revert "s390/mm: make hugepages_supported a boot time decision"

Heiko noticed that the current check for hugepage support on s390 is a
little bit too harsh as systems which do not support will crash.

The reason is that pageblock_order can now get negative when we set
HPAGE_SHIFT to 0.  To avoid all this and to avoid opening another can of
worms with enabling HUGETLB_PAGE_SIZE_VARIABLE I think it would be best
to simply allow architectures to define their own hugepages_supported().

Revert bea41197ead3 ("s390/mm: make hugepages_supported a boot time
decision") in preparation.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 0844b780c6a44b893a9d9e843e2e4b08062c5eeb..53eacbd4f09bf4c32ac051f1be7f9d3e5445e0df 100644 (file)
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -17,10 +17,7 @@
 #define PAGE_DEFAULT_ACC       0
 #define PAGE_DEFAULT_KEY       (PAGE_DEFAULT_ACC << 4)
 
-#include <asm/setup.h>
-#ifndef __ASSEMBLY__
-
-extern unsigned int HPAGE_SHIFT;
+#define HPAGE_SHIFT    20
 #define HPAGE_SIZE     (1UL << HPAGE_SHIFT)
 #define HPAGE_MASK     (~(HPAGE_SIZE - 1))
 #define HUGETLB_PAGE_ORDER     (HPAGE_SHIFT - PAGE_SHIFT)
@@ -30,6 +27,9 @@ extern unsigned int HPAGE_SHIFT;
 #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 f7f027caaaaacb33b279f76b33f3525374b6ae34..ca070d260af2e166b23b48553b2b6c02dc2a1046 100644 (file)
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -885,8 +885,6 @@ 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 16154720bdb60749163ec8ae33b4c451aa044c21..b33f66110ca9401418f7d657b951d8bfb84d99c3 100644 (file)
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -31,8 +31,6 @@
 #define ALLOC_ORDER    2
 #define FRAG_MASK      0x03
 
-unsigned int HPAGE_SHIFT;
-
 unsigned long *crst_table_alloc(struct mm_struct *mm)
 {
        struct page *page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);