2005-04-17 05:20:36 +07:00
|
|
|
/*
|
|
|
|
* 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>
|
2009-02-22 08:50:01 +07:00
|
|
|
#include <linux/random.h>
|
Detach sched.h from mm.h
First thing mm.h does is including sched.h solely for can_do_mlock() inline
function which has "current" dereference inside. By dealing with can_do_mlock()
mm.h can be detached from sched.h which is good. See below, why.
This patch
a) removes unconditional inclusion of sched.h from mm.h
b) makes can_do_mlock() normal function in mm/mlock.c
c) exports can_do_mlock() to not break compilation
d) adds sched.h inclusions back to files that were getting it indirectly.
e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
getting them indirectly
Net result is:
a) mm.h users would get less code to open, read, preprocess, parse, ... if
they don't need sched.h
b) sched.h stops being dependency for significant number of files:
on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
after patch it's only 3744 (-8.3%).
Cross-compile tested on
all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
alpha alpha-up
arm
i386 i386-up i386-defconfig i386-allnoconfig
ia64 ia64-up
m68k
mips
parisc parisc-up
powerpc powerpc-up
s390 s390-up
sparc sparc-up
sparc64 sparc64-up
um-x86_64
x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig
as well as my two usual configs.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-21 04:22:52 +07:00
|
|
|
#include <linux/sched.h>
|
2005-04-17 05:20:36 +07:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Top of mmap area (just below the process stack).
|
|
|
|
*
|
2009-02-22 08:50:06 +07:00
|
|
|
* Leave at least a ~128 MB hole on 32bit applications.
|
|
|
|
*
|
|
|
|
* On 64bit applications we randomise the stack by 1GB so we need to
|
|
|
|
* space our mmap start address by a further 1GB, otherwise there is a
|
|
|
|
* chance the mmap area will end up closer to the stack than our ulimit
|
|
|
|
* requires.
|
2005-04-17 05:20:36 +07:00
|
|
|
*/
|
2009-02-22 08:50:06 +07:00
|
|
|
#define MIN_GAP32 (128*1024*1024)
|
|
|
|
#define MIN_GAP64 ((128 + 1024)*1024*1024UL)
|
|
|
|
#define MIN_GAP ((is_32bit_task()) ? MIN_GAP32 : MIN_GAP64)
|
2005-04-17 05:20:36 +07:00
|
|
|
#define MAX_GAP (TASK_SIZE/6*5)
|
|
|
|
|
2009-02-22 08:50:00 +07:00
|
|
|
static inline int mmap_is_legacy(void)
|
|
|
|
{
|
|
|
|
if (current->personality & ADDR_COMPAT_LAYOUT)
|
|
|
|
return 1;
|
|
|
|
|
2010-01-06 12:24:31 +07:00
|
|
|
if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
|
2009-02-22 08:50:00 +07:00
|
|
|
return 1;
|
|
|
|
|
|
|
|
return sysctl_legacy_va_layout;
|
|
|
|
}
|
|
|
|
|
2009-02-22 08:50:01 +07:00
|
|
|
static unsigned long mmap_rnd(void)
|
|
|
|
{
|
|
|
|
unsigned long rnd = 0;
|
|
|
|
|
|
|
|
if (current->flags & PF_RANDOMIZE) {
|
|
|
|
/* 8MB for 32bit, 1GB for 64bit */
|
|
|
|
if (is_32bit_task())
|
2011-10-17 20:05:23 +07:00
|
|
|
rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
|
2009-02-22 08:50:01 +07:00
|
|
|
else
|
2011-10-17 20:05:23 +07:00
|
|
|
rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
|
2009-02-22 08:50:01 +07:00
|
|
|
}
|
2011-10-17 20:05:23 +07:00
|
|
|
return rnd << PAGE_SHIFT;
|
2009-02-22 08:50:01 +07:00
|
|
|
}
|
|
|
|
|
2005-04-17 05:20:36 +07:00
|
|
|
static inline unsigned long mmap_base(void)
|
|
|
|
{
|
2010-01-06 12:24:31 +07:00
|
|
|
unsigned long gap = rlimit(RLIMIT_STACK);
|
2005-04-17 05:20:36 +07:00
|
|
|
|
|
|
|
if (gap < MIN_GAP)
|
|
|
|
gap = MIN_GAP;
|
|
|
|
else if (gap > MAX_GAP)
|
|
|
|
gap = MAX_GAP;
|
|
|
|
|
2009-02-22 08:50:01 +07:00
|
|
|
return PAGE_ALIGN(TASK_SIZE - gap - mmap_rnd());
|
2005-04-17 05:20:36 +07:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* 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;
|
|
|
|
}
|
|
|
|
}
|