s390: open-code s390_personality syscall
Patch series "s390: rework compat wrapper generation".
As promised, I gave this a go and changed the SYSCALL_DEFINEx()
infrastructure to always include the wrappers for doing the
31-bit argument conversion on s390 compat mode.
This does three main things:
- The UID16 rework saved a lot of duplicated code, and would
probably make sense by itself, but is also required as
we can no longer call sys_*() functions directly after the
last step.
- Removing the compat_wrapper.c file is of course the main
goal here, in order to remove the need to maintain the
compat_wrapper.c file when new system calls get added.
Unfortunately, this requires adding some complexity in
syscall_wrapper.h, and trades a small reduction in source
code lines for a small increase in binary size for
unused wrappers.
- As an added benefit, the use of syscall_wrapper.h now makes
it easy to change the syscall wrappers so they no longer
see all user space register contents, similar to changes
done in commits fa697140f9a2 ("syscalls/x86: Use 'struct pt_regs'
based syscall calling convention for 64-bit syscalls") and
4378a7d4be30 ("arm64: implement syscall wrappers").
I leave the actual implementation of this for you, if you
want to do it later.
I did not test the changes at runtime, but I looked at the
generated object code, which seems fine here and includes
the same conversions as before.
This patch(of 5):
The sys_personality function is not meant to be called from other system
calls. We could introduce an intermediate ksys_personality function,
but it does almost nothing, so this just moves the implementation into
the caller.
Link: https://lore.kernel.org/lkml/20190116131527.2071570-1-arnd@arndb.de
Link: https://lore.kernel.org/lkml/20190116131527.2071570-2-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
1 file changed