From: "David S. Miller" <[email protected]>

This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.

===============

This way we can see exactly what they are derived from, and in particular
how they would change if we were to use a different PAGE_OFFSET value.

Signed-off-by: David S. Miller <[email protected]>
Acked-by: Bob Picco <[email protected]>
---
 arch/sparc/include/asm/page_64.h | 16 ++++++++++++++++
 arch/sparc/kernel/ktlb.S         | 10 +++++-----
 arch/sparc/mm/init_64.h          |  4 +++-
 3 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/arch/sparc/include/asm/page_64.h b/arch/sparc/include/asm/page_64.h
index 9dd0f7360822..978ea6d022e9 100644
--- a/arch/sparc/include/asm/page_64.h
+++ b/arch/sparc/include/asm/page_64.h
@@ -121,6 +121,22 @@ typedef pte_t *pgtable_t;
 #define PAGE_OFFSET_BY_BITS(X) (-(_AC(1,UL) << (X)))
 #define PAGE_OFFSET            PAGE_OFFSET_BY_BITS(MAX_SUPPORTED_PA_BITS)
 
+/* The "virtual" portion of PAGE_OFFSET, used to clip off the non-physical
+ * bits of a linear kernel address.
+ */
+#define PAGE_OFFSET_VA_BITS    (64 - MAX_SUPPORTED_PA_BITS)
+
+/* The actual number of physical memory address bits we support, this is
+ * used to size various tables used to manage kernel TLB misses.
+ */
+#define MAX_PHYS_ADDRESS_BITS  41
+
+/* These two shift counts are used when indexing sparc64_valid_addr_bitmap
+ * and kpte_linear_bitmap.
+ */
+#define ILOG2_4MB              22
+#define ILOG2_256MB            28
+
 #ifndef __ASSEMBLY__
 
 #define __pa(x)                        ((unsigned long)(x) - PAGE_OFFSET)
diff --git a/arch/sparc/kernel/ktlb.S b/arch/sparc/kernel/ktlb.S
index fde5a419cf27..7ad46bc0c698 100644
--- a/arch/sparc/kernel/ktlb.S
+++ b/arch/sparc/kernel/ktlb.S
@@ -153,12 +153,12 @@ kvmap_dtlb_tsb4m_miss:
        /* Clear the PAGE_OFFSET top virtual bits, shift
         * down to get PFN, and make sure PFN is in range.
         */
-       sllx            %g4, 21, %g5
+       sllx            %g4, PAGE_OFFSET_VA_BITS, %g5
 
        /* Check to see if we know about valid memory at the 4MB
         * chunk this physical address will reside within.
         */
-       srlx            %g5, 21 + 41, %g2
+       srlx            %g5, PAGE_OFFSET_VA_BITS + MAX_PHYS_ADDRESS_BITS, %g2
        brnz,pn         %g2, kvmap_dtlb_longpath
         nop
 
@@ -176,7 +176,7 @@ valid_addr_bitmap_patch:
        or              %g7, %lo(sparc64_valid_addr_bitmap), %g7
        .previous
 
-       srlx            %g5, 21 + 22, %g2
+       srlx            %g5, PAGE_OFFSET_VA_BITS + ILOG2_4MB, %g2
        srlx            %g2, 6, %g5
        and             %g2, 63, %g2
        sllx            %g5, 3, %g5
@@ -189,9 +189,9 @@ valid_addr_bitmap_patch:
 2:      sethi          %hi(kpte_linear_bitmap), %g2
 
        /* Get the 256MB physical address index. */
-       sllx            %g4, 21, %g5
+       sllx            %g4, PAGE_OFFSET_VA_BITS, %g5
        or              %g2, %lo(kpte_linear_bitmap), %g2
-       srlx            %g5, 21 + 28, %g5
+       srlx            %g5, PAGE_OFFSET_VA_BITS + ILOG2_256MB, %g5
        and             %g5, (32 - 1), %g7
 
        /* Divide by 32 to get the offset into the bitmask.  */
diff --git a/arch/sparc/mm/init_64.h b/arch/sparc/mm/init_64.h
index 0661aa606dec..5d3782deb403 100644
--- a/arch/sparc/mm/init_64.h
+++ b/arch/sparc/mm/init_64.h
@@ -1,11 +1,13 @@
 #ifndef _SPARC64_MM_INIT_H
 #define _SPARC64_MM_INIT_H
 
+#include <asm/page.h>
+
 /* Most of the symbols in this file are defined in init.c and
  * marked non-static so that assembler code can get at them.
  */
 
-#define MAX_PHYS_ADDRESS       (1UL << 41UL)
+#define MAX_PHYS_ADDRESS       (1UL << MAX_PHYS_ADDRESS_BITS)
 #define KPTE_BITMAP_CHUNK_SZ           (256UL * 1024UL * 1024UL)
 #define KPTE_BITMAP_BYTES      \
        ((MAX_PHYS_ADDRESS / KPTE_BITMAP_CHUNK_SZ) / 4)
-- 
2.1.2

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