x86/syscalls/64: Mark sys_iopl() as using ptregs

sys_iopl() both reads and writes pt_regs->flags.  Mark it as using ptregs.

This isn't strictly necessary, as pt_regs->flags is available
even in the fast path, but this is very lightweight now that we
have syscall qualifiers and it could avoid some pain down the
road.

Reported-and-tested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/3de0ca692fa8bf414c5e3d7afe3e6195d1a10e1f.1454261517.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index dcf107ce2cd4a4302bc3f805eaf4ade334da3cae..2e5b565adacc542415854612ad752e04cfc5df95 100644 (file)
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -178,7 +178,7 @@
 169    common  reboot                  sys_reboot
 170    common  sethostname             sys_sethostname
 171    common  setdomainname           sys_setdomainname
-172    common  iopl                    sys_iopl
+172    common  iopl                    sys_iopl/ptregs
 173    common  ioperm                  sys_ioperm
 174    64      create_module
 175    common  init_module             sys_init_module