[PATCH -V6 08/12] arch/powerpc: Make some of the PGTABLE_RANGE dependency explicit

[Aneesh Kumar K.V]

From: "Aneesh Kumar K.V" <aneesh.kumar at linux.vnet.ibm.com>

slice array size and slice mask size depend on PGTABLE_RANGE. We
can't directly include pgtable.h in these header because there is
a circular dependency. So add compile time check for these values.

Reviewed-by: Paul Mackerras <paulus at samba.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/mmu-hash64.h    |   13 ++++++++-----
 arch/powerpc/include/asm/page_64.h       |   16 ++++++++++++----
 arch/powerpc/include/asm/pgtable-ppc64.h |    8 ++++++++
 3 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index 8f05eec..8c5c5a4 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -420,6 +420,13 @@ extern void slb_set_size(u16 size);
 	srdi	rx,rx,VSID_BITS_##size;	/* extract 2^VSID_BITS bit */	\
 	add	rt,rt,rx
 
+/* 4 bits per slice and we have one slice per 1TB */
+#if 0 /* We can't directly include pgtable.h hence this hack */
+#define SLICE_ARRAY_SIZE  (PGTABLE_RANGE >> 41)
+#else
+/* Right now we only support 64TB */
+#define SLICE_ARRAY_SIZE  32
+#endif
 
 #ifndef __ASSEMBLY__
 
@@ -464,11 +471,7 @@ typedef struct {
 
 #ifdef CONFIG_PPC_MM_SLICES
 	u64 low_slices_psize;	/* SLB page size encodings */
-	/*
-	 * Right now we support 64TB and 4 bits for each
-	 * 1TB slice we need 32 bytes for 64TB.
-	 */
-	unsigned char high_slices_psize[32];  /* 4 bits per slice for now */
+	unsigned char high_slices_psize[SLICE_ARRAY_SIZE];
 #else
 	u16 sllp;		/* SLB page size encoding */
 #endif
diff --git a/arch/powerpc/include/asm/page_64.h b/arch/powerpc/include/asm/page_64.h
index 6c9bef4..b55beb4 100644
--- a/arch/powerpc/include/asm/page_64.h
+++ b/arch/powerpc/include/asm/page_64.h
@@ -78,14 +78,22 @@ extern u64 ppc64_pft_size;
 #define GET_LOW_SLICE_INDEX(addr)	((addr) >> SLICE_LOW_SHIFT)
 #define GET_HIGH_SLICE_INDEX(addr)	((addr) >> SLICE_HIGH_SHIFT)
 
+/* 1 bit per slice and we have one slice per 1TB */
+#if 0 /* We can't directly include pgtable.h hence this hack */
+#define SLICE_MASK_SIZE (PGTABLE_RANGE >> 43)
+#else
+/*
+ * Right now we support only 64TB.
+ * IF we change this we will have to change the type
+ * of high_slices
+ */
+#define SLICE_MASK_SIZE 8
+#endif
+
 #ifndef __ASSEMBLY__
 
 struct slice_mask {
 	u16 low_slices;
-	/*
-	 * This should be derived out of PGTABLE_RANGE. For the current
-	 * max 64TB, u64 should be ok.
-	 */
 	u64 high_slices;
 };
 
diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h
index 8af1cf2..dea953f 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -32,6 +32,14 @@
 #endif
 #endif
 
+#if (PGTABLE_RANGE >> 41) > SLICE_ARRAY_SIZE
+#error PGTABLE_RANGE exceeds SLICE_ARRAY_SIZE
+#endif
+
+#if (PGTABLE_RANGE >> 43) > SLICE_MASK_SIZE
+#error PGTABLE_RANGE exceeds slice_mask high_slices size
+#endif
+
 /*
  * Define the address range of the kernel non-linear virtual area
  */
-- 
1.7.10