From 1ecff5ef0a70e7fd32a0b9cf6ad7ac8285462697 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 16 Jan 2019 14:15:19 +0100 Subject: 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 Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/sys_s390.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'arch') 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; -- cgit v1.2.3