm_for_reboot(); 113 114 /* Clean and invalidate caches */ 115 flush_cache_all(); 116 117 /* Turn off caching */ 118 cpu_proc_fin(); 119 120 /* Push out any further dirty data, and ensure cache is empty */ 121 flush_cache_all(); 122 123 /* Switch to the identity mapping. */ 124 phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset); 125 phys_reset((unsigned long)addr); 126 127 /* Should never get here. */ 128 BUG(); 129 } 130 131 void soft_restart(unsigned long addr) 132 { 133 u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack); 134 135 /* Disable interrupts first */ 136 local_irq_disable(); 137 local_fiq_disable(); 138 139 /* Disable the L2 if we're the last man standing. */ 140 if (num_online_cpus() == 1) 141 outer_disable(); 142 143 /* Change to the new stack and continue with the reset. */ 144 call_with_stack(__soft_restart, (void *)addr, (void *)stack); 145 146 /* Should never get here. */ 147 BUG(); 148 } 149 150 static void null_restart(char mode, const char *cmd) 151 { 152 } 153 154 /* 155 * Function pointers to optional machine specific functions 156 */ 157 void (*pm_power_off)(void); 158 EXPORT_SYMBOL(pm_power_off); 159 160 void (*arm_pm_restart)(char str, const char *cmd) = null_restart; 161 EXPORT_SYMBOL_GPL(arm_pm_restart); 162 163 static void do_nothing(void *unused) 164 { 165 } 166 167 /* 168 * cpu_idle_wait - Used to ensure that all the CPUs discard old value of 169 * pm_idle and update to new pm_idle value. Required while changing pm_idle 170 * handler on SMP systems. 171 * 172 * Caller must have changed pm_idle to the new value before the call. Old 173 * pm_idle value will not be used by any CPU after the return of this function. 174 */ 175 void cpu_idle_wait(void) 176 { 177 smp_mb(); 178 /* kick all the CPUs so that they exit out of pm_idle */ 179 smp_call_function(do_nothing, NULL, 1); 180 } 181 EXPORT_SYMBOL_GPL(cpu_idle_wait); 182 183 /* 184 * This is our default idle handler. We need to disable 185 * interrupts here to ensure we don't miss a wakeup call. 186 */ 187 static void default_idle(void) 188 { 189 if (!need_resched()) 190 arch_idle(); 191 local_irq_enable(); 192 } 193 194 void (*pm_idle)(void) = default_idle; 195 EXPORT_SYMBOL(pm_idle); 196 197 /* 198 * The idle thread, has rather strange semantics for calling pm_idle, 199 * but this is what x86 does and we need to do the same, so that 200 * things like cpuidle get called in the same way. The only difference 201 * is that we always respect 'hlt_counter' to prevent low power idle. 202 */ 203 void cpu_idle(void) 204 { 205 local_fiq_enable(); 206 207 /* endless idle loop with no priority at all */ 208 while (1) { 209 tick_nohz_idle_enter(); 210 rcu_idle_enter(); 211 leds_event(led_idle_start); 212 while (!need_resched()) { 213 #ifdef CONFIG_HOTPLUG_CPU 214 if (cpu_is_offline(smp_processor_id())) 215 cpu_die(); 216 #endif 217 218 local_irq_disable(); 219 #ifdef CONFIG_PL310_ERRATA_769419 220 wmb(); 221 #endif 222 if (hlt_counter) { 223 local_irq_enable(); 224 cpu_relax(); 225 } else { 226 stop_critical_timings(); 227 if (cpuidle_idle_call()) 228 pm_idle(); 229 start_critical_timings(); 230 /* 231 * This will eventually be removed - pm_idle 232 * functions should always return with IRQs 233 * enabled. 234 */ 235 WARN_ON(irqs_disabled()); 236 local_irq_enable(); 237 } 238 } 239 leds_event(led_idle_end); 240 rcu_idle_exit(); 241 tick_nohz_idle_exit(); 242 schedule_preempt_disabled(); 243 } 244 } 245 246 static char reboot_mode = 'h'; 247 248 int __init reboot_setup(char *str) 249 { 250 reboot_mode = str[0]; 251 return 1; 252 } 253 254 __setup("reboot=", reboot_setup); 255 256 void machine_shutdown(void) 257 { 258 #ifdef CONFIG_SMP 259 smp_send_stop(); 260 #endif 261 } 262 263 void machine_halt(void) 264 { 265 machine_shutdown(); 266 while (1); 267 } 268 269 void machine_power_off(void) 270 { 271 machine_shutdown(); 272 if (pm_power_off) 273 pm_power_off(); 274 } 275 276 void machine_restart(char *cmd) 277 { 278 machine_shutdown(); 279 280 arm_pm_restart(reboot_mode, cmd); 281 282 /* Give a grace period for failure to restart of 1s */ 283 mdelay(1000); 284 285 /* Whoops - the platform was unable to reboot. Tell the user! */ 286 printk("Reboot failed -- System halted\n"); 287 while (1); 288 } 289 290 void __show_regs(struct pt_regs *regs) 291 { 292 unsigned long flags; 293 char buf[64]; 294 295 printk("CPU: %d %s (%s %.*s)\n", 296 raw_smp_processor_id(), print_tainted(), 297 init_utsname()->release, 298 (int)strcspn(init_utsname()->version, " "), 299 init_utsname()->version); 300 print_symbol("PC is at %s\n", instruction_pointer(regs)); 301 print_symbol("LR is at %s\n", regs->ARM_lr); 302 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n" 303 "sp : %08lx ip : %08lx fp : %08lx\n", 304 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr, 305 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 306 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 307 regs->ARM_r10, regs->ARM_r9, 308 regs->ARM_r8); 309 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 310 regs->ARM_r7, regs->ARM_r6, 311 regs->ARM_r5, regs->ARM_r4); 312 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 313 regs->ARM_r3, regs->ARM_r2, 314 regs->ARM_r1, regs->ARM_r0); 315 316 flags = regs->ARM_cpsr; 317 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 318 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 319 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 320 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 321 buf[4] = '\0'; 322 323 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 324 buf, interrupts_enabled(regs) ? "n" : "ff", 325 fast_interrupts_enabled(regs) ? "n" : "ff", 326 processor_modes[processor_mode(regs)], 327 isa_modes[isa_mode(regs)], 328 get_fs() == get_ds() ? "kernel" : "user"); 329 #ifdef CONFIG_CPU_CP15 330 { 331 unsigned int ctrl; 332 333 buf[0] = '\0'; 334 #ifdef CONFIG_CPU_CP15_MMU 335 { 336 unsigned int transbase, dac; 337 asm("mrc p15, 0, %0, c2, c0\n\t" 338 "mrc p15, 0, %1, c3, c0\n" 339 : "=r" (transbase), "=r" (dac)); 340 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 341 transbase, dac); 342 } 343 #endif 344 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 345 346 printk("Control: %08x%s\n", ctrl, buf); 347 } 348 #endif 349 } 350 351 void show_regs(struct pt_regs * regs) 352 { 353 printk("\n"); 354 printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm); 355 __show_regs(regs); 356 dump_stack(); 357 } 358 359 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 360 361 EXPORT_SYMBOL_GPL(thread_notify_head); 362 363 /* 364 * Free current thread data structures etc.. 365 */ 366 void exit_thread(void) 367 { 368 thread_notify(THREAD_NOTIFY_EXIT, current_thread_info()); 369 } 370 371 void flush_thread(void) 372 { 373 struct thread_info *thread = current_thread_info(); 374 struct task_struct *tsk = current; 375 376 flush_ptrace_hw_breakpoint(tsk); 377 378 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 379 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 380 memset(&thread->fpstate, 0, sizeof(union fp_state)); 381 382 thread_notify(THREAD_NOTIFY_FLUSH, thread); 383 } 384 385 void release_thread(struct task_struct *dead_task) 386 { 387 } 388 389 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 390 391 int 392 copy_thread(unsigned long clone_flags, unsigned long stack_start, 393 unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs) 394 { 395 struct thread_info *thread = task_thread_info(p); 396 struct pt_regs *childregs = task_pt_regs(p); 397 398 *childregs = *regs; 399 childregs->ARM_r0 = 0; 400 childregs->ARM_sp = stack_start; 401 402 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 403 thread->cpu_context.sp = (unsigned long)childregs; 404 thread->cpu_context.pc = (unsigned long)ret_from_fork; 405 406 clear_ptrace_hw_breakpoint(p); 407 408 if (clone_flags & CLONE_SETTLS) 409 thread->tp_value = regs->ARM_r3; 410 411 thread_notify(THREAD_NOTIFY_COPY, thread); 412 413 return 0; 414 } 415 416 /* 417 * Fill in the task's elfregs structure for a core dump. 418 */ 419 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs) 420 { 421 elf_core_copy_regs(elfregs, task_pt_regs(t)); 422 return 1; 423 } 424 425 /* 426 * fill in the fpe structure for a core dump... 427 */ 428 int dump_fpu (struct pt_regs *regs, struct user_fp *fp) 429 { 430 struct thread_info *thread = current_thread_info(); 431 int used_math = thread->used_cp[1] | thread->used_cp[2]; 432 433 if (used_math) 434 memcpy(fp, &thread->fpstate.soft, sizeof (*fp)); 435 436 return used_math != 0; 437 } 438 EXPORT_SYMBOL(dump_fpu); 439 440 /* 441 * Shuffle the argument into the correct register before calling the 442 * thread function. r4 is the thread argument, r5 is the pointer to 443 * the thread function, and r6 points to the exit function. 444 */ 445 extern void kernel_thread_helper(void); 446 asm( ".pushsection .text\n" 447 " .align\n" 448 " .type kernel_thread_helper, #function\n" 449 "kernel_thread_helper:\n" 450 #ifdef CONFIG_TRACE_IRQFLAGS 451 " bl trace_hardirqs_on\n" 452 #endif 453 " msr cpsr_c, r7\n" 454 " mov r0, r4\n" 455 " mov lr, r6\n" 456 " mov pc, r5\n" 457 " .size kernel_thread_helper, . - kernel_thread_helper\n" 458 " .popsection"); 459 460 #ifdef CONFIG_ARM_UNWIND 461 extern void kernel_thread_exit(long code); 462 asm( ".pushsection .text\n" 463 " .align\n" 464 " .type kernel_thread_exit, #function\n" 465 "kernel_thread_exit:\n" 466 " .fnstart\n" 467 " .cantunwind\n" 468 " bl do_exit\n" 469 " nop\n" 470 " .fnend\n" 471 " .size kernel_thread_exit, . - kernel_thread_exit\n" 472 " .popsection"); 473 #else 474 #define kernel_thread_exit do_exit 475 #endif 476 477 /* 478 * Create a kernel thread. 479 */ 480 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) 481 { 482 struct pt_regs regs; 483 484 memset(®s, 0, sizeof(regs)); 485 486 regs.ARM_r4 = (unsigned long)arg; 487 regs.ARM_r5 = (unsigned long)fn; 488 regs.ARM_r6 = (unsigned long)kernel_thread_exit; 489 regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE; 490 regs.ARM_pc = (unsigned long)kernel_thread_helper; 491 regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT; 492 493 return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); 494 } 495 EXPORT_SYMBOL(kernel_thread); 496 497 unsigned long get_wchan(struct task_struct *p) 498 { 499 struct stackframe frame; 500 int count = 0; 501 if (!p || p == current || p->state == TASK_RUNNING) 502 return 0; 503 504 frame.fp = thread_saved_fp(p); 505 frame.sp = thread_saved_sp(p); 506 frame.lr = 0; /* recovered from the stack */ 507 frame.pc = thread_saved_pc(p); 508 do { 509 int ret = unwind_frame(&frame); 510 if (ret < 0) 511 return 0; 512 if (!in_sched_functions(frame.pc)) 513 return frame.pc; 514 } while (count ++ < 16); 515 return 0; 516 } 517 518 unsigned long arch_randomize_brk(struct mm_struct *mm) 519 { 520 unsigned long range_end = mm->brk + 0x02000000; 521 return randomize_range(mm->brk, range_end, 0) ? : mm->brk; 522 } 523 524 #ifdef CONFIG_MMU 525 /* 526 * The vectors page is always readable from user space for the 527 * atomic helpers and the signal restart code. Let's declare a mapping 528 * for it so it is visible through ptrace and /proc/<pid>/mem. 529 */ 530 531 int vectors_user_mapping(void) 532 { 533 struct mm_struct *mm = current->mm; 534 return install_special_mapping(mm, 0xffff0000, PAGE_SIZE, 535 VM_READ | VM_EXEC | 536 VM_MAYREAD | VM_MAYEXEC | 537 VM_ALWAYSDUMP | VM_RESERVED, 538 NULL); 539 } 540 541 const char *arch_vma_name(struct vm_area_struct *vma) 542 { 543 return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL; 544 } 545 #endif 546