powerpc: Don't force ENOSYS as error on syscall fail

In certain scenarios - e.g. seccomp filtering with ERRNO as default action -
the system call fails for other reasons than the syscall not being available.
The seccomp filter can be configured to store a user-defined error code on
return from a blacklisted syscall. Don't always set ENOSYS on
do_syscall_trace_enter failure.

Delegate setting ENOSYS in case of failure, where appropriate, to
do_syscall_trace_enter.

v4:
- update syscall_exit to be local label on 64bit, after rebasing on top of 3.19

v3:
- keep setting ENOSYS in the syscall entry assembly for scenarios without
  syscall tracing

v2:
- move setting ENOSYS as errno from the syscall entry assembly to
  do_syscall_trace_enter, only in the specific case

Upstream-Status: Pending [https://lkml.org/lkml/2015/2/18/50]

Signed-off-by: Bogdan Purcareata <bogdan.purcareata@freescale.com>
Change-Id: I938a8754407a60c79fe9485cc76a6ec891e08e82
Reviewed-on: http://git.am.freescale.net:8181/33030
Reviewed-by: Scott Wood <scottwood@freescale.com>
Tested-by: Honghua Yin <Hong-Hua.Yin@freescale.com>
Reviewed-by: Honghua Yin <Hong-Hua.Yin@freescale.com>

0 files changed, 0 insertions, 0 deletions