]> git.baikalelectronics.ru Git - kernel.git/commit
x86/entry/64: Remove the SYSCALL64 fast path
authorAndy Lutomirski <luto@kernel.org>
Sun, 28 Jan 2018 18:38:49 +0000 (10:38 -0800)
committerThomas Gleixner <tglx@linutronix.de>
Tue, 30 Jan 2018 14:30:36 +0000 (15:30 +0100)
commit0c1de32181ede391ba677bb73a7d547fd5474132
treeb2b77e5b404afb963a62f51e456a2885022cc164
parent68068d9c7e11704fb3ffa1a51bd36dba3981ad09
x86/entry/64: Remove the SYSCALL64 fast path

The SYCALLL64 fast path was a nice, if small, optimization back in the good
old days when syscalls were actually reasonably fast.  Now there is PTI to
slow everything down, and indirect branches are verboten, making everything
messier.  The retpoline code in the fast path is particularly nasty.

Just get rid of the fast path. The slow path is barely slower.

[ tglx: Split out the 'push all extra regs' part ]

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
Link: https://lkml.kernel.org/r/462dff8d4d64dfbfc851fbf3130641809d980ecd.1517164461.git.luto@kernel.org
arch/x86/entry/entry_64.S
arch/x86/entry/syscall_64.c