1 /* 2 * ARC700 mmap 3 * 4 * (started from arm version - for VIPT alias handling) 5 * 6 * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com) 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13 #include <linux/fs.h> 14 #include <linux/mm.h> 15 #include <linux/mman.h> 16 #include <linux/sched.h> 17 #include <asm/cacheflush.h> 18 19 #define COLOUR_ALIGN(addr, pgoff) \ 20 ((((addr) + SHMLBA - 1) & ~(SHMLBA - 1)) + \ 21 (((pgoff) << PAGE_SHIFT) & (SHMLBA - 1))) 22 23 /* 24 * Ensure that shared mappings are correctly aligned to 25 * avoid aliasing issues with VIPT caches. 26 * We need to ensure that 27 * a specific page of an object is always mapped at a multiple of 28 * SHMLBA bytes. 29 */ 30 unsigned long 31 arch_get_unmapped_area(struct file *filp, unsigned long addr, 32 unsigned long len, unsigned long pgoff, unsigned long flags) 33 { 34 struct mm_struct *mm = current->mm; 35 struct vm_area_struct *vma; 36 int do_align = 0; 37 int aliasing = cache_is_vipt_aliasing(); 38 struct vm_unmapped_area_info info; 39 40 /* 41 * We only need to do colour alignment if D cache aliases. 42 */ 43 if (aliasing) 44 do_align = filp || (flags & MAP_SHARED); 45 46 /* 47 * We enforce the MAP_FIXED case. 48 */ 49 if (flags & MAP_FIXED) { 50 if (aliasing && flags & MAP_SHARED && 51 (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) 52 return -EINVAL; 53 return addr; 54 } 55 56 if (len > TASK_SIZE) 57 return -ENOMEM; 58 59 if (addr) { 60 if (do_align) 61 addr = COLOUR_ALIGN(addr, pgoff); 62 else 63 addr = PAGE_ALIGN(addr); 64 65 vma = find_vma(mm, addr); 66 if (TASK_SIZE - len >= addr && 67 (!vma || addr + len <= vma->vm_start)) 68 return addr; 69 } 70 71 info.flags = 0; 72 info.length = len; 73 info.low_limit = mm->mmap_base; 74 info.high_limit = TASK_SIZE; 75 info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0; 76 info.align_offset = pgoff << PAGE_SHIFT; 77 return vm_unmapped_area(&info); 78 } 79