linux_kernel/arch/riscv/kernel/sys_riscv.c

/*
 * Copyright (C) 2012 Regents of the University of California
 * Copyright (C) 2014 Darius Rad <darius@bluespec.com>
 * Copyright (C) 2017 SiFive
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation, version 2.
 *
 *   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.
 */

#include <linux/syscalls.h>
#include <asm/cmpxchg.h>
#include <asm/unistd.h>

static long riscv_sys_mmap(unsigned long addr, unsigned long len,
			   unsigned long prot, unsigned long flags,
			   unsigned long fd, off_t offset,
			   unsigned long page_shift_offset)
{
	if (unlikely(offset & (~PAGE_MASK >> page_shift_offset)))
		return -EINVAL;
	return sys_mmap_pgoff(addr, len, prot, flags, fd,
			      offset >> (PAGE_SHIFT - page_shift_offset));
}

#ifdef CONFIG_64BIT
SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
	unsigned long, prot, unsigned long, flags,
	unsigned long, fd, off_t, offset)
{
	return riscv_sys_mmap(addr, len, prot, flags, fd, offset, 0);
}
#else
SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
	unsigned long, prot, unsigned long, flags,
	unsigned long, fd, off_t, offset)
{
	/*
	 * Note that the shift for mmap2 is constant (12),
	 * regardless of PAGE_SIZE
	 */
	return riscv_sys_mmap(addr, len, prot, flags, fd, offset, 12);
}
#endif /* !CONFIG_64BIT */