summaryrefslogtreecommitdiff
path: root/arch/arm64/kernel/process.c
blob: 9cce0098f4cde62139029ce954db7e4004e839ce (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
/*
 * Based on arch/arm/kernel/process.c
 *
 * Original Copyright (C) 1995  Linus Torvalds
 * Copyright (C) 1996-2000 Russell King - Converted to ARM.
 * Copyright (C) 2012 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdarg.h>

#include <linux/export.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/user.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/interrupt.h>
#include <linux/kallsyms.h>
#include <linux/init.h>
#include <linux/cpu.h>
#include <linux/elfcore.h>
#include <linux/pm.h>
#include <linux/tick.h>
#include <linux/utsname.h>
#include <linux/uaccess.h>
#include <linux/random.h>
#include <linux/hw_breakpoint.h>
#include <linux/personality.h>
#include <linux/notifier.h>

#include <asm/compat.h>
#include <asm/cacheflush.h>
#include <asm/fpsimd.h>
#include <asm/mmu_context.h>
#include <asm/processor.h>
#include <asm/stacktrace.h>

static void setup_restart(void)
{
	/*
	 * Tell the mm system that we are going to reboot -
	 * we may need it to insert some 1:1 mappings so that
	 * soft boot works.
	 */
	setup_mm_for_reboot();

	/* Clean and invalidate caches */
	flush_cache_all();

	/* Turn D-cache off */
	cpu_cache_off();

	/* Push out any further dirty data, and ensure cache is empty */
	flush_cache_all();
}

void soft_restart(unsigned long addr)
{
	setup_restart();
	cpu_reset(addr);
}

/*
 * Function pointers to optional machine specific functions
 */
void (*pm_power_off)(void);
EXPORT_SYMBOL_GPL(pm_power_off);

void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
EXPORT_SYMBOL_GPL(arm_pm_restart);

/*
 * This is our default idle handler.
 */
void arch_cpu_idle(void)
{
	/*
	 * This should do all the clock switching and wait for interrupt
	 * tricks
	 */
	cpu_do_idle();
	local_irq_enable();
}

#ifdef CONFIG_HOTPLUG_CPU
void arch_cpu_idle_dead(void)
{
       cpu_die();
}
#endif

void machine_shutdown(void)
{
#ifdef CONFIG_SMP
	smp_send_stop();
#endif
}

void machine_halt(void)
{
	machine_shutdown();
	while (1);
}

void machine_power_off(void)
{
	machine_shutdown();
	if (pm_power_off)
		pm_power_off();
}

void machine_restart(char *cmd)
{
	machine_shutdown();

	/* Disable interrupts first */
	local_irq_disable();

	/* Now call the architecture specific reboot code. */
	if (arm_pm_restart)
		arm_pm_restart(reboot_mode, cmd);

	/*
	 * Whoops - the architecture was unable to reboot.
	 */
	printk("Reboot failed -- System halted\n");
	while (1);
}

void __show_regs(struct pt_regs *regs)
{
	int i, top_reg;
	u64 lr, sp;

	if (compat_user_mode(regs)) {
		lr = regs->compat_lr;
		sp = regs->compat_sp;
		top_reg = 12;
	} else {
		lr = regs->regs[30];
		sp = regs->sp;
		top_reg = 29;
	}

	show_regs_print_info(KERN_DEFAULT);
	print_symbol("PC is at %s\n", instruction_pointer(regs));
	print_symbol("LR is at %s\n", lr);
	printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
	       regs->pc, lr, regs->pstate);
	printk("sp : %016llx\n", sp);
	for (i = top_reg; i >= 0; i--) {
		printk("x%-2d: %016llx ", i, regs->regs[i]);
		if (i % 2 == 0)
			printk("\n");
	}
	printk("\n");
}

void show_regs(struct pt_regs * regs)
{
	printk("\n");
	__show_regs(regs);
}

/*
 * Free current thread data structures etc..
 */
void exit_thread(void)
{
}

void flush_thread(void)
{
	fpsimd_flush_thread();
	flush_ptrace_hw_breakpoint(current);
}

void release_thread(struct task_struct *dead_task)
{
}

int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
	fpsimd_save_state(&current->thread.fpsimd_state);
	*dst = *src;
	return 0;
}

asmlinkage void ret_from_fork(void) asm("ret_from_fork");

int copy_thread(unsigned long clone_flags, unsigned long stack_start,
		unsigned long stk_sz, struct task_struct *p)
{
	struct pt_regs *childregs = task_pt_regs(p);
	unsigned long tls = p->thread.tp_value;

	memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));

	if (likely(!(p->flags & PF_KTHREAD))) {
		*childregs = *current_pt_regs();
		childregs->regs[0] = 0;
		if (is_compat_thread(task_thread_info(p))) {
			if (stack_start)
				childregs->compat_sp = stack_start;
		} else {
			/*
			 * Read the current TLS pointer from tpidr_el0 as it may be
			 * out-of-sync with the saved value.
			 */
			asm("mrs %0, tpidr_el0" : "=r" (tls));
			if (stack_start) {
				/* 16-byte aligned stack mandatory on AArch64 */
				if (stack_start & 15)
					return -EINVAL;
				childregs->sp = stack_start;
			}
		}
		/*
		 * If a TLS pointer was passed to clone (4th argument), use it
		 * for the new thread.
		 */
		if (clone_flags & CLONE_SETTLS)
			tls = childregs->regs[3];
	} else {
		memset(childregs, 0, sizeof(struct pt_regs));
		childregs->pstate = PSR_MODE_EL1h;
		p->thread.cpu_context.x19 = stack_start;
		p->thread.cpu_context.x20 = stk_sz;
	}
	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
	p->thread.cpu_context.sp = (unsigned long)childregs;
	p->thread.tp_value = tls;

	ptrace_hw_copy_thread(p);

	return 0;
}

static void tls_thread_switch(struct task_struct *next)
{
	unsigned long tpidr, tpidrro;

	if (!is_compat_task()) {
		asm("mrs %0, tpidr_el0" : "=r" (tpidr));
		current->thread.tp_value = tpidr;
	}

	if (is_compat_thread(task_thread_info(next))) {
		tpidr = 0;
		tpidrro = next->thread.tp_value;
	} else {
		tpidr = next->thread.tp_value;
		tpidrro = 0;
	}

	asm(
	"	msr	tpidr_el0, %0\n"
	"	msr	tpidrro_el0, %1"
	: : "r" (tpidr), "r" (tpidrro));
}

/*
 * Thread switching.
 */
struct task_struct *__switch_to(struct task_struct *prev,
				struct task_struct *next)
{
	struct task_struct *last;

	fpsimd_thread_switch(next);
	tls_thread_switch(next);
	hw_breakpoint_thread_switch(next);
	contextidr_thread_switch(next);

	/*
	 * Complete any pending TLB or cache maintenance on this CPU in case
	 * the thread migrates to a different CPU.
	 */
	dsb();

	/* the actual thread switch */
	last = cpu_switch_to(prev, next);

	return last;
}

unsigned long get_wchan(struct task_struct *p)
{
	struct stackframe frame;
	unsigned long stack_page;
	int count = 0;
	if (!p || p == current || p->state == TASK_RUNNING)
		return 0;

	frame.fp = thread_saved_fp(p);
	frame.sp = thread_saved_sp(p);
	frame.pc = thread_saved_pc(p);
	stack_page = (unsigned long)task_stack_page(p);
	do {
		if (frame.sp < stack_page ||
		    frame.sp >= stack_page + THREAD_SIZE ||
		    unwind_frame(&frame))
			return 0;
		if (!in_sched_functions(frame.pc))
			return frame.pc;
	} while (count ++ < 16);
	return 0;
}

unsigned long arch_align_stack(unsigned long sp)
{
	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
		sp -= get_random_int() & ~PAGE_MASK;
	return sp & ~0xf;
}

static unsigned long randomize_base(unsigned long base)
{
	unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
	return randomize_range(base, range_end, 0) ? : base;
}

unsigned long arch_randomize_brk(struct mm_struct *mm)
{
	return randomize_base(mm->brk);
}

unsigned long randomize_et_dyn(unsigned long base)
{
	return randomize_base(base);
}