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Commit 41318bfe authored by Dominik Dingel's avatar Dominik Dingel Committed by Linus Torvalds
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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 bea41197 ("s390/mm: make hugepages_supported a boot time
decision") in preparation.

Signed-off-by: default avatarDominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: default avatarMartin 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ad4f99e8

arch/s390/include/asm/page.h

+4 −4
Original line number Diff line number Diff line
@@ -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

arch/s390/kernel/setup.c

+0 −2
Original line number Diff line number Diff line
@@ -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.

	 */

arch/s390/mm/pgtable.c

+0 −2
Original line number Diff line number Diff line
@@ -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);