From: "Aneesh Kumar K.V" <aneesh.kumar@linux•vnet.ibm.com>
To: benh@kernel•crashing.org, paulus@samba•org, mpe@ellerman•id.au
Cc: linuxppc-dev@lists•ozlabs.org,
"Aneesh Kumar K.V" <aneesh.kumar@linux•vnet.ibm.com>
Subject: [PATCH] powerpc/mm/hugetlb: Filter out hugepage size not supported by page table layout
Date: Sun, 19 Feb 2017 15:48:47 +0530 [thread overview]
Message-ID: <1487499527-16166-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> (raw)
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(+)
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 8c3389cbcd12..a4f33de4008e 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -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 */
--
2.7.4
next reply other threads:[~2017-02-19 10:19 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-19 10:18 Aneesh Kumar K.V [this message]
2017-02-19 21:05 ` [PATCH] powerpc/mm/hugetlb: Filter out hugepage size not supported by page table layout Benjamin Herrenschmidt
2017-02-20 3:32 ` Aneesh Kumar K.V
2017-02-20 3:35 ` Benjamin Herrenschmidt
2017-02-20 5:36 ` Aneesh Kumar K.V
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