linux_dsm_epyc7002/arch/x86/include
Andy Lutomirski e0ffbaabc4 x86: Split syscall_trace_enter into two phases
This splits syscall_trace_enter into syscall_trace_enter_phase1 and
syscall_trace_enter_phase2.  Only phase 2 has full pt_regs, and only
phase 2 is permitted to modify any of pt_regs except for orig_ax.

The intent is that phase 1 can be called from the syscall fast path.

In this implementation, phase1 can handle any combination of
TIF_NOHZ (RCU context tracking), TIF_SECCOMP, and TIF_SYSCALL_AUDIT,
unless seccomp requests a ptrace event, in which case phase2 is
forced.

In principle, this could yield a big speedup for TIF_NOHZ as well as
for TIF_SECCOMP if syscall exit work were similarly split up.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/2df320a600020fda055fccf2b668145729dd0c04.1409954077.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-09-08 14:14:03 -07:00
..
asm x86: Split syscall_trace_enter into two phases 2014-09-08 14:14:03 -07:00
uapi/asm Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2014-08-16 09:25:34 -06:00