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/user.h> 20 #include <linux/delay.h> 21 #include <linux/reboot.h> 22 #include <linux/interrupt.h> 23 #include <linux/kallsyms.h> 24 #include <linux/init.h> 25 #include <linux/cpu.h> 26 #include <linux/elfcore.h> 27 #include <linux/pm.h> 28 #include <linux/tick.h> 29 #include <linux/utsname.h> 30 #include <linux/uaccess.h> 31 32 #include <asm/leds.h> 33 #include <asm/processor.h> 34 #include <asm/system.h> 35 #include <asm/thread_notify.h> 36 #include <asm/stacktrace.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, const char *cmd) 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, cmd); 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_power_off)(void); 117 EXPORT_SYMBOL(pm_power_off); 118 119 void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart; 120 EXPORT_SYMBOL_GPL(arm_pm_restart); 121 122 123 /* 124 * This is our default idle handler. We need to disable 125 * interrupts here to ensure we don't miss a wakeup call. 126 */ 127 static void default_idle(void) 128 { 129 if (!need_resched()) 130 arch_idle(); 131 local_irq_enable(); 132 } 133 134 void (*pm_idle)(void) = default_idle; 135 EXPORT_SYMBOL(pm_idle); 136 137 /* 138 * The idle thread, has rather strange semantics for calling pm_idle, 139 * but this is what x86 does and we need to do the same, so that 140 * things like cpuidle get called in the same way. The only difference 141 * is that we always respect 'hlt_counter' to prevent low power idle. 142 */ 143 void cpu_idle(void) 144 { 145 local_fiq_enable(); 146 147 /* endless idle loop with no priority at all */ 148 while (1) { 149 tick_nohz_stop_sched_tick(1); 150 leds_event(led_idle_start); 151 while (!need_resched()) { 152 #ifdef CONFIG_HOTPLUG_CPU 153 if (cpu_is_offline(smp_processor_id())) 154 cpu_die(); 155 #endif 156 157 local_irq_disable(); 158 if (hlt_counter) { 159 local_irq_enable(); 160 cpu_relax(); 161 } else { 162 stop_critical_timings(); 163 pm_idle(); 164 start_critical_timings(); 165 /* 166 * This will eventually be removed - pm_idle 167 * functions should always return with IRQs 168 * enabled. 169 */ 170 WARN_ON(irqs_disabled()); 171 local_irq_enable(); 172 } 173 } 174 leds_event(led_idle_end); 175 tick_nohz_restart_sched_tick(); 176 preempt_enable_no_resched(); 177 schedule(); 178 preempt_disable(); 179 } 180 } 181 182 static char reboot_mode = 'h'; 183 184 int __init reboot_setup(char *str) 185 { 186 reboot_mode = str[0]; 187 return 1; 188 } 189 190 __setup("reboot=", reboot_setup); 191 192 void machine_halt(void) 193 { 194 } 195 196 197 void machine_power_off(void) 198 { 199 if (pm_power_off) 200 pm_power_off(); 201 } 202 203 void machine_restart(char *cmd) 204 { 205 arm_pm_restart(reboot_mode, cmd); 206 } 207 208 void __show_regs(struct pt_regs *regs) 209 { 210 unsigned long flags; 211 char buf[64]; 212 213 printk("CPU: %d %s (%s %.*s)\n", 214 raw_smp_processor_id(), print_tainted(), 215 init_utsname()->release, 216 (int)strcspn(init_utsname()->version, " "), 217 init_utsname()->version); 218 print_symbol("PC is at %s\n", instruction_pointer(regs)); 219 print_symbol("LR is at %s\n", regs->ARM_lr); 220 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n" 221 "sp : %08lx ip : %08lx fp : %08lx\n", 222 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr, 223 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 224 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 225 regs->ARM_r10, regs->ARM_r9, 226 regs->ARM_r8); 227 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 228 regs->ARM_r7, regs->ARM_r6, 229 regs->ARM_r5, regs->ARM_r4); 230 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 231 regs->ARM_r3, regs->ARM_r2, 232 regs->ARM_r1, regs->ARM_r0); 233 234 flags = regs->ARM_cpsr; 235 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 236 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 237 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 238 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 239 buf[4] = '\0'; 240 241 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 242 buf, interrupts_enabled(regs) ? "n" : "ff", 243 fast_interrupts_enabled(regs) ? "n" : "ff", 244 processor_modes[processor_mode(regs)], 245 isa_modes[isa_mode(regs)], 246 get_fs() == get_ds() ? "kernel" : "user"); 247 #ifdef CONFIG_CPU_CP15 248 { 249 unsigned int ctrl; 250 251 buf[0] = '\0'; 252 #ifdef CONFIG_CPU_CP15_MMU 253 { 254 unsigned int transbase, dac; 255 asm("mrc p15, 0, %0, c2, c0\n\t" 256 "mrc p15, 0, %1, c3, c0\n" 257 : "=r" (transbase), "=r" (dac)); 258 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 259 transbase, dac); 260 } 261 #endif 262 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 263 264 printk("Control: %08x%s\n", ctrl, buf); 265 } 266 #endif 267 } 268 269 void show_regs(struct pt_regs * regs) 270 { 271 printk("\n"); 272 printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm); 273 __show_regs(regs); 274 __backtrace(); 275 } 276 277 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 278 279 EXPORT_SYMBOL_GPL(thread_notify_head); 280 281 /* 282 * Free current thread data structures etc.. 283 */ 284 void exit_thread(void) 285 { 286 thread_notify(THREAD_NOTIFY_EXIT, current_thread_info()); 287 } 288 289 void flush_thread(void) 290 { 291 struct thread_info *thread = current_thread_info(); 292 struct task_struct *tsk = current; 293 294 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 295 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 296 memset(&thread->fpstate, 0, sizeof(union fp_state)); 297 298 thread_notify(THREAD_NOTIFY_FLUSH, thread); 299 } 300 301 void release_thread(struct task_struct *dead_task) 302 { 303 } 304 305 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 306 307 int 308 copy_thread(unsigned long clone_flags, unsigned long stack_start, 309 unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs) 310 { 311 struct thread_info *thread = task_thread_info(p); 312 struct pt_regs *childregs = task_pt_regs(p); 313 314 *childregs = *regs; 315 childregs->ARM_r0 = 0; 316 childregs->ARM_sp = stack_start; 317 318 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 319 thread->cpu_context.sp = (unsigned long)childregs; 320 thread->cpu_context.pc = (unsigned long)ret_from_fork; 321 322 if (clone_flags & CLONE_SETTLS) 323 thread->tp_value = regs->ARM_r3; 324 325 return 0; 326 } 327 328 /* 329 * Fill in the task's elfregs structure for a core dump. 330 */ 331 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs) 332 { 333 elf_core_copy_regs(elfregs, task_pt_regs(t)); 334 return 1; 335 } 336 337 /* 338 * fill in the fpe structure for a core dump... 339 */ 340 int dump_fpu (struct pt_regs *regs, struct user_fp *fp) 341 { 342 struct thread_info *thread = current_thread_info(); 343 int used_math = thread->used_cp[1] | thread->used_cp[2]; 344 345 if (used_math) 346 memcpy(fp, &thread->fpstate.soft, sizeof (*fp)); 347 348 return used_math != 0; 349 } 350 EXPORT_SYMBOL(dump_fpu); 351 352 /* 353 * Shuffle the argument into the correct register before calling the 354 * thread function. r1 is the thread argument, r2 is the pointer to 355 * the thread function, and r3 points to the exit function. 356 */ 357 extern void kernel_thread_helper(void); 358 asm( ".pushsection .text\n" 359 " .align\n" 360 " .type kernel_thread_helper, #function\n" 361 "kernel_thread_helper:\n" 362 " mov r0, r1\n" 363 " mov lr, r3\n" 364 " mov pc, r2\n" 365 " .size kernel_thread_helper, . - kernel_thread_helper\n" 366 " .popsection"); 367 368 #ifdef CONFIG_ARM_UNWIND 369 extern void kernel_thread_exit(long code); 370 asm( ".pushsection .text\n" 371 " .align\n" 372 " .type kernel_thread_exit, #function\n" 373 "kernel_thread_exit:\n" 374 " .fnstart\n" 375 " .cantunwind\n" 376 " bl do_exit\n" 377 " nop\n" 378 " .fnend\n" 379 " .size kernel_thread_exit, . - kernel_thread_exit\n" 380 " .popsection"); 381 #else 382 #define kernel_thread_exit do_exit 383 #endif 384 385 /* 386 * Create a kernel thread. 387 */ 388 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) 389 { 390 struct pt_regs regs; 391 392 memset(®s, 0, sizeof(regs)); 393 394 regs.ARM_r1 = (unsigned long)arg; 395 regs.ARM_r2 = (unsigned long)fn; 396 regs.ARM_r3 = (unsigned long)kernel_thread_exit; 397 regs.ARM_pc = (unsigned long)kernel_thread_helper; 398 regs.ARM_cpsr = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE; 399 400 return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); 401 } 402 EXPORT_SYMBOL(kernel_thread); 403 404 unsigned long get_wchan(struct task_struct *p) 405 { 406 struct stackframe frame; 407 int count = 0; 408 if (!p || p == current || p->state == TASK_RUNNING) 409 return 0; 410 411 frame.fp = thread_saved_fp(p); 412 frame.sp = thread_saved_sp(p); 413 frame.lr = 0; /* recovered from the stack */ 414 frame.pc = thread_saved_pc(p); 415 do { 416 int ret = unwind_frame(&frame); 417 if (ret < 0) 418 return 0; 419 if (!in_sched_functions(frame.pc)) 420 return frame.pc; 421 } while (count ++ < 16); 422 return 0; 423 } 424