From 13a0c3c269b223f60abfac8a9811d77111a8b4ba Mon Sep 17 00:00:00 2001
From: Yinghai Lu
Date: Fri, 26 Dec 2008 02:05:47 -0800
Subject: sparseirq: work around compiler optimizing away __weak functions

Impact: fix panic on null pointer with sparseirq

Some GCC versions seem to inline the weak global function,
when that function is empty.

Work it around, by making the functions return a (dummy) integer.

Signed-off-by: Yinghai <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 init/main.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

(limited to 'init/main.c')

diff --git a/init/main.c b/init/main.c
index c1f999a3cf31..c314aa15370e 100644
--- a/init/main.c
+++ b/init/main.c
@@ -539,13 +539,14 @@ void __init __weak thread_info_cache_init(void)
 {
 }
 
-void __init __weak arch_early_irq_init(void)
+int __init __weak arch_early_irq_init(void)
 {
+	return 0;
 }
 
-void __init __weak early_irq_init(void)
+int __init __weak early_irq_init(void)
 {
-	arch_early_irq_init();
+	return arch_early_irq_init();
 }
 
 asmlinkage void __init start_kernel(void)
-- 
cgit v1.2.3


From 43a256322ac1fc105c181b3cade3b9bfc0b63ca1 Mon Sep 17 00:00:00 2001
From: Yinghai Lu
Date: Sun, 28 Dec 2008 16:01:13 -0800
Subject: sparseirq: move __weak symbols into separate compilation unit

GCC has a bug with __weak alias functions: if the functions are in
the same compilation unit as their call site, GCC can decide to
inline them - and thus rob the linker of the opportunity to override
the weak alias with the real thing.

So move all the IRQ handling related __weak symbols to kernel/irq/chip.c.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 include/linux/interrupt.h |  6 ++++++
 include/linux/irq.h       |  3 ---
 init/main.c               | 10 ----------
 kernel/irq/manage.c       |  9 ---------
 kernel/softirq.c          | 20 ++++++++++++++++++++
 5 files changed, 26 insertions(+), 22 deletions(-)

(limited to 'init/main.c')

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 777f89e00b4a..d9a370325ae2 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -467,4 +467,10 @@ static inline void init_irq_proc(void)
 
 int show_interrupts(struct seq_file *p, void *v);
 
+struct irq_desc;
+
+extern int early_irq_init(void);
+extern int arch_early_irq_init(void);
+extern int arch_init_chip_data(struct irq_desc *desc, int cpu);
+
 #endif
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 0e40af4bac40..d64a6d49bdef 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -193,9 +193,6 @@ struct irq_desc {
 	const char		*name;
 } ____cacheline_internodealigned_in_smp;
 
-extern int early_irq_init(void);
-extern int arch_early_irq_init(void);
-extern int arch_init_chip_data(struct irq_desc *desc, int cpu);
 extern void arch_init_copy_chip_data(struct irq_desc *old_desc,
 					struct irq_desc *desc, int cpu);
 extern void arch_free_chip_data(struct irq_desc *old_desc, struct irq_desc *desc);
diff --git a/init/main.c b/init/main.c
index c314aa15370e..2c183abbf61c 100644
--- a/init/main.c
+++ b/init/main.c
@@ -539,16 +539,6 @@ void __init __weak thread_info_cache_init(void)
 {
 }
 
-int __init __weak arch_early_irq_init(void)
-{
-	return 0;
-}
-
-int __init __weak early_irq_init(void)
-{
-	return arch_early_irq_init();
-}
-
 asmlinkage void __init start_kernel(void)
 {
 	char * command_line;
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index c2741b02ad38..46953a06f4a8 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -261,15 +261,6 @@ void enable_irq(unsigned int irq)
 }
 EXPORT_SYMBOL(enable_irq);
 
-/*
- * [ Not in kernel/irq/handle.c, so that GCC does not
- *   inline the __weak alias: ]
- */
-int __weak arch_init_chip_data(struct irq_desc *desc, int cpu)
-{
-	return 0;
-}
-
 static int set_irq_wake_real(unsigned int irq, unsigned int on)
 {
 	struct irq_desc *desc = irq_to_desc(irq);
diff --git a/kernel/softirq.c b/kernel/softirq.c
index e7c69a720d69..daf46358d2dd 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -797,3 +797,23 @@ int on_each_cpu(void (*func) (void *info), void *info, int wait)
 }
 EXPORT_SYMBOL(on_each_cpu);
 #endif
+
+/*
+ * [ These __weak aliases are kept in a separate compilation unit, so that
+ *   GCC does not inline them incorrectly. ]
+ */
+
+int __init __weak early_irq_init(void)
+{
+	return 0;
+}
+
+int __init __weak arch_early_irq_init(void)
+{
+	return 0;
+}
+
+int __weak arch_init_chip_data(struct irq_desc *desc, int cpu)
+{
+	return 0;
+}
-- 
cgit v1.2.3