Release 4.14 arch/x86/um/syscalls_64.c

/*
 * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Copyright 2003 PathScale, Inc.
 *
 * Licensed under the GPL
 */

#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <asm/prctl.h> /* XXX This should get the constants from libc */
#include <os.h>



long arch_prctl(struct task_struct *task, int option,
		unsigned long __user *arg2)
{
	unsigned long *ptr = arg2, tmp;
	long ret;
	int pid = task->mm->context.id.u.pid;

	/*
         * With ARCH_SET_FS (and ARCH_SET_GS is treated similarly to
         * be safe), we need to call arch_prctl on the host because
         * setting %fs may result in something else happening (like a
         * GDT or thread.fs being set instead).  So, we let the host
         * fiddle the registers and thread struct and restore the
         * registers afterwards.
         *
         * So, the saved registers are stored to the process (this
         * needed because a stub may have been the last thing to run),
         * arch_prctl is run on the host, then the registers are read
         * back.
         */
	switch (option) {
	case ARCH_SET_FS:
	case ARCH_SET_GS:
		ret = restore_registers(pid, &current->thread.regs.regs);
		if (ret)
			return ret;
		break;
	case ARCH_GET_FS:
	case ARCH_GET_GS:
		/*
                 * With these two, we read to a local pointer and
                 * put_user it to the userspace pointer that we were
                 * given.  If addr isn't valid (because it hasn't been
                 * faulted in or is just bogus), we want put_user to
                 * fault it in (or return -EFAULT) instead of having
                 * the host return -EFAULT.
                 */
		ptr = &tmp;
	}

	ret = os_arch_prctl(pid, option, ptr);
	if (ret)
		return ret;

	switch (option) {
	case ARCH_SET_FS:
		current->thread.arch.fs = (unsigned long) ptr;
		ret = save_registers(pid, &current->thread.regs.regs);
		break;
	case ARCH_SET_GS:
		ret = save_registers(pid, &current->thread.regs.regs);
		break;
	case ARCH_GET_FS:
		ret = put_user(tmp, arg2);
		break;
	case ARCH_GET_GS:
		ret = put_user(tmp, arg2);
		break;
	}

	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Jeff Dike
186
92.08%
7
63.64%
Kyle Huey
14
6.93%
3
27.27%
Paolo 'Blaisorblade' Giarrusso
2
0.99%
1
9.09%
Total
202
100.00%
11
100.00%


SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2)
{
	return arch_prctl(current, option, (unsigned long __user *) arg2);
}



void arch_switch_to(struct task_struct *to)
{
	if ((to->thread.arch.fs == 0) || (to->mm == NULL))
		return;

	arch_prctl(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Jeff Dike
53
100.00%
4
100.00%
Total
53
100.00%
4
100.00%

Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Jeff Dike
263
86.23%
8
50.00%
Kyle Huey
31
10.16%
4
25.00%
Ingo Molnar
3
0.98%
1
6.25%
Richard Weinberger
3
0.98%
1
6.25%
Al Viro
3
0.98%
1
6.25%
Paolo 'Blaisorblade' Giarrusso
2
0.66%
1
6.25%
Total
305
100.00%
16
100.00%
Directory: arch/x86/um

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