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/config.h> 14 #include <linux/module.h> 15 #include <linux/sched.h> 16 #include <linux/kernel.h> 17 #include <linux/mm.h> 18 #include <linux/stddef.h> 19 #include <linux/unistd.h> 20 #include <linux/ptrace.h> 21 #include <linux/slab.h> 22 #include <linux/user.h> 23 #include <linux/a.out.h> 24 #include <linux/delay.h> 25 #include <linux/reboot.h> 26 #include <linux/interrupt.h> 27 #include <linux/kallsyms.h> 28 #include <linux/init.h> 29 #include <linux/cpu.h> 30 31 #include <asm/leds.h> 32 #include <asm/processor.h> 33 #include <asm/system.h> 34 #include <asm/uaccess.h> 35 #include <asm/mach/time.h> 36 37 extern const char *processor_modes[]; 38 extern void setup_mm_for_reboot(char mode); 39 40 static volatile int hlt_counter; 41 42 #include <asm/arch/system.h> 43 44 void disable_hlt(void) 45 { 46 hlt_counter++; 47 } 48 49 EXPORT_SYMBOL(disable_hlt); 50 51 void enable_hlt(void) 52 { 53 hlt_counter--; 54 } 55 56 EXPORT_SYMBOL(enable_hlt); 57 58 static int __init nohlt_setup(char *__unused) 59 { 60 hlt_counter = 1; 61 return 1; 62 } 63 64 static int __init hlt_setup(char *__unused) 65 { 66 hlt_counter = 0; 67 return 1; 68 } 69 70 __setup("nohlt", nohlt_setup); 71 __setup("hlt", hlt_setup); 72 73 /* 74 * The following aren't currently used. 75 */ 76 void (*pm_idle)(void); 77 EXPORT_SYMBOL(pm_idle); 78 79 void (*pm_power_off)(void); 80 EXPORT_SYMBOL(pm_power_off); 81 82 /* 83 * This is our default idle handler. We need to disable 84 * interrupts here to ensure we don't miss a wakeup call. 85 */ 86 void default_idle(void) 87 { 88 if (hlt_counter) 89 cpu_relax(); 90 else { 91 local_irq_disable(); 92 if (!need_resched()) { 93 timer_dyn_reprogram(); 94 arch_idle(); 95 } 96 local_irq_enable(); 97 } 98 } 99 100 /* 101 * The idle thread. We try to conserve power, while trying to keep 102 * overall latency low. The architecture specific idle is passed 103 * a value to indicate the level of "idleness" of the system. 104 */ 105 void cpu_idle(void) 106 { 107 local_fiq_enable(); 108 109 /* endless idle loop with no priority at all */ 110 while (1) { 111 void (*idle)(void) = pm_idle; 112 113 #ifdef CONFIG_HOTPLUG_CPU 114 if (cpu_is_offline(smp_processor_id())) { 115 leds_event(led_idle_start); 116 cpu_die(); 117 } 118 #endif 119 120 if (!idle) 121 idle = default_idle; 122 leds_event(led_idle_start); 123 while (!need_resched()) 124 idle(); 125 leds_event(led_idle_end); 126 preempt_enable_no_resched(); 127 schedule(); 128 preempt_disable(); 129 } 130 } 131 132 static char reboot_mode = 'h'; 133 134 int __init reboot_setup(char *str) 135 { 136 reboot_mode = str[0]; 137 return 1; 138 } 139 140 __setup("reboot=", reboot_setup); 141 142 void machine_halt(void) 143 { 144 } 145 146 147 void machine_power_off(void) 148 { 149 if (pm_power_off) 150 pm_power_off(); 151 } 152 153 154 void machine_restart(char * __unused) 155 { 156 /* 157 * Clean and disable cache, and turn off interrupts 158 */ 159 cpu_proc_fin(); 160 161 /* 162 * Tell the mm system that we are going to reboot - 163 * we may need it to insert some 1:1 mappings so that 164 * soft boot works. 165 */ 166 setup_mm_for_reboot(reboot_mode); 167 168 /* 169 * Now call the architecture specific reboot code. 170 */ 171 arch_reset(reboot_mode); 172 173 /* 174 * Whoops - the architecture was unable to reboot. 175 * Tell the user! 176 */ 177 mdelay(1000); 178 printk("Reboot failed -- System halted\n"); 179 while (1); 180 } 181 182 void __show_regs(struct pt_regs *regs) 183 { 184 unsigned long flags = condition_codes(regs); 185 186 printk("CPU: %d\n", smp_processor_id()); 187 print_symbol("PC is at %s\n", instruction_pointer(regs)); 188 print_symbol("LR is at %s\n", regs->ARM_lr); 189 printk("pc : [<%08lx>] lr : [<%08lx>] %s\n" 190 "sp : %08lx ip : %08lx fp : %08lx\n", 191 instruction_pointer(regs), 192 regs->ARM_lr, print_tainted(), regs->ARM_sp, 193 regs->ARM_ip, regs->ARM_fp); 194 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 195 regs->ARM_r10, regs->ARM_r9, 196 regs->ARM_r8); 197 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 198 regs->ARM_r7, regs->ARM_r6, 199 regs->ARM_r5, regs->ARM_r4); 200 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 201 regs->ARM_r3, regs->ARM_r2, 202 regs->ARM_r1, regs->ARM_r0); 203 printk("Flags: %c%c%c%c", 204 flags & PSR_N_BIT ? 'N' : 'n', 205 flags & PSR_Z_BIT ? 'Z' : 'z', 206 flags & PSR_C_BIT ? 'C' : 'c', 207 flags & PSR_V_BIT ? 'V' : 'v'); 208 printk(" IRQs o%s FIQs o%s Mode %s%s Segment %s\n", 209 interrupts_enabled(regs) ? "n" : "ff", 210 fast_interrupts_enabled(regs) ? "n" : "ff", 211 processor_modes[processor_mode(regs)], 212 thumb_mode(regs) ? " (T)" : "", 213 get_fs() == get_ds() ? "kernel" : "user"); 214 { 215 unsigned int ctrl, transbase, dac; 216 __asm__ ( 217 " mrc p15, 0, %0, c1, c0\n" 218 " mrc p15, 0, %1, c2, c0\n" 219 " mrc p15, 0, %2, c3, c0\n" 220 : "=r" (ctrl), "=r" (transbase), "=r" (dac)); 221 printk("Control: %04X Table: %08X DAC: %08X\n", 222 ctrl, transbase, dac); 223 } 224 } 225 226 void show_regs(struct pt_regs * regs) 227 { 228 printk("\n"); 229 printk("Pid: %d, comm: %20s\n", current->pid, current->comm); 230 __show_regs(regs); 231 __backtrace(); 232 } 233 234 void show_fpregs(struct user_fp *regs) 235 { 236 int i; 237 238 for (i = 0; i < 8; i++) { 239 unsigned long *p; 240 char type; 241 242 p = (unsigned long *)(regs->fpregs + i); 243 244 switch (regs->ftype[i]) { 245 case 1: type = 'f'; break; 246 case 2: type = 'd'; break; 247 case 3: type = 'e'; break; 248 default: type = '?'; break; 249 } 250 if (regs->init_flag) 251 type = '?'; 252 253 printk(" f%d(%c): %08lx %08lx %08lx%c", 254 i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' '); 255 } 256 257 258 printk("FPSR: %08lx FPCR: %08lx\n", 259 (unsigned long)regs->fpsr, 260 (unsigned long)regs->fpcr); 261 } 262 263 /* 264 * Task structure and kernel stack allocation. 265 */ 266 static unsigned long *thread_info_head; 267 static unsigned int nr_thread_info; 268 269 #define EXTRA_TASK_STRUCT 4 270 271 struct thread_info *alloc_thread_info(struct task_struct *task) 272 { 273 struct thread_info *thread = NULL; 274 275 if (EXTRA_TASK_STRUCT) { 276 unsigned long *p = thread_info_head; 277 278 if (p) { 279 thread_info_head = (unsigned long *)p[0]; 280 nr_thread_info -= 1; 281 } 282 thread = (struct thread_info *)p; 283 } 284 285 if (!thread) 286 thread = (struct thread_info *) 287 __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER); 288 289 #ifdef CONFIG_DEBUG_STACK_USAGE 290 /* 291 * The stack must be cleared if you want SYSRQ-T to 292 * give sensible stack usage information 293 */ 294 if (thread) 295 memzero(thread, THREAD_SIZE); 296 #endif 297 return thread; 298 } 299 300 void free_thread_info(struct thread_info *thread) 301 { 302 if (EXTRA_TASK_STRUCT && nr_thread_info < EXTRA_TASK_STRUCT) { 303 unsigned long *p = (unsigned long *)thread; 304 p[0] = (unsigned long)thread_info_head; 305 thread_info_head = p; 306 nr_thread_info += 1; 307 } else 308 free_pages((unsigned long)thread, THREAD_SIZE_ORDER); 309 } 310 311 /* 312 * Free current thread data structures etc.. 313 */ 314 void exit_thread(void) 315 { 316 } 317 318 static void default_fp_init(union fp_state *fp) 319 { 320 memset(fp, 0, sizeof(union fp_state)); 321 } 322 323 void (*fp_init)(union fp_state *) = default_fp_init; 324 EXPORT_SYMBOL(fp_init); 325 326 void flush_thread(void) 327 { 328 struct thread_info *thread = current_thread_info(); 329 struct task_struct *tsk = current; 330 331 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 332 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 333 #if defined(CONFIG_IWMMXT) 334 iwmmxt_task_release(thread); 335 #endif 336 fp_init(&thread->fpstate); 337 #if defined(CONFIG_VFP) 338 vfp_flush_thread(&thread->vfpstate); 339 #endif 340 } 341 342 void release_thread(struct task_struct *dead_task) 343 { 344 #if defined(CONFIG_VFP) 345 vfp_release_thread(&task_thread_info(dead_task)->vfpstate); 346 #endif 347 #if defined(CONFIG_IWMMXT) 348 iwmmxt_task_release(task_thread_info(dead_task)); 349 #endif 350 } 351 352 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 353 354 int 355 copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start, 356 unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs) 357 { 358 struct thread_info *thread = task_thread_info(p); 359 struct pt_regs *childregs = task_pt_regs(p); 360 361 *childregs = *regs; 362 childregs->ARM_r0 = 0; 363 childregs->ARM_sp = stack_start; 364 365 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 366 thread->cpu_context.sp = (unsigned long)childregs; 367 thread->cpu_context.pc = (unsigned long)ret_from_fork; 368 369 if (clone_flags & CLONE_SETTLS) 370 thread->tp_value = regs->ARM_r3; 371 372 return 0; 373 } 374 375 /* 376 * fill in the fpe structure for a core dump... 377 */ 378 int dump_fpu (struct pt_regs *regs, struct user_fp *fp) 379 { 380 struct thread_info *thread = current_thread_info(); 381 int used_math = thread->used_cp[1] | thread->used_cp[2]; 382 383 if (used_math) 384 memcpy(fp, &thread->fpstate.soft, sizeof (*fp)); 385 386 return used_math != 0; 387 } 388 EXPORT_SYMBOL(dump_fpu); 389 390 /* 391 * fill in the user structure for a core dump.. 392 */ 393 void dump_thread(struct pt_regs * regs, struct user * dump) 394 { 395 struct task_struct *tsk = current; 396 397 dump->magic = CMAGIC; 398 dump->start_code = tsk->mm->start_code; 399 dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1); 400 401 dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT; 402 dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT; 403 dump->u_ssize = 0; 404 405 dump->u_debugreg[0] = tsk->thread.debug.bp[0].address; 406 dump->u_debugreg[1] = tsk->thread.debug.bp[1].address; 407 dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn.arm; 408 dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn.arm; 409 dump->u_debugreg[4] = tsk->thread.debug.nsaved; 410 411 if (dump->start_stack < 0x04000000) 412 dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT; 413 414 dump->regs = *regs; 415 dump->u_fpvalid = dump_fpu (regs, &dump->u_fp); 416 } 417 EXPORT_SYMBOL(dump_thread); 418 419 /* 420 * Shuffle the argument into the correct register before calling the 421 * thread function. r1 is the thread argument, r2 is the pointer to 422 * the thread function, and r3 points to the exit function. 423 */ 424 extern void kernel_thread_helper(void); 425 asm( ".section .text\n" 426 " .align\n" 427 " .type kernel_thread_helper, #function\n" 428 "kernel_thread_helper:\n" 429 " mov r0, r1\n" 430 " mov lr, r3\n" 431 " mov pc, r2\n" 432 " .size kernel_thread_helper, . - kernel_thread_helper\n" 433 " .previous"); 434 435 /* 436 * Create a kernel thread. 437 */ 438 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) 439 { 440 struct pt_regs regs; 441 442 memset(®s, 0, sizeof(regs)); 443 444 regs.ARM_r1 = (unsigned long)arg; 445 regs.ARM_r2 = (unsigned long)fn; 446 regs.ARM_r3 = (unsigned long)do_exit; 447 regs.ARM_pc = (unsigned long)kernel_thread_helper; 448 regs.ARM_cpsr = SVC_MODE; 449 450 return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); 451 } 452 EXPORT_SYMBOL(kernel_thread); 453 454 unsigned long get_wchan(struct task_struct *p) 455 { 456 unsigned long fp, lr; 457 unsigned long stack_start, stack_end; 458 int count = 0; 459 if (!p || p == current || p->state == TASK_RUNNING) 460 return 0; 461 462 stack_start = (unsigned long)end_of_stack(p); 463 stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE; 464 465 fp = thread_saved_fp(p); 466 do { 467 if (fp < stack_start || fp > stack_end) 468 return 0; 469 lr = pc_pointer (((unsigned long *)fp)[-1]); 470 if (!in_sched_functions(lr)) 471 return lr; 472 fp = *(unsigned long *) (fp - 12); 473 } while (count ++ < 16); 474 return 0; 475 } 476 EXPORT_SYMBOL(get_wchan); 477