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Ralf Baechle
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May 19, 2011
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,2 +1,2 @@ | ||
| --- | ||
| refs/heads/master: 9c1e8a9138ff92a4ff816ea8a1884ad2461a993a | ||
| refs/heads/master: 6f6c3c33c027f2c83d53e8562cd9daa73fe8108b |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,122 @@ | ||
| /* | ||
| * 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 */ | ||
|
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| EXPORT_SYMBOL(shm_align_mask); | ||
|
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| #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; | ||
|
|
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| 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; | ||
| } | ||
|
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||
| 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(); | ||
|
|
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| rnd = rnd << PAGE_SHIFT; | ||
| /* 8MB for 32bit, 256MB for 64bit */ | ||
| if (TASK_IS_32BIT_ADDR) | ||
| rnd = rnd & 0x7ffffful; | ||
| else | ||
| rnd = rnd & 0xffffffful; | ||
|
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| return rnd; | ||
| } | ||
|
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| unsigned long arch_randomize_brk(struct mm_struct *mm) | ||
| { | ||
| unsigned long base = mm->brk; | ||
| unsigned long ret; | ||
|
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| ret = PAGE_ALIGN(base + brk_rnd()); | ||
|
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| if (ret < mm->brk) | ||
| return mm->brk; | ||
|
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| return ret; | ||
| } |