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_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 raw_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_alloc_free(struct pt_regs * regs)93 void __show_regs_alloc_free(struct pt_regs *regs)
94 {
95 int i;
96
97 /* check for r0 - r12 only */
98 for (i = 0; i < 13; i++) {
99 pr_alert("Register r%d information:", i);
100 mem_dump_obj((void *)regs->uregs[i]);
101 }
102 }
103
__show_regs(struct pt_regs * regs)104 void __show_regs(struct pt_regs *regs)
105 {
106 unsigned long flags;
107 char buf[64];
108 #ifndef CONFIG_CPU_V7M
109 unsigned int domain;
110 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
111 /*
112 * Get the domain register for the parent context. In user
113 * mode, we don't save the DACR, so lets use what it should
114 * be. For other modes, we place it after the pt_regs struct.
115 */
116 if (user_mode(regs)) {
117 domain = DACR_UACCESS_ENABLE;
118 } else {
119 domain = to_svc_pt_regs(regs)->dacr;
120 }
121 #else
122 domain = get_domain();
123 #endif
124 #endif
125
126 show_regs_print_info(KERN_DEFAULT);
127
128 printk("PC is at %pS\n", (void *)instruction_pointer(regs));
129 printk("LR is at %pS\n", (void *)regs->ARM_lr);
130 printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n",
131 regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
132 printk("sp : %08lx ip : %08lx fp : %08lx\n",
133 regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
134 printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
135 regs->ARM_r10, regs->ARM_r9,
136 regs->ARM_r8);
137 printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
138 regs->ARM_r7, regs->ARM_r6,
139 regs->ARM_r5, regs->ARM_r4);
140 printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
141 regs->ARM_r3, regs->ARM_r2,
142 regs->ARM_r1, regs->ARM_r0);
143
144 flags = regs->ARM_cpsr;
145 buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
146 buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
147 buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
148 buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
149 buf[4] = '\0';
150
151 #ifndef CONFIG_CPU_V7M
152 {
153 const char *segment;
154
155 if ((domain & domain_mask(DOMAIN_USER)) ==
156 domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
157 segment = "none";
158 else
159 segment = "user";
160
161 printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n",
162 buf, interrupts_enabled(regs) ? "n" : "ff",
163 fast_interrupts_enabled(regs) ? "n" : "ff",
164 processor_modes[processor_mode(regs)],
165 isa_modes[isa_mode(regs)], segment);
166 }
167 #else
168 printk("xPSR: %08lx\n", regs->ARM_cpsr);
169 #endif
170
171 #ifdef CONFIG_CPU_CP15
172 {
173 unsigned int ctrl;
174
175 buf[0] = '\0';
176 #ifdef CONFIG_CPU_CP15_MMU
177 {
178 unsigned int transbase;
179 asm("mrc p15, 0, %0, c2, c0\n\t"
180 : "=r" (transbase));
181 snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
182 transbase, domain);
183 }
184 #endif
185 asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
186
187 printk("Control: %08x%s\n", ctrl, buf);
188 }
189 #endif
190 }
191
show_regs(struct pt_regs * regs)192 void show_regs(struct pt_regs * regs)
193 {
194 __show_regs(regs);
195 dump_stack();
196 }
197
198 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
199
200 EXPORT_SYMBOL_GPL(thread_notify_head);
201
202 /*
203 * Free current thread data structures etc..
204 */
exit_thread(struct task_struct * tsk)205 void exit_thread(struct task_struct *tsk)
206 {
207 thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
208 }
209
flush_thread(void)210 void flush_thread(void)
211 {
212 struct thread_info *thread = current_thread_info();
213 struct task_struct *tsk = current;
214
215 flush_ptrace_hw_breakpoint(tsk);
216
217 memset(thread->used_cp, 0, sizeof(thread->used_cp));
218 memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
219 memset(&thread->fpstate, 0, sizeof(union fp_state));
220
221 flush_tls();
222
223 thread_notify(THREAD_NOTIFY_FLUSH, thread);
224 }
225
release_thread(struct task_struct * dead_task)226 void release_thread(struct task_struct *dead_task)
227 {
228 }
229
230 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
231
copy_thread(unsigned long clone_flags,unsigned long stack_start,unsigned long stk_sz,struct task_struct * p,unsigned long tls)232 int copy_thread(unsigned long clone_flags, unsigned long stack_start,
233 unsigned long stk_sz, struct task_struct *p, unsigned long tls)
234 {
235 struct thread_info *thread = task_thread_info(p);
236 struct pt_regs *childregs = task_pt_regs(p);
237
238 memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
239
240 #ifdef CONFIG_CPU_USE_DOMAINS
241 /*
242 * Copy the initial value of the domain access control register
243 * from the current thread: thread->addr_limit will have been
244 * copied from the current thread via setup_thread_stack() in
245 * kernel/fork.c
246 */
247 thread->cpu_domain = get_domain();
248 #endif
249
250 if (likely(!(p->flags & (PF_KTHREAD | PF_IO_WORKER)))) {
251 *childregs = *current_pt_regs();
252 childregs->ARM_r0 = 0;
253 if (stack_start)
254 childregs->ARM_sp = stack_start;
255 } else {
256 memset(childregs, 0, sizeof(struct pt_regs));
257 thread->cpu_context.r4 = stk_sz;
258 thread->cpu_context.r5 = stack_start;
259 childregs->ARM_cpsr = SVC_MODE;
260 }
261 thread->cpu_context.pc = (unsigned long)ret_from_fork;
262 thread->cpu_context.sp = (unsigned long)childregs;
263
264 clear_ptrace_hw_breakpoint(p);
265
266 if (clone_flags & CLONE_SETTLS)
267 thread->tp_value[0] = tls;
268 thread->tp_value[1] = get_tpuser();
269
270 thread_notify(THREAD_NOTIFY_COPY, thread);
271
272 #ifdef CONFIG_STACKPROTECTOR_PER_TASK
273 thread->stack_canary = p->stack_canary;
274 #endif
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 if (!p || p == current || task_is_running(p))
285 return 0;
286
287 frame.fp = thread_saved_fp(p);
288 frame.sp = thread_saved_sp(p);
289 frame.lr = 0; /* recovered from the stack */
290 frame.pc = thread_saved_pc(p);
291 stack_page = (unsigned long)task_stack_page(p);
292 do {
293 if (frame.sp < stack_page ||
294 frame.sp >= stack_page + THREAD_SIZE ||
295 unwind_frame(&frame) < 0)
296 return 0;
297 if (!in_sched_functions(frame.pc))
298 return frame.pc;
299 } while (count ++ < 16);
300 return 0;
301 }
302
303 #ifdef CONFIG_MMU
304 #ifdef CONFIG_KUSER_HELPERS
305 /*
306 * The vectors page is always readable from user space for the
307 * atomic helpers. Insert it into the gate_vma so that it is visible
308 * through ptrace and /proc/<pid>/mem.
309 */
310 static struct vm_area_struct gate_vma;
311
gate_vma_init(void)312 static int __init gate_vma_init(void)
313 {
314 vma_init(&gate_vma, NULL);
315 gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
316 gate_vma.vm_start = 0xffff0000;
317 gate_vma.vm_end = 0xffff0000 + PAGE_SIZE;
318 gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC;
319 return 0;
320 }
321 arch_initcall(gate_vma_init);
322
get_gate_vma(struct mm_struct * mm)323 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
324 {
325 return &gate_vma;
326 }
327
in_gate_area(struct mm_struct * mm,unsigned long addr)328 int in_gate_area(struct mm_struct *mm, unsigned long addr)
329 {
330 return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
331 }
332
in_gate_area_no_mm(unsigned long addr)333 int in_gate_area_no_mm(unsigned long addr)
334 {
335 return in_gate_area(NULL, addr);
336 }
337 #define is_gate_vma(vma) ((vma) == &gate_vma)
338 #else
339 #define is_gate_vma(vma) 0
340 #endif
341
arch_vma_name(struct vm_area_struct * vma)342 const char *arch_vma_name(struct vm_area_struct *vma)
343 {
344 return is_gate_vma(vma) ? "[vectors]" : NULL;
345 }
346
347 /* If possible, provide a placement hint at a random offset from the
348 * stack for the sigpage and vdso pages.
349 */
sigpage_addr(const struct mm_struct * mm,unsigned int npages)350 static unsigned long sigpage_addr(const struct mm_struct *mm,
351 unsigned int npages)
352 {
353 unsigned long offset;
354 unsigned long first;
355 unsigned long last;
356 unsigned long addr;
357 unsigned int slots;
358
359 first = PAGE_ALIGN(mm->start_stack);
360
361 last = TASK_SIZE - (npages << PAGE_SHIFT);
362
363 /* No room after stack? */
364 if (first > last)
365 return 0;
366
367 /* Just enough room? */
368 if (first == last)
369 return first;
370
371 slots = ((last - first) >> PAGE_SHIFT) + 1;
372
373 offset = get_random_int() % slots;
374
375 addr = first + (offset << PAGE_SHIFT);
376
377 return addr;
378 }
379
380 static struct page *signal_page;
381 extern struct page *get_signal_page(void);
382
sigpage_mremap(const struct vm_special_mapping * sm,struct vm_area_struct * new_vma)383 static int sigpage_mremap(const struct vm_special_mapping *sm,
384 struct vm_area_struct *new_vma)
385 {
386 current->mm->context.sigpage = new_vma->vm_start;
387 return 0;
388 }
389
390 static const struct vm_special_mapping sigpage_mapping = {
391 .name = "[sigpage]",
392 .pages = &signal_page,
393 .mremap = sigpage_mremap,
394 };
395
arch_setup_additional_pages(struct linux_binprm * bprm,int uses_interp)396 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
397 {
398 struct mm_struct *mm = current->mm;
399 struct vm_area_struct *vma;
400 unsigned long npages;
401 unsigned long addr;
402 unsigned long hint;
403 int ret = 0;
404
405 if (!signal_page)
406 signal_page = get_signal_page();
407 if (!signal_page)
408 return -ENOMEM;
409
410 npages = 1; /* for sigpage */
411 npages += vdso_total_pages;
412
413 if (mmap_write_lock_killable(mm))
414 return -EINTR;
415 hint = sigpage_addr(mm, npages);
416 addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
417 if (IS_ERR_VALUE(addr)) {
418 ret = addr;
419 goto up_fail;
420 }
421
422 vma = _install_special_mapping(mm, addr, PAGE_SIZE,
423 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
424 &sigpage_mapping);
425
426 if (IS_ERR(vma)) {
427 ret = PTR_ERR(vma);
428 goto up_fail;
429 }
430
431 mm->context.sigpage = addr;
432
433 /* Unlike the sigpage, failure to install the vdso is unlikely
434 * to be fatal to the process, so no error check needed
435 * here.
436 */
437 arm_install_vdso(mm, addr + PAGE_SIZE);
438
439 up_fail:
440 mmap_write_unlock(mm);
441 return ret;
442 }
443 #endif
444