On Tue, Oct 31, 2017 at 03:50:53PM +0000, Dave P Martin wrote:

Currently the regset API doesn't allow for the possibility that
regsets (or at least, the amount of meaningful data in a regset)
may change in size.

In particular, this results in useless padding being added to
coredumps if a regset's current size is smaller than its
theoretical maximum size.

This patch adds a get_size() function to struct user_regset.
Individual regset implementations can implement this function to
return the current size of the regset data.  A regset_size()
function is added to provide callers with an abstract interface for
determining the size of a regset without needing to know whether
the regset is dynamically sized or not.

The only affected user of this interface is the ELF coredump code:
This patch ports ELF coredump to dump regsets with their actual
size in the coredump.  This has no effect except for new regsets
that are dynamically sized and provide a get_size() implementation.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Benn?e <redacted>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Thomas Gleixner <redacted>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dmitry Safonov <redacted>
Cc: H. J. Lu <redacted>

---

**Dropped** Reviewed-by: Alex Benn?e [off-list ref]
**Dropped** Reviewed-by: Catalin Marinas [off-list ref]
(due to bug fix applied against v4 of this patch.)

It seems that the Reviewed-by tags are still there ;). Anyway, on the
new patch:

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>