From 8e10a209b0401d9393f4f6418bdf1fec4a875a24 Mon Sep 17 00:00:00 2001
From: arighi <arighi@38d2e660-2303-0410-9eaa-f027e97ec537>
Date: Tue, 18 May 2010 12:22:06 +0000
Subject: [PATCH] ARM7TDMI: gcc stack corruption workaround.

GCC corrupts the stack pointer and the frame pointer when calling
functions with at least one parameter inside ISR functions, declared
with __attribute__((interrupt)):

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41999

As a workaround, we redefine all the ISRs to call only a single
"void isr(void)" function. In this way, inside the actual isr() we can
use any function call as usual.

NOTE: this is inefficient, because it forces a totally unnecessary
additional function call, but it is a reliable way to avoid the
propagation of this bug to any project or architecture port that defines
interrupt routines.

When the bug will be fixed we will add an appropriate #ifdef to apply
the workaround only when old versions of gcc are used.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@3708 38d2e660-2303-0410-9eaa-f027e97ec537
---
 bertos/cpu/irq.h | 49 +++++++++++++++++++++++++++++++-----------------
 1 file changed, 32 insertions(+), 17 deletions(-)

diff --git a/bertos/cpu/irq.h b/bertos/cpu/irq.h
index f4cd21ee..40571142 100644
--- a/bertos/cpu/irq.h
+++ b/bertos/cpu/irq.h
@@ -340,16 +340,16 @@
 			 * IRQs will be automatically re-enabled when restoring
 			 * the context of the user task.
 			 */
-			#define DECLARE_ISR_CONTEXT_SWITCH(func)	\
-				void ISR_FUNC func(void);		\
-				static void __isr_##func(void);		\
-				void ISR_FUNC func(void)		\
-				{					\
-					IRQ_ENTRY();			\
-					IRQ_DISABLE;			\
-					__isr_##func();			\
-					IRQ_EXIT();			\
-				}					\
+			#define DECLARE_ISR_CONTEXT_SWITCH(func)		\
+				void ISR_FUNC func(void);			\
+				static NOINLINE void __isr_##func(void);	\
+				void ISR_FUNC func(void)			\
+				{						\
+					IRQ_ENTRY();				\
+					IRQ_DISABLE;				\
+					__isr_##func();				\
+					IRQ_EXIT();				\
+				}						\
 				static void __isr_##func(void)
 			/**
 			 * Interrupt service routine prototype: can be used for
@@ -376,21 +376,36 @@
 			#endif /* !CONFIG_KERN_PRI */
 		#endif /* CONFIG_KERN_PREEMPT */
 
+		#ifndef ISR_FUNC
+			#define ISR_FUNC  __attribute__((interrupt))
+		#endif
 		#ifndef DECLARE_ISR
 			#define DECLARE_ISR(func) \
-				void __attribute__((interrupt)) func(void)
+				void ISR_FUNC func(void);				\
+				/*							\
+				 * FIXME: avoid the inlining of this function.		\
+				 *							\
+				 * This is terribly inefficient, but it's a		\
+				 * reliable workaround to avoid gcc blowing		\
+				 * away the stack (see the bug below):			\
+				 *							\
+				 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41999	\
+				 */							\
+				static NOINLINE void __isr_##func(void);		\
+				void ISR_FUNC func(void)				\
+				{							\
+					__isr_##func();					\
+				}							\
+				static void __isr_##func(void)
 		#endif
 		#ifndef DECLARE_ISR_CONTEXT_SWITCH
-			#define DECLARE_ISR_CONTEXT_SWITCH(func) \
-				void __attribute__((interrupt)) func(void)
+			#define DECLARE_ISR_CONTEXT_SWITCH(func) DECLARE_ISR(func)
 		#endif
 		#ifndef ISR_PROTO
-			#define ISR_PROTO(func) \
-				void __attribute__((interrupt)) func(void)
+			#define ISR_PROTO(func)	void ISR_FUNC func(void)
 		#endif
 		#ifndef ISR_PROTO_CONTEXT_SWITCH
-			#define ISR_PROTO_CONTEXT_SWITCH(func)	\
-				void __attribute__((interrupt)) func(void)
+			#define ISR_PROTO_CONTEXT_SWITCH(func) ISR_PROTO(func)
 		#endif
 
 	#endif /* !__IAR_SYSTEMS_ICC_ */
-- 
2.25.1