![Jiri Slaby](/assets/img/avatar_default.png)
Make sure compiler won't do weird things with limits. E.g. fetching
them twice may return 2 different values after writable limits are
implemented.
I.e. either use rlimit helpers added in
3e10e716ab
or ACCESS_ONCE if not applicable.
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
167 lines
4.5 KiB
C
167 lines
4.5 KiB
C
/*
|
|
* 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>
|
|
#include <asm/pgalloc.h>
|
|
#include <asm/compat.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 (STACK_TOP/6*5)
|
|
|
|
static inline unsigned long mmap_base(void)
|
|
{
|
|
unsigned long gap = rlimit(RLIMIT_STACK);
|
|
|
|
if (gap < MIN_GAP)
|
|
gap = MIN_GAP;
|
|
else if (gap > MAX_GAP)
|
|
gap = MAX_GAP;
|
|
|
|
return STACK_TOP - (gap & PAGE_MASK);
|
|
}
|
|
|
|
static inline int mmap_is_legacy(void)
|
|
{
|
|
#ifdef CONFIG_64BIT
|
|
/*
|
|
* Force standard allocation for 64 bit programs.
|
|
*/
|
|
if (!is_compat_task())
|
|
return 1;
|
|
#endif
|
|
return sysctl_legacy_va_layout ||
|
|
(current->personality & ADDR_COMPAT_LAYOUT) ||
|
|
rlimit(RLIMIT_STACK) == RLIM_INFINITY;
|
|
}
|
|
|
|
#ifndef CONFIG_64BIT
|
|
|
|
/*
|
|
* 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);
|
|
|
|
#else
|
|
|
|
int s390_mmap_check(unsigned long addr, unsigned long len)
|
|
{
|
|
if (!is_compat_task() &&
|
|
len >= TASK_SIZE && TASK_SIZE < (1UL << 53))
|
|
return crst_table_upgrade(current->mm, 1UL << 53);
|
|
return 0;
|
|
}
|
|
|
|
static unsigned long
|
|
s390_get_unmapped_area(struct file *filp, unsigned long addr,
|
|
unsigned long len, unsigned long pgoff, unsigned long flags)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
unsigned long area;
|
|
int rc;
|
|
|
|
area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
|
|
if (!(area & ~PAGE_MASK))
|
|
return area;
|
|
if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) {
|
|
/* Upgrade the page table to 4 levels and retry. */
|
|
rc = crst_table_upgrade(mm, 1UL << 53);
|
|
if (rc)
|
|
return (unsigned long) rc;
|
|
area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
|
|
}
|
|
return area;
|
|
}
|
|
|
|
static unsigned long
|
|
s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr,
|
|
const unsigned long len, const unsigned long pgoff,
|
|
const unsigned long flags)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
unsigned long area;
|
|
int rc;
|
|
|
|
area = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);
|
|
if (!(area & ~PAGE_MASK))
|
|
return area;
|
|
if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) {
|
|
/* Upgrade the page table to 4 levels and retry. */
|
|
rc = crst_table_upgrade(mm, 1UL << 53);
|
|
if (rc)
|
|
return (unsigned long) rc;
|
|
area = arch_get_unmapped_area_topdown(filp, addr, len,
|
|
pgoff, flags);
|
|
}
|
|
return area;
|
|
}
|
|
/*
|
|
* 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 = s390_get_unmapped_area;
|
|
mm->unmap_area = arch_unmap_area;
|
|
} else {
|
|
mm->mmap_base = mmap_base();
|
|
mm->get_unmapped_area = s390_get_unmapped_area_topdown;
|
|
mm->unmap_area = arch_unmap_area_topdown;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(arch_pick_mmap_layout);
|
|
|
|
#endif
|