s390: system call path micro optimization

Add a pointer to the system call table to the thread_info structure.
The TIF_31BIT bit is set or cleared by SET_PERSONALITY exactly once
for the lifetime of a process. With the pointer to the correct system
call table in thread_info the system call code in entry64.S path can
drop the check for TIF_31BIT which saves a couple of instructions.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 17d5cc057893..4d5e6f8a7978 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -188,6 +188,7 @@ sysc_vtime:
         mvc     __PT_INT_CODE(4,%r11),__LC_SVC_ILC
 sysc_do_svc:
         oi      __TI_flags+3(%r12),_TIF_SYSCALL
+        l       %r10,__TI_sysc_table(%r12)      # 31 bit system call table
         lh      %r8,__PT_INT_CODE+2(%r11)
         sla     %r8,2                           # shift and test for svc0
         jnz     sysc_nr_ok
@@ -198,7 +199,6 @@ sysc_do_svc:
         lr      %r8,%r1
         sla     %r8,2
 sysc_nr_ok:
-        l       %r10,BASED(.Lsys_call_table)    # 31 bit system call table
         xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
         st      %r2,__PT_ORIG_GPR2(%r11)
         st      %r7,STACK_FRAME_OVERHEAD(%r15)
@@ -906,7 +906,6 @@ cleanup_idle_wait:
 .Ltrace_enter:          .long   do_syscall_trace_enter
 .Ltrace_exit:           .long   do_syscall_trace_exit
 .Lschedule_tail:        .long   schedule_tail
-.Lsys_call_table:       .long   sys_call_table
 .Lsysc_per:             .long   sysc_per + 0x80000000
 #ifdef CONFIG_TRACE_IRQFLAGS
 .Lhardirqs_on:          .long   trace_hardirqs_on_caller