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_power_off)(void); 118 EXPORT_SYMBOL(pm_power_off); 119 120 void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart; 121 EXPORT_SYMBOL_GPL(arm_pm_restart); 122 123 124 /* 125 * This is our default idle handler. We need to disable 126 * interrupts here to ensure we don't miss a wakeup call. 127 */ 128 static void default_idle(void) 129 { 130 if (!need_resched()) 131 arch_idle(); 132 local_irq_enable(); 133 } 134 135 void (*pm_idle)(void) = default_idle; 136 EXPORT_SYMBOL(pm_idle); 137 138 /* 139 * The idle thread, has rather strange semantics for calling pm_idle, 140 * but this is what x86 does and we need to do the same, so that 141 * things like cpuidle get called in the same way. The only difference 142 * is that we always respect 'hlt_counter' to prevent low power idle. 143 */ 144 void cpu_idle(void) 145 { 146 local_fiq_enable(); 147 148 /* endless idle loop with no priority at all */ 149 while (1) { 150 tick_nohz_stop_sched_tick(1); 151 leds_event(led_idle_start); 152 while (!need_resched()) { 153 #ifdef CONFIG_HOTPLUG_CPU 154 if (cpu_is_offline(smp_processor_id())) 155 cpu_die(); 156 #endif 157 158 local_irq_disable(); 159 if (hlt_counter) { 160 local_irq_enable(); 161 cpu_relax(); 162 } else { 163 stop_critical_timings(); 164 pm_idle(); 165 start_critical_timings(); 166 /* 167 * This will eventually be removed - pm_idle 168 * functions should always return with IRQs 169 * enabled. 170 */ 171 WARN_ON(irqs_disabled()); 172 local_irq_enable(); 173 } 174 } 175 leds_event(led_idle_end); 176 tick_nohz_restart_sched_tick(); 177 preempt_enable_no_resched(); 178 schedule(); 179 preempt_disable(); 180 } 181 } 182 183 static char reboot_mode = 'h'; 184 185 int __init reboot_setup(char *str) 186 { 187 reboot_mode = str[0]; 188 return 1; 189 } 190 191 __setup("reboot=", reboot_setup); 192 193 void machine_halt(void) 194 { 195 } 196 197 198 void machine_power_off(void) 199 { 200 if (pm_power_off) 201 pm_power_off(); 202 } 203 204 void machine_restart(char *cmd) 205 { 206 arm_pm_restart(reboot_mode, cmd); 207 } 208 209 void __show_regs(struct pt_regs *regs) 210 { 211 unsigned long flags; 212 char buf[64]; 213 214 printk("CPU: %d %s (%s %.*s)\n", 215 raw_smp_processor_id(), print_tainted(), 216 init_utsname()->release, 217 (int)strcspn(init_utsname()->version, " "), 218 init_utsname()->version); 219 print_symbol("PC is at %s\n", instruction_pointer(regs)); 220 print_symbol("LR is at %s\n", regs->ARM_lr); 221 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n" 222 "sp : %08lx ip : %08lx fp : %08lx\n", 223 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr, 224 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 225 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 226 regs->ARM_r10, regs->ARM_r9, 227 regs->ARM_r8); 228 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 229 regs->ARM_r7, regs->ARM_r6, 230 regs->ARM_r5, regs->ARM_r4); 231 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 232 regs->ARM_r3, regs->ARM_r2, 233 regs->ARM_r1, regs->ARM_r0); 234 235 flags = regs->ARM_cpsr; 236 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 237 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 238 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 239 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 240 buf[4] = '\0'; 241 242 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 243 buf, interrupts_enabled(regs) ? "n" : "ff", 244 fast_interrupts_enabled(regs) ? "n" : "ff", 245 processor_modes[processor_mode(regs)], 246 isa_modes[isa_mode(regs)], 247 get_fs() == get_ds() ? "kernel" : "user"); 248 #ifdef CONFIG_CPU_CP15 249 { 250 unsigned int ctrl; 251 252 buf[0] = '\0'; 253 #ifdef CONFIG_CPU_CP15_MMU 254 { 255 unsigned int transbase, dac; 256 asm("mrc p15, 0, %0, c2, c0\n\t" 257 "mrc p15, 0, %1, c3, c0\n" 258 : "=r" (transbase), "=r" (dac)); 259 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 260 transbase, dac); 261 } 262 #endif 263 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 264 265 printk("Control: %08x%s\n", ctrl, buf); 266 } 267 #endif 268 } 269 270 void show_regs(struct pt_regs * regs) 271 { 272 printk("\n"); 273 printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm); 274 __show_regs(regs); 275 __backtrace(); 276 } 277 278 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 279 280 EXPORT_SYMBOL_GPL(thread_notify_head); 281 282 /* 283 * Free current thread data structures etc.. 284 */ 285 void exit_thread(void) 286 { 287 thread_notify(THREAD_NOTIFY_EXIT, current_thread_info()); 288 } 289 290 void flush_thread(void) 291 { 292 struct thread_info *thread = current_thread_info(); 293 struct task_struct *tsk = current; 294 295 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 296 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 297 memset(&thread->fpstate, 0, sizeof(union fp_state)); 298 299 thread_notify(THREAD_NOTIFY_FLUSH, thread); 300 } 301 302 void release_thread(struct task_struct *dead_task) 303 { 304 } 305 306 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 307 308 int 309 copy_thread(unsigned long clone_flags, unsigned long stack_start, 310 unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs) 311 { 312 struct thread_info *thread = task_thread_info(p); 313 struct pt_regs *childregs = task_pt_regs(p); 314 315 *childregs = *regs; 316 childregs->ARM_r0 = 0; 317 childregs->ARM_sp = stack_start; 318 319 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 320 thread->cpu_context.sp = (unsigned long)childregs; 321 thread->cpu_context.pc = (unsigned long)ret_from_fork; 322 323 if (clone_flags & CLONE_SETTLS) 324 thread->tp_value = regs->ARM_r3; 325 326 return 0; 327 } 328 329 /* 330 * Fill in the task's elfregs structure for a core dump. 331 */ 332 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs) 333 { 334 elf_core_copy_regs(elfregs, task_pt_regs(t)); 335 return 1; 336 } 337 338 /* 339 * fill in the fpe structure for a core dump... 340 */ 341 int dump_fpu (struct pt_regs *regs, struct user_fp *fp) 342 { 343 struct thread_info *thread = current_thread_info(); 344 int used_math = thread->used_cp[1] | thread->used_cp[2]; 345 346 if (used_math) 347 memcpy(fp, &thread->fpstate.soft, sizeof (*fp)); 348 349 return used_math != 0; 350 } 351 EXPORT_SYMBOL(dump_fpu); 352 353 /* 354 * Shuffle the argument into the correct register before calling the 355 * thread function. r1 is the thread argument, r2 is the pointer to 356 * the thread function, and r3 points to the exit function. 357 */ 358 extern void kernel_thread_helper(void); 359 asm( ".section .text\n" 360 " .align\n" 361 " .type kernel_thread_helper, #function\n" 362 "kernel_thread_helper:\n" 363 " mov r0, r1\n" 364 " mov lr, r3\n" 365 " mov pc, r2\n" 366 " .size kernel_thread_helper, . - kernel_thread_helper\n" 367 " .previous"); 368 369 #ifdef CONFIG_ARM_UNWIND 370 extern void kernel_thread_exit(long code); 371 asm( ".section .text\n" 372 " .align\n" 373 " .type kernel_thread_exit, #function\n" 374 "kernel_thread_exit:\n" 375 " .fnstart\n" 376 " .cantunwind\n" 377 " bl do_exit\n" 378 " nop\n" 379 " .fnend\n" 380 " .size kernel_thread_exit, . - kernel_thread_exit\n" 381 " .previous"); 382 #else 383 #define kernel_thread_exit do_exit 384 #endif 385 386 /* 387 * Create a kernel thread. 388 */ 389 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) 390 { 391 struct pt_regs regs; 392 393 memset(®s, 0, sizeof(regs)); 394 395 regs.ARM_r1 = (unsigned long)arg; 396 regs.ARM_r2 = (unsigned long)fn; 397 regs.ARM_r3 = (unsigned long)kernel_thread_exit; 398 regs.ARM_pc = (unsigned long)kernel_thread_helper; 399 regs.ARM_cpsr = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE; 400 401 return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); 402 } 403 EXPORT_SYMBOL(kernel_thread); 404 405 unsigned long get_wchan(struct task_struct *p) 406 { 407 struct stackframe frame; 408 int count = 0; 409 if (!p || p == current || p->state == TASK_RUNNING) 410 return 0; 411 412 frame.fp = thread_saved_fp(p); 413 frame.sp = thread_saved_sp(p); 414 frame.lr = 0; /* recovered from the stack */ 415 frame.pc = thread_saved_pc(p); 416 do { 417 int ret = unwind_frame(&frame); 418 if (ret < 0) 419 return 0; 420 if (!in_sched_functions(frame.pc)) 421 return frame.pc; 422 } while (count ++ < 16); 423 return 0; 424 } 425