// 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> #define COLOUR_ALIGN(addr,pgoff) \ ((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \ (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1))) /* * We need to ensure that shared mappings are correctly aligned to * avoid aliasing issues with VIPT caches. We need to ensure that * a specific page of an object is always mapped at a multiple of * SHMLBA bytes. * * We unconditionally provide this function for all cases. */ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma; int do_align = 0; struct vm_unmapped_area_info info; /* * We only need to do colour alignment if either the I or D * caches alias. */ do_align = filp || (flags & MAP_SHARED); /* * We enforce the MAP_FIXED case. */ if (flags & MAP_FIXED) { if (flags & MAP_SHARED && (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) return -EINVAL; return addr; } if (len > TASK_SIZE) return -ENOMEM; if (addr) { if (do_align) addr = COLOUR_ALIGN(addr, pgoff); else addr = PAGE_ALIGN(addr); vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && (!vma || addr + len <= vm_start_gap(vma))) return addr; } info.flags = 0; info.length = len; info.low_limit = mm->mmap_base; info.high_limit = TASK_SIZE; info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0; info.align_offset = pgoff << PAGE_SHIFT; return vm_unmapped_area(&info); }