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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/sched/debug.h>
 16 #include <linux/sched/task.h>
 17 #include <linux/sched/task_stack.h>
 18 #include <linux/kernel.h>
 19 #include <linux/mm.h>
 20 #include <linux/stddef.h>
 21 #include <linux/unistd.h>
 22 #include <linux/user.h>
 23 #include <linux/interrupt.h>
 24 #include <linux/init.h>
 25 #include <linux/elfcore.h>
 26 #include <linux/pm.h>
 27 #include <linux/tick.h>
 28 #include <linux/utsname.h>
 29 #include <linux/uaccess.h>
 30 #include <linux/random.h>
 31 #include <linux/hw_breakpoint.h>
 32 #include <linux/leds.h>
 33 
 34 #include <asm/processor.h>
 35 #include <asm/thread_notify.h>
 36 #include <asm/stacktrace.h>
 37 #include <asm/system_misc.h>
 38 #include <asm/mach/time.h>
 39 #include <asm/tls.h>
 40 #include <asm/vdso.h>
 41 
 42 #ifdef CONFIG_STACKPROTECTOR
 43 #include <linux/stackprotector.h>
 44 unsigned long __stack_chk_guard __read_mostly;
 45 EXPORT_SYMBOL(__stack_chk_guard);
 46 #endif
 47 
 48 static const char *processor_modes[] __maybe_unused = {
 49   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
 50   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
 51   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
 52   "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
 53 };
 54 
 55 static const char *isa_modes[] __maybe_unused = {
 56   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
 57 };
 58 
 59 /*
 60  * This is our default idle handler.
 61  */
 62 
 63 void (*arm_pm_idle)(void);
 64 
 65 /*
 66  * Called from the core idle loop.
 67  */
 68 
 69 void arch_cpu_idle(void)
 70 {
 71         if (arm_pm_idle)
 72                 arm_pm_idle();
 73         else
 74                 cpu_do_idle();
 75         local_irq_enable();
 76 }
 77 
 78 void arch_cpu_idle_prepare(void)
 79 {
 80         local_fiq_enable();
 81 }
 82 
 83 void arch_cpu_idle_enter(void)
 84 {
 85         ledtrig_cpu(CPU_LED_IDLE_START);
 86 #ifdef CONFIG_PL310_ERRATA_769419
 87         wmb();
 88 #endif
 89 }
 90 
 91 void arch_cpu_idle_exit(void)
 92 {
 93         ledtrig_cpu(CPU_LED_IDLE_END);
 94 }
 95 
 96 void __show_regs(struct pt_regs *regs)
 97 {
 98         unsigned long flags;
 99         char buf[64];
100 #ifndef CONFIG_CPU_V7M
101         unsigned int domain, fs;
102 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
103         /*
104          * Get the domain register for the parent context. In user
105          * mode, we don't save the DACR, so lets use what it should
106          * be. For other modes, we place it after the pt_regs struct.
107          */
108         if (user_mode(regs)) {
109                 domain = DACR_UACCESS_ENABLE;
110                 fs = get_fs();
111         } else {
112                 domain = to_svc_pt_regs(regs)->dacr;
113                 fs = to_svc_pt_regs(regs)->addr_limit;
114         }
115 #else
116         domain = get_domain();
117         fs = get_fs();
118 #endif
119 #endif
120 
121         show_regs_print_info(KERN_DEFAULT);
122 
123         printk("PC is at %pS\n", (void *)instruction_pointer(regs));
124         printk("LR is at %pS\n", (void *)regs->ARM_lr);
125         printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n",
126                regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
127         printk("sp : %08lx  ip : %08lx  fp : %08lx\n",
128                regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
129         printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
130                 regs->ARM_r10, regs->ARM_r9,
131                 regs->ARM_r8);
132         printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
133                 regs->ARM_r7, regs->ARM_r6,
134                 regs->ARM_r5, regs->ARM_r4);
135         printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
136                 regs->ARM_r3, regs->ARM_r2,
137                 regs->ARM_r1, regs->ARM_r0);
138 
139         flags = regs->ARM_cpsr;
140         buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
141         buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
142         buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
143         buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
144         buf[4] = '\0';
145 
146 #ifndef CONFIG_CPU_V7M
147         {
148                 const char *segment;
149 
150                 if ((domain & domain_mask(DOMAIN_USER)) ==
151                     domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
152                         segment = "none";
153                 else if (fs == get_ds())
154                         segment = "kernel";
155                 else
156                         segment = "user";
157 
158                 printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
159                         buf, interrupts_enabled(regs) ? "n" : "ff",
160                         fast_interrupts_enabled(regs) ? "n" : "ff",
161                         processor_modes[processor_mode(regs)],
162                         isa_modes[isa_mode(regs)], segment);
163         }
164 #else
165         printk("xPSR: %08lx\n", regs->ARM_cpsr);
166 #endif
167 
168 #ifdef CONFIG_CPU_CP15
169         {
170                 unsigned int ctrl;
171 
172                 buf[0] = '\0';
173 #ifdef CONFIG_CPU_CP15_MMU
174                 {
175                         unsigned int transbase;
176                         asm("mrc p15, 0, %0, c2, c0\n\t"
177                             : "=r" (transbase));
178                         snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
179                                 transbase, domain);
180                 }
181 #endif
182                 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
183 
184                 printk("Control: %08x%s\n", ctrl, buf);
185         }
186 #endif
187 }
188 
189 void show_regs(struct pt_regs * regs)
190 {
191         __show_regs(regs);
192         dump_stack();
193 }
194 
195 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
196 
197 EXPORT_SYMBOL_GPL(thread_notify_head);
198 
199 /*
200  * Free current thread data structures etc..
201  */
202 void exit_thread(struct task_struct *tsk)
203 {
204         thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
205 }
206 
207 void flush_thread(void)
208 {
209         struct thread_info *thread = current_thread_info();
210         struct task_struct *tsk = current;
211 
212         flush_ptrace_hw_breakpoint(tsk);
213 
214         memset(thread->used_cp, 0, sizeof(thread->used_cp));
215         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
216         memset(&thread->fpstate, 0, sizeof(union fp_state));
217 
218         flush_tls();
219 
220         thread_notify(THREAD_NOTIFY_FLUSH, thread);
221 }
222 
223 void release_thread(struct task_struct *dead_task)
224 {
225 }
226 
227 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
228 
229 int
230 copy_thread(unsigned long clone_flags, unsigned long stack_start,
231             unsigned long stk_sz, struct task_struct *p)
232 {
233         struct thread_info *thread = task_thread_info(p);
234         struct pt_regs *childregs = task_pt_regs(p);
235 
236         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
237 
238 #ifdef CONFIG_CPU_USE_DOMAINS
239         /*
240          * Copy the initial value of the domain access control register
241          * from the current thread: thread->addr_limit will have been
242          * copied from the current thread via setup_thread_stack() in
243          * kernel/fork.c
244          */
245         thread->cpu_domain = get_domain();
246 #endif
247 
248         if (likely(!(p->flags & PF_KTHREAD))) {
249                 *childregs = *current_pt_regs();
250                 childregs->ARM_r0 = 0;
251                 if (stack_start)
252                         childregs->ARM_sp = stack_start;
253         } else {
254                 memset(childregs, 0, sizeof(struct pt_regs));
255                 thread->cpu_context.r4 = stk_sz;
256                 thread->cpu_context.r5 = stack_start;
257                 childregs->ARM_cpsr = SVC_MODE;
258         }
259         thread->cpu_context.pc = (unsigned long)ret_from_fork;
260         thread->cpu_context.sp = (unsigned long)childregs;
261 
262         clear_ptrace_hw_breakpoint(p);
263 
264         if (clone_flags & CLONE_SETTLS)
265                 thread->tp_value[0] = childregs->ARM_r3;
266         thread->tp_value[1] = get_tpuser();
267 
268         thread_notify(THREAD_NOTIFY_COPY, thread);
269 
270         return 0;
271 }
272 
273 /*
274  * Fill in the task's elfregs structure for a core dump.
275  */
276 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
277 {
278         elf_core_copy_regs(elfregs, task_pt_regs(t));
279         return 1;
280 }
281 
282 /*
283  * fill in the fpe structure for a core dump...
284  */
285 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
286 {
287         struct thread_info *thread = current_thread_info();
288         int used_math = thread->used_cp[1] | thread->used_cp[2];
289 
290         if (used_math)
291                 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
292 
293         return used_math != 0;
294 }
295 EXPORT_SYMBOL(dump_fpu);
296 
297 unsigned long get_wchan(struct task_struct *p)
298 {
299         struct stackframe frame;
300         unsigned long stack_page;
301         int count = 0;
302         if (!p || p == current || p->state == TASK_RUNNING)
303                 return 0;
304 
305         frame.fp = thread_saved_fp(p);
306         frame.sp = thread_saved_sp(p);
307         frame.lr = 0;                   /* recovered from the stack */
308         frame.pc = thread_saved_pc(p);
309         stack_page = (unsigned long)task_stack_page(p);
310         do {
311                 if (frame.sp < stack_page ||
312                     frame.sp >= stack_page + THREAD_SIZE ||
313                     unwind_frame(&frame) < 0)
314                         return 0;
315                 if (!in_sched_functions(frame.pc))
316                         return frame.pc;
317         } while (count ++ < 16);
318         return 0;
319 }
320 
321 unsigned long arch_randomize_brk(struct mm_struct *mm)
322 {
323         return randomize_page(mm->brk, 0x02000000);
324 }
325 
326 #ifdef CONFIG_MMU
327 #ifdef CONFIG_KUSER_HELPERS
328 /*
329  * The vectors page is always readable from user space for the
330  * atomic helpers. Insert it into the gate_vma so that it is visible
331  * through ptrace and /proc/<pid>/mem.
332  */
333 static struct vm_area_struct gate_vma;
334 
335 static int __init gate_vma_init(void)
336 {
337         vma_init(&gate_vma, NULL);
338         gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
339         gate_vma.vm_start = 0xffff0000;
340         gate_vma.vm_end = 0xffff0000 + PAGE_SIZE;
341         gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC;
342         return 0;
343 }
344 arch_initcall(gate_vma_init);
345 
346 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
347 {
348         return &gate_vma;
349 }
350 
351 int in_gate_area(struct mm_struct *mm, unsigned long addr)
352 {
353         return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
354 }
355 
356 int in_gate_area_no_mm(unsigned long addr)
357 {
358         return in_gate_area(NULL, addr);
359 }
360 #define is_gate_vma(vma)        ((vma) == &gate_vma)
361 #else
362 #define is_gate_vma(vma)        0
363 #endif
364 
365 const char *arch_vma_name(struct vm_area_struct *vma)
366 {
367         return is_gate_vma(vma) ? "[vectors]" : NULL;
368 }
369 
370 /* If possible, provide a placement hint at a random offset from the
371  * stack for the sigpage and vdso pages.
372  */
373 static unsigned long sigpage_addr(const struct mm_struct *mm,
374                                   unsigned int npages)
375 {
376         unsigned long offset;
377         unsigned long first;
378         unsigned long last;
379         unsigned long addr;
380         unsigned int slots;
381 
382         first = PAGE_ALIGN(mm->start_stack);
383 
384         last = TASK_SIZE - (npages << PAGE_SHIFT);
385 
386         /* No room after stack? */
387         if (first > last)
388                 return 0;
389 
390         /* Just enough room? */
391         if (first == last)
392                 return first;
393 
394         slots = ((last - first) >> PAGE_SHIFT) + 1;
395 
396         offset = get_random_int() % slots;
397 
398         addr = first + (offset << PAGE_SHIFT);
399 
400         return addr;
401 }
402 
403 static struct page *signal_page;
404 extern struct page *get_signal_page(void);
405 
406 static int sigpage_mremap(const struct vm_special_mapping *sm,
407                 struct vm_area_struct *new_vma)
408 {
409         current->mm->context.sigpage = new_vma->vm_start;
410         return 0;
411 }
412 
413 static const struct vm_special_mapping sigpage_mapping = {
414         .name = "[sigpage]",
415         .pages = &signal_page,
416         .mremap = sigpage_mremap,
417 };
418 
419 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
420 {
421         struct mm_struct *mm = current->mm;
422         struct vm_area_struct *vma;
423         unsigned long npages;
424         unsigned long addr;
425         unsigned long hint;
426         int ret = 0;
427 
428         if (!signal_page)
429                 signal_page = get_signal_page();
430         if (!signal_page)
431                 return -ENOMEM;
432 
433         npages = 1; /* for sigpage */
434         npages += vdso_total_pages;
435 
436         if (down_write_killable(&mm->mmap_sem))
437                 return -EINTR;
438         hint = sigpage_addr(mm, npages);
439         addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
440         if (IS_ERR_VALUE(addr)) {
441                 ret = addr;
442                 goto up_fail;
443         }
444 
445         vma = _install_special_mapping(mm, addr, PAGE_SIZE,
446                 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
447                 &sigpage_mapping);
448 
449         if (IS_ERR(vma)) {
450                 ret = PTR_ERR(vma);
451                 goto up_fail;
452         }
453 
454         mm->context.sigpage = addr;
455 
456         /* Unlike the sigpage, failure to install the vdso is unlikely
457          * to be fatal to the process, so no error check needed
458          * here.
459          */
460         arm_install_vdso(mm, addr + PAGE_SIZE);
461 
462  up_fail:
463         up_write(&mm->mmap_sem);
464         return ret;
465 }
466 #endif
467 

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