From 7978f76c4495c194183e03f65406f78cdda37882 Mon Sep 17 00:00:00 2001 From: Laurent Dufour Date: Tue, 5 May 2015 17:30:21 +0200 Subject: [PATCH] powerpc: Enable sys_kcmp() for CRIU The commit 8170a83f15ee ("powerpc: Wireup the kcmp syscall to sys_ni") has disabled the kcmp syscall for powerpc. This has been done due to the use of unsigned long parameters which may require a dedicated wrapper to handle 32bit process on top of 64bit kernel. However in the kcmp() case, the 2 unsigned long parameters are currently only used to carry file descriptors from user space to the kernel. Since such a parameter is passed through register, and file descriptor doesn't need to get extended, there is, today, no need for a wrapper. In the case there will be a need to pass address in or out of this system call, then a wrapper could be required, it will then be to care of it. As today this is not the case, it is safe to enable kcmp() on powerpc. Tested (by Laurent) on 64-bit, 32-bit, and 32-bit userspace on 64-bit kernel using tools/testing/selftests/kcmp [mpe]. Signed-off-by: Laurent Dufour Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/systbl.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/systbl.h b/arch/powerpc/include/asm/systbl.h index f1863a1..71f2b3f 100644 --- a/arch/powerpc/include/asm/systbl.h +++ b/arch/powerpc/include/asm/systbl.h @@ -358,7 +358,7 @@ SYSCALL_SPU(setns) COMPAT_SYS(process_vm_readv) COMPAT_SYS(process_vm_writev) SYSCALL(finit_module) -SYSCALL(ni_syscall) /* sys_kcmp */ +SYSCALL(kcmp) /* sys_kcmp */ SYSCALL_SPU(sched_setattr) SYSCALL_SPU(sched_getattr) SYSCALL_SPU(renameat2) -- 2.7.4