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Re: Possible bug in sysdeps/unix/sysv/linux/powerpc/mmap64.c
On Sat, May 19, 2001 at 08:30:08PM -0700, Geoff Keating wrote:
> > Cc: Jack Howarth <howarth@bromo.med.uc.edu>, libc-alpha@sourceware.cygnus.com
> > Reply-To: drepper@cygnus.com (Ulrich Drepper)
> > From: Ulrich Drepper <drepper@redhat.com>
> > Date: 19 May 2001 16:33:21 -0700
> >
> > "H . J . Lu" <hjl@lucon.org> writes:
> >
> > > 1. Even on PPC, the kernel page size may change.
> > > 2. Linux may have variable page size one day.
>
> Hi HJ,
>
> I understood at the time that even if the kernel page size changed,
> and even if linux implemented a variable page size, this syscall would
> still need a shift of 12. The constant 12 is part of the ABI and not
> necessarily related to the actual page size.
It is very odd. As far as I know, Linux implements the SVR4/ELF ABI
only to the extend of calling conventions and relocations. We.never
implemented the binary interface of system calls and library functions.
I don't know why the SVR4 PPC ABI speficies the page size and why we
care what it says about the page size for mmap. For all I know, under
Linux,
# man mmap
....
offset should ordinarily be a multiple of the page size
returned by getpagesize(2).
and posix/tst-mmap.c in glibc does the same. To me, Linux/PPC doesn't
follow the Linux/glibc ABI. Did I miss something?
H.J.