Subject: Re: [PATCH] [POWERPC] Wire up sys_sync_file_range

From: Ralf Baechle <[email-masked]>
Date: Fri, 9 Mar 2007 11:59:02 +0000

On Thu, Mar 08, 2007 at 11:13:41PM -0800, David Miller wrote:

> > On Fri, 2007-03-09 at 15:22 +1100, Stephen Rothwell wrote:
> > > This requires an architecture specific compat routine as u64s are passed
> > > in odd/even (high/low) register pairs on ppc32.
> > > 
> > > Signed-off-by: Stephen Rothwell <[email-masked]>
> > 
> > Doesn't that apply to ARM and to 32-bit MIPS too? And perhaps others?
> 
> Unfortunately in the MIPS case you'll have to do some ifdef'ing because
> the order of the "high" and "low" sub-part arguments is dependant upon
> endianness and MIPS can be both big and little endian.

I'd rather let the C compiler sort it out:

asmlinkage long compat_sys_sync_file_range(int fd, int dummy,
	loff_t offset, loff_t nbytes, unsigned int flags)
{
	sys_sync_file_range(fd, offset, nbytes, flags);
}

Which looks like it could be portable to PPC even, so maybe a little cpp
magic like:

#ifdef CONFIG_ABI_NEEDS_PADDING_
#define PAD_64BIT_ARG(x)	unsigned int x,
#else
#define PAD_64BIT_ARG(x)
#endif

[...]
asmlinkage long sys_sync_file_range(int fd,  PAD_64BIT_ARG(pad1)
	loff_t offset, loff_t nbytes, unsigned int flags)

  Ralf