sparc32: Preserve clone syscall flags argument for restarts due to signals

This fixes a bug where a clone syscall that is restarted due to a
pending signal is restarted with garbage in the register %o0 that holds
the clone flags.

This keep the original %i0 of a syscall (as seen from the trap handler)
in %l6 rather than %l5. This is done because for clone (and also qfork)
%l5 is used as a temporary variable in the same register window. Before
this, that temporary value would be the value that was then incorrectly
used as the orig_i0 argument to do_notify_resume.

In order to preserve %l6, the temporary usage of %l6 in ret_sys_call is
changed to use %l5 instead and the setting %l6 to 0 or 1 was removed.
The use of that 0 or 1 value in %l6 was removed in commit
28e61036.
Signed-off-by: NAndreas Larsson <andreas@gaisler.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc/kernel/entry.S

@@ -1009,7 +1009,7 @@ do_syscall:
 	andcc	%l5, _TIF_SYSCALL_TRACE, %g0
 	mov	%i4, %o4
 	bne	linux_syscall_trace
-	 mov	%i0, %l5
+	 mov	%i0, %l6
 2:
 	call	%l7
 	 mov	%i5, %o5
@@ -1018,16 +1018,15 @@ do_syscall:
 	st	%o0, [%sp + STACKFRAME_SZ + PT_I0]
 
 ret_sys_call:
-	ld	[%curptr + TI_FLAGS], %l6
+	ld	[%curptr + TI_FLAGS], %l5
 	cmp	%o0, -ERESTART_RESTARTBLOCK
 	ld	[%sp + STACKFRAME_SZ + PT_PSR], %g3
 	set	PSR_C, %g2
 	bgeu	1f
-	 andcc	%l6, _TIF_SYSCALL_TRACE, %g0
+	 andcc	%l5, _TIF_SYSCALL_TRACE, %g0
 
 	/* System call success, clear Carry condition code. */
 	andn	%g3, %g2, %g3
-	clr	%l6
 	st	%g3, [%sp + STACKFRAME_SZ + PT_PSR]	
 	bne	linux_syscall_trace2
 	 ld	[%sp + STACKFRAME_SZ + PT_NPC], %l1 /* pc = npc */
@@ -1042,7 +1041,6 @@ ret_sys_call:
 	sub	%g0, %o0, %o0
 	or	%g3, %g2, %g3
 	st	%o0, [%sp + STACKFRAME_SZ + PT_I0]
-	mov	1, %l6
 	st	%g3, [%sp + STACKFRAME_SZ + PT_PSR]
 	bne	linux_syscall_trace2
 	 ld	[%sp + STACKFRAME_SZ + PT_NPC], %l1 /* pc = npc */

arch/sparc/kernel/rtrap_32.S

@@ -75,7 +75,7 @@ signal_p:
 	 ld	[%sp + STACKFRAME_SZ + PT_PSR], %t_psr
 
 	mov	%g2, %o2
-	mov	%l5, %o1
+	mov	%l6, %o1
 	call	do_notify_resume
 	 add	%sp, STACKFRAME_SZ, %o0	! pt_regs ptr