From: Dominik Dingel <dingel@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: Russell King <linux@arm.linux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Tony Luck <tony.luck@intel.com>,
Fenghua Yu <fenghua.yu@intel.com>,
James Hogan <james.hogan@imgtec.com>,
Ralf Baechle <ralf@linux-mips.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
linux390@de.ibm.com, "David S. Miller" <davem@davemloft.net>,
Chris Metcalf <cmetcalf@ezchip.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Andrew Morton <akpm@linux-foundation.org>,
Zhang Zhen <zhenzhang.zhang@huawei.com>,
Dominik Dingel <dingel@linux.vnet.ibm.com>,
David Rientjes <rientjes@google.com>,
Aneesh Kumar K.V
Subject: [PATCH 1/5] s390/mm: make hugepages_supported a boot time decision
Date: Thu, 28 May 2015 13:52:33 +0200 [thread overview]
Message-ID: <1432813957-46874-2-git-send-email-dingel@linux.vnet.ibm.com> (raw)
In-Reply-To: <1432813957-46874-1-git-send-email-dingel@linux.vnet.ibm.com>
By dropping support for hugepages on machines which do not have
the hardware feature EDAT1, we fix a potential s390 KVM bug.
The bug would happen if a guest is backed by hugetlbfs (not supported currently),
but does not get pagetables with PGSTE.
This would lead to random memory overwrites.
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
---
arch/s390/include/asm/page.h | 8 ++++----
arch/s390/kernel/setup.c | 2 ++
arch/s390/mm/pgtable.c | 2 ++
3 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 53eacbd..0844b78 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -17,7 +17,10 @@
#define PAGE_DEFAULT_ACC 0
#define PAGE_DEFAULT_KEY (PAGE_DEFAULT_ACC << 4)
-#define HPAGE_SHIFT 20
+#include <asm/setup.h>
+#ifndef __ASSEMBLY__
+
+extern unsigned int HPAGE_SHIFT;
#define HPAGE_SIZE (1UL << HPAGE_SHIFT)
#define HPAGE_MASK (~(HPAGE_SIZE - 1))
#define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT)
@@ -27,9 +30,6 @@
#define ARCH_HAS_PREPARE_HUGEPAGE
#define ARCH_HAS_HUGEPAGE_CLEAR_FLUSH
-#include <asm/setup.h>
-#ifndef __ASSEMBLY__
-
static inline void storage_key_init_range(unsigned long start, unsigned long end)
{
#if PAGE_DEFAULT_KEY
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index a5ea8bc..9ac282b 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -915,6 +915,8 @@ void __init setup_arch(char **cmdline_p)
*/
setup_hwcaps();
+ HPAGE_SHIFT = MACHINE_HAS_HPAGE ? 20 : 0;
+
/*
* Create kernel page tables and switch to virtual addressing.
*/
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index b2c1542..f76791e 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -36,6 +36,8 @@
#endif
+unsigned int HPAGE_SHIFT;
+
unsigned long *crst_table_alloc(struct mm_struct *mm)
{
struct page *page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
--
2.3.7
next prev parent reply other threads:[~2015-05-28 11:52 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-28 11:52 [PATCH 0/5] Remove s390 sw-emulated hugepages and cleanup Dominik Dingel
2015-05-28 11:52 ` Dominik Dingel [this message]
2015-05-28 11:52 ` [PATCH 2/5] mm/hugetlb: remove unused arch hook prepare/release_hugepage Dominik Dingel
2015-05-28 11:52 ` [PATCH 3/5] mm/hugetlb: remove arch_prepare/release_hugepage from arch headers Dominik Dingel
2015-05-28 13:59 ` Ralf Baechle
2015-05-28 11:52 ` [PATCH 4/5] s390/hugetlb: remove dead code for sw emulated huge pages Dominik Dingel
2015-05-28 11:52 ` [PATCH 5/5] s390/mm: forward check for huge pmds to pmd_large() Dominik Dingel
2015-06-01 7:35 ` [PATCH 0/5] Remove s390 sw-emulated hugepages and cleanup Christian Borntraeger
[not found] ` <556C0B5D.40205-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>
2015-06-02 7:46 ` Dominik Dingel
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