Bootlin logo

Elixir Cross Referencer

  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
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
/*
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Copyright 2003 PathScale, Inc.
 * Licensed under the GPL
 */

#include <linux/stddef.h>
#include <linux/err.h>
#include <linux/hardirq.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/personality.h>
#include <linux/proc_fs.h>
#include <linux/ptrace.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/tick.h>
#include <linux/threads.h>
#include <asm/current.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include "as-layout.h"
#include "kern_util.h"
#include "os.h"
#include "skas.h"
#include "tlb.h"

/*
 * This is a per-cpu array.  A processor only modifies its entry and it only
 * cares about its entry, so it's OK if another processor is modifying its
 * entry.
 */
struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };

static inline int external_pid(void)
{
	/* FIXME: Need to look up userspace_pid by cpu */
	return userspace_pid[0];
}

int pid_to_processor_id(int pid)
{
	int i;

	for (i = 0; i < ncpus; i++) {
		if (cpu_tasks[i].pid == pid)
			return i;
	}
	return -1;
}

void free_stack(unsigned long stack, int order)
{
	free_pages(stack, order);
}

unsigned long alloc_stack(int order, int atomic)
{
	unsigned long page;
	gfp_t flags = GFP_KERNEL;

	if (atomic)
		flags = GFP_ATOMIC;
	page = __get_free_pages(flags, order);

	return page;
}

int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
	int pid;

	current->thread.request.u.thread.proc = fn;
	current->thread.request.u.thread.arg = arg;
	pid = do_fork(CLONE_VM | CLONE_UNTRACED | flags, 0,
		      &current->thread.regs, 0, NULL, NULL);
	return pid;
}

static inline void set_current(struct task_struct *task)
{
	cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
		{ external_pid(), task });
}

extern void arch_switch_to(struct task_struct *to);

void *_switch_to(void *prev, void *next, void *last)
{
	struct task_struct *from = prev;
	struct task_struct *to = next;

	to->thread.prev_sched = from;
	set_current(to);

	do {
		current->thread.saved_task = NULL;

		switch_threads(&from->thread.switch_buf,
			       &to->thread.switch_buf);

		arch_switch_to(current);

		if (current->thread.saved_task)
			show_regs(&(current->thread.regs));
		to = current->thread.saved_task;
		from = current;
	} while (current->thread.saved_task);

	return current->thread.prev_sched;

}

void interrupt_end(void)
{
	if (need_resched())
		schedule();
	if (test_tsk_thread_flag(current, TIF_SIGPENDING))
		do_signal();
}

void exit_thread(void)
{
}

void *get_current(void)
{
	return current;
}

/*
 * This is called magically, by its address being stuffed in a jmp_buf
 * and being longjmp-d to.
 */
void new_thread_handler(void)
{
	int (*fn)(void *), n;
	void *arg;

	if (current->thread.prev_sched != NULL)
		schedule_tail(current->thread.prev_sched);
	current->thread.prev_sched = NULL;

	fn = current->thread.request.u.thread.proc;
	arg = current->thread.request.u.thread.arg;

	/*
	 * The return value is 1 if the kernel thread execs a process,
	 * 0 if it just exits
	 */
	n = run_kernel_thread(fn, arg, &current->thread.exec_buf);
	if (n == 1) {
		/* Handle any immediate reschedules or signals */
		interrupt_end();
		userspace(&current->thread.regs.regs);
	}
	else do_exit(0);
}

/* Called magically, see new_thread_handler above */
void fork_handler(void)
{
	force_flush_all();

	schedule_tail(current->thread.prev_sched);

	/*
	 * XXX: if interrupt_end() calls schedule, this call to
	 * arch_switch_to isn't needed. We could want to apply this to
	 * improve performance. -bb
	 */
	arch_switch_to(current);

	current->thread.prev_sched = NULL;

	/* Handle any immediate reschedules or signals */
	interrupt_end();

	userspace(&current->thread.regs.regs);
}

int copy_thread(unsigned long clone_flags, unsigned long sp,
		unsigned long stack_top, struct task_struct * p,
		struct pt_regs *regs)
{
	void (*handler)(void);
	int ret = 0;

	p->thread = (struct thread_struct) INIT_THREAD;

	if (current->thread.forking) {
	  	memcpy(&p->thread.regs.regs, &regs->regs,
		       sizeof(p->thread.regs.regs));
		REGS_SET_SYSCALL_RETURN(p->thread.regs.regs.gp, 0);
		if (sp != 0)
			REGS_SP(p->thread.regs.regs.gp) = sp;

		handler = fork_handler;

		arch_copy_thread(&current->thread.arch, &p->thread.arch);
	}
	else {
		get_safe_registers(p->thread.regs.regs.gp);
		p->thread.request.u.thread = current->thread.request.u.thread;
		handler = new_thread_handler;
	}

	new_thread(task_stack_page(p), &p->thread.switch_buf, handler);

	if (current->thread.forking) {
		clear_flushed_tls(p);

		/*
		 * Set a new TLS for the child thread?
		 */
		if (clone_flags & CLONE_SETTLS)
			ret = arch_copy_tls(p);
	}

	return ret;
}

void initial_thread_cb(void (*proc)(void *), void *arg)
{
	int save_kmalloc_ok = kmalloc_ok;

	kmalloc_ok = 0;
	initial_thread_cb_skas(proc, arg);
	kmalloc_ok = save_kmalloc_ok;
}

void default_idle(void)
{
	unsigned long long nsecs;

	while (1) {
		/* endless idle loop with no priority at all */

		/*
		 * although we are an idle CPU, we do not want to
		 * get into the scheduler unnecessarily.
		 */
		if (need_resched())
			schedule();

		tick_nohz_stop_sched_tick(1);
		nsecs = disable_timer();
		idle_sleep(nsecs);
		tick_nohz_restart_sched_tick();
	}
}

void cpu_idle(void)
{
	cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
	default_idle();
}

int __cant_sleep(void) {
	return in_atomic() || irqs_disabled() || in_interrupt();
	/* Is in_interrupt() really needed? */
}

int user_context(unsigned long sp)
{
	unsigned long stack;

	stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
	return stack != (unsigned long) current_thread_info();
}

extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;

void do_uml_exitcalls(void)
{
	exitcall_t *call;

	call = &__uml_exitcall_end;
	while (--call >= &__uml_exitcall_begin)
		(*call)();
}

char *uml_strdup(const char *string)
{
	return kstrdup(string, GFP_KERNEL);
}

int copy_to_user_proc(void __user *to, void *from, int size)
{
	return copy_to_user(to, from, size);
}

int copy_from_user_proc(void *to, void __user *from, int size)
{
	return copy_from_user(to, from, size);
}

int clear_user_proc(void __user *buf, int size)
{
	return clear_user(buf, size);
}

int strlen_user_proc(char __user *str)
{
	return strlen_user(str);
}

int smp_sigio_handler(void)
{
#ifdef CONFIG_SMP
	int cpu = current_thread_info()->cpu;
	IPI_handler(cpu);
	if (cpu != 0)
		return 1;
#endif
	return 0;
}

int cpu(void)
{
	return current_thread_info()->cpu;
}

static atomic_t using_sysemu = ATOMIC_INIT(0);
int sysemu_supported;

void set_using_sysemu(int value)
{
	if (value > sysemu_supported)
		return;
	atomic_set(&using_sysemu, value);
}

int get_using_sysemu(void)
{
	return atomic_read(&using_sysemu);
}

static int sysemu_proc_show(struct seq_file *m, void *v)
{
	seq_printf(m, "%d\n", get_using_sysemu());
	return 0;
}

static int sysemu_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, sysemu_proc_show, NULL);
}

static ssize_t sysemu_proc_write(struct file *file, const char __user *buf,
				 size_t count, loff_t *pos)
{
	char tmp[2];

	if (copy_from_user(tmp, buf, 1))
		return -EFAULT;

	if (tmp[0] >= '0' && tmp[0] <= '2')
		set_using_sysemu(tmp[0] - '0');
	/* We use the first char, but pretend to write everything */
	return count;
}

static const struct file_operations sysemu_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= sysemu_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= sysemu_proc_write,
};

int __init make_proc_sysemu(void)
{
	struct proc_dir_entry *ent;
	if (!sysemu_supported)
		return 0;

	ent = proc_create("sysemu", 0600, NULL, &sysemu_proc_fops);

	if (ent == NULL)
	{
		printk(KERN_WARNING "Failed to register /proc/sysemu\n");
		return 0;
	}

	return 0;
}

late_initcall(make_proc_sysemu);

int singlestepping(void * t)
{
	struct task_struct *task = t ? t : current;

	if (!(task->ptrace & PT_DTRACE))
		return 0;

	if (task->thread.singlestep_syscall)
		return 1;

	return 2;
}

/*
 * Only x86 and x86_64 have an arch_align_stack().
 * All other arches have "#define arch_align_stack(x) (x)"
 * in their asm/system.h
 * As this is included in UML from asm-um/system-generic.h,
 * we can use it to behave as the subarch does.
 */
#ifndef arch_align_stack
unsigned long arch_align_stack(unsigned long sp)
{
	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
		sp -= get_random_int() % 8192;
	return sp & ~0xf;
}
#endif

unsigned long get_wchan(struct task_struct *p)
{
	unsigned long stack_page, sp, ip;
	bool seen_sched = 0;

	if ((p == NULL) || (p == current) || (p->state == TASK_RUNNING))
		return 0;

	stack_page = (unsigned long) task_stack_page(p);
	/* Bail if the process has no kernel stack for some reason */
	if (stack_page == 0)
		return 0;

	sp = p->thread.switch_buf->JB_SP;
	/*
	 * Bail if the stack pointer is below the bottom of the kernel
	 * stack for some reason
	 */
	if (sp < stack_page)
		return 0;

	while (sp < stack_page + THREAD_SIZE) {
		ip = *((unsigned long *) sp);
		if (in_sched_functions(ip))
			/* Ignore everything until we're above the scheduler */
			seen_sched = 1;
		else if (kernel_text_address(ip) && seen_sched)
			return ip;

		sp += sizeof(unsigned long);
	}

	return 0;
}

int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
{
	int cpu = current_thread_info()->cpu;

	return save_fp_registers(userspace_pid[cpu], (unsigned long *) fpu);
}