Re: [microblaze-uclinux] [PATCH 10/11] microblaze: use generic system.h

[Arnd Bergmann <arnd@arndb.de>]

On Wednesday 01 July 2009, Michal Simek wrote:
> this patch can't be applied because generic implementation expect pointer to task struct
> but microblaze low level code expect thread_info. I have one patch for MMU kernel which fixed it
> but I don't have it for noMMU kernel.

Ok, just leave it out for now then, it's not important because it does not impact the ABI.

Maybe I should allow overriding switch_to() in the generic file?

	Arnd <><
---
asm-generic: make parts of system.h optional

The asm-generic/system.h file was originally meant as an example, but by
letting the architecture override some of its contents, it immediately
becomes much more useful.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

--- a/include/asm-generic/system.h
+++ b/include/asm-generic/system.h
@@ -24,6 +24,7 @@
 
 struct task_struct;
 
+#ifndef switch_to
 /* context switching is now performed out-of-line in switch_to.S */
 extern struct task_struct *__switch_to(struct task_struct *,
 		struct task_struct *);
@@ -31,10 +32,15 @@ extern struct task_struct *__switch_to(struct task_struct *,
 	do {								\
 		((last) = __switch_to((prev), (next)));			\
 	} while (0)
+#endif
 
+#ifndef arch_align_stack
 #define arch_align_stack(x) (x)
+#endif
 
+#ifndef nop
 #define nop() asm volatile ("nop")
+#define nop
 
 #endif /* !__ASSEMBLY__ */
 
@@ -46,9 +52,11 @@ extern struct task_struct *__switch_to(struct task_struct *,
  * This implementation only contains a compiler barrier.
  */
 
+#ifndef mb()
 #define mb()	asm volatile ("": : :"memory")
 #define rmb()	mb()
 #define wmb()	asm volatile ("": : :"memory")
+#endif
 
 #ifdef CONFIG_SMP
 #define smp_mb()	mb()