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