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Linux/arch/arm/kernel/process.c

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  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         local_irq_disable();
201         smp_send_stop();
202 
203         local_irq_disable();
204         while (1);
205 }
206 
207 /*
208  * Power-off simply requires that the secondary CPUs stop performing any
209  * activity (executing tasks, handling interrupts). smp_send_stop()
210  * achieves this. When the system power is turned off, it will take all CPUs
211  * with it.
212  */
213 void machine_power_off(void)
214 {
215         local_irq_disable();
216         smp_send_stop();
217 
218         if (pm_power_off)
219                 pm_power_off();
220 }
221 
222 /*
223  * Restart requires that the secondary CPUs stop performing any activity
224  * while the primary CPU resets the system. Systems with a single CPU can
225  * use soft_restart() as their machine descriptor's .restart hook, since that
226  * will cause the only available CPU to reset. Systems with multiple CPUs must
227  * provide a HW restart implementation, to ensure that all CPUs reset at once.
228  * This is required so that any code running after reset on the primary CPU
229  * doesn't have to co-ordinate with other CPUs to ensure they aren't still
230  * executing pre-reset code, and using RAM that the primary CPU's code wishes
231  * to use. Implementing such co-ordination would be essentially impossible.
232  */
233 void machine_restart(char *cmd)
234 {
235         local_irq_disable();
236         smp_send_stop();
237 
238         arm_pm_restart(reboot_mode, cmd);
239 
240         /* Give a grace period for failure to restart of 1s */
241         mdelay(1000);
242 
243         /* Whoops - the platform was unable to reboot. Tell the user! */
244         printk("Reboot failed -- System halted\n");
245         local_irq_disable();
246         while (1);
247 }
248 
249 void __show_regs(struct pt_regs *regs)
250 {
251         unsigned long flags;
252         char buf[64];
253 
254         show_regs_print_info(KERN_DEFAULT);
255 
256         print_symbol("PC is at %s\n", instruction_pointer(regs));
257         print_symbol("LR is at %s\n", regs->ARM_lr);
258         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
259                "sp : %08lx  ip : %08lx  fp : %08lx\n",
260                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
261                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
262         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
263                 regs->ARM_r10, regs->ARM_r9,
264                 regs->ARM_r8);
265         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
266                 regs->ARM_r7, regs->ARM_r6,
267                 regs->ARM_r5, regs->ARM_r4);
268         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
269                 regs->ARM_r3, regs->ARM_r2,
270                 regs->ARM_r1, regs->ARM_r0);
271 
272         flags = regs->ARM_cpsr;
273         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
274         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
275         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
276         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
277         buf[4] = '\0';
278 
279         printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
280                 buf, interrupts_enabled(regs) ? "n" : "ff",
281                 fast_interrupts_enabled(regs) ? "n" : "ff",
282                 processor_modes[processor_mode(regs)],
283                 isa_modes[isa_mode(regs)],
284                 get_fs() == get_ds() ? "kernel" : "user");
285 #ifdef CONFIG_CPU_CP15
286         {
287                 unsigned int ctrl;
288 
289                 buf[0] = '\0';
290 #ifdef CONFIG_CPU_CP15_MMU
291                 {
292                         unsigned int transbase, dac;
293                         asm("mrc p15, 0, %0, c2, c0\n\t"
294                             "mrc p15, 0, %1, c3, c0\n"
295                             : "=r" (transbase), "=r" (dac));
296                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
297                                 transbase, dac);
298                 }
299 #endif
300                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
301 
302                 printk("Control: %08x%s\n", ctrl, buf);
303         }
304 #endif
305 }
306 
307 void show_regs(struct pt_regs * regs)
308 {
309         printk("\n");
310         __show_regs(regs);
311         dump_stack();
312 }
313 
314 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
315 
316 EXPORT_SYMBOL_GPL(thread_notify_head);
317 
318 /*
319  * Free current thread data structures etc..
320  */
321 void exit_thread(void)
322 {
323         thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
324 }
325 
326 void flush_thread(void)
327 {
328         struct thread_info *thread = current_thread_info();
329         struct task_struct *tsk = current;
330 
331         flush_ptrace_hw_breakpoint(tsk);
332 
333         memset(thread->used_cp, 0, sizeof(thread->used_cp));
334         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
335         memset(&thread->fpstate, 0, sizeof(union fp_state));
336 
337         thread_notify(THREAD_NOTIFY_FLUSH, thread);
338 }
339 
340 void release_thread(struct task_struct *dead_task)
341 {
342 }
343 
344 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
345 
346 int
347 copy_thread(unsigned long clone_flags, unsigned long stack_start,
348             unsigned long stk_sz, struct task_struct *p)
349 {
350         struct thread_info *thread = task_thread_info(p);
351         struct pt_regs *childregs = task_pt_regs(p);
352 
353         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
354 
355         if (likely(!(p->flags & PF_KTHREAD))) {
356                 *childregs = *current_pt_regs();
357                 childregs->ARM_r0 = 0;
358                 if (stack_start)
359                         childregs->ARM_sp = stack_start;
360         } else {
361                 memset(childregs, 0, sizeof(struct pt_regs));
362                 thread->cpu_context.r4 = stk_sz;
363                 thread->cpu_context.r5 = stack_start;
364                 childregs->ARM_cpsr = SVC_MODE;
365         }
366         thread->cpu_context.pc = (unsigned long)ret_from_fork;
367         thread->cpu_context.sp = (unsigned long)childregs;
368 
369         clear_ptrace_hw_breakpoint(p);
370 
371         if (clone_flags & CLONE_SETTLS)
372                 thread->tp_value[0] = childregs->ARM_r3;
373         thread->tp_value[1] = get_tpuser();
374 
375         thread_notify(THREAD_NOTIFY_COPY, thread);
376 
377         return 0;
378 }
379 
380 /*
381  * Fill in the task's elfregs structure for a core dump.
382  */
383 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
384 {
385         elf_core_copy_regs(elfregs, task_pt_regs(t));
386         return 1;
387 }
388 
389 /*
390  * fill in the fpe structure for a core dump...
391  */
392 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
393 {
394         struct thread_info *thread = current_thread_info();
395         int used_math = thread->used_cp[1] | thread->used_cp[2];
396 
397         if (used_math)
398                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
399 
400         return used_math != 0;
401 }
402 EXPORT_SYMBOL(dump_fpu);
403 
404 unsigned long get_wchan(struct task_struct *p)
405 {
406         struct stackframe frame;
407         unsigned long stack_page;
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         stack_page = (unsigned long)task_stack_page(p);
417         do {
418                 if (frame.sp < stack_page ||
419                     frame.sp >= stack_page + THREAD_SIZE ||
420                     unwind_frame(&frame) < 0)
421                         return 0;
422                 if (!in_sched_functions(frame.pc))
423                         return frame.pc;
424         } while (count ++ < 16);
425         return 0;
426 }
427 
428 unsigned long arch_randomize_brk(struct mm_struct *mm)
429 {
430         unsigned long range_end = mm->brk + 0x02000000;
431         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
432 }
433 
434 #ifdef CONFIG_MMU
435 #ifdef CONFIG_KUSER_HELPERS
436 /*
437  * The vectors page is always readable from user space for the
438  * atomic helpers. Insert it into the gate_vma so that it is visible
439  * through ptrace and /proc/<pid>/mem.
440  */
441 static struct vm_area_struct gate_vma = {
442         .vm_start       = 0xffff0000,
443         .vm_end         = 0xffff0000 + PAGE_SIZE,
444         .vm_flags       = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
445 };
446 
447 static int __init gate_vma_init(void)
448 {
449         gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
450         return 0;
451 }
452 arch_initcall(gate_vma_init);
453 
454 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
455 {
456         return &gate_vma;
457 }
458 
459 int in_gate_area(struct mm_struct *mm, unsigned long addr)
460 {
461         return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
462 }
463 
464 int in_gate_area_no_mm(unsigned long addr)
465 {
466         return in_gate_area(NULL, addr);
467 }
468 #define is_gate_vma(vma)        ((vma) == &gate_vma)
469 #else
470 #define is_gate_vma(vma)        0
471 #endif
472 
473 const char *arch_vma_name(struct vm_area_struct *vma)
474 {
475         return is_gate_vma(vma) ? "[vectors]" :
476                 (vma->vm_mm && vma->vm_start == vma->vm_mm->context.sigpage) ?
477                  "[sigpage]" : NULL;
478 }
479 
480 static struct page *signal_page;
481 extern struct page *get_signal_page(void);
482 
483 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
484 {
485         struct mm_struct *mm = current->mm;
486         unsigned long addr;
487         int ret;
488 
489         if (!signal_page)
490                 signal_page = get_signal_page();
491         if (!signal_page)
492                 return -ENOMEM;
493 
494         down_write(&mm->mmap_sem);
495         addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
496         if (IS_ERR_VALUE(addr)) {
497                 ret = addr;
498                 goto up_fail;
499         }
500 
501         ret = install_special_mapping(mm, addr, PAGE_SIZE,
502                 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
503                 &signal_page);
504 
505         if (ret == 0)
506                 mm->context.sigpage = addr;
507 
508  up_fail:
509         up_write(&mm->mmap_sem);
510         return ret;
511 }
512 #endif
513 

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