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