[PATCH] m68knommu: improve syscall entry and fix strace

Here is a patch to the system call handling for 5307/5272/etc to:

- fix the strace support (one tested the wrong bit)
- make all system calls a little bit faster by inlining set_esp0 and
  supporting ENOSYS out of the critical path.
- remove extraneous spaces
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/m68knommu/platform/5307/entry.S

@@ -5,7 +5,7 @@
  *  Copyright (C) 1998  D. Jeff Dionne <jeff@lineo.ca>,
  *                      Kenneth Albanowski <kjahds@kjahds.com>,
  *  Copyright (C) 2000  Lineo Inc. (www.lineo.com)
- *  Copyright (C) 2004  Macq Electronique SA. (www.macqel.com)
+ *  Copyright (C) 2004-2006  Macq Electronique SA. (www.macqel.com)
  *
  * Based on:
  *
@@ -56,32 +56,27 @@ sw_usp:
 .globl inthandler
 .globl fasthandler
 
+enosys:
+	mov.l	#sys_ni_syscall,%d3
+	bra	1f
+
 ENTRY(system_call)
 	SAVE_ALL
 	move	#0x2000,%sr		/* enable intrs again */
 
-	movel	#-LENOSYS,%d2
-	movel	%d2,PT_D0(%sp)		/* default return value in d0 */
-					/* original D0 is in orig_d0 */
-	movel	%d0,%d2
-
-	/* save top of frame */
-	pea	%sp@
-	jbsr	set_esp0
-	addql	#4,%sp
-
-	cmpl	#NR_syscalls,%d2
-	jcc	ret_from_exception
+	cmpl	#NR_syscalls,%d0
+	jcc	enosys
 	lea	sys_call_table,%a0
-	lsll	#2,%d2			/* movel %a0@(%d2:l:4),%d3 */
-	movel	%a0@(%d2),%d3
-	jeq	ret_from_exception
-	lsrl	#2,%d2
+	lsll	#2,%d0			/* movel %a0@(%d0:l:4),%d3 */
+	movel	%a0@(%d0),%d3
+	jeq	enosys
 
+1:
 	movel	%sp,%d2			/* get thread_info pointer */
 	andl	#-THREAD_SIZE,%d2	/* at start of kernel stack */
 	movel	%d2,%a0
-	btst	#TIF_SYSCALL_TRACE,%a0@(TI_FLAGS)
+	movel	%sp,%a0@(THREAD_ESP0)	/* save top of frame */
+	btst	#(TIF_SYSCALL_TRACE%8),%a0@(TI_FLAGS+(31-TIF_SYSCALL_TRACE)/8)
 	bnes	1f
 
 	movel	%d3,%a0
@@ -265,4 +260,3 @@ ENTRY(resume)
 	movew	%a1@(TASK_THREAD+THREAD_SR),%d0	/* restore thread status reg */
 	movew	%d0, %sr
 	rts
-