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/slab.h> 20 #include <linux/user.h> 21 #include <linux/delay.h> 22 #include <linux/reboot.h> 23 #include <linux/interrupt.h> 24 #include <linux/kallsyms.h> 25 #include <linux/init.h> 26 #include <linux/cpu.h> 27 #include <linux/elfcore.h> 28 #include <linux/pm.h> 29 #include <linux/tick.h> 30 #include <linux/utsname.h> 31 #include <linux/uaccess.h> 32 33 #include <asm/leds.h> 34 #include <asm/processor.h> 35 #include <asm/system.h> 36 #include <asm/thread_notify.h> 37 #include <asm/mach/time.h> 38 39 static const char *processor_modes[] = { 40 "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" , 41 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26", 42 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" , 43 "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32" 44 }; 45 46 static const char *isa_modes[] = { 47 "ARM" , "Thumb" , "Jazelle", "ThumbEE" 48 }; 49 50 extern void setup_mm_for_reboot(char mode); 51 52 static volatile int hlt_counter; 53 54 #include <mach/system.h> 55 56 void disable_hlt(void) 57 { 58 hlt_counter++; 59 } 60 61 EXPORT_SYMBOL(disable_hlt); 62 63 void enable_hlt(void) 64 { 65 hlt_counter--; 66 } 67 68 EXPORT_SYMBOL(enable_hlt); 69 70 static int __init nohlt_setup(char *__unused) 71 { 72 hlt_counter = 1; 73 return 1; 74 } 75 76 static int __init hlt_setup(char *__unused) 77 { 78 hlt_counter = 0; 79 return 1; 80 } 81 82 __setup("nohlt", nohlt_setup); 83 __setup("hlt", hlt_setup); 84 85 void arm_machine_restart(char mode) 86 { 87 /* 88 * Clean and disable cache, and turn off interrupts 89 */ 90 cpu_proc_fin(); 91 92 /* 93 * Tell the mm system that we are going to reboot - 94 * we may need it to insert some 1:1 mappings so that 95 * soft boot works. 96 */ 97 setup_mm_for_reboot(mode); 98 99 /* 100 * Now call the architecture specific reboot code. 101 */ 102 arch_reset(mode); 103 104 /* 105 * Whoops - the architecture was unable to reboot. 106 * Tell the user! 107 */ 108 mdelay(1000); 109 printk("Reboot failed -- System halted\n"); 110 while (1); 111 } 112 113 /* 114 * Function pointers to optional machine specific functions 115 */ 116 void (*pm_idle)(void); 117 EXPORT_SYMBOL(pm_idle); 118 119 void (*pm_power_off)(void); 120 EXPORT_SYMBOL(pm_power_off); 121 122 void (*arm_pm_restart)(char str) = arm_machine_restart; 123 EXPORT_SYMBOL_GPL(arm_pm_restart); 124 125 126 /* 127 * This is our default idle handler. We need to disable 128 * interrupts here to ensure we don't miss a wakeup call. 129 */ 130 static void default_idle(void) 131 { 132 if (hlt_counter) 133 cpu_relax(); 134 else { 135 local_irq_disable(); 136 if (!need_resched()) 137 arch_idle(); 138 local_irq_enable(); 139 } 140 } 141 142 /* 143 * The idle thread. We try to conserve power, while trying to keep 144 * overall latency low. The architecture specific idle is passed 145 * a value to indicate the level of "idleness" of the system. 146 */ 147 void cpu_idle(void) 148 { 149 local_fiq_enable(); 150 151 /* endless idle loop with no priority at all */ 152 while (1) { 153 void (*idle)(void) = pm_idle; 154 155 #ifdef CONFIG_HOTPLUG_CPU 156 if (cpu_is_offline(smp_processor_id())) { 157 leds_event(led_idle_start); 158 cpu_die(); 159 } 160 #endif 161 162 if (!idle) 163 idle = default_idle; 164 leds_event(led_idle_start); 165 tick_nohz_stop_sched_tick(1); 166 while (!need_resched()) 167 idle(); 168 leds_event(led_idle_end); 169 tick_nohz_restart_sched_tick(); 170 preempt_enable_no_resched(); 171 schedule(); 172 preempt_disable(); 173 } 174 } 175 176 static char reboot_mode = 'h'; 177 178 int __init reboot_setup(char *str) 179 { 180 reboot_mode = str[0]; 181 return 1; 182 } 183 184 __setup("reboot=", reboot_setup); 185 186 void machine_halt(void) 187 { 188 } 189 190 191 void machine_power_off(void) 192 { 193 if (pm_power_off) 194 pm_power_off(); 195 } 196 197 void machine_restart(char * __unused) 198 { 199 arm_pm_restart(reboot_mode); 200 } 201 202 void __show_regs(struct pt_regs *regs) 203 { 204 unsigned long flags; 205 char buf[64]; 206 207 printk("CPU: %d %s (%s %.*s)\n", 208 smp_processor_id(), print_tainted(), init_utsname()->release, 209 (int)strcspn(init_utsname()->version, " "), 210 init_utsname()->version); 211 print_symbol("PC is at %s\n", instruction_pointer(regs)); 212 print_symbol("LR is at %s\n", regs->ARM_lr); 213 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n" 214 "sp : %08lx ip : %08lx fp : %08lx\n", 215 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr, 216 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 217 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 218 regs->ARM_r10, regs->ARM_r9, 219 regs->ARM_r8); 220 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 221 regs->ARM_r7, regs->ARM_r6, 222 regs->ARM_r5, regs->ARM_r4); 223 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 224 regs->ARM_r3, regs->ARM_r2, 225 regs->ARM_r1, regs->ARM_r0); 226 227 flags = regs->ARM_cpsr; 228 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 229 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 230 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 231 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 232 buf[4] = '\0'; 233 234 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 235 buf, interrupts_enabled(regs) ? "n" : "ff", 236 fast_interrupts_enabled(regs) ? "n" : "ff", 237 processor_modes[processor_mode(regs)], 238 isa_modes[isa_mode(regs)], 239 get_fs() == get_ds() ? "kernel" : "user"); 240 #ifdef CONFIG_CPU_CP15 241 { 242 unsigned int ctrl; 243 244 buf[0] = '\0'; 245 #ifdef CONFIG_CPU_CP15_MMU 246 { 247 unsigned int transbase, dac; 248 asm("mrc p15, 0, %0, c2, c0\n\t" 249 "mrc p15, 0, %1, c3, c0\n" 250 : "=r" (transbase), "=r" (dac)); 251 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 252 transbase, dac); 253 } 254 #endif 255 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 256 257 printk("Control: %08x%s\n", ctrl, buf); 258 } 259 #endif 260 } 261 262 void show_regs(struct pt_regs * regs) 263 { 264 printk("\n"); 265 printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm); 266 __show_regs(regs); 267 __backtrace(); 268 } 269 270 /* 271 * Free current thread data structures etc.. 272 */ 273 void exit_thread(void) 274 { 275 } 276 277 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 278 279 EXPORT_SYMBOL_GPL(thread_notify_head); 280 281 void flush_thread(void) 282 { 283 struct thread_info *thread = current_thread_info(); 284 struct task_struct *tsk = current; 285 286 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 287 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 288 memset(&thread->fpstate, 0, sizeof(union fp_state)); 289 290 thread_notify(THREAD_NOTIFY_FLUSH, thread); 291 } 292 293 void release_thread(struct task_struct *dead_task) 294 { 295 struct thread_info *thread = task_thread_info(dead_task); 296 297 thread_notify(THREAD_NOTIFY_RELEASE, thread); 298 } 299 300 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 301 302 int 303 copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start, 304 unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs) 305 { 306 struct thread_info *thread = task_thread_info(p); 307 struct pt_regs *childregs = task_pt_regs(p); 308 309 *childregs = *regs; 310 childregs->ARM_r0 = 0; 311 childregs->ARM_sp = stack_start; 312 313 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 314 thread->cpu_context.sp = (unsigned long)childregs; 315 thread->cpu_context.pc = (unsigned long)ret_from_fork; 316 317 if (clone_flags & CLONE_SETTLS) 318 thread->tp_value = regs->ARM_r3; 319 320 return 0; 321 } 322 323 /* 324 * fill in the fpe structure for a core dump... 325 */ 326 int dump_fpu (struct pt_regs *regs, struct user_fp *fp) 327 { 328 struct thread_info *thread = current_thread_info(); 329 int used_math = thread->used_cp[1] | thread->used_cp[2]; 330 331 if (used_math) 332 memcpy(fp, &thread->fpstate.soft, sizeof (*fp)); 333 334 return used_math != 0; 335 } 336 EXPORT_SYMBOL(dump_fpu); 337 338 /* 339 * Shuffle the argument into the correct register before calling the 340 * thread function. r1 is the thread argument, r2 is the pointer to 341 * the thread function, and r3 points to the exit function. 342 */ 343 extern void kernel_thread_helper(void); 344 asm( ".section .text\n" 345 " .align\n" 346 " .type kernel_thread_helper, #function\n" 347 "kernel_thread_helper:\n" 348 " mov r0, r1\n" 349 " mov lr, r3\n" 350 " mov pc, r2\n" 351 " .size kernel_thread_helper, . - kernel_thread_helper\n" 352 " .previous"); 353 354 /* 355 * Create a kernel thread. 356 */ 357 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) 358 { 359 struct pt_regs regs; 360 361 memset(®s, 0, sizeof(regs)); 362 363 regs.ARM_r1 = (unsigned long)arg; 364 regs.ARM_r2 = (unsigned long)fn; 365 regs.ARM_r3 = (unsigned long)do_exit; 366 regs.ARM_pc = (unsigned long)kernel_thread_helper; 367 regs.ARM_cpsr = SVC_MODE; 368 369 return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); 370 } 371 EXPORT_SYMBOL(kernel_thread); 372 373 unsigned long get_wchan(struct task_struct *p) 374 { 375 unsigned long fp, lr; 376 unsigned long stack_start, stack_end; 377 int count = 0; 378 if (!p || p == current || p->state == TASK_RUNNING) 379 return 0; 380 381 stack_start = (unsigned long)end_of_stack(p); 382 stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE; 383 384 fp = thread_saved_fp(p); 385 do { 386 if (fp < stack_start || fp > stack_end) 387 return 0; 388 lr = ((unsigned long *)fp)[-1]; 389 if (!in_sched_functions(lr)) 390 return lr; 391 fp = *(unsigned long *) (fp - 12); 392 } while (count ++ < 16); 393 return 0; 394 } 395