mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-24 02:18:54 +00:00
6f6c3c33c0
It never really belonged into syscall.c and it's about to become well more complex. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
123 lines
2.8 KiB
C
123 lines
2.8 KiB
C
/*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file "COPYING" in the main directory of this archive
|
|
* for more details.
|
|
*
|
|
* Copyright (C) 2011 Wind River Systems,
|
|
* written by Ralf Baechle <ralf@linux-mips.org>
|
|
*/
|
|
#include <linux/errno.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/mman.h>
|
|
#include <linux/module.h>
|
|
#include <linux/random.h>
|
|
#include <linux/sched.h>
|
|
|
|
unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */
|
|
|
|
EXPORT_SYMBOL(shm_align_mask);
|
|
|
|
#define COLOUR_ALIGN(addr,pgoff) \
|
|
((((addr) + shm_align_mask) & ~shm_align_mask) + \
|
|
(((pgoff) << PAGE_SHIFT) & shm_align_mask))
|
|
|
|
unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
|
|
unsigned long len, unsigned long pgoff, unsigned long flags)
|
|
{
|
|
struct vm_area_struct * vmm;
|
|
int do_color_align;
|
|
|
|
if (len > TASK_SIZE)
|
|
return -ENOMEM;
|
|
|
|
if (flags & MAP_FIXED) {
|
|
/* Even MAP_FIXED mappings must reside within TASK_SIZE. */
|
|
if (TASK_SIZE - len < addr)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* We do not accept a shared mapping if it would violate
|
|
* cache aliasing constraints.
|
|
*/
|
|
if ((flags & MAP_SHARED) &&
|
|
((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
|
|
return -EINVAL;
|
|
return addr;
|
|
}
|
|
|
|
do_color_align = 0;
|
|
if (filp || (flags & MAP_SHARED))
|
|
do_color_align = 1;
|
|
if (addr) {
|
|
if (do_color_align)
|
|
addr = COLOUR_ALIGN(addr, pgoff);
|
|
else
|
|
addr = PAGE_ALIGN(addr);
|
|
vmm = find_vma(current->mm, addr);
|
|
if (TASK_SIZE - len >= addr &&
|
|
(!vmm || addr + len <= vmm->vm_start))
|
|
return addr;
|
|
}
|
|
addr = current->mm->mmap_base;
|
|
if (do_color_align)
|
|
addr = COLOUR_ALIGN(addr, pgoff);
|
|
else
|
|
addr = PAGE_ALIGN(addr);
|
|
|
|
for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
|
|
/* At this point: (!vmm || addr < vmm->vm_end). */
|
|
if (TASK_SIZE - len < addr)
|
|
return -ENOMEM;
|
|
if (!vmm || addr + len <= vmm->vm_start)
|
|
return addr;
|
|
addr = vmm->vm_end;
|
|
if (do_color_align)
|
|
addr = COLOUR_ALIGN(addr, pgoff);
|
|
}
|
|
}
|
|
|
|
void arch_pick_mmap_layout(struct mm_struct *mm)
|
|
{
|
|
unsigned long random_factor = 0UL;
|
|
|
|
if (current->flags & PF_RANDOMIZE) {
|
|
random_factor = get_random_int();
|
|
random_factor = random_factor << PAGE_SHIFT;
|
|
if (TASK_IS_32BIT_ADDR)
|
|
random_factor &= 0xfffffful;
|
|
else
|
|
random_factor &= 0xffffffful;
|
|
}
|
|
|
|
mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
|
|
mm->get_unmapped_area = arch_get_unmapped_area;
|
|
mm->unmap_area = arch_unmap_area;
|
|
}
|
|
|
|
static inline unsigned long brk_rnd(void)
|
|
{
|
|
unsigned long rnd = get_random_int();
|
|
|
|
rnd = rnd << PAGE_SHIFT;
|
|
/* 8MB for 32bit, 256MB for 64bit */
|
|
if (TASK_IS_32BIT_ADDR)
|
|
rnd = rnd & 0x7ffffful;
|
|
else
|
|
rnd = rnd & 0xffffffful;
|
|
|
|
return rnd;
|
|
}
|
|
|
|
unsigned long arch_randomize_brk(struct mm_struct *mm)
|
|
{
|
|
unsigned long base = mm->brk;
|
|
unsigned long ret;
|
|
|
|
ret = PAGE_ALIGN(base + brk_rnd());
|
|
|
|
if (ret < mm->brk)
|
|
return mm->brk;
|
|
|
|
return ret;
|
|
}
|