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/kernel.h>
16#include <linux/mm.h>
17#include <linux/stddef.h>
18#include <linux/unistd.h>
19#include <linux/user.h>
20#include <linux/interrupt.h>
21#include <linux/kallsyms.h>
22#include <linux/init.h>
23#include <linux/elfcore.h>
24#include <linux/pm.h>
25#include <linux/tick.h>
26#include <linux/utsname.h>
27#include <linux/uaccess.h>
28#include <linux/random.h>
29#include <linux/hw_breakpoint.h>
30#include <linux/leds.h>
31
32#include <asm/processor.h>
33#include <asm/thread_notify.h>
34#include <asm/stacktrace.h>
35#include <asm/system_misc.h>
36#include <asm/mach/time.h>
37#include <asm/tls.h>
38#include <asm/vdso.h>
39
40#ifdef CONFIG_CC_STACKPROTECTOR
41#include <linux/stackprotector.h>
42unsigned long __stack_chk_guard __read_mostly;
43EXPORT_SYMBOL(__stack_chk_guard);
44#endif
45
46static const char *processor_modes[] __maybe_unused = {
47  "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
48  "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
49  "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
50  "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
51};
52
53static const char *isa_modes[] __maybe_unused = {
54  "ARM" , "Thumb" , "Jazelle", "ThumbEE"
55};
56
57/*
58 * This is our default idle handler.
59 */
60
61void (*arm_pm_idle)(void);
62
63/*
64 * Called from the core idle loop.
65 */
66
67void arch_cpu_idle(void)
68{
69	if (arm_pm_idle)
70		arm_pm_idle();
71	else
72		cpu_do_idle();
73	local_irq_enable();
74}
75
76void arch_cpu_idle_prepare(void)
77{
78	local_fiq_enable();
79}
80
81void arch_cpu_idle_enter(void)
82{
83	ledtrig_cpu(CPU_LED_IDLE_START);
84#ifdef CONFIG_PL310_ERRATA_769419
85	wmb();
86#endif
87}
88
89void arch_cpu_idle_exit(void)
90{
91	ledtrig_cpu(CPU_LED_IDLE_END);
92}
93
94#ifdef CONFIG_HOTPLUG_CPU
95void arch_cpu_idle_dead(void)
96{
97	cpu_die();
98}
99#endif
100
101void __show_regs(struct pt_regs *regs)
102{
103	unsigned long flags;
104	char buf[64];
105
106	show_regs_print_info(KERN_DEFAULT);
107
108	print_symbol("PC is at %s\n", instruction_pointer(regs));
109	print_symbol("LR is at %s\n", regs->ARM_lr);
110	printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
111	       "sp : %08lx  ip : %08lx  fp : %08lx\n",
112		regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
113		regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
114	printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
115		regs->ARM_r10, regs->ARM_r9,
116		regs->ARM_r8);
117	printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
118		regs->ARM_r7, regs->ARM_r6,
119		regs->ARM_r5, regs->ARM_r4);
120	printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
121		regs->ARM_r3, regs->ARM_r2,
122		regs->ARM_r1, regs->ARM_r0);
123
124	flags = regs->ARM_cpsr;
125	buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
126	buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
127	buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
128	buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
129	buf[4] = '\0';
130
131#ifndef CONFIG_CPU_V7M
132	printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
133		buf, interrupts_enabled(regs) ? "n" : "ff",
134		fast_interrupts_enabled(regs) ? "n" : "ff",
135		processor_modes[processor_mode(regs)],
136		isa_modes[isa_mode(regs)],
137		get_fs() == get_ds() ? "kernel" : "user");
138#else
139	printk("xPSR: %08lx\n", regs->ARM_cpsr);
140#endif
141
142#ifdef CONFIG_CPU_CP15
143	{
144		unsigned int ctrl;
145
146		buf[0] = '\0';
147#ifdef CONFIG_CPU_CP15_MMU
148		{
149			unsigned int transbase, dac;
150			asm("mrc p15, 0, %0, c2, c0\n\t"
151			    "mrc p15, 0, %1, c3, c0\n"
152			    : "=r" (transbase), "=r" (dac));
153			snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
154			  	transbase, dac);
155		}
156#endif
157		asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
158
159		printk("Control: %08x%s\n", ctrl, buf);
160	}
161#endif
162}
163
164void show_regs(struct pt_regs * regs)
165{
166	__show_regs(regs);
167	dump_stack();
168}
169
170ATOMIC_NOTIFIER_HEAD(thread_notify_head);
171
172EXPORT_SYMBOL_GPL(thread_notify_head);
173
174/*
175 * Free current thread data structures etc..
176 */
177void exit_thread(void)
178{
179	thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
180}
181
182void flush_thread(void)
183{
184	struct thread_info *thread = current_thread_info();
185	struct task_struct *tsk = current;
186
187	flush_ptrace_hw_breakpoint(tsk);
188
189	memset(thread->used_cp, 0, sizeof(thread->used_cp));
190	memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
191	memset(&thread->fpstate, 0, sizeof(union fp_state));
192
193	flush_tls();
194
195	thread_notify(THREAD_NOTIFY_FLUSH, thread);
196}
197
198void release_thread(struct task_struct *dead_task)
199{
200}
201
202asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
203
204int
205copy_thread(unsigned long clone_flags, unsigned long stack_start,
206	    unsigned long stk_sz, struct task_struct *p)
207{
208	struct thread_info *thread = task_thread_info(p);
209	struct pt_regs *childregs = task_pt_regs(p);
210
211	memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
212
213	if (likely(!(p->flags & PF_KTHREAD))) {
214		*childregs = *current_pt_regs();
215		childregs->ARM_r0 = 0;
216		if (stack_start)
217			childregs->ARM_sp = stack_start;
218	} else {
219		memset(childregs, 0, sizeof(struct pt_regs));
220		thread->cpu_context.r4 = stk_sz;
221		thread->cpu_context.r5 = stack_start;
222		childregs->ARM_cpsr = SVC_MODE;
223	}
224	thread->cpu_context.pc = (unsigned long)ret_from_fork;
225	thread->cpu_context.sp = (unsigned long)childregs;
226
227	clear_ptrace_hw_breakpoint(p);
228
229	if (clone_flags & CLONE_SETTLS)
230		thread->tp_value[0] = childregs->ARM_r3;
231	thread->tp_value[1] = get_tpuser();
232
233	thread_notify(THREAD_NOTIFY_COPY, thread);
234
235	return 0;
236}
237
238/*
239 * Fill in the task's elfregs structure for a core dump.
240 */
241int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
242{
243	elf_core_copy_regs(elfregs, task_pt_regs(t));
244	return 1;
245}
246
247/*
248 * fill in the fpe structure for a core dump...
249 */
250int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
251{
252	struct thread_info *thread = current_thread_info();
253	int used_math = thread->used_cp[1] | thread->used_cp[2];
254
255	if (used_math)
256		memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
257
258	return used_math != 0;
259}
260EXPORT_SYMBOL(dump_fpu);
261
262unsigned long get_wchan(struct task_struct *p)
263{
264	struct stackframe frame;
265	unsigned long stack_page;
266	int count = 0;
267	if (!p || p == current || p->state == TASK_RUNNING)
268		return 0;
269
270	frame.fp = thread_saved_fp(p);
271	frame.sp = thread_saved_sp(p);
272	frame.lr = 0;			/* recovered from the stack */
273	frame.pc = thread_saved_pc(p);
274	stack_page = (unsigned long)task_stack_page(p);
275	do {
276		if (frame.sp < stack_page ||
277		    frame.sp >= stack_page + THREAD_SIZE ||
278		    unwind_frame(&frame) < 0)
279			return 0;
280		if (!in_sched_functions(frame.pc))
281			return frame.pc;
282	} while (count ++ < 16);
283	return 0;
284}
285
286unsigned long arch_randomize_brk(struct mm_struct *mm)
287{
288	unsigned long range_end = mm->brk + 0x02000000;
289	return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
290}
291
292#ifdef CONFIG_MMU
293#ifdef CONFIG_KUSER_HELPERS
294/*
295 * The vectors page is always readable from user space for the
296 * atomic helpers. Insert it into the gate_vma so that it is visible
297 * through ptrace and /proc/<pid>/mem.
298 */
299static struct vm_area_struct gate_vma = {
300	.vm_start	= 0xffff0000,
301	.vm_end		= 0xffff0000 + PAGE_SIZE,
302	.vm_flags	= VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC,
303};
304
305static int __init gate_vma_init(void)
306{
307	gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
308	return 0;
309}
310arch_initcall(gate_vma_init);
311
312struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
313{
314	return &gate_vma;
315}
316
317int in_gate_area(struct mm_struct *mm, unsigned long addr)
318{
319	return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
320}
321
322int in_gate_area_no_mm(unsigned long addr)
323{
324	return in_gate_area(NULL, addr);
325}
326#define is_gate_vma(vma)	((vma) == &gate_vma)
327#else
328#define is_gate_vma(vma)	0
329#endif
330
331const char *arch_vma_name(struct vm_area_struct *vma)
332{
333	return is_gate_vma(vma) ? "[vectors]" : NULL;
334}
335
336/* If possible, provide a placement hint at a random offset from the
337 * stack for the sigpage and vdso pages.
338 */
339static unsigned long sigpage_addr(const struct mm_struct *mm,
340				  unsigned int npages)
341{
342	unsigned long offset;
343	unsigned long first;
344	unsigned long last;
345	unsigned long addr;
346	unsigned int slots;
347
348	first = PAGE_ALIGN(mm->start_stack);
349
350	last = TASK_SIZE - (npages << PAGE_SHIFT);
351
352	/* No room after stack? */
353	if (first > last)
354		return 0;
355
356	/* Just enough room? */
357	if (first == last)
358		return first;
359
360	slots = ((last - first) >> PAGE_SHIFT) + 1;
361
362	offset = get_random_int() % slots;
363
364	addr = first + (offset << PAGE_SHIFT);
365
366	return addr;
367}
368
369static struct page *signal_page;
370extern struct page *get_signal_page(void);
371
372static const struct vm_special_mapping sigpage_mapping = {
373	.name = "[sigpage]",
374	.pages = &signal_page,
375};
376
377int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
378{
379	struct mm_struct *mm = current->mm;
380	struct vm_area_struct *vma;
381	unsigned long npages;
382	unsigned long addr;
383	unsigned long hint;
384	int ret = 0;
385
386	if (!signal_page)
387		signal_page = get_signal_page();
388	if (!signal_page)
389		return -ENOMEM;
390
391	npages = 1; /* for sigpage */
392	npages += vdso_total_pages;
393
394	down_write(&mm->mmap_sem);
395	hint = sigpage_addr(mm, npages);
396	addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
397	if (IS_ERR_VALUE(addr)) {
398		ret = addr;
399		goto up_fail;
400	}
401
402	vma = _install_special_mapping(mm, addr, PAGE_SIZE,
403		VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
404		&sigpage_mapping);
405
406	if (IS_ERR(vma)) {
407		ret = PTR_ERR(vma);
408		goto up_fail;
409	}
410
411	mm->context.sigpage = addr;
412
413	/* Unlike the sigpage, failure to install the vdso is unlikely
414	 * to be fatal to the process, so no error check needed
415	 * here.
416	 */
417	arm_install_vdso(mm, addr + PAGE_SIZE);
418
419 up_fail:
420	up_write(&mm->mmap_sem);
421	return ret;
422}
423#endif
424