Release 4.11 arch/x86/mm/mmap.c
/*
* Flexible mmap layout support
*
* Based on code by Ingo Molnar and Andi Kleen, copyrighted
* as follows:
*
* Copyright 2003-2009 Red Hat Inc.
* All Rights Reserved.
* Copyright 2005 Andi Kleen, SUSE Labs.
* Copyright 2007 Jiri Kosina, SUSE Labs.
*
* 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
*/
#include <linux/personality.h>
#include <linux/mm.h>
#include <linux/random.h>
#include <linux/limits.h>
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#include <asm/elf.h>
struct va_alignment __read_mostly va_align = {
.flags = -1,
};
static unsigned long stack_maxrandom_size(void)
{
unsigned long max = 0;
if ((current->flags & PF_RANDOMIZE) &&
!(current->personality & ADDR_NO_RANDOMIZE)) {
max = ((-1UL) & STACK_RND_MASK) << PAGE_SHIFT;
}
return max;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Michal Hocko | 49 | 94.23% | 1 | 50.00% |
| Hector Marco-Gisbert | 3 | 5.77% | 1 | 50.00% |
| Total | 52 | 100.00% | 2 | 100.00% |
/*
* Top of mmap area (just below the process stack).
*
* Leave an at least ~128 MB hole with possible stack randomization.
*/
#define MIN_GAP (128*1024*1024UL + stack_maxrandom_size())
#define MAX_GAP (TASK_SIZE/6*5)
static int mmap_is_legacy(void)
{
if (current->personality & ADDR_COMPAT_LAYOUT)
return 1;
if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
return 1;
return sysctl_legacy_va_layout;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Jiri Kosina | 31 | 91.18% | 1 | 50.00% |
| Jiri Slaby | 3 | 8.82% | 1 | 50.00% |
| Total | 34 | 100.00% | 2 | 100.00% |
unsigned long arch_mmap_rnd(void)
{
unsigned long rnd;
if (mmap_is_ia32())
#ifdef CONFIG_COMPAT
rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1);
#else
rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1);
#endif
else
rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1);
return rnd << PAGE_SHIFT;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Daniel Cashman | 38 | 50.67% | 2 | 33.33% |
| Harvey Harrison | 27 | 36.00% | 1 | 16.67% |
| Jiri Kosina | 6 | 8.00% | 1 | 16.67% |
| Andi Kleen | 3 | 4.00% | 1 | 16.67% |
| Kees Cook | 1 | 1.33% | 1 | 16.67% |
| Total | 75 | 100.00% | 6 | 100.00% |
static unsigned long mmap_base(unsigned long rnd)
{
unsigned long gap = rlimit(RLIMIT_STACK);
if (gap < MIN_GAP)
gap = MIN_GAP;
else if (gap > MAX_GAP)
gap = MAX_GAP;
return PAGE_ALIGN(TASK_SIZE - gap - rnd);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Harvey Harrison | 36 | 70.59% | 1 | 20.00% |
| Andi Kleen | 5 | 9.80% | 1 | 20.00% |
| Kees Cook | 4 | 7.84% | 1 | 20.00% |
| Jiri Slaby | 3 | 5.88% | 1 | 20.00% |
| Jiri Kosina | 3 | 5.88% | 1 | 20.00% |
| Total | 51 | 100.00% | 5 | 100.00% |
/*
* 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)
{
unsigned long random_factor = 0UL;
if (current->flags & PF_RANDOMIZE)
random_factor = arch_mmap_rnd();
mm->mmap_legacy_base = TASK_UNMAPPED_BASE + random_factor;
if (mmap_is_legacy()) {
mm->mmap_base = mm->mmap_legacy_base;
mm->get_unmapped_area = arch_get_unmapped_area;
} else {
mm->mmap_base = mmap_base(random_factor);
mm->get_unmapped_area = arch_get_unmapped_area_topdown;
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Kees Cook | 26 | 34.21% | 2 | 28.57% |
| Jiri Kosina | 22 | 28.95% | 1 | 14.29% |
| Harvey Harrison | 10 | 13.16% | 1 | 14.29% |
| Radu Caragea | 10 | 13.16% | 1 | 14.29% |
| Andi Kleen | 6 | 7.89% | 1 | 14.29% |
| Hector Marco-Gisbert | 2 | 2.63% | 1 | 14.29% |
| Total | 76 | 100.00% | 7 | 100.00% |
const char *arch_vma_name(struct vm_area_struct *vma)
{
if (vma->vm_flags & VM_MPX)
return "[mpx]";
return NULL;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Kirill A. Shutemov | 26 | 100.00% | 1 | 100.00% |
| Total | 26 | 100.00% | 1 | 100.00% |
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Jiri Kosina | 74 | 20.61% | 1 | 5.56% |
| Harvey Harrison | 74 | 20.61% | 1 | 5.56% |
| Michal Hocko | 54 | 15.04% | 1 | 5.56% |
| Daniel Cashman | 38 | 10.58% | 2 | 11.11% |
| Kees Cook | 31 | 8.64% | 2 | 11.11% |
| Kirill A. Shutemov | 26 | 7.24% | 1 | 5.56% |
| Andi Kleen | 23 | 6.41% | 1 | 5.56% |
| Borislav Petkov | 12 | 3.34% | 1 | 5.56% |
| Radu Caragea | 10 | 2.79% | 1 | 5.56% |
| Jiri Slaby | 6 | 1.67% | 1 | 5.56% |
| Ingo Molnar | 5 | 1.39% | 3 | 16.67% |
| Hector Marco-Gisbert | 5 | 1.39% | 2 | 11.11% |
| Jan-Simon Möller | 1 | 0.28% | 1 | 5.56% |
| Total | 359 | 100.00% | 18 | 100.00% |
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