[PATCH] ppc64: support 64k pages

Adds a new CONFIG_PPC_64K_PAGES which, when enabled, changes the kernel
base page size to 64K.  The resulting kernel still boots on any
hardware.  On current machines with 4K pages support only, the kernel
will maintain 16 "subpages" for each 64K page transparently.

Note that while real 64K capable HW has been tested, the current patch
will not enable it yet as such hardware is not released yet, and I'm
still verifying with the firmware architects the proper to get the
information from the newer hypervisors.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 9 insertions, 4 deletions

diff --git a/include/asm-ppc64/paca.h b/include/asm-ppc64/paca.h
index f68fe91debaf..bccacd6aa93a 100644
--- a/include/asm-ppc64/paca.h
+++ b/include/asm-ppc64/paca.h
@@ -72,10 +72,15 @@ struct paca_struct {
 	/*
 	 * Now, starting in cacheline 2, the exception save areas
 	 */
-	u64 exgen[8] __attribute__((aligned(0x80))); /* used for most interrupts/exceptions */
-	u64 exmc[8];		/* used for machine checks */
-	u64 exslb[8];		/* used for SLB/segment table misses
-				 * on the linear mapping */
+	/* used for most interrupts/exceptions */
+	u64 exgen[10] __attribute__((aligned(0x80)));
+	u64 exmc[10];		/* used for machine checks */
+	u64 exslb[10];		/* used for SLB/segment table misses
+ 				 * on the linear mapping */
+#ifdef CONFIG_PPC_64K_PAGES
+	pgd_t *pgdir;
+#endif /* CONFIG_PPC_64K_PAGES */
+
 	mm_context_t context;
 	u16 slb_cache[SLB_CACHE_ENTRIES];
 	u16 slb_cache_ptr;