FIXED: Exception reporting from FIQ mode

rsta2 · Nov 8, 2018 · 66909aa · 66909aa
1 parent ec20c93
commit 66909aa
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Showing 4 changed files with 23 additions and 6 deletions.
diff --git a/include/circle/exceptionstub.h b/include/circle/exceptionstub.h
@@ -2,7 +2,7 @@
 // exceptionstub.h
 //
 // Circle - A C++ bare metal environment for Raspberry Pi
-// Copyright (C) 2014-2017  R. Stange <rsta2@o2online.de>
+// Copyright (C) 2014-2018  R. Stange <rsta2@o2online.de>
 // 
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU General Public License as published by
@@ -47,6 +47,8 @@ struct TAbortFrame
 {
 	u32	sp_irq;
 	u32	lr_irq;
+	u32	sp_fiq;
+	u32	lr_fiq;
 	u32	r0;
 	u32	r1;
 	u32	r2;

diff --git a/lib/debug.cpp b/lib/debug.cpp
@@ -2,7 +2,7 @@
 // debug.cpp
 //
 // Circle - A C++ bare metal environment for Raspberry Pi
-// Copyright (C) 2016  R. Stange <rsta2@o2online.de>
+// Copyright (C) 2016-2018  R. Stange <rsta2@o2online.de>
 // 
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU General Public License as published by
@@ -80,7 +80,8 @@ void debug_stacktrace (const u32 *pStackPtr, const char *pSource)
 		extern unsigned char _etext;
 
 		if (   *pStackPtr >= MEM_KERNEL_START
-		    && *pStackPtr < (u32) &_etext)
+		    && *pStackPtr < (u32) &_etext
+		    && (*pStackPtr & 3) == 0)
 		{
 			CLogger::Get ()->Write (pSource, LogDebug, "stack[%u] is 0x%X", i, (unsigned) *pStackPtr);
 		}

diff --git a/lib/exceptionhandler.cpp b/lib/exceptionhandler.cpp
@@ -106,12 +106,19 @@ void CExceptionHandler::Throw (unsigned nException, TAbortFrame *pFrame)
 	u32 lr = pFrame->lr;
 	u32 sp = pFrame->sp;
 
-	if ((pFrame->spsr & 0x1F) == 0x12)	// IRQ mode?
+	switch (pFrame->spsr & 0x1F)
 	{
+	case 0x11:			// FIQ mode?
+		lr = pFrame->lr_fiq;
+		sp = pFrame->sp_fiq;
+		break;
+
+	case 0x12:			// IRQ mode?
 		lr = pFrame->lr_irq;
 		sp = pFrame->sp_irq;
+		break;
 	}
-	
+
 #ifndef NDEBUG
 	debug_stacktrace ((u32 *) sp, FromExcept);
 #endif
@@ -133,6 +140,10 @@ void ExceptionHandler (u32 nException, TAbortFrame *pFrame)
 {
 	PeripheralExit ();	// exit from interrupted peripheral
 
+	// if an exception occurs on FIQ_LEVEL, the system would otherwise hang in the next spin lock
+	CInterruptSystem::DisableFIQ ();
+	EnableFIQs ();
+
 	CExceptionHandler::Get ()->Throw (nException, pFrame);
 }
 

diff --git a/lib/exceptionstub.S b/lib/exceptionstub.S
@@ -35,9 +35,12 @@
 	cps	#0x12				/* set IRQ mode to access sp_irq and lr_irq */
 	mov	r2, sp
 	mov	r3, lr
+	cps	#0x11				/* set FIQ mode to access sp_fiq and lr_fiq */
+	mov	r4, sp
+	mov	r5, lr
 	cps	#0x1F				/* our abort handler runs in system mode */
 	mov	sp, r1				/* set sp_sys to stack top of abort stack */
-	stmfd	sp!, {r2, r3}			/* store lr_irq and sp_irq onto stack */
+	stmfd	sp!, {r2-r5}			/* store lr_fiq, sp_fiq, lr_irq, sp_irq onto stack */
 	mov	r1, sp				/* r1: pointer to register frame */
 	mov	r0, #\exception			/* r0: exception identifier */
 	b	ExceptionHandler		/* jump to ExceptionHandler (never returns) */