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>

diff --git a/arch/alpha/kernel/entry.S b/arch/alpha/kernel/entry.S
index 2a359c9ee3cd88a341550c57f34177288ee61ecd..802108b15be83b67424f22acec13f7c2c55ce322 100644 (file)
--- 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