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 /* 176 * The idle thread. 177 * We always respect 'hlt_counter' to prevent low power idle. 178 */ 179 void cpu_idle(void) 180 { 181 local_fiq_enable(); 182 183 /* endless idle loop with no priority at all */ 184 while (1) { 185 tick_nohz_idle_enter(); 186 rcu_idle_enter(); 187 ledtrig_cpu(CPU_LED_IDLE_START); 188 while (!need_resched()) { 189 #ifdef CONFIG_HOTPLUG_CPU 190 if (cpu_is_offline(smp_processor_id())) 191 cpu_die(); 192 #endif 193 194 /* 195 * We need to disable interrupts here 196 * to ensure we don't miss a wakeup call. 197 */ 198 local_irq_disable(); 199 #ifdef CONFIG_PL310_ERRATA_769419 200 wmb(); 201 #endif 202 if (hlt_counter) { 203 local_irq_enable(); 204 cpu_relax(); 205 } else if (!need_resched()) { 206 stop_critical_timings(); 207 if (cpuidle_idle_call()) 208 default_idle(); 209 start_critical_timings(); 210 /* 211 * default_idle functions must always 212 * return with IRQs enabled. 213 */ 214 WARN_ON(irqs_disabled()); 215 } else 216 local_irq_enable(); 217 } 218 ledtrig_cpu(CPU_LED_IDLE_END); 219 rcu_idle_exit(); 220 tick_nohz_idle_exit(); 221 schedule_preempt_disabled(); 222 } 223 } 224 225 static char reboot_mode = 'h'; 226 227 int __init reboot_setup(char *str) 228 { 229 reboot_mode = str[0]; 230 return 1; 231 } 232 233 __setup("reboot=", reboot_setup); 234 235 void machine_shutdown(void) 236 { 237 #ifdef CONFIG_SMP 238 smp_send_stop(); 239 #endif 240 } 241 242 void machine_halt(void) 243 { 244 machine_shutdown(); 245 local_irq_disable(); 246 while (1); 247 } 248 249 void machine_power_off(void) 250 { 251 machine_shutdown(); 252 if (pm_power_off) 253 pm_power_off(); 254 } 255 256 void machine_restart(char *cmd) 257 { 258 machine_shutdown(); 259 260 arm_pm_restart(reboot_mode, cmd); 261 262 /* Give a grace period for failure to restart of 1s */ 263 mdelay(1000); 264 265 /* Whoops - the platform was unable to reboot. Tell the user! */ 266 printk("Reboot failed -- System halted\n"); 267 local_irq_disable(); 268 while (1); 269 } 270 271 void __show_regs(struct pt_regs *regs) 272 { 273 unsigned long flags; 274 char buf[64]; 275 276 printk("CPU: %d %s (%s %.*s)\n", 277 raw_smp_processor_id(), print_tainted(), 278 init_utsname()->release, 279 (int)strcspn(init_utsname()->version, " "), 280 init_utsname()->version); 281 print_symbol("PC is at %s\n", instruction_pointer(regs)); 282 print_symbol("LR is at %s\n", regs->ARM_lr); 283 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n" 284 "sp : %08lx ip : %08lx fp : %08lx\n", 285 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr, 286 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 287 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 288 regs->ARM_r10, regs->ARM_r9, 289 regs->ARM_r8); 290 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 291 regs->ARM_r7, regs->ARM_r6, 292 regs->ARM_r5, regs->ARM_r4); 293 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 294 regs->ARM_r3, regs->ARM_r2, 295 regs->ARM_r1, regs->ARM_r0); 296 297 flags = regs->ARM_cpsr; 298 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 299 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 300 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 301 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 302 buf[4] = '\0'; 303 304 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 305 buf, interrupts_enabled(regs) ? "n" : "ff", 306 fast_interrupts_enabled(regs) ? "n" : "ff", 307 processor_modes[processor_mode(regs)], 308 isa_modes[isa_mode(regs)], 309 get_fs() == get_ds() ? "kernel" : "user"); 310 #ifdef CONFIG_CPU_CP15 311 { 312 unsigned int ctrl; 313 314 buf[0] = '\0'; 315 #ifdef CONFIG_CPU_CP15_MMU 316 { 317 unsigned int transbase, dac; 318 asm("mrc p15, 0, %0, c2, c0\n\t" 319 "mrc p15, 0, %1, c3, c0\n" 320 : "=r" (transbase), "=r" (dac)); 321 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 322 transbase, dac); 323 } 324 #endif 325 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 326 327 printk("Control: %08x%s\n", ctrl, buf); 328 } 329 #endif 330 } 331 332 void show_regs(struct pt_regs * regs) 333 { 334 printk("\n"); 335 printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm); 336 __show_regs(regs); 337 dump_stack(); 338 } 339 340 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 341 342 EXPORT_SYMBOL_GPL(thread_notify_head); 343 344 /* 345 * Free current thread data structures etc.. 346 */ 347 void exit_thread(void) 348 { 349 thread_notify(THREAD_NOTIFY_EXIT, current_thread_info()); 350 } 351 352 void flush_thread(void) 353 { 354 struct thread_info *thread = current_thread_info(); 355 struct task_struct *tsk = current; 356 357 flush_ptrace_hw_breakpoint(tsk); 358 359 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 360 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 361 memset(&thread->fpstate, 0, sizeof(union fp_state)); 362 363 thread_notify(THREAD_NOTIFY_FLUSH, thread); 364 } 365 366 void release_thread(struct task_struct *dead_task) 367 { 368 } 369 370 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 371 372 int 373 copy_thread(unsigned long clone_flags, unsigned long stack_start, 374 unsigned long stk_sz, struct task_struct *p) 375 { 376 struct thread_info *thread = task_thread_info(p); 377 struct pt_regs *childregs = task_pt_regs(p); 378 379 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 380 381 if (likely(!(p->flags & PF_KTHREAD))) { 382 *childregs = *current_pt_regs(); 383 childregs->ARM_r0 = 0; 384 if (stack_start) 385 childregs->ARM_sp = stack_start; 386 } else { 387 memset(childregs, 0, sizeof(struct pt_regs)); 388 thread->cpu_context.r4 = stk_sz; 389 thread->cpu_context.r5 = stack_start; 390 childregs->ARM_cpsr = SVC_MODE; 391 } 392 thread->cpu_context.pc = (unsigned long)ret_from_fork; 393 thread->cpu_context.sp = (unsigned long)childregs; 394 395 clear_ptrace_hw_breakpoint(p); 396 397 if (clone_flags & CLONE_SETTLS) 398 thread->tp_value = childregs->ARM_r3; 399 400 thread_notify(THREAD_NOTIFY_COPY, thread); 401 402 return 0; 403 } 404 405 /* 406 * Fill in the task's elfregs structure for a core dump. 407 */ 408 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs) 409 { 410 elf_core_copy_regs(elfregs, task_pt_regs(t)); 411 return 1; 412 } 413 414 /* 415 * fill in the fpe structure for a core dump... 416 */ 417 int dump_fpu (struct pt_regs *regs, struct user_fp *fp) 418 { 419 struct thread_info *thread = current_thread_info(); 420 int used_math = thread->used_cp[1] | thread->used_cp[2]; 421 422 if (used_math) 423 memcpy(fp, &thread->fpstate.soft, sizeof (*fp)); 424 425 return used_math != 0; 426 } 427 EXPORT_SYMBOL(dump_fpu); 428 429 unsigned long get_wchan(struct task_struct *p) 430 { 431 struct stackframe frame; 432 int count = 0; 433 if (!p || p == current || p->state == TASK_RUNNING) 434 return 0; 435 436 frame.fp = thread_saved_fp(p); 437 frame.sp = thread_saved_sp(p); 438 frame.lr = 0; /* recovered from the stack */ 439 frame.pc = thread_saved_pc(p); 440 do { 441 int ret = unwind_frame(&frame); 442 if (ret < 0) 443 return 0; 444 if (!in_sched_functions(frame.pc)) 445 return frame.pc; 446 } while (count ++ < 16); 447 return 0; 448 } 449 450 unsigned long arch_randomize_brk(struct mm_struct *mm) 451 { 452 unsigned long range_end = mm->brk + 0x02000000; 453 return randomize_range(mm->brk, range_end, 0) ? : mm->brk; 454 } 455 456 #ifdef CONFIG_MMU 457 /* 458 * The vectors page is always readable from user space for the 459 * atomic helpers and the signal restart code. Insert it into the 460 * gate_vma so that it is visible through ptrace and /proc/<pid>/mem. 461 */ 462 static struct vm_area_struct gate_vma; 463 464 static int __init gate_vma_init(void) 465 { 466 gate_vma.vm_start = 0xffff0000; 467 gate_vma.vm_end = 0xffff0000 + PAGE_SIZE; 468 gate_vma.vm_page_prot = PAGE_READONLY_EXEC; 469 gate_vma.vm_flags = VM_READ | VM_EXEC | 470 VM_MAYREAD | VM_MAYEXEC; 471 return 0; 472 } 473 arch_initcall(gate_vma_init); 474 475 struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 476 { 477 return &gate_vma; 478 } 479 480 int in_gate_area(struct mm_struct *mm, unsigned long addr) 481 { 482 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end); 483 } 484 485 int in_gate_area_no_mm(unsigned long addr) 486 { 487 return in_gate_area(NULL, addr); 488 } 489 490 const char *arch_vma_name(struct vm_area_struct *vma) 491 { 492 return (vma == &gate_vma) ? "[vectors]" : NULL; 493 } 494 #endif 495