Commit 3ce05cb3 authored by Arjan van de Ven's avatar Arjan van de Ven Committed by Linus Torvalds

[PATCH] flex mmap for s390(x)

Below is a patch from Pete Zaitcev (zaitcev@redhat.com) to also use the
flex mmap infrastructure for s390(x).  The IBM Domino guys *really* seem to
want this.
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 64e3b6b6
...@@ -2,6 +2,6 @@ ...@@ -2,6 +2,6 @@
# Makefile for the linux s390-specific parts of the memory manager. # Makefile for the linux s390-specific parts of the memory manager.
# #
obj-y := init.o fault.o ioremap.o extmem.o obj-y := init.o fault.o ioremap.o extmem.o mmap.o
obj-$(CONFIG_CMM) += cmm.o obj-$(CONFIG_CMM) += cmm.o
/*
* 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>
/*
* 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->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_ARCH_S390X
/*
* 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->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;
}
}
...@@ -76,6 +76,8 @@ extern struct task_struct *last_task_used_math; ...@@ -76,6 +76,8 @@ extern struct task_struct *last_task_used_math;
#define MM_VM_SIZE(mm) DEFAULT_TASK_SIZE #define MM_VM_SIZE(mm) DEFAULT_TASK_SIZE
#define HAVE_ARCH_PICK_MMAP_LAYOUT
typedef struct { typedef struct {
__u32 ar4; __u32 ar4;
} mm_segment_t; } mm_segment_t;
......
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