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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2008-07-31 03:07:30 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-08-01 15:46:41 -0400
commit0ef89d25d3e390dfa7c46772907951744a4067dc (patch)
tree768d97175d6df35408733f6fe40cf414b4ac75bd /mm/hugetlb.c
parentc6de002617c199f80f9a2a713dffc263bdc69b81 (diff)
mm/hugetlb: don't crash when HPAGE_SHIFT is 0
Some platform decide whether they support huge pages at boot time. On these, such as powerpc, HPAGE_SHIFT is a variable, not a constant, and is set to 0 when there is no such support. The patches to introduce multiple huge pages support broke that causing the kernel to crash at boot time on machines such as POWER3 which lack support for multiple page sizes. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r--mm/hugetlb.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index d237a02eb22..28a2980ee43 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1283,7 +1283,12 @@ module_exit(hugetlb_exit);
1283 1283
1284static int __init hugetlb_init(void) 1284static int __init hugetlb_init(void)
1285{ 1285{
1286 BUILD_BUG_ON(HPAGE_SHIFT == 0); 1286 /* Some platform decide whether they support huge pages at boot
1287 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
1288 * there is no such support
1289 */
1290 if (HPAGE_SHIFT == 0)
1291 return 0;
1287 1292
1288 if (!size_to_hstate(default_hstate_size)) { 1293 if (!size_to_hstate(default_hstate_size)) {
1289 default_hstate_size = HPAGE_SIZE; 1294 default_hstate_size = HPAGE_SIZE;