[PATCH 20/25] arm64:ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it

Arnd Bergmann
2016-05-11T08:09:52Z

On Wednesday 11 May 2016 10:04:16 Zhangjian wrote:
> > I don't remember. It's probably not important whether we have the shift
> > in there, as long as it's independent of the actual kernel page size and
> > user space and kernel agree on the calling conventions.
> Well. I am ok with where to shift the pages size because we get the same
> result. I was just thinking if we should get rid of the name of mmap2 in our
> ILP32 porting. Actually, it is mmap but we name it as mmap2. User may confused
> if they do not know the implementations.

That is a good point: If the implementation matches the mmap() behavior rather than
mmap2(), we should rename the macro by doing

#undef __NR_mmap2
#define __NR_mmap 222

in the uapi/asm/unistd.h file for ilp32 mode. Alternatively we can keep the
__NR_mmap2 definition but then we need to pass the pgoff (value shifted by
12 bits) argument rather than the size in bytes.

Arnd