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>
122 lines
2.8 KiB
C
122 lines
2.8 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2011 Wind River Systems,
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* written by Ralf Baechle <ralf@linux-mips.org>
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*/
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/mman.h>
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#include <linux/module.h>
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#include <linux/random.h>
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#include <linux/sched.h>
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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) \
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((((addr) + shm_align_mask) & ~shm_align_mask) + \
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(((pgoff) << PAGE_SHIFT) & shm_align_mask))
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unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
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unsigned long len, unsigned long pgoff, unsigned long flags)
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{
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struct vm_area_struct * vmm;
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int do_color_align;
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if (len > TASK_SIZE)
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return -ENOMEM;
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if (flags & MAP_FIXED) {
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/* Even MAP_FIXED mappings must reside within TASK_SIZE. */
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if (TASK_SIZE - len < addr)
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return -EINVAL;
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/*
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* We do not accept a shared mapping if it would violate
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* cache aliasing constraints.
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*/
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if ((flags & MAP_SHARED) &&
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((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
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return -EINVAL;
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return addr;
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}
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do_color_align = 0;
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if (filp || (flags & MAP_SHARED))
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do_color_align = 1;
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if (addr) {
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if (do_color_align)
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addr = COLOUR_ALIGN(addr, pgoff);
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else
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addr = PAGE_ALIGN(addr);
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vmm = find_vma(current->mm, addr);
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if (TASK_SIZE - len >= addr &&
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(!vmm || addr + len <= vmm->vm_start))
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return addr;
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}
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addr = current->mm->mmap_base;
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if (do_color_align)
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addr = COLOUR_ALIGN(addr, pgoff);
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else
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addr = PAGE_ALIGN(addr);
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for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
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/* At this point: (!vmm || addr < vmm->vm_end). */
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if (TASK_SIZE - len < addr)
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return -ENOMEM;
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if (!vmm || addr + len <= vmm->vm_start)
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return addr;
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addr = vmm->vm_end;
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if (do_color_align)
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addr = COLOUR_ALIGN(addr, pgoff);
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}
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}
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void arch_pick_mmap_layout(struct mm_struct *mm)
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{
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unsigned long random_factor = 0UL;
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if (current->flags & PF_RANDOMIZE) {
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random_factor = get_random_int();
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random_factor = random_factor << PAGE_SHIFT;
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if (TASK_IS_32BIT_ADDR)
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random_factor &= 0xfffffful;
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else
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random_factor &= 0xffffffful;
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}
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mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
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mm->get_unmapped_area = arch_get_unmapped_area;
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mm->unmap_area = arch_unmap_area;
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}
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static inline unsigned long brk_rnd(void)
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{
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unsigned long rnd = get_random_int();
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rnd = rnd << PAGE_SHIFT;
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/* 8MB for 32bit, 256MB for 64bit */
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if (TASK_IS_32BIT_ADDR)
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rnd = rnd & 0x7ffffful;
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else
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rnd = rnd & 0xffffffful;
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return rnd;
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}
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unsigned long arch_randomize_brk(struct mm_struct *mm)
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{
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unsigned long base = mm->brk;
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unsigned long ret;
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ret = PAGE_ALIGN(base + brk_rnd());
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if (ret < mm->brk)
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return mm->brk;
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return ret;
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}
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