[PATCH 29/31] Add debugger entry points for POWERPC

[Jeffrey Merkey <jeffmerkey@gmail.com>]

This patch series adds an export which can be set by system debuggers to
direct the hard lockup and soft lockup detector to trigger a breakpoint
exception and enter a debugger if one is active.  It is assumed that if
someone sets this variable, then an breakpoint handler of some sort will
be actively loaded or registered via the notify die handler chain.

This addition is extremely useful for debugging hard and soft lockups
real time and quickly from a console debugger.

Signed-off-by: Jeffrey Merkey <jeffmerkey@gmail.com>
---
 arch/powerpc/include/asm/kdebug.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/powerpc/include/asm/kdebug.h b/arch/powerpc/include/asm/kdebug.h
index ae6d206..54f5ca8 100644
--- a/arch/powerpc/include/asm/kdebug.h
+++ b/arch/powerpc/include/asm/kdebug.h
@@ -11,5 +11,10 @@ enum die_val {
 	DIE_SSTEP,
 };
 
+static inline void arch_breakpoint(void)
+{
+	asm(".long 0x7d821008"); /* twge r2, r2 */
+}
+
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_KDEBUG_H */
-- 
1.8.3.1