From 180e04ee41f988e707078620bae65d598c91314c Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@gmx.de>
Date: Fri, 25 Jan 2013 14:48:57 +0100
Subject: [PATCH] omap: fix breakpoint instruction trap handling (from sources)

---
 sys/src/9/omap/arm.h  |  6 ++++++
 sys/src/9/omap/fns.h  |  1 +
 sys/src/9/omap/l.s    |  8 ++++++--
 sys/src/9/omap/trap.c | 18 +++++++++++++++++-
 4 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/sys/src/9/omap/arm.h b/sys/src/9/omap/arm.h
index 12443d849..0376f36fb 100644
--- a/sys/src/9/omap/arm.h
+++ b/sys/src/9/omap/arm.h
@@ -33,6 +33,12 @@
 #define CpDFP		11			/* double FP */
 #define CpSC		15			/* System Control */
 
+ /*
+  * CpFSR op1==0, Crm==0 opcode 2 values.
+  */
+#define CpDFSR		0			/* data fault status */
+#define CpIFSR		1			/* instruction fault status */
+
 /*
  * Primary (CRn) CpSC registers.
  */
diff --git a/sys/src/9/omap/fns.h b/sys/src/9/omap/fns.h
index 342af1604..a1e486dda 100644
--- a/sys/src/9/omap/fns.h
+++ b/sys/src/9/omap/fns.h
@@ -50,6 +50,7 @@ extern u32int fsrget(void);
 extern u32int getscr(void);
 extern u32int getpsr(void);
 extern ulong getwayssets(void);
+extern u32int ifsrget(void);
 extern void intrsoff(void);
 extern int isaconfig(char*, int, ISAConf*);
 extern int isdmadone(int);
diff --git a/sys/src/9/omap/l.s b/sys/src/9/omap/l.s
index 9950cd2ad..0e9a5b67c 100644
--- a/sys/src/9/omap/l.s
+++ b/sys/src/9/omap/l.s
@@ -474,10 +474,14 @@ TEXT dacput(SB), 1, $-4				/* domain access control */
 	ISB
 	RET
 
-TEXT fsrget(SB), 1, $-4				/* fault status */
-	MRC	CpSC, 0, R0, C(CpFSR), C(0)
+TEXT fsrget(SB), 1, $-4				/* data fault status */
+	MRC	CpSC, 0, R0, C(CpFSR), C(0), CpDFSR
 	RET
 
+TEXT ifsrget(SB), 1, $-4			/* instruction fault status */
+	MRC	CpSC, 0, R0, C(CpFSR), C(0), CpIFSR
+ 	RET
+
 TEXT farget(SB), 1, $-4				/* fault address */
 	MRC	CpSC, 0, R0, C(CpFAR), C(0x0)
 	RET
diff --git a/sys/src/9/omap/trap.c b/sys/src/9/omap/trap.c
index 2a97b71c5..7fab7c778 100644
--- a/sys/src/9/omap/trap.c
+++ b/sys/src/9/omap/trap.c
@@ -493,7 +493,23 @@ trap(Ureg *ureg)
 		break;
 	case PsrMabt:			/* prefetch fault */
 		ldrexvalid = 0;
-		faultarm(ureg, ureg->pc, user, 1);
+		x = ifsrget();
+		fsr = (x>>7) & 0x8 | x & 0x7;
+		switch(fsr){
+		case 0x02:		/* instruction debug event (BKPT) */
+			if(user){
+				snprint(buf, sizeof buf, "sys: breakpoint");
+				postnote(up, 1, buf, NDebug);
+			}else{
+				iprint("kernel bkpt: pc %#lux inst %#ux\n",
+					ureg->pc, *(u32int*)ureg->pc);
+				panic("kernel bkpt");
+			}
+			break;
+		default:
+			faultarm(ureg, ureg->pc, user, 1);
+			break;
+		}
 		break;
 	case PsrMabt+1:			/* data fault */
 		ldrexvalid = 0;