Subject: [PATCH 2/4] powerpc: function for allocating gigantic pages

From: Jon Tollefson <[email-masked]>
Date: Wed, 26 Mar 2008 16:26:13 -0500

The 16G page locations have been saved during early boot in an array.  The
alloc_bm_huge_page() function adds a page from here to the huge_boot_pages list.

Signed-off-by: Jon Tollefson <[email-masked]>
---

 hugetlbpage.c |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 94625db..31d977b 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -29,6 +29,10 @@
 
 #define NUM_LOW_AREAS	(0x100000000UL >> SID_SHIFT)
 #define NUM_HIGH_AREAS	(PGTABLE_RANGE >> HTLB_AREA_SHIFT)
+#define MAX_NUMBER_GPAGES	1024
+
+static void *gpage_freearray[MAX_NUMBER_GPAGES];
+static unsigned nr_gpages;
 
 unsigned int hugepte_shift;
 #define PTRS_PER_HUGEPTE	(1 << hugepte_shift)
@@ -104,6 +108,21 @@ pmd_t *hpmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long addr)
 }
 #endif
 
+/* Put 16G page address into temporary huge page list because the mem_map
+ * is not up yet.
+ */
+int alloc_bm_huge_page(struct hstate *h)
+{
+	struct huge_bm_page *m;
+	if (nr_gpages == 0)
+		return 0;
+	m = gpage_freearray[--nr_gpages];
+	list_add(&m->list, &huge_boot_pages);
+	m->hstate = h;
+	return 1;
+}
+
+
 /* Modelled after find_linux_pte() */
 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 {