@@ -753,6 +753,24 @@ static int __init add_huge_page_size(unsigned long long size)
if ((mmu_psize = shift_to_mmu_psize(shift)) < 0)
return -EINVAL;
+#ifdef CONFIG_PPC_BOOK3S_64
+ /*
+ * We need to make sure that for different page sizes reported by
+ * firmware we only add hugetlb support for page sizes that can be
+ * supported by linux page table layout.
+ * For now we have
+ * Radix: 2M
+ * Hash: 16M and 16G
+ */
+ if (radix_enabled()) {
+ if (mmu_psize != MMU_PAGE_2M)
+ return -EINVAL;
+ } else {
+ if (mmu_psize != MMU_PAGE_16M && mmu_psize != MMU_PAGE_16G)
+ return -EINVAL;
+ }
+#endif
+
BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);
/* Return if huge page size has already been setup */
Without this if firmware reports 1MB page size support we will crash trying to use 1MB as hugetlb page size. echo 300 > /sys/kernel/mm/hugepages/hugepages-1024kB/nr_hugepages kernel BUG at ./arch/powerpc/include/asm/hugetlb.h:19! ..... .... [c0000000e2c27b30] c00000000029dae8 .hugetlb_fault+0x638/0xda0 [c0000000e2c27c30] c00000000026fb64 .handle_mm_fault+0x844/0x1d70 [c0000000e2c27d70] c00000000004805c .do_page_fault+0x3dc/0x7c0 [c0000000e2c27e30] c00000000000ac98 handle_page_fault+0x10/0x30 With fix, we don't enable 1MB as hugepage size. bash-4.2# cd /sys/kernel/mm/hugepages/ bash-4.2# ls hugepages-16384kB hugepages-16777216kB Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> --- arch/powerpc/mm/hugetlbpage.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)