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