2 * linux/arch/s390/mm/mmap.c
4 * flexible mmap layout support
6 * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 * Started by Ingo Molnar <mingo@elte.hu>
27 #include <linux/personality.h>
29 #include <linux/module.h>
30 #include <asm/pgalloc.h>
33 * Top of mmap area (just below the process stack).
35 * Leave an at least ~128 MB hole.
37 #define MIN_GAP (128*1024*1024)
38 #define MAX_GAP (STACK_TOP/6*5)
40 static inline unsigned long mmap_base(void)
42 unsigned long gap
= current
->signal
->rlim
[RLIMIT_STACK
].rlim_cur
;
46 else if (gap
> MAX_GAP
)
49 return STACK_TOP
- (gap
& PAGE_MASK
);
52 static inline int mmap_is_legacy(void)
56 * Force standard allocation for 64 bit programs.
58 if (!test_thread_flag(TIF_31BIT
))
61 return sysctl_legacy_va_layout
||
62 (current
->personality
& ADDR_COMPAT_LAYOUT
) ||
63 current
->signal
->rlim
[RLIMIT_STACK
].rlim_cur
== RLIM_INFINITY
;
69 * This function, called very early during the creation of a new
70 * process VM image, sets up which VM layout function to use:
72 void arch_pick_mmap_layout(struct mm_struct
*mm
)
75 * Fall back to the standard layout if the personality
76 * bit is set, or if the expected stack growth is unlimited:
78 if (mmap_is_legacy()) {
79 mm
->mmap_base
= TASK_UNMAPPED_BASE
;
80 mm
->get_unmapped_area
= arch_get_unmapped_area
;
81 mm
->unmap_area
= arch_unmap_area
;
83 mm
->mmap_base
= mmap_base();
84 mm
->get_unmapped_area
= arch_get_unmapped_area_topdown
;
85 mm
->unmap_area
= arch_unmap_area_topdown
;
88 EXPORT_SYMBOL_GPL(arch_pick_mmap_layout
);
92 int s390_mmap_check(unsigned long addr
, unsigned long len
)
94 if (!test_thread_flag(TIF_31BIT
) &&
95 len
>= TASK_SIZE
&& TASK_SIZE
< (1UL << 53))
96 return crst_table_upgrade(current
->mm
, 1UL << 53);
101 s390_get_unmapped_area(struct file
*filp
, unsigned long addr
,
102 unsigned long len
, unsigned long pgoff
, unsigned long flags
)
104 struct mm_struct
*mm
= current
->mm
;
108 area
= arch_get_unmapped_area(filp
, addr
, len
, pgoff
, flags
);
109 if (!(area
& ~PAGE_MASK
))
111 if (area
== -ENOMEM
&&
112 !test_thread_flag(TIF_31BIT
) && TASK_SIZE
< (1UL << 53)) {
113 /* Upgrade the page table to 4 levels and retry. */
114 rc
= crst_table_upgrade(mm
, 1UL << 53);
116 return (unsigned long) rc
;
117 area
= arch_get_unmapped_area(filp
, addr
, len
, pgoff
, flags
);
123 s390_get_unmapped_area_topdown(struct file
*filp
, const unsigned long addr
,
124 const unsigned long len
, const unsigned long pgoff
,
125 const unsigned long flags
)
127 struct mm_struct
*mm
= current
->mm
;
131 area
= arch_get_unmapped_area_topdown(filp
, addr
, len
, pgoff
, flags
);
132 if (!(area
& ~PAGE_MASK
))
134 if (area
== -ENOMEM
&&
135 !test_thread_flag(TIF_31BIT
) && TASK_SIZE
< (1UL << 53)) {
136 /* Upgrade the page table to 4 levels and retry. */
137 rc
= crst_table_upgrade(mm
, 1UL << 53);
139 return (unsigned long) rc
;
140 area
= arch_get_unmapped_area_topdown(filp
, addr
, len
,
146 * This function, called very early during the creation of a new
147 * process VM image, sets up which VM layout function to use:
149 void arch_pick_mmap_layout(struct mm_struct
*mm
)
152 * Fall back to the standard layout if the personality
153 * bit is set, or if the expected stack growth is unlimited:
155 if (mmap_is_legacy()) {
156 mm
->mmap_base
= TASK_UNMAPPED_BASE
;
157 mm
->get_unmapped_area
= s390_get_unmapped_area
;
158 mm
->unmap_area
= arch_unmap_area
;
160 mm
->mmap_base
= mmap_base();
161 mm
->get_unmapped_area
= s390_get_unmapped_area_topdown
;
162 mm
->unmap_area
= arch_unmap_area_topdown
;
165 EXPORT_SYMBOL_GPL(arch_pick_mmap_layout
);