1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
6 #include <linux/mman.h>
8 #include <linux/sched.h>
9 #include <linux/random.h>
12 unsigned long shm_align_mask = (0x4000 >> 1) - 1; /* Sane caches */
14 #define COLOUR_ALIGN(addr, pgoff) \
15 ((((addr) + shm_align_mask) & ~shm_align_mask) + \
16 (((pgoff) << PAGE_SHIFT) & shm_align_mask))
18 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
19 unsigned long len, unsigned long pgoff, unsigned long flags)
21 struct vm_area_struct *vmm;
24 if (flags & MAP_FIXED) {
26 * We do not accept a shared mapping if it would violate
27 * cache aliasing constraints.
29 if ((flags & MAP_SHARED) &&
30 ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
38 if (filp || (flags & MAP_SHARED))
42 addr = COLOUR_ALIGN(addr, pgoff);
44 addr = PAGE_ALIGN(addr);
45 vmm = find_vma(current->mm, addr);
46 if (TASK_SIZE - len >= addr &&
47 (!vmm || addr + len <= vmm->vm_start))
50 addr = TASK_UNMAPPED_BASE;
52 addr = COLOUR_ALIGN(addr, pgoff);
54 addr = PAGE_ALIGN(addr);
56 for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
57 /* At this point: (!vmm || addr < vmm->vm_end). */
58 if (TASK_SIZE - len < addr)
60 if (!vmm || addr + len <= vmm->vm_start)
64 addr = COLOUR_ALIGN(addr, pgoff);