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