Release 4.14 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/elf-randomize.h>
#include <linux/personality.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#include <linux/random.h>
#include <linux/compat.h>
#include <linux/security.h>
#include <asm/pgalloc.h>
#include <asm/elf.h>
static unsigned long stack_maxrandom_size(void)
{
if (!(current->flags & PF_RANDOMIZE))
return 0;
if (current->personality & ADDR_NO_RANDOMIZE)
return 0;
return STACK_RND_MASK << PAGE_SHIFT;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Heiko Carstens | 39 | 100.00% | 1 | 100.00% |
| Total | 39 | 100.00% | 1 | 100.00% |
/*
* Top of mmap area (just below the process stack).
*
* Leave at least a ~32 MB hole.
*/
#define MIN_GAP (32*1024*1024)
#define MAX_GAP (STACK_TOP/6*5)
static inline 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 |
| Heiko Carstens | 35 | 100.00% | 1 | 100.00% |
| Total | 35 | 100.00% | 1 | 100.00% |
unsigned long arch_mmap_rnd(void)
{
return (get_random_int() & MMAP_RND_MASK) << PAGE_SHIFT;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Heiko Carstens | 11 | 61.11% | 1 | 25.00% |
| Martin Schwidefsky | 6 | 33.33% | 2 | 50.00% |
| Kees Cook | 1 | 5.56% | 1 | 25.00% |
| Total | 18 | 100.00% | 4 | 100.00% |
static unsigned long mmap_base_legacy(unsigned long rnd)
{
return TASK_UNMAPPED_BASE + rnd;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Heiko Carstens | 12 | 75.00% | 1 | 50.00% |
| Kees Cook | 4 | 25.00% | 1 | 50.00% |
| Total | 16 | 100.00% | 2 | 100.00% |
static inline 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;
gap &= PAGE_MASK;
return STACK_TOP - stack_maxrandom_size() - rnd - gap;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Arjan van de Ven | 40 | 71.43% | 1 | 16.67% |
| Heiko Carstens | 8 | 14.29% | 2 | 33.33% |
| Kees Cook | 4 | 7.14% | 1 | 16.67% |
| Jiri Slaby | 3 | 5.36% | 1 | 16.67% |
| Martin Schwidefsky | 1 | 1.79% | 1 | 16.67% |
| Total | 56 | 100.00% | 6 | 100.00% |
unsigned long
arch_get_unmapped_area(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
struct vm_unmapped_area_info info;
int rc;
if (len > TASK_SIZE - mmap_min_addr)
return -ENOMEM;
if (flags & MAP_FIXED)
goto check_asce_limit;
if (addr) {
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
(!vma || addr + len <= vm_start_gap(vma)))
goto check_asce_limit;
}
info.flags = 0;
info.length = len;
info.low_limit = mm->mmap_base;
info.high_limit = TASK_SIZE;
if (filp || (flags & MAP_SHARED))
info.align_mask = MMAP_ALIGN_MASK << PAGE_SHIFT;
else
info.align_mask = 0;
info.align_offset = pgoff << PAGE_SHIFT;
addr = vm_unmapped_area(&info);
if (addr & ~PAGE_MASK)
return addr;
check_asce_limit:
if (addr + len > current->mm->context.asce_limit &&
addr + len <= TASK_SIZE) {
rc = crst_table_upgrade(mm, addr + len);
if (rc)
return (unsigned long) rc;
}
return addr;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Martin Schwidefsky | 243 | 98.78% | 5 | 83.33% |
| Hugh Dickins | 3 | 1.22% | 1 | 16.67% |
| Total | 246 | 100.00% | 6 | 100.00% |
unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
const unsigned long len, const unsigned long pgoff,
const unsigned long flags)
{
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
unsigned long addr = addr0;
struct vm_unmapped_area_info info;
int rc;
/* requested length too big for entire address space */
if (len > TASK_SIZE - mmap_min_addr)
return -ENOMEM;
if (flags & MAP_FIXED)
goto check_asce_limit;
/* requesting a specific address */
if (addr) {
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
(!vma || addr + len <= vm_start_gap(vma)))
goto check_asce_limit;
}
info.flags = VM_UNMAPPED_AREA_TOPDOWN;
info.length = len;
info.low_limit = max(PAGE_SIZE, mmap_min_addr);
info.high_limit = mm->mmap_base;
if (filp || (flags & MAP_SHARED))
info.align_mask = MMAP_ALIGN_MASK << PAGE_SHIFT;
else
info.align_mask = 0;
info.align_offset = pgoff << PAGE_SHIFT;
addr = vm_unmapped_area(&info);
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
if (addr & ~PAGE_MASK) {
VM_BUG_ON(addr != -ENOMEM);
info.flags = 0;
info.low_limit = TASK_UNMAPPED_BASE;
info.high_limit = TASK_SIZE;
addr = vm_unmapped_area(&info);
if (addr & ~PAGE_MASK)
return addr;
}
check_asce_limit:
if (addr + len > current->mm->context.asce_limit &&
addr + len <= TASK_SIZE) {
rc = crst_table_upgrade(mm, addr + len);
if (rc)
return (unsigned long) rc;
}
return addr;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Martin Schwidefsky | 304 | 99.02% | 8 | 88.89% |
| Hugh Dickins | 3 | 0.98% | 1 | 11.11% |
| Total | 307 | 100.00% | 9 | 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();
/*
* 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 = mmap_base_legacy(random_factor);
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 |
| Martin Schwidefsky | 44 | 62.86% | 2 | 40.00% |
| Kees Cook | 25 | 35.71% | 2 | 40.00% |
| Heiko Carstens | 1 | 1.43% | 1 | 20.00% |
| Total | 70 | 100.00% | 5 | 100.00% |
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Martin Schwidefsky | 609 | 73.29% | 11 | 40.74% |
| Heiko Carstens | 116 | 13.96% | 8 | 29.63% |
| Arjan van de Ven | 52 | 6.26% | 1 | 3.70% |
| Kees Cook | 34 | 4.09% | 2 | 7.41% |
| Hugh Dickins | 6 | 0.72% | 1 | 3.70% |
| Ingo Molnar | 6 | 0.72% | 2 | 7.41% |
| Paul Gortmaker | 5 | 0.60% | 1 | 3.70% |
| Jiri Slaby | 3 | 0.36% | 1 | 3.70% |
| Total | 831 | 100.00% | 27 | 100.00% |
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