[PATCH] powerpc: Remove lppaca structure from the PACA

At present the lppaca - the structure shared with the iSeries
hypervisor and phyp - is contained within the PACA, our own low-level
per-cpu structure.  This doesn't have to be so, the patch below
removes it, making a separate array of lppaca structures.

This saves approximately 500*NR_CPUS bytes of image size and kernel
memory, because we don't need aligning gap between the Linux and
hypervisor portions of every PACA.  On the other hand it means an
extra level of dereference in many accesses to the lppaca.

The patch also gets rid of several places where we assign the paca
address to a local variable for no particular reason.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

4 files changed, 9 insertions, 18 deletions

diff --git a/include/asm-powerpc/lppaca.h b/include/asm-powerpc/lppaca.h
index ff82ea7c482..cd9f11f1ef1 100644
--- a/include/asm-powerpc/lppaca.h
+++ b/include/asm-powerpc/lppaca.h
@@ -29,7 +29,9 @@
 //----------------------------------------------------------------------------
 #include <asm/types.h>
 
-struct lppaca {
+/* The Hypervisor barfs if the lppaca crosses a page boundary.  A 1k
+ * alignment is sufficient to prevent this */
+struct __attribute__((__aligned__(0x400))) lppaca {
 //=============================================================================
 // CACHE_LINE_1 0x0000 - 0x007F Contains read-only data
 // NOTE: The xDynXyz fields are fields that will be dynamically changed by
@@ -129,5 +131,7 @@ struct lppaca {
 	u8	pmc_save_area[256];	// PMC interrupt Area           x00-xFF
 };
 
+extern struct lppaca lppaca[];
+
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_LPPACA_H */
diff --git a/include/asm-powerpc/paca.h b/include/asm-powerpc/paca.h
index a64b4d425da..c9add8f1ad9 100644
--- a/include/asm-powerpc/paca.h
+++ b/include/asm-powerpc/paca.h
@@ -23,6 +23,7 @@
 
 register struct paca_struct *local_paca asm("r13");
 #define get_paca()	local_paca
+#define get_lppaca()	(get_paca()->lppaca_ptr)
 
 struct task_struct;
 
@@ -95,19 +96,6 @@ struct paca_struct {
 	u64 saved_r1;			/* r1 save for RTAS calls */
 	u64 saved_msr;			/* MSR saved here by enter_rtas */
 	u8 proc_enabled;		/* irq soft-enable flag */
-
-	/*
-	 * iSeries structure which the hypervisor knows about -
-	 * this structure should not cross a page boundary.
-	 * The vpa_init/register_vpa call is now known to fail if the
-	 * lppaca structure crosses a page boundary.
-	 * The lppaca is also used on POWER5 pSeries boxes.
-	 * The lppaca is 640 bytes long, and cannot readily change
-	 * since the hypervisor knows its layout, so a 1kB
-	 * alignment will suffice to ensure that it doesn't
-	 * cross a page boundary.
-	 */
-	struct lppaca lppaca __attribute__((__aligned__(0x400)));
 };
 
 extern struct paca_struct paca[];
diff --git a/include/asm-powerpc/spinlock.h b/include/asm-powerpc/spinlock.h
index 754900901cd..26b8744ed52 100644
--- a/include/asm-powerpc/spinlock.h
+++ b/include/asm-powerpc/spinlock.h
@@ -80,7 +80,7 @@ static int __inline__ __raw_spin_trylock(raw_spinlock_t *lock)
 
 #if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES)
 /* We only yield to the hypervisor if we are in shared processor mode */
-#define SHARED_PROCESSOR (get_paca()->lppaca.shared_proc)
+#define SHARED_PROCESSOR (get_lppaca()->shared_proc)
 extern void __spin_yield(raw_spinlock_t *lock);
 extern void __rw_yield(raw_rwlock_t *lock);
 #else /* SPLPAR || ISERIES */
diff --git a/include/asm-powerpc/time.h b/include/asm-powerpc/time.h
index d9b86a17271..baddc9ab57a 100644
--- a/include/asm-powerpc/time.h
+++ b/include/asm-powerpc/time.h
@@ -175,11 +175,10 @@ static inline void set_dec(int val)
 	set_dec_cpu6(val);
 #else
 #ifdef CONFIG_PPC_ISERIES
-	struct paca_struct *lpaca = get_paca();
 	int cur_dec;
 
-	if (lpaca->lppaca.shared_proc) {
-		lpaca->lppaca.virtual_decr = val;
+	if (get_lppaca()->shared_proc) {
+		get_lppaca()->virtual_decr = val;
 		cur_dec = get_dec();
 		if (cur_dec > val)
 			HvCall_setVirtualDecr();