Commit-ID: 1ecff5ef0a70e7fd32a0b9cf6ad7ac8285462697
Gitweb: https://git.kernel.org/tip/1ecff5ef0a70e7fd32a0b9cf6ad7ac8285462697
Author: Arnd Bergmann <arnd@xxxxxxxx>
AuthorDate: Wed, 16 Jan 2019 14:15:19 +0100
Committer: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
CommitDate: Fri, 18 Jan 2019 09:33:17 +0100
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@xxxxxxxx
Link: https://lore.kernel.org/lkml/20190116131527.2071570-2-arnd@xxxxxxxx
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Reviewed-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
---
arch/s390/kernel/sys_s390.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/s390/kernel/sys_s390.c b/arch/s390/kernel/sys_s390.c
index 31cefe0c28c0..560bdaf8a74f 100644
--- a/arch/s390/kernel/sys_s390.c
+++ b/arch/s390/kernel/sys_s390.c
@@ -79,12 +79,15 @@ SYSCALL_DEFINE5(s390_ipc, uint, call, int, first, unsigned long, second,
SYSCALL_DEFINE1(s390_personality, unsigned int, personality)
{
- unsigned int ret;
+ unsigned int ret = current->personality;
if (personality(current->personality) == PER_LINUX32 &&
personality(personality) == PER_LINUX)
personality |= PER_LINUX32;
- ret = sys_personality(personality);
+
+ if (personality != 0xffffffff)
+ set_personality(personality);
+
if (personality(ret) == PER_LINUX32)
ret &= ~PER_LINUX32;
|