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(evt: 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(evt: 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(object: (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(task: 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(addr: 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(ceil: 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 | spec: &sigpage_mapping); |
424 | |
425 | if (IS_ERR(ptr: vma)) { |
426 | ret = PTR_ERR(ptr: 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 | |