[PATCH 4/6 v2] powerpc: define page support for 16G pages

From: Jon Tollefson
Date: Tue May 13 2008 - 13:23:26 EST


The huge page size is defined for 16G pages. If a hugepagesz of 16G is
specified at boot-time then it becomes the huge page size instead of
the default 16M.

The change in pgtable-64K.h is to the macro
pte_iterate_hashed_subpages to make the increment to va (the 1
being shifted) be a long so that it is not shifted to 0. Otherwise it
would create an infinite loop when the shift value is for a 16G page
(when base page size is 64K).



Signed-off-by: Jon Tollefson <kniht@xxxxxxxxxxxxxxxxxx>
---

arch/powerpc/mm/hugetlbpage.c | 62 ++++++++++++++++++++++++++------------
include/asm-powerpc/pgtable-64k.h | 2 -
2 files changed, 45 insertions(+), 19 deletions(-)

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index a27b80c..063ec36 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -24,8 +24,9 @@
#include <asm/cputable.h>
#include <asm/spu.h>

-#define HPAGE_SHIFT_64K 16
-#define HPAGE_SHIFT_16M 24
+#define PAGE_SHIFT_64K 16
+#define PAGE_SHIFT_16M 24
+#define PAGE_SHIFT_16G 34

#define NUM_LOW_AREAS (0x100000000UL >> SID_SHIFT)
#define NUM_HIGH_AREAS (PGTABLE_RANGE >> HTLB_AREA_SHIFT)
@@ -95,7 +96,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
static inline
pmd_t *hpmd_offset(pud_t *pud, unsigned long addr)
{
- if (HPAGE_SHIFT == HPAGE_SHIFT_64K)
+ if (HPAGE_SHIFT == PAGE_SHIFT_64K)
return pmd_offset(pud, addr);
else
return (pmd_t *) pud;
@@ -103,7 +104,7 @@ pmd_t *hpmd_offset(pud_t *pud, unsigned long addr)
static inline
pmd_t *hpmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long addr)
{
- if (HPAGE_SHIFT == HPAGE_SHIFT_64K)
+ if (HPAGE_SHIFT == PAGE_SHIFT_64K)
return pmd_alloc(mm, pud, addr);
else
return (pmd_t *) pud;
@@ -260,7 +261,7 @@ static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
continue;
hugetlb_free_pmd_range(tlb, pud, addr, next, floor, ceiling);
#else
- if (HPAGE_SHIFT == HPAGE_SHIFT_64K) {
+ if (HPAGE_SHIFT == PAGE_SHIFT_64K) {
if (pud_none_or_clear_bad(pud))
continue;
hugetlb_free_pmd_range(tlb, pud, addr, next, floor, ceiling);
@@ -591,20 +592,40 @@ void set_huge_psize(int psize)
{
/* Check that it is a page size supported by the hardware and
* that it fits within pagetable limits. */
- if (mmu_psize_defs[psize].shift && mmu_psize_defs[psize].shift < SID_SHIFT &&
+ if (mmu_psize_defs[psize].shift &&
+ mmu_psize_defs[psize].shift < SID_SHIFT_1T &&
(mmu_psize_defs[psize].shift > MIN_HUGEPTE_SHIFT ||
- mmu_psize_defs[psize].shift == HPAGE_SHIFT_64K)) {
+ mmu_psize_defs[psize].shift == PAGE_SHIFT_64K ||
+ mmu_psize_defs[psize].shift == PAGE_SHIFT_16G)) {
+ /* Return if huge page size is the same as the
+ * base page size. */
+ if (mmu_psize_defs[psize].shift == PAGE_SHIFT)
+ return;
+
HPAGE_SHIFT = mmu_psize_defs[psize].shift;
mmu_huge_psize = psize;
-#ifdef CONFIG_PPC_64K_PAGES
- hugepte_shift = (PMD_SHIFT-HPAGE_SHIFT);
-#else
- if (HPAGE_SHIFT == HPAGE_SHIFT_64K)
- hugepte_shift = (PMD_SHIFT-HPAGE_SHIFT);
- else
- hugepte_shift = (PUD_SHIFT-HPAGE_SHIFT);
-#endif

+ switch (HPAGE_SHIFT) {
+ case PAGE_SHIFT_64K:
+ /* We only allow 64k hpages with 4k base page,
+ * which was checked above, and always put them
+ * at the PMD */
+ hugepte_shift = PMD_SHIFT;
+ break;
+ case PAGE_SHIFT_16M:
+ /* 16M pages can be at two different levels
+ * of pagestables based on base page size */
+ if (PAGE_SHIFT == PAGE_SHIFT_64K)
+ hugepte_shift = PMD_SHIFT;
+ else /* 4k base page */
+ hugepte_shift = PUD_SHIFT;
+ break;
+ case PAGE_SHIFT_16G:
+ /* 16G pages are always at PGD level */
+ hugepte_shift = PGDIR_SHIFT;
+ break;
+ }
+ hugepte_shift -= HPAGE_SHIFT;
} else
HPAGE_SHIFT = 0;
}
@@ -620,17 +641,22 @@ static int __init hugepage_setup_sz(char *str)
shift = __ffs(size);
switch (shift) {
#ifndef CONFIG_PPC_64K_PAGES
- case HPAGE_SHIFT_64K:
+ case PAGE_SHIFT_64K:
mmu_psize = MMU_PAGE_64K;
break;
#endif
- case HPAGE_SHIFT_16M:
+ case PAGE_SHIFT_16M:
mmu_psize = MMU_PAGE_16M;
break;
+ case PAGE_SHIFT_16G:
+ mmu_psize = MMU_PAGE_16G;
+ break;
}

- if (mmu_psize >=0 && mmu_psize_defs[mmu_psize].shift)
+ if (mmu_psize >= 0 && mmu_psize_defs[mmu_psize].shift) {
set_huge_psize(mmu_psize);
+ huge_add_hstate(shift - PAGE_SHIFT);
+ }
else
printk(KERN_WARNING "Invalid huge page size specified(%llu)\n", size);

diff --git a/include/asm-powerpc/pgtable-64k.h b/include/asm-powerpc/pgtable-64k.h
index 1cbd6b3..55f0861 100644
--- a/include/asm-powerpc/pgtable-64k.h
+++ b/include/asm-powerpc/pgtable-64k.h
@@ -125,7 +125,7 @@ static inline struct subpage_prot_table *pgd_subpage_prot(pgd_t *pgd)
unsigned __split = (psize == MMU_PAGE_4K || \
psize == MMU_PAGE_64K_AP); \
shift = mmu_psize_defs[psize].shift; \
- for (index = 0; va < __end; index++, va += (1 << shift)) { \
+ for (index = 0; va < __end; index++, va += (1L << shift)) { \
if (!__split || __rpte_sub_valid(rpte, index)) do { \

#define pte_iterate_hashed_end() } while(0); } } while(0)


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