[POWERPC] irqtrace support for 64-bit powerpc

This adds the low level irq tracing hooks to the powerpc architecture
needed to enable full lockdep functionality.

This is partly based on Johannes Berg's initial version.  I removed
the asm trampoline that isn't needed (thus improving performance) and
modified all sorts of bits and pieces, reworking most of the assembly,
etc...

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/include/asm-powerpc/irqflags.h b/include/asm-powerpc/irqflags.h
index 7970cba..cc6fdba 100644
--- a/include/asm-powerpc/irqflags.h
+++ b/include/asm-powerpc/irqflags.h
@@ -2,30 +2,43 @@
  * include/asm-powerpc/irqflags.h
  *
  * IRQ flags handling
- *
- * This file gets included from lowlevel asm headers too, to provide
- * wrapped versions of the local_irq_*() APIs, based on the
- * raw_local_irq_*() macros from the lowlevel headers.
  */
 #ifndef _ASM_IRQFLAGS_H
 #define _ASM_IRQFLAGS_H
 
+#ifndef __ASSEMBLY__
 /*
  * Get definitions for raw_local_save_flags(x), etc.
  */
 #include <asm-powerpc/hw_irq.h>
 
-/*
- * Do the CPU's IRQ-state tracing from assembly code. We call a
- * C function, so save all the C-clobbered registers:
- */
-#ifdef CONFIG_TRACE_IRQFLAGS
-
-#error No support on PowerPC yet for CONFIG_TRACE_IRQFLAGS
-
 #else
-# define TRACE_IRQS_ON
-# define TRACE_IRQS_OFF
+#ifdef CONFIG_TRACE_IRQFLAGS
+/*
+ * Most of the CPU's IRQ-state tracing is done from assembly code; we
+ * have to call a C function so call a wrapper that saves all the
+ * C-clobbered registers.
+ */
+#define TRACE_ENABLE_INTS	bl .trace_hardirqs_on
+#define TRACE_DISABLE_INTS	bl .trace_hardirqs_off
+#define TRACE_AND_RESTORE_IRQ_PARTIAL(en,skip)	\
+	cmpdi	en, 0;				\
+	bne	95f;				\
+	stb	en,PACASOFTIRQEN(r13);		\
+	bl	.trace_hardirqs_off;		\
+	b	skip;				\
+95:	bl	.trace_hardirqs_on;		\
+	li	en,1;
+#define TRACE_AND_RESTORE_IRQ(en)		\
+	TRACE_AND_RESTORE_IRQ_PARTIAL(en,96f);	\
+96:	stb	en,PACASOFTIRQEN(r13)
+#else
+#define TRACE_ENABLE_INTS
+#define TRACE_DISABLE_INTS
+#define TRACE_AND_RESTORE_IRQ_PARTIAL(en,skip)
+#define TRACE_AND_RESTORE_IRQ(en)		\
+	stb	en,PACASOFTIRQEN(r13)
+#endif
 #endif
 
 #endif