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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2008-06-11 15:37:10 +1000
committerPaul Mackerras <paulus@samba.org>2008-06-30 22:30:53 +1000
commit41743a4e34f0777f51c1cf0675b91508ba143050 (patch)
tree9e63c8c8d70169e6c8be699167234db33b102a1f /include/asm-powerpc
parentff1f4ee94c3c4480b9cee95da2d19668262636c6 (diff)
powerpc: Free a PTE bit on ppc64 with 64K pages
This frees a PTE bit when using 64K pages on ppc64. This is done by getting rid of the separate _PAGE_HASHPTE bit. Instead, we just test if any of the 16 sub-page bits is set. For non-combo pages (ie. real 64K pages), we set SUB0 and the location encoding in that field. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'include/asm-powerpc')
-rw-r--r--include/asm-powerpc/pgtable-4k.h1
-rw-r--r--include/asm-powerpc/pgtable-64k.h17
-rw-r--r--include/asm-powerpc/pgtable-ppc64.h1
3 files changed, 16 insertions, 3 deletions
diff --git a/include/asm-powerpc/pgtable-4k.h b/include/asm-powerpc/pgtable-4k.h
index 818e2abc81e..fd2090dc1dc 100644
--- a/include/asm-powerpc/pgtable-4k.h
+++ b/include/asm-powerpc/pgtable-4k.h
@@ -41,6 +41,7 @@
#define PGDIR_MASK (~(PGDIR_SIZE-1))
/* PTE bits */
+#define _PAGE_HASHPTE 0x0400 /* software: pte has an associated HPTE */
#define _PAGE_SECONDARY 0x8000 /* software: HPTE is in secondary group */
#define _PAGE_GROUP_IX 0x7000 /* software: HPTE index within group */
#define _PAGE_F_SECOND _PAGE_SECONDARY
diff --git a/include/asm-powerpc/pgtable-64k.h b/include/asm-powerpc/pgtable-64k.h
index 1cbd6b377ee..c5007712473 100644
--- a/include/asm-powerpc/pgtable-64k.h
+++ b/include/asm-powerpc/pgtable-64k.h
@@ -75,6 +75,20 @@ static inline struct subpage_prot_table *pgd_subpage_prot(pgd_t *pgd)
#define _PAGE_COMBO 0x10000000 /* this is a combo 4k page */
#define _PAGE_4K_PFN 0x20000000 /* PFN is for a single 4k page */
+/* For 64K page, we don't have a separate _PAGE_HASHPTE bit. Instead,
+ * we set that to be the whole sub-bits mask. The C code will only
+ * test this, so a multi-bit mask will work. For combo pages, this
+ * is equivalent as effectively, the old _PAGE_HASHPTE was an OR of
+ * all the sub bits. For real 64k pages, we now have the assembly set
+ * _PAGE_HPTE_SUB0 in addition to setting the HIDX bits which overlap
+ * that mask. This is fine as long as the HIDX bits are never set on
+ * a PTE that isn't hashed, which is the case today.
+ *
+ * A little nit is for the huge page C code, which does the hashing
+ * in C, we need to provide which bit to use.
+ */
+#define _PAGE_HASHPTE _PAGE_HPTE_SUB
+
/* Note the full page bits must be in the same location as for normal
* 4k pages as the same asssembly will be used to insert 64K pages
* wether the kernel has CONFIG_PPC_64K_PAGES or not
@@ -83,8 +97,7 @@ static inline struct subpage_prot_table *pgd_subpage_prot(pgd_t *pgd)
#define _PAGE_F_GIX 0x00007000 /* full page: hidx bits */
/* PTE flags to conserve for HPTE identification */
-#define _PAGE_HPTEFLAGS (_PAGE_BUSY | _PAGE_HASHPTE | _PAGE_HPTE_SUB |\
- _PAGE_COMBO)
+#define _PAGE_HPTEFLAGS (_PAGE_BUSY | _PAGE_HASHPTE | _PAGE_COMBO)
/* Shift to put page number into pte.
*
diff --git a/include/asm-powerpc/pgtable-ppc64.h b/include/asm-powerpc/pgtable-ppc64.h
index cc6a43ba41d..2e48be841cc 100644
--- a/include/asm-powerpc/pgtable-ppc64.h
+++ b/include/asm-powerpc/pgtable-ppc64.h
@@ -91,7 +91,6 @@
#define _PAGE_DIRTY 0x0080 /* C: page changed */
#define _PAGE_ACCESSED 0x0100 /* R: page referenced */
#define _PAGE_RW 0x0200 /* software: user write access allowed */
-#define _PAGE_HASHPTE 0x0400 /* software: pte has an associated HPTE */
#define _PAGE_BUSY 0x0800 /* software: PTE & hash are busy */
#define _PAGE_BASE (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_COHERENT)