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[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [arch/] [s390/] [mm/] [mmap.c] - Blame information for rev 3

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/*
 *  linux/arch/s390/mm/mmap.c
 *
 *  flexible mmap layout support
 *
 * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *
 * Started by Ingo Molnar <mingo@elte.hu>
 */
 
#include <linux/personality.h>
#include <linux/mm.h>
#include <linux/module.h>
 
/*
 * Top of mmap area (just below the process stack).
 *
 * Leave an at least ~128 MB hole.
 */
#define MIN_GAP (128*1024*1024)
#define MAX_GAP (TASK_SIZE/6*5)
 
static inline unsigned long mmap_base(void)
{
        unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur;
 
        if (gap < MIN_GAP)
                gap = MIN_GAP;
        else if (gap > MAX_GAP)
                gap = MAX_GAP;
 
        return TASK_SIZE - (gap & PAGE_MASK);
}
 
static inline int mmap_is_legacy(void)
{
#ifdef CONFIG_64BIT
        /*
         * Force standard allocation for 64 bit programs.
         */
        if (!test_thread_flag(TIF_31BIT))
                return 1;
#endif
        return sysctl_legacy_va_layout ||
            (current->personality & ADDR_COMPAT_LAYOUT) ||
            current->signal->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY;
}
 
/*
 * This function, called very early during the creation of a new
 * process VM image, sets up which VM layout function to use:
 */
void arch_pick_mmap_layout(struct mm_struct *mm)
{
        /*
         * Fall back to the standard layout if the personality
         * bit is set, or if the expected stack growth is unlimited:
         */
        if (mmap_is_legacy()) {
                mm->mmap_base = TASK_UNMAPPED_BASE;
                mm->get_unmapped_area = arch_get_unmapped_area;
                mm->unmap_area = arch_unmap_area;
        } else {
                mm->mmap_base = mmap_base();
                mm->get_unmapped_area = arch_get_unmapped_area_topdown;
                mm->unmap_area = arch_unmap_area_topdown;
        }
}
EXPORT_SYMBOL_GPL(arch_pick_mmap_layout);
 

Line No.	Rev	Author	Line
1	3	xianfeng	`/*`
2			`* linux/arch/s390/mm/mmap.c`
3			`*`
4			`* flexible mmap layout support`
5			`*`
6			`* Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.`
7			`* All Rights Reserved.`
8			`*`
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.`
13			`*`
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.`
18			`*`
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`
22			`*`
23			`*`
24			`* Started by Ingo Molnar <mingo@elte.hu>`
25			`*/`
26
27			`#include <linux/personality.h>`
28			`#include <linux/mm.h>`
29			`#include <linux/module.h>`
30
31			`/*`
32			`* Top of mmap area (just below the process stack).`
33			`*`
34			`* Leave an at least ~128 MB hole.`
35			`*/`
36			`#define MIN_GAP (12810241024)`
37			`#define MAX_GAP (TASK_SIZE/6*5)`
38
39			`static inline unsigned long mmap_base(void)`
40			`{`
41			`unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur;`
42
43			`if (gap < MIN_GAP)`
44			`gap = MIN_GAP;`
45			`else if (gap > MAX_GAP)`
46			`gap = MAX_GAP;`
47
48			`return TASK_SIZE - (gap & PAGE_MASK);`
49			`}`
50
51			`static inline int mmap_is_legacy(void)`
52			`{`
53			`#ifdef CONFIG_64BIT`
54			`/*`
55			`* Force standard allocation for 64 bit programs.`
56			`*/`
57			`if (!test_thread_flag(TIF_31BIT))`
58			`return 1;`
59			`#endif`
60			`return sysctl_legacy_va_layout \|\|`
61			`(current->personality & ADDR_COMPAT_LAYOUT) \|\|`
62			`current->signal->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY;`
63			`}`
64
65			`/*`
66			`* This function, called very early during the creation of a new`
67			`* process VM image, sets up which VM layout function to use:`
68			`*/`
69			`void arch_pick_mmap_layout(struct mm_struct *mm)`
70			`{`
71			`/*`
72			`* Fall back to the standard layout if the personality`
73			`* bit is set, or if the expected stack growth is unlimited:`
74			`*/`
75			`if (mmap_is_legacy()) {`
76			`mm->mmap_base = TASK_UNMAPPED_BASE;`
77			`mm->get_unmapped_area = arch_get_unmapped_area;`
78			`mm->unmap_area = arch_unmap_area;`
79			`} else {`
80			`mm->mmap_base = mmap_base();`
81			`mm->get_unmapped_area = arch_get_unmapped_area_topdown;`
82			`mm->unmap_area = arch_unmap_area_topdown;`
83			`}`
84			`}`
85			`EXPORT_SYMBOL_GPL(arch_pick_mmap_layout);`
86

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[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [arch/] [s390/] [mm/] [mmap.c] - Blame information for rev 3