[PATCH v6 13/17] arm64:ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it

Arnd Bergmann arnd at arndb.de
Thu Nov 12 05:24:57 PST 2015

On Thursday 12 November 2015 10:44:55 Andreas Schwab wrote:
> Arnd Bergmann <arnd at arndb.de> writes:
> > What do you mean with 32-bit off_t?
> An ABI with 32-bit off_t, ie. all currently implemented 32-bit ABIs.
> > Do you mean that glibc emulates a 32-bit off_t on top of the 64-bit
> > __kernel_loff_t?
> Glibc is bridging the user-space ABI to the kernel ABI.

Ok, but why?

The kernel headers for all recent architectures (arc, c6x, h8300,
hexagon, metag, nios2, openrisc, tile and unicore32) deliberately
leave out the __kernel_off_t based system calls to simplify the
ABI in a way that we never have to support a 32-bit off_t
in user space.

Are there programs that require using a 32-bit off_t by default
on 32-bit architectures but not on 64-bit architectures?
Did the previous version of the ilp32 patch set also emulate
this the same way?


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