[RFC/PATCH 1/15] get_unmapped_area handles MAP_FIXED on powerpc

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

 arch/powerpc/mm/hugetlbpage.c |   21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

Index: linux-cell/arch/powerpc/mm/hugetlbpage.c
===================================================================
--- linux-cell.orig/arch/powerpc/mm/hugetlbpage.c	2007-03-22 14:52:07.000000000 +1100
+++ linux-cell/arch/powerpc/mm/hugetlbpage.c	2007-03-22 14:57:40.000000000 +1100
@@ -572,6 +572,13 @@ unsigned long arch_get_unmapped_area(str
 	if (len > TASK_SIZE)
 		return -ENOMEM;
 
+	/* handle fixed mapping: prevent overlap with huge pages */
+	if (flags & MAP_FIXED) {
+		if (is_hugepage_only_range(mm, addr, len))
+			return -EINVAL;
+		return addr;
+	}
+
 	if (addr) {
 		addr = PAGE_ALIGN(addr);
 		vma = find_vma(mm, addr);
@@ -647,6 +654,13 @@ arch_get_unmapped_area_topdown(struct fi
 	if (len > TASK_SIZE)
 		return -ENOMEM;
 
+	/* handle fixed mapping: prevent overlap with huge pages */
+	if (flags & MAP_FIXED) {
+		if (is_hugepage_only_range(mm, addr, len))
+			return -EINVAL;
+		return addr;
+	}
+
 	/* dont allow allocations above current base */
 	if (mm->free_area_cache > base)
 		mm->free_area_cache = base;
@@ -829,6 +843,13 @@ unsigned long hugetlb_get_unmapped_area(
 	/* Paranoia, caller should have dealt with this */
 	BUG_ON((addr + len)  < addr);
 
+	/* Handle MAP_FIXED */
+	if (flags & MAP_FIXED) {
+		if (prepare_hugepage_range(addr, len, pgoff))
+			return -EINVAL;
+		return addr;
+	}
+
 	if (test_thread_flag(TIF_32BIT)) {
 		curareas = current->mm->context.low_htlb_areas;