alpha: simplify TIF_NEED_RESCHED handling

In case we have both NEED_RESCHED and SIGPENDING/NOTIFY_RESUME,
handle the latter first.  We'll get to original priorities in
the next commit, but now that allows to simplify the treatment
of NEED_RESCHED-only case nicely.  Namely, now there no need to
preserve the data for restarts across the call of schedule() in
$work_resched; we can get there only if we had either returned
from syscall without SIGPENDING (in which case we should've
had no restart-worthy return value and want no restarts) or
already got through do_notify_resume() call (in which case we
want no restarts anymore).  So we can just slap 0 into $19
instead of preserving it (and $20).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 9 insertions, 17 deletions

diff --git a/arch/alpha/kernel/entry.S b/arch/alpha/kernel/entry.S
index 2a359c9ee3c..802108b15be 100644
--- a/arch/alpha/kernel/entry.S
+++ b/arch/alpha/kernel/entry.S
@@ -372,26 +372,18 @@ $ret_success:
         .align  4
         .ent    work_pending
 work_pending:
-        and     $5, _TIF_NEED_RESCHED, $2
-        beq     $2, $work_notifysig
+        and     $5, _TIF_NOTIFY_RESUME | _TIF_SIGPENDING, $2
+        bne     $2, $work_notifysig
 
 $work_resched:
-        subq    $sp, 16, $sp
-        stq     $19, 0($sp)              /* save syscall nr */
-        stq     $20, 8($sp)              /* and error indication (a3) */
+        /*
+         * We can get here only if we returned from syscall without SIGPENDING
+         * or got through work_notifysig already.  Either case means no syscall
+         * restarts for us, so let $19 and $20 burn.
+         */
         jsr     $26, schedule
-        ldq     $19, 0($sp)
-        ldq     $20, 8($sp)
-        addq    $sp, 16, $sp
-        /* Make sure need_resched and sigpending don't change between
-                sampling and the rti.  */
-        lda     $16, 7
-        call_pal PAL_swpipl
-        ldl     $5, TI_FLAGS($8)
-        and     $5, _TIF_WORK_MASK, $2
-        beq     $2, restore_all
-        and     $5, _TIF_NEED_RESCHED, $2
-        bne     $2, $work_resched
+        mov     0, $19
+        br      ret_to_user
 
 $work_notifysig:
         mov     $sp, $16