xref: /openbmc/linux/arch/arm/kernel/process.c (revision ae0be8de) 
1 /*
2  *  linux/arch/arm/kernel/process.c
3  *
4  *  Copyright (C) 1996-2000 Russell King - Converted to ARM.
5  *  Original Copyright (C) 1995  Linus Torvalds
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 #include <stdarg.h>
12 
13 #include <linux/export.h>
14 #include <linux/sched.h>
15 #include <linux/sched/debug.h>
16 #include <linux/sched/task.h>
17 #include <linux/sched/task_stack.h>
18 #include <linux/kernel.h>
19 #include <linux/mm.h>
20 #include <linux/stddef.h>
21 #include <linux/unistd.h>
22 #include <linux/user.h>
23 #include <linux/interrupt.h>
24 #include <linux/init.h>
25 #include <linux/elfcore.h>
26 #include <linux/pm.h>
27 #include <linux/tick.h>
28 #include <linux/utsname.h>
29 #include <linux/uaccess.h>
30 #include <linux/random.h>
31 #include <linux/hw_breakpoint.h>
32 #include <linux/leds.h>
33 
34 #include <asm/processor.h>
35 #include <asm/thread_notify.h>
36 #include <asm/stacktrace.h>
37 #include <asm/system_misc.h>
38 #include <asm/mach/time.h>
39 #include <asm/tls.h>
40 #include <asm/vdso.h>
41 
42 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
43 #include <linux/stackprotector.h>
44 unsigned long __stack_chk_guard __read_mostly;
45 EXPORT_SYMBOL(__stack_chk_guard);
46 #endif
47 
48 static const char *processor_modes[] __maybe_unused = {
49   "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
50   "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
51   "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
52   "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
53 };
54 
55 static const char *isa_modes[] __maybe_unused = {
56   "ARM" , "Thumb" , "Jazelle", "ThumbEE"
57 };
58 
59 /*
60  * This is our default idle handler.
61  */
62 
63 void (*arm_pm_idle)(void);
64 
65 /*
66  * Called from the core idle loop.
67  */
68 
69 void arch_cpu_idle(void)
70 {
71 	if (arm_pm_idle)
72 		arm_pm_idle();
73 	else
74 		cpu_do_idle();
75 	local_irq_enable();
76 }
77 
78 void arch_cpu_idle_prepare(void)
79 {
80 	local_fiq_enable();
81 }
82 
83 void arch_cpu_idle_enter(void)
84 {
85 	ledtrig_cpu(CPU_LED_IDLE_START);
86 #ifdef CONFIG_PL310_ERRATA_769419
87 	wmb();
88 #endif
89 }
90 
91 void arch_cpu_idle_exit(void)
92 {
93 	ledtrig_cpu(CPU_LED_IDLE_END);
94 }
95 
96 void __show_regs(struct pt_regs *regs)
97 {
98 	unsigned long flags;
99 	char buf[64];
100 #ifndef CONFIG_CPU_V7M
101 	unsigned int domain, fs;
102 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
103 	/*
104 	 * Get the domain register for the parent context. In user
105 	 * mode, we don't save the DACR, so lets use what it should
106 	 * be. For other modes, we place it after the pt_regs struct.
107 	 */
108 	if (user_mode(regs)) {
109 		domain = DACR_UACCESS_ENABLE;
110 		fs = get_fs();
111 	} else {
112 		domain = to_svc_pt_regs(regs)->dacr;
113 		fs = to_svc_pt_regs(regs)->addr_limit;
114 	}
115 #else
116 	domain = get_domain();
117 	fs = get_fs();
118 #endif
119 #endif
120 
121 	show_regs_print_info(KERN_DEFAULT);
122 
123 	printk("PC is at %pS\n", (void *)instruction_pointer(regs));
124 	printk("LR is at %pS\n", (void *)regs->ARM_lr);
125 	printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n",
126 	       regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
127 	printk("sp : %08lx  ip : %08lx  fp : %08lx\n",
128 	       regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
129 	printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
130 		regs->ARM_r10, regs->ARM_r9,
131 		regs->ARM_r8);
132 	printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
133 		regs->ARM_r7, regs->ARM_r6,
134 		regs->ARM_r5, regs->ARM_r4);
135 	printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
136 		regs->ARM_r3, regs->ARM_r2,
137 		regs->ARM_r1, regs->ARM_r0);
138 
139 	flags = regs->ARM_cpsr;
140 	buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
141 	buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
142 	buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
143 	buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
144 	buf[4] = '\0';
145 
146 #ifndef CONFIG_CPU_V7M
147 	{
148 		const char *segment;
149 
150 		if ((domain & domain_mask(DOMAIN_USER)) ==
151 		    domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
152 			segment = "none";
153 		else if (fs == KERNEL_DS)
154 			segment = "kernel";
155 		else
156 			segment = "user";
157 
158 		printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
159 			buf, interrupts_enabled(regs) ? "n" : "ff",
160 			fast_interrupts_enabled(regs) ? "n" : "ff",
161 			processor_modes[processor_mode(regs)],
162 			isa_modes[isa_mode(regs)], segment);
163 	}
164 #else
165 	printk("xPSR: %08lx\n", regs->ARM_cpsr);
166 #endif
167 
168 #ifdef CONFIG_CPU_CP15
169 	{
170 		unsigned int ctrl;
171 
172 		buf[0] = '\0';
173 #ifdef CONFIG_CPU_CP15_MMU
174 		{
175 			unsigned int transbase;
176 			asm("mrc p15, 0, %0, c2, c0\n\t"
177 			    : "=r" (transbase));
178 			snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
179 				transbase, domain);
180 		}
181 #endif
182 		asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
183 
184 		printk("Control: %08x%s\n", ctrl, buf);
185 	}
186 #endif
187 }
188 
189 void show_regs(struct pt_regs * regs)
190 {
191 	__show_regs(regs);
192 	dump_stack();
193 }
194 
195 ATOMIC_NOTIFIER_HEAD(thread_notify_head);
196 
197 EXPORT_SYMBOL_GPL(thread_notify_head);
198 
199 /*
200  * Free current thread data structures etc..
201  */
202 void exit_thread(struct task_struct *tsk)
203 {
204 	thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
205 }
206 
207 void flush_thread(void)
208 {
209 	struct thread_info *thread = current_thread_info();
210 	struct task_struct *tsk = current;
211 
212 	flush_ptrace_hw_breakpoint(tsk);
213 
214 	memset(thread->used_cp, 0, sizeof(thread->used_cp));
215 	memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
216 	memset(&thread->fpstate, 0, sizeof(union fp_state));
217 
218 	flush_tls();
219 
220 	thread_notify(THREAD_NOTIFY_FLUSH, thread);
221 }
222 
223 void release_thread(struct task_struct *dead_task)
224 {
225 }
226 
227 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
228 
229 int
230 copy_thread(unsigned long clone_flags, unsigned long stack_start,
231 	    unsigned long stk_sz, struct task_struct *p)
232 {
233 	struct thread_info *thread = task_thread_info(p);
234 	struct pt_regs *childregs = task_pt_regs(p);
235 
236 	memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
237 
238 #ifdef CONFIG_CPU_USE_DOMAINS
239 	/*
240 	 * Copy the initial value of the domain access control register
241 	 * from the current thread: thread->addr_limit will have been
242 	 * copied from the current thread via setup_thread_stack() in
243 	 * kernel/fork.c
244 	 */
245 	thread->cpu_domain = get_domain();
246 #endif
247 
248 	if (likely(!(p->flags & PF_KTHREAD))) {
249 		*childregs = *current_pt_regs();
250 		childregs->ARM_r0 = 0;
251 		if (stack_start)
252 			childregs->ARM_sp = stack_start;
253 	} else {
254 		memset(childregs, 0, sizeof(struct pt_regs));
255 		thread->cpu_context.r4 = stk_sz;
256 		thread->cpu_context.r5 = stack_start;
257 		childregs->ARM_cpsr = SVC_MODE;
258 	}
259 	thread->cpu_context.pc = (unsigned long)ret_from_fork;
260 	thread->cpu_context.sp = (unsigned long)childregs;
261 
262 	clear_ptrace_hw_breakpoint(p);
263 
264 	if (clone_flags & CLONE_SETTLS)
265 		thread->tp_value[0] = childregs->ARM_r3;
266 	thread->tp_value[1] = get_tpuser();
267 
268 	thread_notify(THREAD_NOTIFY_COPY, thread);
269 
270 #ifdef CONFIG_STACKPROTECTOR_PER_TASK
271 	thread->stack_canary = p->stack_canary;
272 #endif
273 
274 	return 0;
275 }
276 
277 /*
278  * Fill in the task's elfregs structure for a core dump.
279  */
280 int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
281 {
282 	elf_core_copy_regs(elfregs, task_pt_regs(t));
283 	return 1;
284 }
285 
286 /*
287  * fill in the fpe structure for a core dump...
288  */
289 int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
290 {
291 	struct thread_info *thread = current_thread_info();
292 	int used_math = thread->used_cp[1] | thread->used_cp[2];
293 
294 	if (used_math)
295 		memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
296 
297 	return used_math != 0;
298 }
299 EXPORT_SYMBOL(dump_fpu);
300 
301 unsigned long get_wchan(struct task_struct *p)
302 {
303 	struct stackframe frame;
304 	unsigned long stack_page;
305 	int count = 0;
306 	if (!p || p == current || p->state == TASK_RUNNING)
307 		return 0;
308 
309 	frame.fp = thread_saved_fp(p);
310 	frame.sp = thread_saved_sp(p);
311 	frame.lr = 0;			/* recovered from the stack */
312 	frame.pc = thread_saved_pc(p);
313 	stack_page = (unsigned long)task_stack_page(p);
314 	do {
315 		if (frame.sp < stack_page ||
316 		    frame.sp >= stack_page + THREAD_SIZE ||
317 		    unwind_frame(&frame) < 0)
318 			return 0;
319 		if (!in_sched_functions(frame.pc))
320 			return frame.pc;
321 	} while (count ++ < 16);
322 	return 0;
323 }
324 
325 unsigned long arch_randomize_brk(struct mm_struct *mm)
326 {
327 	return randomize_page(mm->brk, 0x02000000);
328 }
329 
330 #ifdef CONFIG_MMU
331 #ifdef CONFIG_KUSER_HELPERS
332 /*
333  * The vectors page is always readable from user space for the
334  * atomic helpers. Insert it into the gate_vma so that it is visible
335  * through ptrace and /proc/<pid>/mem.
336  */
337 static struct vm_area_struct gate_vma;
338 
339 static int __init gate_vma_init(void)
340 {
341 	vma_init(&gate_vma, NULL);
342 	gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
343 	gate_vma.vm_start = 0xffff0000;
344 	gate_vma.vm_end	= 0xffff0000 + PAGE_SIZE;
345 	gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC;
346 	return 0;
347 }
348 arch_initcall(gate_vma_init);
349 
350 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
351 {
352 	return &gate_vma;
353 }
354 
355 int in_gate_area(struct mm_struct *mm, unsigned long addr)
356 {
357 	return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
358 }
359 
360 int in_gate_area_no_mm(unsigned long addr)
361 {
362 	return in_gate_area(NULL, addr);
363 }
364 #define is_gate_vma(vma)	((vma) == &gate_vma)
365 #else
366 #define is_gate_vma(vma)	0
367 #endif
368 
369 const char *arch_vma_name(struct vm_area_struct *vma)
370 {
371 	return is_gate_vma(vma) ? "[vectors]" : NULL;
372 }
373 
374 /* If possible, provide a placement hint at a random offset from the
375  * stack for the sigpage and vdso pages.
376  */
377 static unsigned long sigpage_addr(const struct mm_struct *mm,
378 				  unsigned int npages)
379 {
380 	unsigned long offset;
381 	unsigned long first;
382 	unsigned long last;
383 	unsigned long addr;
384 	unsigned int slots;
385 
386 	first = PAGE_ALIGN(mm->start_stack);
387 
388 	last = TASK_SIZE - (npages << PAGE_SHIFT);
389 
390 	/* No room after stack? */
391 	if (first > last)
392 		return 0;
393 
394 	/* Just enough room? */
395 	if (first == last)
396 		return first;
397 
398 	slots = ((last - first) >> PAGE_SHIFT) + 1;
399 
400 	offset = get_random_int() % slots;
401 
402 	addr = first + (offset << PAGE_SHIFT);
403 
404 	return addr;
405 }
406 
407 static struct page *signal_page;
408 extern struct page *get_signal_page(void);
409 
410 static int sigpage_mremap(const struct vm_special_mapping *sm,
411 		struct vm_area_struct *new_vma)
412 {
413 	current->mm->context.sigpage = new_vma->vm_start;
414 	return 0;
415 }
416 
417 static const struct vm_special_mapping sigpage_mapping = {
418 	.name = "[sigpage]",
419 	.pages = &signal_page,
420 	.mremap = sigpage_mremap,
421 };
422 
423 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
424 {
425 	struct mm_struct *mm = current->mm;
426 	struct vm_area_struct *vma;
427 	unsigned long npages;
428 	unsigned long addr;
429 	unsigned long hint;
430 	int ret = 0;
431 
432 	if (!signal_page)
433 		signal_page = get_signal_page();
434 	if (!signal_page)
435 		return -ENOMEM;
436 
437 	npages = 1; /* for sigpage */
438 	npages += vdso_total_pages;
439 
440 	if (down_write_killable(&mm->mmap_sem))
441 		return -EINTR;
442 	hint = sigpage_addr(mm, npages);
443 	addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
444 	if (IS_ERR_VALUE(addr)) {
445 		ret = addr;
446 		goto up_fail;
447 	}
448 
449 	vma = _install_special_mapping(mm, addr, PAGE_SIZE,
450 		VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
451 		&sigpage_mapping);
452 
453 	if (IS_ERR(vma)) {
454 		ret = PTR_ERR(vma);
455 		goto up_fail;
456 	}
457 
458 	mm->context.sigpage = addr;
459 
460 	/* Unlike the sigpage, failure to install the vdso is unlikely
461 	 * to be fatal to the process, so no error check needed
462 	 * here.
463 	 */
464 	arm_install_vdso(mm, addr + PAGE_SIZE);
465 
466  up_fail:
467 	up_write(&mm->mmap_sem);
468 	return ret;
469 }
470 #endif
471