From 1f271fcf4843352917f17b2a7501dfe299fcdf5c Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Sun, 16 Sep 2018 13:21:39 +0100
Subject: [PATCH] tickless: fix dumb bug propogated across multiple platforms

This makes things work far better than before.
---
 Kernel/platform-rc2014-tiny/main.c |  2 +-
 Kernel/platform-rc2014/main.c      |  2 +-
 Kernel/platform-sbcv2/main.c       |  2 +-
 Kernel/platform-sc108/main.c       | 33 +++++++++++++++---------------
 4 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/Kernel/platform-rc2014-tiny/main.c b/Kernel/platform-rc2014-tiny/main.c
index 143c20ee..c3a21199 100644
--- a/Kernel/platform-rc2014-tiny/main.c
+++ b/Kernel/platform-rc2014-tiny/main.c
@@ -105,8 +105,8 @@ void sync_clock(void)
 					timer_interrupt();
 				}
 			}
-			re_enter--;
 		}
+		re_enter--;
 		irqrestore(irq);
 	}
 }
diff --git a/Kernel/platform-rc2014/main.c b/Kernel/platform-rc2014/main.c
index 2b3636ee..ea81b6f0 100644
--- a/Kernel/platform-rc2014/main.c
+++ b/Kernel/platform-rc2014/main.c
@@ -115,8 +115,8 @@ void sync_clock(void)
 				/* FIXME: need to cover ACIA option.. */
 				tty_pollirq_sio();
 			}
-			re_enter--;
 		}
+		re_enter--;
 		irqrestore(irq);
 	}
 }
diff --git a/Kernel/platform-sbcv2/main.c b/Kernel/platform-sbcv2/main.c
index 53ceb442..3e5d5105 100644
--- a/Kernel/platform-sbcv2/main.c
+++ b/Kernel/platform-sbcv2/main.c
@@ -134,8 +134,8 @@ void sync_clock(void)
 				/* Poll the PropIOv2 */
 				platform_interrupt();
 			}
-			re_enter--;
 		} 
+		re_enter--;
 		irqrestore(irq);
 	}
 }
diff --git a/Kernel/platform-sc108/main.c b/Kernel/platform-sc108/main.c
index a27ea784..64925183 100644
--- a/Kernel/platform-sc108/main.c
+++ b/Kernel/platform-sc108/main.c
@@ -9,7 +9,6 @@
 
 extern unsigned char irqvector;
 struct blkbuf *bufpool_end = bufpool + NBUFS;	/* minimal for boot -- expanded after we're done with _DISCARD */
-uint8_t timermsr = 0;
 uint16_t swap_dev = 0xFFFF;
 uint16_t ramtop = 0xF000;
 uint8_t need_resched = 0;
@@ -35,7 +34,7 @@ void platform_idle(void)
 	/* Check the clock. We try and reduce the impact of the clock on
 	   latency by not doing it so often. 256 may be too small a divide
 	   need t see what 1/10th sec looks like in poll loops */
-	if (!idlect++)
+	if (!++idlect)
 		sync_clock();
 }
 
@@ -94,24 +93,24 @@ static void sync_clock_read(void)
  */
 void sync_clock(void)
 {
-	if (!timermsr) {
-		irqflags_t irq = di();
-		int16_t tmp;
-		if (!re_enter++) {
-			sync_clock_read();
-			if (oldticks != 0xFF) {
-				tmp = newticks - oldticks;
-				if (tmp < 0)
-					tmp += 60;
-				tmp *= 10;
-				while(tmp--) {
-					timer_interrupt();
-				}
+	irqflags_t irq = di();
+	int16_t tmp;
+	if (!re_enter++) {
+		sync_clock_read();
+		if (oldticks != 0xFF) {
+			tmp = newticks - oldticks;
+			if (tmp < 0)
+				tmp += 60;
+			tmp *= 10;
+			while(tmp--) {
+				timer_interrupt();
 			}
-			re_enter--;
 		}
-		irqrestore(irq);
 	}
+	re_enter--;
+	if (re_enter > 1)
+		kputs("oops");
+	irqrestore(irq);
 }
 
 /*
-- 
2.34.1