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73 lines
1.8 KiB
73 lines
1.8 KiB
// SPDX-License-Identifier: GPL-2.0 |
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// Copyright (C) 2005-2017 Andes Technology Corporation |
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#include <linux/sched.h> |
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#include <linux/mman.h> |
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#include <linux/shm.h> |
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#define COLOUR_ALIGN(addr,pgoff) \ |
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((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \ |
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(((pgoff)<<PAGE_SHIFT) & (SHMLBA-1))) |
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/* |
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* We need to ensure that shared mappings are correctly aligned to |
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* avoid aliasing issues with VIPT caches. We need to ensure that |
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* a specific page of an object is always mapped at a multiple of |
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* SHMLBA bytes. |
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* |
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* We unconditionally provide this function for all cases, however |
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* in the VIVT case, we optimise out the alignment rules. |
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*/ |
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unsigned long |
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arch_get_unmapped_area(struct file *filp, unsigned long addr, |
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unsigned long len, unsigned long pgoff, |
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unsigned long flags) |
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{ |
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struct mm_struct *mm = current->mm; |
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struct vm_area_struct *vma; |
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int do_align = 0; |
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struct vm_unmapped_area_info info; |
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int aliasing = 0; |
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if(IS_ENABLED(CONFIG_CPU_CACHE_ALIASING)) |
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aliasing = 1; |
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/* |
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* We only need to do colour alignment if either the I or D |
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* caches alias. |
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*/ |
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if (aliasing) |
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do_align = filp || (flags & MAP_SHARED); |
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/* |
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* We enforce the MAP_FIXED case. |
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*/ |
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if (flags & MAP_FIXED) { |
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if (aliasing && flags & MAP_SHARED && |
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(addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) |
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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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if (addr) { |
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if (do_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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vma = find_vma(mm, addr); |
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if (TASK_SIZE - len >= addr && |
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(!vma || addr + len <= vma->vm_start)) |
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return addr; |
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} |
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info.flags = 0; |
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info.length = len; |
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info.low_limit = mm->mmap_base; |
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info.high_limit = TASK_SIZE; |
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info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0; |
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info.align_offset = pgoff << PAGE_SHIFT; |
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return vm_unmapped_area(&info); |
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}
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