linux/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 <registers.h>
#include <os.h>

long arch_prctl(struct task_struct *task, int option,
		unsigned long __user *arg2)
{
	long ret = -EINVAL;

	switch (option) {
	case ARCH_SET_FS:
		current->thread.regs.regs.gp[FS_BASE / sizeof(unsigned long)] =
			(unsigned long) arg2;
		ret = 0;
		break;
	case ARCH_SET_GS:
		current->thread.regs.regs.gp[GS_BASE / sizeof(unsigned long)] =
			(unsigned long) arg2;
		ret = 0;
		break;
	case ARCH_GET_FS:
		ret = put_user(current->thread.regs.regs.gp[FS_BASE / sizeof(unsigned long)], arg2);
		break;
	case ARCH_GET_GS:
		ret = put_user(current->thread.regs.regs.gp[GS_BASE / sizeof(unsigned long)], arg2);
		break;
	}

	return ret;
}

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)
{
	/*
	 * Nothing needs to be done on x86_64.
	 * The FS_BASE/GS_BASE registers are saved in the ptrace register set.
	 */
}

SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
		unsigned long, prot, unsigned long, flags,
		unsigned long, fd, unsigned long, off)
{
	if (off & ~PAGE_MASK)
		return -EINVAL;

	return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
}