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