1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/arch/arm/kernel/process.c
4 *
5 * Copyright (C) 1996-2000 Russell King - Converted to ARM.
6 * Original Copyright (C) 1995 Linus Torvalds
7 */
8 #include <stdarg.h>
9
10 #include <linux/export.h>
11 #include <linux/sched.h>
12 #include <linux/sched/debug.h>
13 #include <linux/sched/task.h>
14 #include <linux/sched/task_stack.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/init.h>
22 #include <linux/elfcore.h>
23 #include <linux/pm.h>
24 #include <linux/tick.h>
25 #include <linux/utsname.h>
26 #include <linux/uaccess.h>
27 #include <linux/random.h>
28 #include <linux/hw_breakpoint.h>
29 #include <linux/leds.h>
30
31 #include <asm/processor.h>
32 #include <asm/thread_notify.h>
33 #include <asm/stacktrace.h>
34 #include <asm/system_misc.h>
35 #include <asm/mach/time.h>
36 #include <asm/tls.h>
37 #include <asm/vdso.h>
38
39 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
40 #include <linux/stackprotector.h>
41 unsigned long __stack_chk_guard __read_mostly;
42 EXPORT_SYMBOL(__stack_chk_guard);
43 #endif
44
45 static const char *processor_modes[] __maybe_unused = {
46 "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
47 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
48 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
49 "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
50 };
51
52 static const char *isa_modes[] __maybe_unused = {
53 "ARM" , "Thumb" , "Jazelle", "ThumbEE"
54 };
55
56 /*
57 * This is our default idle handler.
58 */
59
60 void (*arm_pm_idle)(void);
61
62 /*
63 * Called from the core idle loop.
64 */
65
arch_cpu_idle(void)66 void arch_cpu_idle(void)
67 {
68 if (arm_pm_idle)
69 arm_pm_idle();
70 else
71 cpu_do_idle();
72 local_irq_enable();
73 }
74
arch_cpu_idle_prepare(void)75 void arch_cpu_idle_prepare(void)
76 {
77 local_fiq_enable();
78 }
79
arch_cpu_idle_enter(void)80 void arch_cpu_idle_enter(void)
81 {
82 ledtrig_cpu(CPU_LED_IDLE_START);
83 #ifdef CONFIG_PL310_ERRATA_769419
84 wmb();
85 #endif
86 }
87
arch_cpu_idle_exit(void)88 void arch_cpu_idle_exit(void)
89 {
90 ledtrig_cpu(CPU_LED_IDLE_END);
91 }
92
__show_regs(struct pt_regs * regs)93 void __show_regs(struct pt_regs *regs)
94 {
95 unsigned long flags;
96 char buf[64];
97 #ifndef CONFIG_CPU_V7M
98 unsigned int domain, fs;
99 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
100 /*
101 * Get the domain register for the parent context. In user
102 * mode, we don't save the DACR, so lets use what it should
103 * be. For other modes, we place it after the pt_regs struct.
104 */
105 if (user_mode(regs)) {
106 domain = DACR_UACCESS_ENABLE;
107 fs = get_fs();
108 } else {
109 domain = to_svc_pt_regs(regs)->dacr;
110 fs = to_svc_pt_regs(regs)->addr_limit;
111 }
112 #else
113 domain = get_domain();
114 fs = get_fs();
115 #endif
116 #endif
117
118 show_regs_print_info(KERN_DEFAULT);
119
120 printk("PC is at %pS\n", (void *)instruction_pointer(regs));
121 printk("LR is at %pS\n", (void *)regs->ARM_lr);
122 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n",
123 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
124 printk("sp : %08lx ip : %08lx fp : %08lx\n",
125 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
126 printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
127 regs->ARM_r10, regs->ARM_r9,
128 regs->ARM_r8);
129 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
130 regs->ARM_r7, regs->ARM_r6,
131 regs->ARM_r5, regs->ARM_r4);
132 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
133 regs->ARM_r3, regs->ARM_r2,
134 regs->ARM_r1, regs->ARM_r0);
135
136 flags = regs->ARM_cpsr;
137 buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
138 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
139 buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
140 buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
141 buf[4] = '\0';
142
143 #ifndef CONFIG_CPU_V7M
144 {
145 const char *segment;
146
147 if ((domain & domain_mask(DOMAIN_USER)) ==
148 domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
149 segment = "none";
150 else if (fs == KERNEL_DS)
151 segment = "kernel";
152 else
153 segment = "user";
154
155 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n",
156 buf, interrupts_enabled(regs) ? "n" : "ff",
157 fast_interrupts_enabled(regs) ? "n" : "ff",
158 processor_modes[processor_mode(regs)],
159 isa_modes[isa_mode(regs)], segment);
160 }
161 #else
162 printk("xPSR: %08lx\n", regs->ARM_cpsr);
163 #endif
164
165 #ifdef CONFIG_CPU_CP15
166 {
167 unsigned int ctrl;
168
169 buf[0] = '\0';
170 #ifdef CONFIG_CPU_CP15_MMU
171 {
172 unsigned int transbase;
173 asm("mrc p15, 0, %0, c2, c0\n\t"
174 : "=r" (transbase));
175 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
176 transbase, domain);
177 }
178 #endif
179 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
180
181 printk("Control: %08x%s\n", ctrl, buf);
182 }
183 #endif
184 }
185
show_regs(struct pt_regs * regs)186 void show_regs(struct pt_regs * regs)
187 {
188 __show_regs(regs);
189 dump_stack();
190 }
191
192 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
193
194 EXPORT_SYMBOL_GPL(thread_notify_head);
195
196 /*
197 * Free current thread data structures etc..
198 */
exit_thread(struct task_struct * tsk)199 void exit_thread(struct task_struct *tsk)
200 {
201 thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
202 }
203
flush_thread(void)204 void flush_thread(void)
205 {
206 struct thread_info *thread = current_thread_info();
207 struct task_struct *tsk = current;
208
209 flush_ptrace_hw_breakpoint(tsk);
210
211 memset(thread->used_cp, 0, sizeof(thread->used_cp));
212 memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
213 memset(&thread->fpstate, 0, sizeof(union fp_state));
214
215 flush_tls();
216
217 thread_notify(THREAD_NOTIFY_FLUSH, thread);
218 }
219
release_thread(struct task_struct * dead_task)220 void release_thread(struct task_struct *dead_task)
221 {
222 }
223
224 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
225
226 int
copy_thread(unsigned long clone_flags,unsigned long stack_start,unsigned long stk_sz,struct task_struct * p)227 copy_thread(unsigned long clone_flags, unsigned long stack_start,
228 unsigned long stk_sz, struct task_struct *p)
229 {
230 struct thread_info *thread = task_thread_info(p);
231 struct pt_regs *childregs = task_pt_regs(p);
232
233 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
234
235 #ifdef CONFIG_CPU_USE_DOMAINS
236 /*
237 * Copy the initial value of the domain access control register
238 * from the current thread: thread->addr_limit will have been
239 * copied from the current thread via setup_thread_stack() in
240 * kernel/fork.c
241 */
242 thread->cpu_domain = get_domain();
243 #endif
244
245 if (likely(!(p->flags & PF_KTHREAD))) {
246 *childregs = *current_pt_regs();
247 childregs->ARM_r0 = 0;
248 if (stack_start)
249 childregs->ARM_sp = stack_start;
250 } else {
251 memset(childregs, 0, sizeof(struct pt_regs));
252 thread->cpu_context.r4 = stk_sz;
253 thread->cpu_context.r5 = stack_start;
254 childregs->ARM_cpsr = SVC_MODE;
255 }
256 thread->cpu_context.pc = (unsigned long)ret_from_fork;
257 thread->cpu_context.sp = (unsigned long)childregs;
258
259 clear_ptrace_hw_breakpoint(p);
260
261 if (clone_flags & CLONE_SETTLS)
262 thread->tp_value[0] = childregs->ARM_r3;
263 thread->tp_value[1] = get_tpuser();
264
265 thread_notify(THREAD_NOTIFY_COPY, thread);
266
267 #ifdef CONFIG_STACKPROTECTOR_PER_TASK
268 thread->stack_canary = p->stack_canary;
269 #endif
270
271 return 0;
272 }
273
274 /*
275 * Fill in the task's elfregs structure for a core dump.
276 */
dump_task_regs(struct task_struct * t,elf_gregset_t * elfregs)277 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
278 {
279 elf_core_copy_regs(elfregs, task_pt_regs(t));
280 return 1;
281 }
282
283 /*
284 * fill in the fpe structure for a core dump...
285 */
dump_fpu(struct pt_regs * regs,struct user_fp * fp)286 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
287 {
288 struct thread_info *thread = current_thread_info();
289 int used_math = thread->used_cp[1] | thread->used_cp[2];
290
291 if (used_math)
292 memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
293
294 return used_math != 0;
295 }
296 EXPORT_SYMBOL(dump_fpu);
297
get_wchan(struct task_struct * p)298 unsigned long get_wchan(struct task_struct *p)
299 {
300 struct stackframe frame;
301 unsigned long stack_page;
302 int count = 0;
303 if (!p || p == current || p->state == TASK_RUNNING)
304 return 0;
305
306 frame.fp = thread_saved_fp(p);
307 frame.sp = thread_saved_sp(p);
308 frame.lr = 0; /* recovered from the stack */
309 frame.pc = thread_saved_pc(p);
310 stack_page = (unsigned long)task_stack_page(p);
311 do {
312 if (frame.sp < stack_page ||
313 frame.sp >= stack_page + THREAD_SIZE ||
314 unwind_frame(&frame) < 0)
315 return 0;
316 if (!in_sched_functions(frame.pc))
317 return frame.pc;
318 } while (count ++ < 16);
319 return 0;
320 }
321
322 #ifdef CONFIG_MMU
323 #ifdef CONFIG_KUSER_HELPERS
324 /*
325 * The vectors page is always readable from user space for the
326 * atomic helpers. Insert it into the gate_vma so that it is visible
327 * through ptrace and /proc/<pid>/mem.
328 */
329 static struct vm_area_struct gate_vma;
330
gate_vma_init(void)331 static int __init gate_vma_init(void)
332 {
333 vma_init(&gate_vma, NULL);
334 gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
335 gate_vma.vm_start = 0xffff0000;
336 gate_vma.vm_end = 0xffff0000 + PAGE_SIZE;
337 gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC;
338 return 0;
339 }
340 arch_initcall(gate_vma_init);
341
get_gate_vma(struct mm_struct * mm)342 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
343 {
344 return &gate_vma;
345 }
346
in_gate_area(struct mm_struct * mm,unsigned long addr)347 int in_gate_area(struct mm_struct *mm, unsigned long addr)
348 {
349 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
350 }
351
in_gate_area_no_mm(unsigned long addr)352 int in_gate_area_no_mm(unsigned long addr)
353 {
354 return in_gate_area(NULL, addr);
355 }
356 #define is_gate_vma(vma) ((vma) == &gate_vma)
357 #else
358 #define is_gate_vma(vma) 0
359 #endif
360
arch_vma_name(struct vm_area_struct * vma)361 const char *arch_vma_name(struct vm_area_struct *vma)
362 {
363 return is_gate_vma(vma) ? "[vectors]" : NULL;
364 }
365
366 /* If possible, provide a placement hint at a random offset from the
367 * stack for the sigpage and vdso pages.
368 */
sigpage_addr(const struct mm_struct * mm,unsigned int npages)369 static unsigned long sigpage_addr(const struct mm_struct *mm,
370 unsigned int npages)
371 {
372 unsigned long offset;
373 unsigned long first;
374 unsigned long last;
375 unsigned long addr;
376 unsigned int slots;
377
378 first = PAGE_ALIGN(mm->start_stack);
379
380 last = TASK_SIZE - (npages << PAGE_SHIFT);
381
382 /* No room after stack? */
383 if (first > last)
384 return 0;
385
386 /* Just enough room? */
387 if (first == last)
388 return first;
389
390 slots = ((last - first) >> PAGE_SHIFT) + 1;
391
392 offset = get_random_int() % slots;
393
394 addr = first + (offset << PAGE_SHIFT);
395
396 return addr;
397 }
398
399 static struct page *signal_page;
400 extern struct page *get_signal_page(void);
401
sigpage_mremap(const struct vm_special_mapping * sm,struct vm_area_struct * new_vma)402 static int sigpage_mremap(const struct vm_special_mapping *sm,
403 struct vm_area_struct *new_vma)
404 {
405 current->mm->context.sigpage = new_vma->vm_start;
406 return 0;
407 }
408
409 static const struct vm_special_mapping sigpage_mapping = {
410 .name = "[sigpage]",
411 .pages = &signal_page,
412 .mremap = sigpage_mremap,
413 };
414
arch_setup_additional_pages(struct linux_binprm * bprm,int uses_interp)415 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
416 {
417 struct mm_struct *mm = current->mm;
418 struct vm_area_struct *vma;
419 unsigned long npages;
420 unsigned long addr;
421 unsigned long hint;
422 int ret = 0;
423
424 if (!signal_page)
425 signal_page = get_signal_page();
426 if (!signal_page)
427 return -ENOMEM;
428
429 npages = 1; /* for sigpage */
430 npages += vdso_total_pages;
431
432 if (down_write_killable(&mm->mmap_sem))
433 return -EINTR;
434 hint = sigpage_addr(mm, npages);
435 addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
436 if (IS_ERR_VALUE(addr)) {
437 ret = addr;
438 goto up_fail;
439 }
440
441 vma = _install_special_mapping(mm, addr, PAGE_SIZE,
442 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
443 &sigpage_mapping);
444
445 if (IS_ERR(vma)) {
446 ret = PTR_ERR(vma);
447 goto up_fail;
448 }
449
450 mm->context.sigpage = addr;
451
452 /* Unlike the sigpage, failure to install the vdso is unlikely
453 * to be fatal to the process, so no error check needed
454 * here.
455 */
456 arm_install_vdso(mm, addr + PAGE_SIZE);
457
458 up_fail:
459 up_write(&mm->mmap_sem);
460 return ret;
461 }
462 #endif
463
