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)
40DEFINE_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>
45unsigned long __stack_chk_guard __read_mostly;
46EXPORT_SYMBOL(__stack_chk_guard);
47#endif
48
49#ifndef CONFIG_CURRENT_POINTER_IN_TPIDRURO
50asmlinkage struct task_struct *__current;
51EXPORT_SYMBOL(__current);
52#endif
53
54static 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
61static const char *isa_modes[] __maybe_unused = {
62  "ARM" , "Thumb" , "Jazelle", "ThumbEE"
63};
64
65/*
66 * This is our default idle handler.
67 */
68
69void (*arm_pm_idle)(void);
70
71/*
72 * Called from the core idle loop.
73 */
74
75void arch_cpu_idle(void)
76{
77	if (arm_pm_idle)
78		arm_pm_idle();
79	else
80		cpu_do_idle();
81}
82
83void arch_cpu_idle_prepare(void)
84{
85	local_fiq_enable();
86}
87
88void 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
96void arch_cpu_idle_exit(void)
97{
98	ledtrig_cpu(CPU_LED_IDLE_END);
99}
100
101void __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
112void __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
200void show_regs(struct pt_regs * regs)
201{
202	__show_regs(regs);
203	dump_backtrace(regs, NULL, KERN_DEFAULT);
204}
205
206ATOMIC_NOTIFIER_HEAD(thread_notify_head);
207
208EXPORT_SYMBOL_GPL(thread_notify_head);
209
210/*
211 * Free current thread data structures etc..
212 */
213void exit_thread(struct task_struct *tsk)
214{
215	thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
216}
217
218void 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
233asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
234
235int 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
280unsigned 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 */
309static struct vm_area_struct gate_vma;
310
311static 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}
320arch_initcall(gate_vma_init);
321
322struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
323{
324	return &gate_vma;
325}
326
327int 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
332int 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
341const 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 */
349static 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
379static struct page *signal_page;
380extern struct page *get_signal_page(void);
381
382static 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
389static const struct vm_special_mapping sigpage_mapping = {
390	.name = "[sigpage]",
391	.pages = &signal_page,
392	.mremap = sigpage_mremap,
393};
394
395int 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