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