Re: [PATCH] SLB shadow buffer

On Mon Aug  7 2006 01:19:19 AM CDT, Michael Neuling wrote:

Updated with comments from Milton.

Better

+#define SHADOW_SLB_BOLTED_STACK_ESID \
+		(SLBSHADOW_SAVEAREA + 0x10*(SLB_NUM_BOLTED-1))
+#define SHADOW_SLB_BOLTED_STACK_VSID \
+		(SLBSHADOW_SAVEAREA + 0x10*(SLB_NUM_BOLTED-1) + 8)
+

Still a bit of magic size, but not likely to change.

Maybe an expicit define for the slot?

+	/* Update the last bolted SLB */
+	ld	r9,PACA_SLBSHADOWPTR(r13)
+ 	li	r12,0
+  	std	r12,SHADOW_SLB_BOLTED_STACK_ESID(r9) /* Clear ESID */
+	std	r7,SHADOW_SLB_BOLTED_STACK_VSID(r9)  /* Save VSID */
+ 	std	r0,SHADOW_SLB_BOLTED_STACK_ESID(r9)  /* Save ESID */
+

 Still some leading spaces hiding

 Index: linux-2.6-ozlabs/include/asm-powerpc/lppaca.h

C comments ... or in the separate cleanup patch

+extern struct slb_shadow slb_shadow[];
+
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_LPPACA_H */
Index: linux-2.6-ozlabs/include/asm-powerpc/paca.h
===================================================================

 	/* accumulated system TB ticks */
 	u64 startpurr;			/* PURR/TB value snapshot */
+
+	struct slb_shadow *slb_shadow_ptr;
 };

 
Do we need the extra line?  (I haven't looked at the result)

milton

quoted

+#define SHADOW_SLB_BOLTED_STACK_ESID \
+		(SLBSHADOW_SAVEAREA + 0x10*(SLB_NUM_BOLTED-1))
+#define SHADOW_SLB_BOLTED_STACK_VSID \
+		(SLBSHADOW_SAVEAREA + 0x10*(SLB_NUM_BOLTED-1) + 8)
+

Still a bit of magic size, but not likely to change.

Maybe an expicit define for the slot?

Arrh nice, I can do this all in asm-offsets.  Much less magic.

quoted

+	/* Update the last bolted SLB */
+	ld	r9,PACA_SLBSHADOWPTR(r13)
+ 	li	r12,0
+  	std	r12,SHADOW_SLB_BOLTED_STACK_ESID(r9) /* Clear ESID */
+	std	r7,SHADOW_SLB_BOLTED_STACK_VSID(r9)  /* Save VSID */
+ 	std	r0,SHADOW_SLB_BOLTED_STACK_ESID(r9)  /* Save ESID */
+

 Still some leading spaces hiding

Yep... oops.  

quoted

 Index: linux-2.6-ozlabs/include/asm-powerpc/lppaca.h

quoted

@@ -133,5 +135,22 @@ struct > > > lppaca {
 
 extern struct lppaca lppaca[];
 
+/*
+ * SLB shadow buffer structure as defined in the PAPR.  The save_area
+ * contains adjacent ESID and VSID pairs for each shadowed SLB.  The
+ * ESID is stored in the lower 64bits, then the VSID.
+ */
+struct slb_shadow {
+	u32	persistent;		// Number of persistent SLBs	x00-x03
+	u32	buffer_length;		// Total shadow buffer length	x04-x07
+	u64	reserved;		// Alignment			x08-x0f
+	struct	{
+		u64     esid;
+		u64	vsid;
+	} save_area[SLB_NUM_BOLTED];	//				x10-x40
+} ____cacheline_aligned;
+

C comments ... or in the separate cleanup patch

I think I'll post a full lppaca cleanup patch in a bit.  

quoted

+extern struct slb_shadow slb_shadow[];
+
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_LPPACA_H */
Index: linux-2.6-ozlabs/include/asm-powerpc/paca.h
===================================================================

 	/* accumulated system TB ticks */
 	u64 startpurr;			/* PURR/TB value snapshot */
+
+	struct slb_shadow *slb_shadow_ptr;
 };

 
Do we need the extra line?  (I haven't looked at the result)

They are broken into logical groups, so no.

Updated patch to come.

Michael