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authorDavid S. Miller <davem@davemloft.net>2013-09-18 22:39:06 (GMT)
committerDavid S. Miller <davem@davemloft.net>2013-11-12 23:22:34 (GMT)
commitbb7b435388b9f035ecfb16f42b5c6bf428359c63 (patch)
tree5e64fe2772da7d787f88a6e7854db642c2dc2bb1 /arch/sparc/kernel
parente0a45e3580a033669b24b04c3535515d69bb9702 (diff)
sparc64: Document the shift counts used to validate linear kernel addresses.
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 <davem@davemloft.net> Acked-by: Bob Picco <bob.picco@oracle.com>
Diffstat (limited to 'arch/sparc/kernel')
-rw-r--r--arch/sparc/kernel/ktlb.S10
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/sparc/kernel/ktlb.S b/arch/sparc/kernel/ktlb.S
index fde5a41..7ad46bc 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. */

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