67 lines
1.7 KiB
C
67 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/mman.h>
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#include <linux/shm.h>
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#include <linux/sched.h>
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#include <linux/random.h>
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#include <linux/io.h>
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unsigned long shm_align_mask = (0x4000 >> 1) - 1; /* Sane caches */
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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 (flags & MAP_FIXED) {
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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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if (len > TASK_SIZE)
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return -ENOMEM;
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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 = TASK_UNMAPPED_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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