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/export.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 #include <linux/random.h> 32 #include <linux/hw_breakpoint.h> 33 #include <linux/cpuidle.h> 34 #include <linux/leds.h> 35 #include <linux/reboot.h> 36 37 #include <asm/cacheflush.h> 38 #include <asm/idmap.h> 39 #include <asm/processor.h> 40 #include <asm/thread_notify.h> 41 #include <asm/stacktrace.h> 42 #include <asm/mach/time.h> 43 #include <asm/tls.h> 44 45 #ifdef CONFIG_CC_STACKPROTECTOR 46 #include <linux/stackprotector.h> 47 unsigned long __stack_chk_guard __read_mostly; 48 EXPORT_SYMBOL(__stack_chk_guard); 49 #endif 50 51 static const char *processor_modes[] = { 52 "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" , 53 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26", 54 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" , 55 "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32" 56 }; 57 58 static const char *isa_modes[] = { 59 "ARM" , "Thumb" , "Jazelle", "ThumbEE" 60 }; 61 62 extern void call_with_stack(void (*fn)(void *), void *arg, void *sp); 63 typedef void (*phys_reset_t)(unsigned long); 64 65 /* 66 * A temporary stack to use for CPU reset. This is static so that we 67 * don't clobber it with the identity mapping. When running with this 68 * stack, any references to the current task *will not work* so you 69 * should really do as little as possible before jumping to your reset 70 * code. 71 */ 72 static u64 soft_restart_stack[16]; 73 74 static void __soft_restart(void *addr) 75 { 76 phys_reset_t phys_reset; 77 78 /* Take out a flat memory mapping. */ 79 setup_mm_for_reboot(); 80 81 /* Clean and invalidate caches */ 82 flush_cache_all(); 83 84 /* Turn off caching */ 85 cpu_proc_fin(); 86 87 /* Push out any further dirty data, and ensure cache is empty */ 88 flush_cache_all(); 89 90 /* Switch to the identity mapping. */ 91 phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset); 92 phys_reset((unsigned long)addr); 93 94 /* Should never get here. */ 95 BUG(); 96 } 97 98 void soft_restart(unsigned long addr) 99 { 100 u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack); 101 102 /* Disable interrupts first */ 103 local_irq_disable(); 104 local_fiq_disable(); 105 106 /* Disable the L2 if we're the last man standing. */ 107 if (num_online_cpus() == 1) 108 outer_disable(); 109 110 /* Change to the new stack and continue with the reset. */ 111 call_with_stack(__soft_restart, (void *)addr, (void *)stack); 112 113 /* Should never get here. */ 114 BUG(); 115 } 116 117 static void null_restart(enum reboot_mode reboot_mode, const char *cmd) 118 { 119 } 120 121 /* 122 * Function pointers to optional machine specific functions 123 */ 124 void (*pm_power_off)(void); 125 EXPORT_SYMBOL(pm_power_off); 126 127 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd) = null_restart; 128 EXPORT_SYMBOL_GPL(arm_pm_restart); 129 130 /* 131 * This is our default idle handler. 132 */ 133 134 void (*arm_pm_idle)(void); 135 136 static void default_idle(void) 137 { 138 if (arm_pm_idle) 139 arm_pm_idle(); 140 else 141 cpu_do_idle(); 142 local_irq_enable(); 143 } 144 145 void arch_cpu_idle_prepare(void) 146 { 147 local_fiq_enable(); 148 } 149 150 void arch_cpu_idle_enter(void) 151 { 152 ledtrig_cpu(CPU_LED_IDLE_START); 153 #ifdef CONFIG_PL310_ERRATA_769419 154 wmb(); 155 #endif 156 } 157 158 void arch_cpu_idle_exit(void) 159 { 160 ledtrig_cpu(CPU_LED_IDLE_END); 161 } 162 163 #ifdef CONFIG_HOTPLUG_CPU 164 void arch_cpu_idle_dead(void) 165 { 166 cpu_die(); 167 } 168 #endif 169 170 /* 171 * Called from the core idle loop. 172 */ 173 void arch_cpu_idle(void) 174 { 175 if (cpuidle_idle_call()) 176 default_idle(); 177 } 178 179 /* 180 * Called by kexec, immediately prior to machine_kexec(). 181 * 182 * This must completely disable all secondary CPUs; simply causing those CPUs 183 * to execute e.g. a RAM-based pin loop is not sufficient. This allows the 184 * kexec'd kernel to use any and all RAM as it sees fit, without having to 185 * avoid any code or data used by any SW CPU pin loop. The CPU hotplug 186 * functionality embodied in disable_nonboot_cpus() to achieve this. 187 */ 188 void machine_shutdown(void) 189 { 190 disable_nonboot_cpus(); 191 } 192 193 /* 194 * Halting simply requires that the secondary CPUs stop performing any 195 * activity (executing tasks, handling interrupts). smp_send_stop() 196 * achieves this. 197 */ 198 void machine_halt(void) 199 { 200 smp_send_stop(); 201 202 local_irq_disable(); 203 while (1); 204 } 205 206 /* 207 * Power-off simply requires that the secondary CPUs stop performing any 208 * activity (executing tasks, handling interrupts). smp_send_stop() 209 * achieves this. When the system power is turned off, it will take all CPUs 210 * with it. 211 */ 212 void machine_power_off(void) 213 { 214 smp_send_stop(); 215 216 if (pm_power_off) 217 pm_power_off(); 218 } 219 220 /* 221 * Restart requires that the secondary CPUs stop performing any activity 222 * while the primary CPU resets the system. Systems with a single CPU can 223 * use soft_restart() as their machine descriptor's .restart hook, since that 224 * will cause the only available CPU to reset. Systems with multiple CPUs must 225 * provide a HW restart implementation, to ensure that all CPUs reset at once. 226 * This is required so that any code running after reset on the primary CPU 227 * doesn't have to co-ordinate with other CPUs to ensure they aren't still 228 * executing pre-reset code, and using RAM that the primary CPU's code wishes 229 * to use. Implementing such co-ordination would be essentially impossible. 230 */ 231 void machine_restart(char *cmd) 232 { 233 smp_send_stop(); 234 235 arm_pm_restart(reboot_mode, cmd); 236 237 /* Give a grace period for failure to restart of 1s */ 238 mdelay(1000); 239 240 /* Whoops - the platform was unable to reboot. Tell the user! */ 241 printk("Reboot failed -- System halted\n"); 242 local_irq_disable(); 243 while (1); 244 } 245 246 void __show_regs(struct pt_regs *regs) 247 { 248 unsigned long flags; 249 char buf[64]; 250 251 show_regs_print_info(KERN_DEFAULT); 252 253 print_symbol("PC is at %s\n", instruction_pointer(regs)); 254 print_symbol("LR is at %s\n", regs->ARM_lr); 255 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n" 256 "sp : %08lx ip : %08lx fp : %08lx\n", 257 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr, 258 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp); 259 printk("r10: %08lx r9 : %08lx r8 : %08lx\n", 260 regs->ARM_r10, regs->ARM_r9, 261 regs->ARM_r8); 262 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n", 263 regs->ARM_r7, regs->ARM_r6, 264 regs->ARM_r5, regs->ARM_r4); 265 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", 266 regs->ARM_r3, regs->ARM_r2, 267 regs->ARM_r1, regs->ARM_r0); 268 269 flags = regs->ARM_cpsr; 270 buf[0] = flags & PSR_N_BIT ? 'N' : 'n'; 271 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z'; 272 buf[2] = flags & PSR_C_BIT ? 'C' : 'c'; 273 buf[3] = flags & PSR_V_BIT ? 'V' : 'v'; 274 buf[4] = '\0'; 275 276 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n", 277 buf, interrupts_enabled(regs) ? "n" : "ff", 278 fast_interrupts_enabled(regs) ? "n" : "ff", 279 processor_modes[processor_mode(regs)], 280 isa_modes[isa_mode(regs)], 281 get_fs() == get_ds() ? "kernel" : "user"); 282 #ifdef CONFIG_CPU_CP15 283 { 284 unsigned int ctrl; 285 286 buf[0] = '\0'; 287 #ifdef CONFIG_CPU_CP15_MMU 288 { 289 unsigned int transbase, dac; 290 asm("mrc p15, 0, %0, c2, c0\n\t" 291 "mrc p15, 0, %1, c3, c0\n" 292 : "=r" (transbase), "=r" (dac)); 293 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x", 294 transbase, dac); 295 } 296 #endif 297 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl)); 298 299 printk("Control: %08x%s\n", ctrl, buf); 300 } 301 #endif 302 } 303 304 void show_regs(struct pt_regs * regs) 305 { 306 printk("\n"); 307 __show_regs(regs); 308 dump_stack(); 309 } 310 311 ATOMIC_NOTIFIER_HEAD(thread_notify_head); 312 313 EXPORT_SYMBOL_GPL(thread_notify_head); 314 315 /* 316 * Free current thread data structures etc.. 317 */ 318 void exit_thread(void) 319 { 320 thread_notify(THREAD_NOTIFY_EXIT, current_thread_info()); 321 } 322 323 void flush_thread(void) 324 { 325 struct thread_info *thread = current_thread_info(); 326 struct task_struct *tsk = current; 327 328 flush_ptrace_hw_breakpoint(tsk); 329 330 memset(thread->used_cp, 0, sizeof(thread->used_cp)); 331 memset(&tsk->thread.debug, 0, sizeof(struct debug_info)); 332 memset(&thread->fpstate, 0, sizeof(union fp_state)); 333 334 thread_notify(THREAD_NOTIFY_FLUSH, thread); 335 } 336 337 void release_thread(struct task_struct *dead_task) 338 { 339 } 340 341 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); 342 343 int 344 copy_thread(unsigned long clone_flags, unsigned long stack_start, 345 unsigned long stk_sz, struct task_struct *p) 346 { 347 struct thread_info *thread = task_thread_info(p); 348 struct pt_regs *childregs = task_pt_regs(p); 349 350 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); 351 352 if (likely(!(p->flags & PF_KTHREAD))) { 353 *childregs = *current_pt_regs(); 354 childregs->ARM_r0 = 0; 355 if (stack_start) 356 childregs->ARM_sp = stack_start; 357 } else { 358 memset(childregs, 0, sizeof(struct pt_regs)); 359 thread->cpu_context.r4 = stk_sz; 360 thread->cpu_context.r5 = stack_start; 361 childregs->ARM_cpsr = SVC_MODE; 362 } 363 thread->cpu_context.pc = (unsigned long)ret_from_fork; 364 thread->cpu_context.sp = (unsigned long)childregs; 365 366 clear_ptrace_hw_breakpoint(p); 367 368 if (clone_flags & CLONE_SETTLS) 369 thread->tp_value[0] = childregs->ARM_r3; 370 thread->tp_value[1] = get_tpuser(); 371 372 thread_notify(THREAD_NOTIFY_COPY, thread); 373 374 return 0; 375 } 376 377 /* 378 * Fill in the task's elfregs structure for a core dump. 379 */ 380 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs) 381 { 382 elf_core_copy_regs(elfregs, task_pt_regs(t)); 383 return 1; 384 } 385 386 /* 387 * fill in the fpe structure for a core dump... 388 */ 389 int dump_fpu (struct pt_regs *regs, struct user_fp *fp) 390 { 391 struct thread_info *thread = current_thread_info(); 392 int used_math = thread->used_cp[1] | thread->used_cp[2]; 393 394 if (used_math) 395 memcpy(fp, &thread->fpstate.soft, sizeof (*fp)); 396 397 return used_math != 0; 398 } 399 EXPORT_SYMBOL(dump_fpu); 400 401 unsigned long get_wchan(struct task_struct *p) 402 { 403 struct stackframe frame; 404 int count = 0; 405 if (!p || p == current || p->state == TASK_RUNNING) 406 return 0; 407 408 frame.fp = thread_saved_fp(p); 409 frame.sp = thread_saved_sp(p); 410 frame.lr = 0; /* recovered from the stack */ 411 frame.pc = thread_saved_pc(p); 412 do { 413 int ret = unwind_frame(&frame); 414 if (ret < 0) 415 return 0; 416 if (!in_sched_functions(frame.pc)) 417 return frame.pc; 418 } while (count ++ < 16); 419 return 0; 420 } 421 422 unsigned long arch_randomize_brk(struct mm_struct *mm) 423 { 424 unsigned long range_end = mm->brk + 0x02000000; 425 return randomize_range(mm->brk, range_end, 0) ? : mm->brk; 426 } 427 428 #ifdef CONFIG_MMU 429 /* 430 * The vectors page is always readable from user space for the 431 * atomic helpers and the signal restart code. Insert it into the 432 * gate_vma so that it is visible through ptrace and /proc/<pid>/mem. 433 */ 434 static struct vm_area_struct gate_vma = { 435 .vm_start = 0xffff0000, 436 .vm_end = 0xffff0000 + PAGE_SIZE, 437 .vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC, 438 }; 439 440 static int __init gate_vma_init(void) 441 { 442 gate_vma.vm_page_prot = PAGE_READONLY_EXEC; 443 return 0; 444 } 445 arch_initcall(gate_vma_init); 446 447 struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 448 { 449 return &gate_vma; 450 } 451 452 int in_gate_area(struct mm_struct *mm, unsigned long addr) 453 { 454 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end); 455 } 456 457 int in_gate_area_no_mm(unsigned long addr) 458 { 459 return in_gate_area(NULL, addr); 460 } 461 462 const char *arch_vma_name(struct vm_area_struct *vma) 463 { 464 return (vma == &gate_vma) ? "[vectors]" : NULL; 465 } 466 #endif 467