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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/interrupt.h>
 21 #include <linux/kallsyms.h>
 22 #include <linux/init.h>
 23 #include <linux/elfcore.h>
 24 #include <linux/pm.h>
 25 #include <linux/tick.h>
 26 #include <linux/utsname.h>
 27 #include <linux/uaccess.h>
 28 #include <linux/random.h>
 29 #include <linux/hw_breakpoint.h>
 30 #include <linux/leds.h>
 31 
 32 #include <asm/processor.h>
 33 #include <asm/thread_notify.h>
 34 #include <asm/stacktrace.h>
 35 #include <asm/system_misc.h>
 36 #include <asm/mach/time.h>
 37 #include <asm/tls.h>
 38 #include <asm/vdso.h>
 39 
 40 #ifdef CONFIG_CC_STACKPROTECTOR
 41 #include <linux/stackprotector.h>
 42 unsigned long __stack_chk_guard __read_mostly;
 43 EXPORT_SYMBOL(__stack_chk_guard);
 44 #endif
 45 
 46 static const char *processor_modes[] __maybe_unused = {
 47   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
 48   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
 49   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
 50   "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
 51 };
 52 
 53 static const char *isa_modes[] __maybe_unused = {
 54   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
 55 };
 56 
 57 /*
 58  * This is our default idle handler.
 59  */
 60 
 61 void (*arm_pm_idle)(void);
 62 
 63 /*
 64  * Called from the core idle loop.
 65  */
 66 
 67 void arch_cpu_idle(void)
 68 {
 69         if (arm_pm_idle)
 70                 arm_pm_idle();
 71         else
 72                 cpu_do_idle();
 73         local_irq_enable();
 74 }
 75 
 76 void arch_cpu_idle_prepare(void)
 77 {
 78         local_fiq_enable();
 79 }
 80 
 81 void arch_cpu_idle_enter(void)
 82 {
 83         ledtrig_cpu(CPU_LED_IDLE_START);
 84 #ifdef CONFIG_PL310_ERRATA_769419
 85         wmb();
 86 #endif
 87 }
 88 
 89 void arch_cpu_idle_exit(void)
 90 {
 91         ledtrig_cpu(CPU_LED_IDLE_END);
 92 }
 93 
 94 void __show_regs(struct pt_regs *regs)
 95 {
 96         unsigned long flags;
 97         char buf[64];
 98 #ifndef CONFIG_CPU_V7M
 99         unsigned int domain;
100 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
101         /*
102          * Get the domain register for the parent context. In user
103          * mode, we don't save the DACR, so lets use what it should
104          * be. For other modes, we place it after the pt_regs struct.
105          */
106         if (user_mode(regs))
107                 domain = DACR_UACCESS_ENABLE;
108         else
109                 domain = *(unsigned int *)(regs + 1);
110 #else
111         domain = get_domain();
112 #endif
113 #endif
114 
115         show_regs_print_info(KERN_DEFAULT);
116 
117         print_symbol("PC is at %s\n", instruction_pointer(regs));
118         print_symbol("LR is at %s\n", regs->ARM_lr);
119         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
120                "sp : %08lx  ip : %08lx  fp : %08lx\n",
121                 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
122                 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
123         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
124                 regs->ARM_r10, regs->ARM_r9,
125                 regs->ARM_r8);
126         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
127                 regs->ARM_r7, regs->ARM_r6,
128                 regs->ARM_r5, regs->ARM_r4);
129         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
130                 regs->ARM_r3, regs->ARM_r2,
131                 regs->ARM_r1, regs->ARM_r0);
132 
133         flags = regs->ARM_cpsr;
134         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
135         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
136         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
137         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
138         buf[4] = '\0';
139 
140 #ifndef CONFIG_CPU_V7M
141         {
142                 const char *segment;
143 
144                 if ((domain & domain_mask(DOMAIN_USER)) ==
145                     domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
146                         segment = "none";
147                 else if (get_fs() == get_ds())
148                         segment = "kernel";
149                 else
150                         segment = "user";
151 
152                 printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
153                         buf, interrupts_enabled(regs) ? "n" : "ff",
154                         fast_interrupts_enabled(regs) ? "n" : "ff",
155                         processor_modes[processor_mode(regs)],
156                         isa_modes[isa_mode(regs)], segment);
157         }
158 #else
159         printk("xPSR: %08lx\n", regs->ARM_cpsr);
160 #endif
161 
162 #ifdef CONFIG_CPU_CP15
163         {
164                 unsigned int ctrl;
165 
166                 buf[0] = '\0';
167 #ifdef CONFIG_CPU_CP15_MMU
168                 {
169                         unsigned int transbase;
170                         asm("mrc p15, 0, %0, c2, c0\n\t"
171                             : "=r" (transbase));
172                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
173                                 transbase, domain);
174                 }
175 #endif
176                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
177 
178                 printk("Control: %08x%s\n", ctrl, buf);
179         }
180 #endif
181 }
182 
183 void show_regs(struct pt_regs * regs)
184 {
185         __show_regs(regs);
186         dump_stack();
187 }
188 
189 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
190 
191 EXPORT_SYMBOL_GPL(thread_notify_head);
192 
193 /*
194  * Free current thread data structures etc..
195  */
196 void exit_thread(struct task_struct *tsk)
197 {
198         thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
199 }
200 
201 void flush_thread(void)
202 {
203         struct thread_info *thread = current_thread_info();
204         struct task_struct *tsk = current;
205 
206         flush_ptrace_hw_breakpoint(tsk);
207 
208         memset(thread->used_cp, 0, sizeof(thread->used_cp));
209         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
210         memset(&thread->fpstate, 0, sizeof(union fp_state));
211 
212         flush_tls();
213 
214         thread_notify(THREAD_NOTIFY_FLUSH, thread);
215 }
216 
217 void release_thread(struct task_struct *dead_task)
218 {
219 }
220 
221 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
222 
223 int
224 copy_thread(unsigned long clone_flags, unsigned long stack_start,
225             unsigned long stk_sz, struct task_struct *p)
226 {
227         struct thread_info *thread = task_thread_info(p);
228         struct pt_regs *childregs = task_pt_regs(p);
229 
230         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
231 
232 #ifdef CONFIG_CPU_USE_DOMAINS
233         /*
234          * Copy the initial value of the domain access control register
235          * from the current thread: thread->addr_limit will have been
236          * copied from the current thread via setup_thread_stack() in
237          * kernel/fork.c
238          */
239         thread->cpu_domain = get_domain();
240 #endif
241 
242         if (likely(!(p->flags & PF_KTHREAD))) {
243                 *childregs = *current_pt_regs();
244                 childregs->ARM_r0 = 0;
245                 if (stack_start)
246                         childregs->ARM_sp = stack_start;
247         } else {
248                 memset(childregs, 0, sizeof(struct pt_regs));
249                 thread->cpu_context.r4 = stk_sz;
250                 thread->cpu_context.r5 = stack_start;
251                 childregs->ARM_cpsr = SVC_MODE;
252         }
253         thread->cpu_context.pc = (unsigned long)ret_from_fork;
254         thread->cpu_context.sp = (unsigned long)childregs;
255 
256         clear_ptrace_hw_breakpoint(p);
257 
258         if (clone_flags & CLONE_SETTLS)
259                 thread->tp_value[0] = childregs->ARM_r3;
260         thread->tp_value[1] = get_tpuser();
261 
262         thread_notify(THREAD_NOTIFY_COPY, thread);
263 
264         return 0;
265 }
266 
267 /*
268  * Fill in the task's elfregs structure for a core dump.
269  */
270 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
271 {
272         elf_core_copy_regs(elfregs, task_pt_regs(t));
273         return 1;
274 }
275 
276 /*
277  * fill in the fpe structure for a core dump...
278  */
279 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
280 {
281         struct thread_info *thread = current_thread_info();
282         int used_math = thread->used_cp[1] | thread->used_cp[2];
283 
284         if (used_math)
285                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
286 
287         return used_math != 0;
288 }
289 EXPORT_SYMBOL(dump_fpu);
290 
291 unsigned long get_wchan(struct task_struct *p)
292 {
293         struct stackframe frame;
294         unsigned long stack_page;
295         int count = 0;
296         if (!p || p == current || p->state == TASK_RUNNING)
297                 return 0;
298 
299         frame.fp = thread_saved_fp(p);
300         frame.sp = thread_saved_sp(p);
301         frame.lr = 0;                   /* recovered from the stack */
302         frame.pc = thread_saved_pc(p);
303         stack_page = (unsigned long)task_stack_page(p);
304         do {
305                 if (frame.sp < stack_page ||
306                     frame.sp >= stack_page + THREAD_SIZE ||
307                     unwind_frame(&frame) < 0)
308                         return 0;
309                 if (!in_sched_functions(frame.pc))
310                         return frame.pc;
311         } while (count ++ < 16);
312         return 0;
313 }
314 
315 unsigned long arch_randomize_brk(struct mm_struct *mm)
316 {
317         unsigned long range_end = mm->brk + 0x02000000;
318         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
319 }
320 
321 #ifdef CONFIG_MMU
322 #ifdef CONFIG_KUSER_HELPERS
323 /*
324  * The vectors page is always readable from user space for the
325  * atomic helpers. Insert it into the gate_vma so that it is visible
326  * through ptrace and /proc/<pid>/mem.
327  */
328 static struct vm_area_struct gate_vma = {
329         .vm_start       = 0xffff0000,
330         .vm_end         = 0xffff0000 + PAGE_SIZE,
331         .vm_flags       = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
332 };
333 
334 static int __init gate_vma_init(void)
335 {
336         gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
337         return 0;
338 }
339 arch_initcall(gate_vma_init);
340 
341 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
342 {
343         return &gate_vma;
344 }
345 
346 int in_gate_area(struct mm_struct *mm, unsigned long addr)
347 {
348         return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
349 }
350 
351 int in_gate_area_no_mm(unsigned long addr)
352 {
353         return in_gate_area(NULL, addr);
354 }
355 #define is_gate_vma(vma)        ((vma) == &gate_vma)
356 #else
357 #define is_gate_vma(vma)        0
358 #endif
359 
360 const char *arch_vma_name(struct vm_area_struct *vma)
361 {
362         return is_gate_vma(vma) ? "[vectors]" : NULL;
363 }
364 
365 /* If possible, provide a placement hint at a random offset from the
366  * stack for the sigpage and vdso pages.
367  */
368 static unsigned long sigpage_addr(const struct mm_struct *mm,
369                                   unsigned int npages)
370 {
371         unsigned long offset;
372         unsigned long first;
373         unsigned long last;
374         unsigned long addr;
375         unsigned int slots;
376 
377         first = PAGE_ALIGN(mm->start_stack);
378 
379         last = TASK_SIZE - (npages << PAGE_SHIFT);
380 
381         /* No room after stack? */
382         if (first > last)
383                 return 0;
384 
385         /* Just enough room? */
386         if (first == last)
387                 return first;
388 
389         slots = ((last - first) >> PAGE_SHIFT) + 1;
390 
391         offset = get_random_int() % slots;
392 
393         addr = first + (offset << PAGE_SHIFT);
394 
395         return addr;
396 }
397 
398 static struct page *signal_page;
399 extern struct page *get_signal_page(void);
400 
401 static const struct vm_special_mapping sigpage_mapping = {
402         .name = "[sigpage]",
403         .pages = &signal_page,
404 };
405 
406 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
407 {
408         struct mm_struct *mm = current->mm;
409         struct vm_area_struct *vma;
410         unsigned long npages;
411         unsigned long addr;
412         unsigned long hint;
413         int ret = 0;
414 
415         if (!signal_page)
416                 signal_page = get_signal_page();
417         if (!signal_page)
418                 return -ENOMEM;
419 
420         npages = 1; /* for sigpage */
421         npages += vdso_total_pages;
422 
423         if (down_write_killable(&mm->mmap_sem))
424                 return -EINTR;
425         hint = sigpage_addr(mm, npages);
426         addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
427         if (IS_ERR_VALUE(addr)) {
428                 ret = addr;
429                 goto up_fail;
430         }
431 
432         vma = _install_special_mapping(mm, addr, PAGE_SIZE,
433                 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
434                 &sigpage_mapping);
435 
436         if (IS_ERR(vma)) {
437                 ret = PTR_ERR(vma);
438                 goto up_fail;
439         }
440 
441         mm->context.sigpage = addr;
442 
443         /* Unlike the sigpage, failure to install the vdso is unlikely
444          * to be fatal to the process, so no error check needed
445          * here.
446          */
447         arm_install_vdso(mm, addr + PAGE_SIZE);
448 
449  up_fail:
450         up_write(&mm->mmap_sem);
451         return ret;
452 }
453 #endif
454 

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