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[/] [test_project/] [trunk/] [linux_sd_driver/] [arch/] [s390/] [mm/] [mmap.c] - Blame information for rev 79

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Line No. Rev Author Line
1 63 marcus.erl
/*
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 *  linux/arch/s390/mm/mmap.c
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 *
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 *  flexible mmap layout support
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 *
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 * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
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 * All Rights Reserved.
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 *
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 *
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 * Started by Ingo Molnar <mingo@elte.hu>
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 */
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#include <linux/personality.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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/*
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 * Top of mmap area (just below the process stack).
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 *
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 * Leave an at least ~128 MB hole.
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 */
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#define MIN_GAP (128*1024*1024)
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#define MAX_GAP (TASK_SIZE/6*5)
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static inline unsigned long mmap_base(void)
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{
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        unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur;
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        if (gap < MIN_GAP)
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                gap = MIN_GAP;
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        else if (gap > MAX_GAP)
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                gap = MAX_GAP;
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        return TASK_SIZE - (gap & PAGE_MASK);
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}
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static inline int mmap_is_legacy(void)
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{
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#ifdef CONFIG_64BIT
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        /*
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         * Force standard allocation for 64 bit programs.
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         */
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        if (!test_thread_flag(TIF_31BIT))
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                return 1;
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#endif
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        return sysctl_legacy_va_layout ||
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            (current->personality & ADDR_COMPAT_LAYOUT) ||
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            current->signal->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY;
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}
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/*
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 * This function, called very early during the creation of a new
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 * process VM image, sets up which VM layout function to use:
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 */
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void arch_pick_mmap_layout(struct mm_struct *mm)
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{
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        /*
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         * Fall back to the standard layout if the personality
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         * bit is set, or if the expected stack growth is unlimited:
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         */
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        if (mmap_is_legacy()) {
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                mm->mmap_base = TASK_UNMAPPED_BASE;
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                mm->get_unmapped_area = arch_get_unmapped_area;
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                mm->unmap_area = arch_unmap_area;
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        } else {
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                mm->mmap_base = mmap_base();
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                mm->get_unmapped_area = arch_get_unmapped_area_topdown;
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                mm->unmap_area = arch_unmap_area_topdown;
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        }
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}
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EXPORT_SYMBOL_GPL(arch_pick_mmap_layout);
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