Re: [PATCH 16/17] RISC-V: User-facing API

[Christoph Hellwig <hch@infradead.org>]

> +++ b/arch/riscv/kernel/sys_riscv.c
> @@ -0,0 +1,43 @@
> +/*
> + * 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>

Should not be needed.

> +#ifdef CONFIG_64BIT
> +SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
> +	unsigned long, prot, unsigned long, flags,
> +	unsigned long, fd, off_t, offset)
> +{
> +	if (unlikely(offset & (~PAGE_MASK)))
> +		return -EINVAL;
> +	return sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
> +}
> +#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
> +	 */
> +	if (unlikely(offset & (~PAGE_MASK >> 12)))
> +		return -EINVAL;
> +	return sys_mmap_pgoff(addr, len, prot, flags, fd,
> +		offset >> (PAGE_SHIFT - 12));
> +}
> +#endif /* !CONFIG_64BIT */

Most modern ports seem to expose sys_mmap_pgoff as the
syscall directly.  Any reason you're doing this differently?

But even the code for the older ones should probably be consolidated..