Blackfin: sanitize manual control of IPEND[4]

Cleanup is performed in two ways:

- remove extraneous updates of IPEND[4] w/ CONFIG_IPIPE,
  and document remaining use.

- substitute pop-reg-from-stack instructions with plain SP fixups in
  all save-RETI-then-discard patterns.

Signed-off-by: Philippe Gerum <rpm@xenomai.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

1 files changed, 11 insertions, 14 deletions

diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index 919f7aef0773..2c58b60ff131 100644
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -708,8 +708,14 @@ ENTRY(_system_call)
 #ifdef CONFIG_IPIPE
         cc = BITTST(r7, TIF_IRQ_SYNC);
         if !cc jump .Lsyscall_no_irqsync;
+        /*
+         * Clear IPEND[4] manually to undo what resume_userspace_1 just did;
+         * we need this so that high priority domain interrupts may still
+         * preempt the current domain while the pipeline log is being played
+         * back.
+         */
         [--sp] = reti;
-        r0 = [sp++];
+        SP += 4; /* don't merge with next insn to keep the pattern obvious */
         SP += -12;
         call ___ipipe_sync_root;
         SP += 12;
@@ -721,7 +727,7 @@ ENTRY(_system_call)
 
         /* Reenable interrupts.  */
         [--sp] = reti;
-        r0 = [sp++];
+        sp += 4;
 
         SP += -12;
         call _schedule;
@@ -737,7 +743,7 @@ ENTRY(_system_call)
 .Lsyscall_do_signals:
         /* Reenable interrupts.  */
         [--sp] = reti;
-        r0 = [sp++];
+        sp += 4;
 
         r0 = sp;
         SP += -12;
@@ -747,10 +753,6 @@ ENTRY(_system_call)
 .Lsyscall_really_exit:
         r5 = [sp + PT_RESERVED];
         rets = r5;
-#ifdef CONFIG_IPIPE
-        [--sp] = reti;
-        r5 = [sp++];
-#endif /* CONFIG_IPIPE */
         rts;
 ENDPROC(_system_call)
 
@@ -904,14 +906,9 @@ ENDPROC(_ret_from_exception)
 
 #ifdef CONFIG_IPIPE
 
-_sync_root_irqs:
-        [--sp] = reti;          /* Reenable interrupts */
-        r0 = [sp++];
-        jump.l ___ipipe_sync_root
-
 _resume_kernel_from_int:
-        r0.l = _sync_root_irqs
-        r0.h = _sync_root_irqs
+        r0.l = ___ipipe_sync_root;
+        r0.h = ___ipipe_sync_root;
         [--sp] = rets;
         [--sp] = ( r7:4, p5:3 );
         SP += -12;