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