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