From af52201d991624d2d5adce2c123805b3d42a8d4d Mon Sep 17 00:00:00 2001 From: Dominik Brodowski Date: Tue, 6 Mar 2018 22:18:08 +0100 Subject: x86/entry: Do not special-case clone(2) in compat entry With the CPU renaming registers on its own, and all the overhead of the syscall entry/exit, it is doubtful whether the compiled output of mov %r8, %rax mov %rcx, %r8 mov %rax, %rcx jmpq sys_clone is measurably slower than the hand-crafted version of xchg %r8, %rcx So get rid of this special case. Signed-off-by: Dominik Brodowski Acked-by: Linus Torvalds Acked-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: luto@amacapital.net Cc: viro@zeniv.linux.org.uk Signed-off-by: Ingo Molnar --- arch/x86/include/asm/sys_ia32.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/x86/include/asm/sys_ia32.h') diff --git a/arch/x86/include/asm/sys_ia32.h b/arch/x86/include/asm/sys_ia32.h index 32831905d97a..906794aa034e 100644 --- a/arch/x86/include/asm/sys_ia32.h +++ b/arch/x86/include/asm/sys_ia32.h @@ -55,6 +55,8 @@ asmlinkage long compat_sys_x86_fadvise64(int, unsigned int, unsigned int, size_t, int); asmlinkage long compat_sys_x86_fallocate(int, int, unsigned int, unsigned int, unsigned int, unsigned int); +asmlinkage long compat_sys_x86_clone(unsigned long, unsigned long, int __user *, + unsigned long, int __user *); /* ia32/ia32_signal.c */ asmlinkage long sys32_sigreturn(void); -- cgit v1.2.3