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 34 #include <asm/cacheflush.h> 35 #include <asm/leds.h> 36 #include <asm/processor.h> 37 #include <asm/system.h> 38 #include <asm/thread_notify.h> 39 #include <asm/stacktrace.h> 40 #include <asm/mach/time.h> 41 42 #ifdef CONFIG_CC_STACKPROTECTOR 43 #include <linux/stackprotector.h> 44 unsigned long __stack_chk_guard __read_mostly; 45 EXPORT_SYMBOL(__stack_chk_guard); 46 #endif 47 48 static const char *processor_modes[] = { 49 "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" , 50 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26", 51 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" , 52 "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32" 53 }; 54 55 static const char *isa_modes[] = { 56 "ARM" , "Thumb" , "Jazelle", "ThumbEE" 57 }; 58 59 extern void setup_mm_for_reboot(char mode); 60 61 static volatile int hlt_counter; 62 63 #include <mach/system.h> 64 65 void disable_hlt(void) 66 { 67 hlt_counter++; 68 } 69 70 EXPORT_SYMBOL(disable_hlt); 71 72 void enable_hlt(void) 73 { 74 hlt_counter--; 75 } 76 77 EXPORT_SYMBOL(enable_hlt); 78 79 static int __init nohlt_setup(char *__unused) 80 { 81 hlt_counter = 1; 82 return 1; 83 } 84 85 static int __init hlt_setup(char *__unused) 86 { 87 hlt_counter = 0; 88 return 1; 89 } 90 91 __setup("nohlt", nohlt_setup); 92 __setup("hlt", hlt_setup); 93 94 void arm_machine_restart(char mode, const char *cmd) 95 { 96 /* Disable interrupts first */ 97 local_irq_disable(); 98 local_fiq_disable(); 99 100 /* 101 * Tell the mm system that we are going to reboot - 102 * we may need it to insert some 1:1 mappings so that 103 * soft boot works. 104 */ 105 setup_mm_for_reboot(mode); 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 /* 117 * Now call the architecture specific reboot code. 118 */ 119 arch_reset(mode, cmd); 120 121 /* 122 * Whoops - the architecture was unable to reboot. 123 * Tell the user! 124 */ 125 mdelay(1000); 126 printk("Reboot failed -- System halted\n"); 127 while (1); 128 } 129 130 /* 131 * Function pointers to optional machine specific functions 132 */ 133 void (*pm_power_off)(void); 134 EXPORT_SYMBOL(pm_power_off); 135 136 void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart; 137 EXPORT_SYMBOL_GPL(arm_pm_restart); 138 139 static void do_nothing(void *unused) 140 { 141 } 142 143 /* 144 * cpu_idle_wait - Used to ensure that all the CPUs discard old value of 145 * pm_idle and update to new pm_idle value. Required while changing pm_idle 146 * handler on SMP systems. 147 * 148 * Caller must have changed pm_idle to the new value before the call. Old 149 * pm_idle value will not be used by any CPU after the return of this function. 150 */ 151 void cpu_idle_wait(void) 152 { 153 smp_mb(); 154 /* kick all the CPUs so that they exit out of pm_idle */ 155 smp_call_function(do_nothing, NULL, 1); 156 } 157 EXPORT_SYMBOL_GPL(cpu_idle_wait); 158 159 /* 160 * This is our default idle handler. We need to disable 161 * interrupts here to ensure we don't miss a wakeup call. 162 */ 163 static void default_idle(void) 164 { 165 if (!need_resched()) 166 arch_idle(); 167 local_irq_enable(); 168 } 169 170 void (*pm_idle)(void) = default_idle; 171 EXPORT_SYMBOL(pm_idle); 172 173 /* 174 * The idle thread, has rather strange semantics for calling pm_idle, 175 * but this is what x86 does and we need to do the same, so that 176 * things like cpuidle get called in the same way. The only difference 177 * is that 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_stop_sched_tick(1); 186 leds_event(led_idle_start); 187 while (!need_resched()) { 188 #ifdef CONFIG_HOTPLUG_CPU 189 if (cpu_is_offline(smp_processor_id())) 190 cpu_die(); 191 #endif 192 193 local_irq_disable(); 194 if (hlt_counter) { 195 local_irq_enable(); 196 cpu_relax(); 197 } else { 198 stop_critical_timings(); 199 pm_idle(); 200 start_critical_timings(); 201 /* 202 * This will eventually be removed - pm_idle 203 * functions should always return with IRQs 204 * enabled. 205 */ 206 WARN_ON(irqs_disabled()); 207 local_irq_enable(); 208 } 209 } 210 leds_event(led_idle_end); 211 tick_nohz_restart_sched_tick(); 212 preempt_enable_no_resched(); 213 schedule(); 214 preempt_disable(); 215 } 216 } 217 218 static char reboot_mode = 'h'; 219 220 int __init reboot_setup(char *str) 221 { 222 reboot_mode = str[0]; 223 return 1; 224 } 225 226 __setup("reboot=", reboot_setup); 227 228 void machine_shutdown(void) 229 { 230 #ifdef CONFIG_SMP 231 smp_send_stop(); 232 #endif 233 } 234 235 void machine_halt(void) 236 { 237 machine_shutdown(); 238 while (1); 239 } 240 241 void machine_power_off(void) 242 { 243 machine_shutdown(); 244 if (pm_power_off) 245 pm_power_off(); 246 } 247 248 void machine_restart(char *cmd) 249 { 250 machine_shutdown(); 251 arm_pm_restart(reboot_mode, cmd); 252 } 253 254 void __show_regs(struct pt_regs *regs) 255 { 256 unsigned long flags; 257 char buf[64]; 258 259 printk("CPU: %d %s (%s %.*s)\n", 260 raw_smp_processor_id(), print_tainted(), 261 init_utsname()->release, 262 (int)strcspn(init_utsname()->version, " "), 263 init_utsname()->version); 264 print_symbol("PC is at %s\n", instruction_pointer(regs)); 265 print_symbol("LR is at %s\n", regs->ARM_lr); 266 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n" 267 "sp : %08lx ip : %08lx fp : %08lx\n", 268 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr, 269 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 270 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 271 regs->ARM_r10, regs->ARM_r9, 272 regs->ARM_r8); 273 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 274 regs->ARM_r7, regs->ARM_r6, 275 regs->ARM_r5, regs->ARM_r4); 276 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 277 regs->ARM_r3, regs->ARM_r2, 278 regs->ARM_r1, regs->ARM_r0); 279 280 flags = regs->ARM_cpsr; 281 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 282 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 283 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 284 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 285 buf[4] = '\0'; 286 287 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 288 buf, interrupts_enabled(regs) ? "n" : "ff", 289 fast_interrupts_enabled(regs) ? "n" : "ff", 290 processor_modes[processor_mode(regs)], 291 isa_modes[isa_mode(regs)], 292 get_fs() == get_ds() ? "kernel" : "user"); 293 #ifdef CONFIG_CPU_CP15 294 { 295 unsigned int ctrl; 296 297 buf[0] = '\0'; 298 #ifdef CONFIG_CPU_CP15_MMU 299 { 300 unsigned int transbase, dac; 301 asm("mrc p15, 0, %0, c2, c0\n\t" 302 "mrc p15, 0, %1, c3, c0\n" 303 : "=r" (transbase), "=r" (dac)); 304 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 305 transbase, dac); 306 } 307 #endif 308 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 309 310 printk("Control: %08x%s\n", ctrl, buf); 311 } 312 #endif 313 } 314 315 void show_regs(struct pt_regs * regs) 316 { 317 printk("\n"); 318 printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm); 319 __show_regs(regs); 320 __backtrace(); 321 } 322 323 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 324 325 EXPORT_SYMBOL_GPL(thread_notify_head); 326 327 /* 328 * Free current thread data structures etc.. 329 */ 330 void exit_thread(void) 331 { 332 thread_notify(THREAD_NOTIFY_EXIT, current_thread_info()); 333 } 334 335 void flush_thread(void) 336 { 337 struct thread_info *thread = current_thread_info(); 338 struct task_struct *tsk = current; 339 340 flush_ptrace_hw_breakpoint(tsk); 341 342 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 343 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 344 memset(&thread->fpstate, 0, sizeof(union fp_state)); 345 346 thread_notify(THREAD_NOTIFY_FLUSH, thread); 347 } 348 349 void release_thread(struct task_struct *dead_task) 350 { 351 } 352 353 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 354 355 int 356 copy_thread(unsigned long clone_flags, unsigned long stack_start, 357 unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs) 358 { 359 struct thread_info *thread = task_thread_info(p); 360 struct pt_regs *childregs = task_pt_regs(p); 361 362 *childregs = *regs; 363 childregs->ARM_r0 = 0; 364 childregs->ARM_sp = stack_start; 365 366 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 367 thread->cpu_context.sp = (unsigned long)childregs; 368 thread->cpu_context.pc = (unsigned long)ret_from_fork; 369 370 clear_ptrace_hw_breakpoint(p); 371 372 if (clone_flags & CLONE_SETTLS) 373 thread->tp_value = regs->ARM_r3; 374 375 return 0; 376 } 377 378 /* 379 * Fill in the task's elfregs structure for a core dump. 380 */ 381 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs) 382 { 383 elf_core_copy_regs(elfregs, task_pt_regs(t)); 384 return 1; 385 } 386 387 /* 388 * fill in the fpe structure for a core dump... 389 */ 390 int dump_fpu (struct pt_regs *regs, struct user_fp *fp) 391 { 392 struct thread_info *thread = current_thread_info(); 393 int used_math = thread->used_cp[1] | thread->used_cp[2]; 394 395 if (used_math) 396 memcpy(fp, &thread->fpstate.soft, sizeof (*fp)); 397 398 return used_math != 0; 399 } 400 EXPORT_SYMBOL(dump_fpu); 401 402 /* 403 * Shuffle the argument into the correct register before calling the 404 * thread function. r4 is the thread argument, r5 is the pointer to 405 * the thread function, and r6 points to the exit function. 406 */ 407 extern void kernel_thread_helper(void); 408 asm( ".pushsection .text\n" 409 " .align\n" 410 " .type kernel_thread_helper, #function\n" 411 "kernel_thread_helper:\n" 412 #ifdef CONFIG_TRACE_IRQFLAGS 413 " bl trace_hardirqs_on\n" 414 #endif 415 " msr cpsr_c, r7\n" 416 " mov r0, r4\n" 417 " mov lr, r6\n" 418 " mov pc, r5\n" 419 " .size kernel_thread_helper, . - kernel_thread_helper\n" 420 " .popsection"); 421 422 #ifdef CONFIG_ARM_UNWIND 423 extern void kernel_thread_exit(long code); 424 asm( ".pushsection .text\n" 425 " .align\n" 426 " .type kernel_thread_exit, #function\n" 427 "kernel_thread_exit:\n" 428 " .fnstart\n" 429 " .cantunwind\n" 430 " bl do_exit\n" 431 " nop\n" 432 " .fnend\n" 433 " .size kernel_thread_exit, . - kernel_thread_exit\n" 434 " .popsection"); 435 #else 436 #define kernel_thread_exit do_exit 437 #endif 438 439 /* 440 * Create a kernel thread. 441 */ 442 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) 443 { 444 struct pt_regs regs; 445 446 memset(®s, 0, sizeof(regs)); 447 448 regs.ARM_r4 = (unsigned long)arg; 449 regs.ARM_r5 = (unsigned long)fn; 450 regs.ARM_r6 = (unsigned long)kernel_thread_exit; 451 regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE; 452 regs.ARM_pc = (unsigned long)kernel_thread_helper; 453 regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT; 454 455 return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); 456 } 457 EXPORT_SYMBOL(kernel_thread); 458 459 unsigned long get_wchan(struct task_struct *p) 460 { 461 struct stackframe frame; 462 int count = 0; 463 if (!p || p == current || p->state == TASK_RUNNING) 464 return 0; 465 466 frame.fp = thread_saved_fp(p); 467 frame.sp = thread_saved_sp(p); 468 frame.lr = 0; /* recovered from the stack */ 469 frame.pc = thread_saved_pc(p); 470 do { 471 int ret = unwind_frame(&frame); 472 if (ret < 0) 473 return 0; 474 if (!in_sched_functions(frame.pc)) 475 return frame.pc; 476 } while (count ++ < 16); 477 return 0; 478 } 479 480 unsigned long arch_randomize_brk(struct mm_struct *mm) 481 { 482 unsigned long range_end = mm->brk + 0x02000000; 483 return randomize_range(mm->brk, range_end, 0) ? : mm->brk; 484 } 485 486 #ifdef CONFIG_MMU 487 /* 488 * The vectors page is always readable from user space for the 489 * atomic helpers and the signal restart code. Let's declare a mapping 490 * for it so it is visible through ptrace and /proc/<pid>/mem. 491 */ 492 493 int vectors_user_mapping(void) 494 { 495 struct mm_struct *mm = current->mm; 496 return install_special_mapping(mm, 0xffff0000, PAGE_SIZE, 497 VM_READ | VM_EXEC | 498 VM_MAYREAD | VM_MAYEXEC | 499 VM_ALWAYSDUMP | VM_RESERVED, 500 NULL); 501 } 502 503 const char *arch_vma_name(struct vm_area_struct *vma) 504 { 505 return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL; 506 } 507 #endif 508