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 #include <linux/elfcore.h> 31 32 #include <asm/leds.h> 33 #include <asm/processor.h> 34 #include <asm/system.h> 35 #include <asm/uaccess.h> 36 #include <asm/mach/time.h> 37 38 extern const char *processor_modes[]; 39 extern void setup_mm_for_reboot(char mode); 40 41 static volatile int hlt_counter; 42 43 #include <asm/arch/system.h> 44 45 void disable_hlt(void) 46 { 47 hlt_counter++; 48 } 49 50 EXPORT_SYMBOL(disable_hlt); 51 52 void enable_hlt(void) 53 { 54 hlt_counter--; 55 } 56 57 EXPORT_SYMBOL(enable_hlt); 58 59 static int __init nohlt_setup(char *__unused) 60 { 61 hlt_counter = 1; 62 return 1; 63 } 64 65 static int __init hlt_setup(char *__unused) 66 { 67 hlt_counter = 0; 68 return 1; 69 } 70 71 __setup("nohlt", nohlt_setup); 72 __setup("hlt", hlt_setup); 73 74 /* 75 * The following aren't currently used. 76 */ 77 void (*pm_idle)(void); 78 EXPORT_SYMBOL(pm_idle); 79 80 void (*pm_power_off)(void); 81 EXPORT_SYMBOL(pm_power_off); 82 83 /* 84 * This is our default idle handler. We need to disable 85 * interrupts here to ensure we don't miss a wakeup call. 86 */ 87 static void default_idle(void) 88 { 89 if (hlt_counter) 90 cpu_relax(); 91 else { 92 local_irq_disable(); 93 if (!need_resched()) { 94 timer_dyn_reprogram(); 95 arch_idle(); 96 } 97 local_irq_enable(); 98 } 99 } 100 101 /* 102 * The idle thread. We try to conserve power, while trying to keep 103 * overall latency low. The architecture specific idle is passed 104 * a value to indicate the level of "idleness" of the system. 105 */ 106 void cpu_idle(void) 107 { 108 local_fiq_enable(); 109 110 /* endless idle loop with no priority at all */ 111 while (1) { 112 void (*idle)(void) = pm_idle; 113 114 #ifdef CONFIG_HOTPLUG_CPU 115 if (cpu_is_offline(smp_processor_id())) { 116 leds_event(led_idle_start); 117 cpu_die(); 118 } 119 #endif 120 121 if (!idle) 122 idle = default_idle; 123 leds_event(led_idle_start); 124 while (!need_resched()) 125 idle(); 126 leds_event(led_idle_end); 127 preempt_enable_no_resched(); 128 schedule(); 129 preempt_disable(); 130 } 131 } 132 133 static char reboot_mode = 'h'; 134 135 int __init reboot_setup(char *str) 136 { 137 reboot_mode = str[0]; 138 return 1; 139 } 140 141 __setup("reboot=", reboot_setup); 142 143 void machine_halt(void) 144 { 145 } 146 147 148 void machine_power_off(void) 149 { 150 if (pm_power_off) 151 pm_power_off(); 152 } 153 154 155 void machine_restart(char * __unused) 156 { 157 /* 158 * Clean and disable cache, and turn off interrupts 159 */ 160 cpu_proc_fin(); 161 162 /* 163 * Tell the mm system that we are going to reboot - 164 * we may need it to insert some 1:1 mappings so that 165 * soft boot works. 166 */ 167 setup_mm_for_reboot(reboot_mode); 168 169 /* 170 * Now call the architecture specific reboot code. 171 */ 172 arch_reset(reboot_mode); 173 174 /* 175 * Whoops - the architecture was unable to reboot. 176 * Tell the user! 177 */ 178 mdelay(1000); 179 printk("Reboot failed -- System halted\n"); 180 while (1); 181 } 182 183 void __show_regs(struct pt_regs *regs) 184 { 185 unsigned long flags = condition_codes(regs); 186 187 printk("CPU: %d\n", smp_processor_id()); 188 print_symbol("PC is at %s\n", instruction_pointer(regs)); 189 print_symbol("LR is at %s\n", regs->ARM_lr); 190 printk("pc : [<%08lx>] lr : [<%08lx>] %s\n" 191 "sp : %08lx ip : %08lx fp : %08lx\n", 192 instruction_pointer(regs), 193 regs->ARM_lr, print_tainted(), regs->ARM_sp, 194 regs->ARM_ip, regs->ARM_fp); 195 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 196 regs->ARM_r10, regs->ARM_r9, 197 regs->ARM_r8); 198 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 199 regs->ARM_r7, regs->ARM_r6, 200 regs->ARM_r5, regs->ARM_r4); 201 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 202 regs->ARM_r3, regs->ARM_r2, 203 regs->ARM_r1, regs->ARM_r0); 204 printk("Flags: %c%c%c%c", 205 flags & PSR_N_BIT ? 'N' : 'n', 206 flags & PSR_Z_BIT ? 'Z' : 'z', 207 flags & PSR_C_BIT ? 'C' : 'c', 208 flags & PSR_V_BIT ? 'V' : 'v'); 209 printk(" IRQs o%s FIQs o%s Mode %s%s Segment %s\n", 210 interrupts_enabled(regs) ? "n" : "ff", 211 fast_interrupts_enabled(regs) ? "n" : "ff", 212 processor_modes[processor_mode(regs)], 213 thumb_mode(regs) ? " (T)" : "", 214 get_fs() == get_ds() ? "kernel" : "user"); 215 { 216 unsigned int ctrl, transbase, dac; 217 __asm__ ( 218 " mrc p15, 0, %0, c1, c0\n" 219 " mrc p15, 0, %1, c2, c0\n" 220 " mrc p15, 0, %2, c3, c0\n" 221 : "=r" (ctrl), "=r" (transbase), "=r" (dac)); 222 printk("Control: %04X Table: %08X DAC: %08X\n", 223 ctrl, transbase, dac); 224 } 225 } 226 227 void show_regs(struct pt_regs * regs) 228 { 229 printk("\n"); 230 printk("Pid: %d, comm: %20s\n", current->pid, current->comm); 231 __show_regs(regs); 232 __backtrace(); 233 } 234 235 void show_fpregs(struct user_fp *regs) 236 { 237 int i; 238 239 for (i = 0; i < 8; i++) { 240 unsigned long *p; 241 char type; 242 243 p = (unsigned long *)(regs->fpregs + i); 244 245 switch (regs->ftype[i]) { 246 case 1: type = 'f'; break; 247 case 2: type = 'd'; break; 248 case 3: type = 'e'; break; 249 default: type = '?'; break; 250 } 251 if (regs->init_flag) 252 type = '?'; 253 254 printk(" f%d(%c): %08lx %08lx %08lx%c", 255 i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' '); 256 } 257 258 259 printk("FPSR: %08lx FPCR: %08lx\n", 260 (unsigned long)regs->fpsr, 261 (unsigned long)regs->fpcr); 262 } 263 264 /* 265 * Task structure and kernel stack allocation. 266 */ 267 static unsigned long *thread_info_head; 268 static unsigned int nr_thread_info; 269 270 #define EXTRA_TASK_STRUCT 4 271 272 struct thread_info *alloc_thread_info(struct task_struct *task) 273 { 274 struct thread_info *thread = NULL; 275 276 if (EXTRA_TASK_STRUCT) { 277 unsigned long *p = thread_info_head; 278 279 if (p) { 280 thread_info_head = (unsigned long *)p[0]; 281 nr_thread_info -= 1; 282 } 283 thread = (struct thread_info *)p; 284 } 285 286 if (!thread) 287 thread = (struct thread_info *) 288 __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER); 289 290 #ifdef CONFIG_DEBUG_STACK_USAGE 291 /* 292 * The stack must be cleared if you want SYSRQ-T to 293 * give sensible stack usage information 294 */ 295 if (thread) 296 memzero(thread, THREAD_SIZE); 297 #endif 298 return thread; 299 } 300 301 void free_thread_info(struct thread_info *thread) 302 { 303 if (EXTRA_TASK_STRUCT && nr_thread_info < EXTRA_TASK_STRUCT) { 304 unsigned long *p = (unsigned long *)thread; 305 p[0] = (unsigned long)thread_info_head; 306 thread_info_head = p; 307 nr_thread_info += 1; 308 } else 309 free_pages((unsigned long)thread, THREAD_SIZE_ORDER); 310 } 311 312 /* 313 * Free current thread data structures etc.. 314 */ 315 void exit_thread(void) 316 { 317 } 318 319 static void default_fp_init(union fp_state *fp) 320 { 321 memset(fp, 0, sizeof(union fp_state)); 322 } 323 324 void (*fp_init)(union fp_state *) = default_fp_init; 325 EXPORT_SYMBOL(fp_init); 326 327 void flush_thread(void) 328 { 329 struct thread_info *thread = current_thread_info(); 330 struct task_struct *tsk = current; 331 332 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 333 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 334 #if defined(CONFIG_IWMMXT) 335 iwmmxt_task_release(thread); 336 #endif 337 fp_init(&thread->fpstate); 338 #if defined(CONFIG_VFP) 339 vfp_flush_thread(&thread->vfpstate); 340 #endif 341 } 342 343 void release_thread(struct task_struct *dead_task) 344 { 345 #if defined(CONFIG_VFP) 346 vfp_release_thread(&task_thread_info(dead_task)->vfpstate); 347 #endif 348 #if defined(CONFIG_IWMMXT) 349 iwmmxt_task_release(task_thread_info(dead_task)); 350 #endif 351 } 352 353 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 354 355 int 356 copy_thread(int nr, 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 if (clone_flags & CLONE_SETTLS) 371 thread->tp_value = regs->ARM_r3; 372 373 return 0; 374 } 375 376 /* 377 * fill in the fpe structure for a core dump... 378 */ 379 int dump_fpu (struct pt_regs *regs, struct user_fp *fp) 380 { 381 struct thread_info *thread = current_thread_info(); 382 int used_math = thread->used_cp[1] | thread->used_cp[2]; 383 384 if (used_math) 385 memcpy(fp, &thread->fpstate.soft, sizeof (*fp)); 386 387 return used_math != 0; 388 } 389 EXPORT_SYMBOL(dump_fpu); 390 391 /* 392 * fill in the user structure for a core dump.. 393 */ 394 void dump_thread(struct pt_regs * regs, struct user * dump) 395 { 396 struct task_struct *tsk = current; 397 398 dump->magic = CMAGIC; 399 dump->start_code = tsk->mm->start_code; 400 dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1); 401 402 dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT; 403 dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT; 404 dump->u_ssize = 0; 405 406 dump->u_debugreg[0] = tsk->thread.debug.bp[0].address; 407 dump->u_debugreg[1] = tsk->thread.debug.bp[1].address; 408 dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn.arm; 409 dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn.arm; 410 dump->u_debugreg[4] = tsk->thread.debug.nsaved; 411 412 if (dump->start_stack < 0x04000000) 413 dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT; 414 415 dump->regs = *regs; 416 dump->u_fpvalid = dump_fpu (regs, &dump->u_fp); 417 } 418 EXPORT_SYMBOL(dump_thread); 419 420 /* 421 * Shuffle the argument into the correct register before calling the 422 * thread function. r1 is the thread argument, r2 is the pointer to 423 * the thread function, and r3 points to the exit function. 424 */ 425 extern void kernel_thread_helper(void); 426 asm( ".section .text\n" 427 " .align\n" 428 " .type kernel_thread_helper, #function\n" 429 "kernel_thread_helper:\n" 430 " mov r0, r1\n" 431 " mov lr, r3\n" 432 " mov pc, r2\n" 433 " .size kernel_thread_helper, . - kernel_thread_helper\n" 434 " .previous"); 435 436 /* 437 * Create a kernel thread. 438 */ 439 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) 440 { 441 struct pt_regs regs; 442 443 memset(®s, 0, sizeof(regs)); 444 445 regs.ARM_r1 = (unsigned long)arg; 446 regs.ARM_r2 = (unsigned long)fn; 447 regs.ARM_r3 = (unsigned long)do_exit; 448 regs.ARM_pc = (unsigned long)kernel_thread_helper; 449 regs.ARM_cpsr = SVC_MODE; 450 451 return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); 452 } 453 EXPORT_SYMBOL(kernel_thread); 454 455 unsigned long get_wchan(struct task_struct *p) 456 { 457 unsigned long fp, lr; 458 unsigned long stack_start, stack_end; 459 int count = 0; 460 if (!p || p == current || p->state == TASK_RUNNING) 461 return 0; 462 463 stack_start = (unsigned long)end_of_stack(p); 464 stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE; 465 466 fp = thread_saved_fp(p); 467 do { 468 if (fp < stack_start || fp > stack_end) 469 return 0; 470 lr = pc_pointer (((unsigned long *)fp)[-1]); 471 if (!in_sched_functions(lr)) 472 return lr; 473 fp = *(unsigned long *) (fp - 12); 474 } while (count ++ < 16); 475 return 0; 476 } 477 EXPORT_SYMBOL(get_wchan); 478