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 <linux/export.h>
9 #include <linux/sched.h>
10 #include <linux/sched/debug.h>
11 #include <linux/sched/task.h>
12 #include <linux/sched/task_stack.h>
13 #include <linux/kernel.h>
14 #include <linux/mm.h>
15 #include <linux/stddef.h>
16 #include <linux/unistd.h>
17 #include <linux/user.h>
18 #include <linux/interrupt.h>
19 #include <linux/init.h>
20 #include <linux/elfcore.h>
21 #include <linux/pm.h>
22 #include <linux/tick.h>
23 #include <linux/utsname.h>
24 #include <linux/uaccess.h>
25 #include <linux/random.h>
26 #include <linux/hw_breakpoint.h>
27 #include <linux/leds.h>
28
29 #include <asm/processor.h>
30 #include <asm/thread_notify.h>
31 #include <asm/stacktrace.h>
32 #include <asm/system_misc.h>
33 #include <asm/mach/time.h>
34 #include <asm/tls.h>
35 #include <asm/vdso.h>
36
37 #include "signal.h"
38
39 #if defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || defined(CONFIG_SMP)
40 DEFINE_PER_CPU(struct task_struct *, __entry_task);
41 #endif
42
43 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
44 #include <linux/stackprotector.h>
45 unsigned long __stack_chk_guard __read_mostly;
46 EXPORT_SYMBOL(__stack_chk_guard);
47 #endif
48
49 #ifndef CONFIG_CURRENT_POINTER_IN_TPIDRURO
50 asmlinkage struct task_struct *__current;
51 EXPORT_SYMBOL(__current);
52 #endif
53
54 static const char *processor_modes[] __maybe_unused = {
55 "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
56 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
57 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
58 "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
59 };
60
61 static const char *isa_modes[] __maybe_unused = {
62 "ARM" , "Thumb" , "Jazelle", "ThumbEE"
63 };
64
65 /*
66 * This is our default idle handler.
67 */
68
69 void (*arm_pm_idle)(void);
70
71 /*
72 * Called from the core idle loop.
73 */
74
75 void arch_cpu_idle(void)
76 {
77 if (arm_pm_idle)
78 arm_pm_idle();
79 else
80 cpu_do_idle();
81 }
82
83 void arch_cpu_idle_prepare(void)
84 {
85 local_fiq_enable();
86 }
87
88 void arch_cpu_idle_enter(void)
89 {
90 ledtrig_cpu(CPU_LED_IDLE_START);
91 #ifdef CONFIG_PL310_ERRATA_769419
92 wmb();
93 #endif
94 }
95
96 void arch_cpu_idle_exit(void)
97 {
98 ledtrig_cpu(CPU_LED_IDLE_END);
99 }
100
101 void __show_regs_alloc_free(struct pt_regs *regs)
102 {
103 int i;
104
105 /* check for r0 - r12 only */
106 for (i = 0; i < 13; i++) {
107 pr_alert("Register r%d information:", i);
108 mem_dump_obj((void *)regs->uregs[i]);
109 }
110 }
111
112 void __show_regs(struct pt_regs *regs)
113 {
114 unsigned long flags;
115 char buf[64];
116 #ifndef CONFIG_CPU_V7M
117 unsigned int domain;
118 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
119 /*
120 * Get the domain register for the parent context. In user
121 * mode, we don't save the DACR, so lets use what it should
122 * be. For other modes, we place it after the pt_regs struct.
123 */
124 if (user_mode(regs)) {
125 domain = DACR_UACCESS_ENABLE;
126 } else {
127 domain = to_svc_pt_regs(regs)->dacr;
128 }
129 #else
130 domain = get_domain();
131 #endif
132 #endif
133
134 show_regs_print_info(KERN_DEFAULT);
135
136 printk("PC is at %pS\n", (void *)instruction_pointer(regs));
137 printk("LR is at %pS\n", (void *)regs->ARM_lr);
138 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n",
139 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
140 printk("sp : %08lx ip : %08lx fp : %08lx\n",
141 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
142 printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
143 regs->ARM_r10, regs->ARM_r9,
144 regs->ARM_r8);
145 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
146 regs->ARM_r7, regs->ARM_r6,
147 regs->ARM_r5, regs->ARM_r4);
148 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
149 regs->ARM_r3, regs->ARM_r2,
150 regs->ARM_r1, regs->ARM_r0);
151
152 flags = regs->ARM_cpsr;
153 buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
154 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
155 buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
156 buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
157 buf[4] = '\0';
158
159 #ifndef CONFIG_CPU_V7M
160 {
161 const char *segment;
162
163 if ((domain & domain_mask(DOMAIN_USER)) ==
164 domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
165 segment = "none";
166 else
167 segment = "user";
168
169 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n",
170 buf, interrupts_enabled(regs) ? "n" : "ff",
171 fast_interrupts_enabled(regs) ? "n" : "ff",
172 processor_modes[processor_mode(regs)],
173 isa_modes[isa_mode(regs)], segment);
174 }
175 #else
176 printk("xPSR: %08lx\n", regs->ARM_cpsr);
177 #endif
178
179 #ifdef CONFIG_CPU_CP15
180 {
181 unsigned int ctrl;
182
183 buf[0] = '\0';
184 #ifdef CONFIG_CPU_CP15_MMU
185 {
186 unsigned int transbase;
187 asm("mrc p15, 0, %0, c2, c0\n\t"
188 : "=r" (transbase));
189 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
190 transbase, domain);
191 }
192 #endif
193 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
194
195 printk("Control: %08x%s\n", ctrl, buf);
196 }
197 #endif
198 }
199
200 void show_regs(struct pt_regs * regs)
201 {
202 __show_regs(regs);
203 dump_backtrace(regs, NULL, KERN_DEFAULT);
204 }
205
206 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
207
208 EXPORT_SYMBOL_GPL(thread_notify_head);
209
210 /*
211 * Free current thread data structures etc..
212 */
213 void exit_thread(struct task_struct *tsk)
214 {
215 thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
216 }
217
218 void flush_thread(void)
219 {
220 struct thread_info *thread = current_thread_info();
221 struct task_struct *tsk = current;
222
223 flush_ptrace_hw_breakpoint(tsk);
224
225 memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
226 memset(&thread->fpstate, 0, sizeof(union fp_state));
227
228 flush_tls();
229
230 thread_notify(THREAD_NOTIFY_FLUSH, thread);
231 }
232
233 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
234
235 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
236 {
237 unsigned long clone_flags = args->flags;
238 unsigned long stack_start = args->stack;
239 unsigned long tls = args->tls;
240 struct thread_info *thread = task_thread_info(p);
241 struct pt_regs *childregs = task_pt_regs(p);
242
243 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
244
245 #ifdef CONFIG_CPU_USE_DOMAINS
246 /*
247 * Copy the initial value of the domain access control register
248 * from the current thread: thread->addr_limit will have been
249 * copied from the current thread via setup_thread_stack() in
250 * kernel/fork.c
251 */
252 thread->cpu_domain = get_domain();
253 #endif
254
255 if (likely(!args->fn)) {
256 *childregs = *current_pt_regs();
257 childregs->ARM_r0 = 0;
258 if (stack_start)
259 childregs->ARM_sp = stack_start;
260 } else {
261 memset(childregs, 0, sizeof(struct pt_regs));
262 thread->cpu_context.r4 = (unsigned long)args->fn_arg;
263 thread->cpu_context.r5 = (unsigned long)args->fn;
264 childregs->ARM_cpsr = SVC_MODE;
265 }
266 thread->cpu_context.pc = (unsigned long)ret_from_fork;
267 thread->cpu_context.sp = (unsigned long)childregs;
268
269 clear_ptrace_hw_breakpoint(p);
270
271 if (clone_flags & CLONE_SETTLS)
272 thread->tp_value[0] = tls;
273 thread->tp_value[1] = get_tpuser();
274
275 thread_notify(THREAD_NOTIFY_COPY, thread);
276
277 return 0;
278 }
279
280 unsigned long __get_wchan(struct task_struct *p)
281 {
282 struct stackframe frame;
283 unsigned long stack_page;
284 int count = 0;
285
286 frame.fp = thread_saved_fp(p);
287 frame.sp = thread_saved_sp(p);
288 frame.lr = 0; /* recovered from the stack */
289 frame.pc = thread_saved_pc(p);
290 stack_page = (unsigned long)task_stack_page(p);
291 do {
292 if (frame.sp < stack_page ||
293 frame.sp >= stack_page + THREAD_SIZE ||
294 unwind_frame(&frame) < 0)
295 return 0;
296 if (!in_sched_functions(frame.pc))
297 return frame.pc;
298 } while (count ++ < 16);
299 return 0;
300 }
301
302 #ifdef CONFIG_MMU
303 #ifdef CONFIG_KUSER_HELPERS
304 /*
305 * The vectors page is always readable from user space for the
306 * atomic helpers. Insert it into the gate_vma so that it is visible
307 * through ptrace and /proc/<pid>/mem.
308 */
309 static struct vm_area_struct gate_vma;
310
311 static int __init gate_vma_init(void)
312 {
313 vma_init(&gate_vma, NULL);
314 gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
315 gate_vma.vm_start = 0xffff0000;
316 gate_vma.vm_end = 0xffff0000 + PAGE_SIZE;
317 vm_flags_init(&gate_vma, VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC);
318 return 0;
319 }
320 arch_initcall(gate_vma_init);
321
322 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
323 {
324 return &gate_vma;
325 }
326
327 int in_gate_area(struct mm_struct *mm, unsigned long addr)
328 {
329 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
330 }
331
332 int in_gate_area_no_mm(unsigned long addr)
333 {
334 return in_gate_area(NULL, addr);
335 }
336 #define is_gate_vma(vma) ((vma) == &gate_vma)
337 #else
338 #define is_gate_vma(vma) 0
339 #endif
340
341 const char *arch_vma_name(struct vm_area_struct *vma)
342 {
343 return is_gate_vma(vma) ? "[vectors]" : NULL;
344 }
345
346 /* If possible, provide a placement hint at a random offset from the
347 * stack for the sigpage and vdso pages.
348 */
349 static unsigned long sigpage_addr(const struct mm_struct *mm,
350 unsigned int npages)
351 {
352 unsigned long offset;
353 unsigned long first;
354 unsigned long last;
355 unsigned long addr;
356 unsigned int slots;
357
358 first = PAGE_ALIGN(mm->start_stack);
359
360 last = TASK_SIZE - (npages << PAGE_SHIFT);
361
362 /* No room after stack? */
363 if (first > last)
364 return 0;
365
366 /* Just enough room? */
367 if (first == last)
368 return first;
369
370 slots = ((last - first) >> PAGE_SHIFT) + 1;
371
372 offset = get_random_u32_below(slots);
373
374 addr = first + (offset << PAGE_SHIFT);
375
376 return addr;
377 }
378
379 static struct page *signal_page;
380 extern struct page *get_signal_page(void);
381
382 static int sigpage_mremap(const struct vm_special_mapping *sm,
383 struct vm_area_struct *new_vma)
384 {
385 current->mm->context.sigpage = new_vma->vm_start;
386 return 0;
387 }
388
389 static const struct vm_special_mapping sigpage_mapping = {
390 .name = "[sigpage]",
391 .pages = &signal_page,
392 .mremap = sigpage_mremap,
393 };
394
395 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
396 {
397 struct mm_struct *mm = current->mm;
398 struct vm_area_struct *vma;
399 unsigned long npages;
400 unsigned long addr;
401 unsigned long hint;
402 int ret = 0;
403
404 if (!signal_page)
405 signal_page = get_signal_page();
406 if (!signal_page)
407 return -ENOMEM;
408
409 npages = 1; /* for sigpage */
410 npages += vdso_total_pages;
411
412 if (mmap_write_lock_killable(mm))
413 return -EINTR;
414 hint = sigpage_addr(mm, npages);
415 addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
416 if (IS_ERR_VALUE(addr)) {
417 ret = addr;
418 goto up_fail;
419 }
420
421 vma = _install_special_mapping(mm, addr, PAGE_SIZE,
422 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
423 &sigpage_mapping);
424
425 if (IS_ERR(vma)) {
426 ret = PTR_ERR(vma);
427 goto up_fail;
428 }
429
430 mm->context.sigpage = addr;
431
432 /* Unlike the sigpage, failure to install the vdso is unlikely
433 * to be fatal to the process, so no error check needed
434 * here.
435 */
436 arm_install_vdso(mm, addr + PAGE_SIZE);
437
438 up_fail:
439 mmap_write_unlock(mm);
440 return ret;
441 }
442 #endif
443
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