arc/mm/mmap.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * ARC700 mmap
0004  *
0005  * (started from arm version - for VIPT alias handling)
0006  *
0007  * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
0008  */
0009
0010 #include <linux/fs.h>
0011 #include <linux/mm.h>
0012 #include <linux/mman.h>
0013 #include <linux/sched/mm.h>
0014
0015 #include <asm/cacheflush.h>
0016
0017 #define COLOUR_ALIGN(addr, pgoff)           \
0018     ((((addr) + SHMLBA - 1) & ~(SHMLBA - 1)) +  \
0019      (((pgoff) << PAGE_SHIFT) & (SHMLBA - 1)))
0020
0021 /*
0022  * Ensure that shared mappings are correctly aligned to
0023  * avoid aliasing issues with VIPT caches.
0024  * We need to ensure that
0025  * a specific page of an object is always mapped at a multiple of
0026  * SHMLBA bytes.
0027  */
0028 unsigned long
0029 arch_get_unmapped_area(struct file *filp, unsigned long addr,
0030         unsigned long len, unsigned long pgoff, unsigned long flags)
0031 {
0032     struct mm_struct *mm = current->mm;
0033     struct vm_area_struct *vma;
0034     int do_align = 0;
0035     int aliasing = cache_is_vipt_aliasing();
0036     struct vm_unmapped_area_info info;
0037
0038     /*
0039      * We only need to do colour alignment if D cache aliases.
0040      */
0041     if (aliasing)
0042         do_align = filp || (flags & MAP_SHARED);
0043
0044     /*
0045      * We enforce the MAP_FIXED case.
0046      */
0047     if (flags & MAP_FIXED) {
0048         if (aliasing && flags & MAP_SHARED &&
0049             (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
0050             return -EINVAL;
0051         return addr;
0052     }
0053
0054     if (len > TASK_SIZE)
0055         return -ENOMEM;
0056
0057     if (addr) {
0058         if (do_align)
0059             addr = COLOUR_ALIGN(addr, pgoff);
0060         else
0061             addr = PAGE_ALIGN(addr);
0062
0063         vma = find_vma(mm, addr);
0064         if (TASK_SIZE - len >= addr &&
0065             (!vma || addr + len <= vm_start_gap(vma)))
0066             return addr;
0067     }
0068
0069     info.flags = 0;
0070     info.length = len;
0071     info.low_limit = mm->mmap_base;
0072     info.high_limit = TASK_SIZE;
0073     info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
0074     info.align_offset = pgoff << PAGE_SHIFT;
0075     return vm_unmapped_area(&info);
0076 }
0077
0078 static const pgprot_t protection_map[16] = {
0079     [VM_NONE]                   = PAGE_U_NONE,
0080     [VM_READ]                   = PAGE_U_R,
0081     [VM_WRITE]                  = PAGE_U_R,
0082     [VM_WRITE | VM_READ]                = PAGE_U_R,
0083     [VM_EXEC]                   = PAGE_U_X_R,
0084     [VM_EXEC | VM_READ]             = PAGE_U_X_R,
0085     [VM_EXEC | VM_WRITE]                = PAGE_U_X_R,
0086     [VM_EXEC | VM_WRITE | VM_READ]          = PAGE_U_X_R,
0087     [VM_SHARED]                 = PAGE_U_NONE,
0088     [VM_SHARED | VM_READ]               = PAGE_U_R,
0089     [VM_SHARED | VM_WRITE]              = PAGE_U_W_R,
0090     [VM_SHARED | VM_WRITE | VM_READ]        = PAGE_U_W_R,
0091     [VM_SHARED | VM_EXEC]               = PAGE_U_X_R,
0092     [VM_SHARED | VM_EXEC | VM_READ]         = PAGE_U_X_R,
0093     [VM_SHARED | VM_EXEC | VM_WRITE]        = PAGE_U_X_W_R,
0094     [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]  = PAGE_U_X_W_R
0095 };
0096 DECLARE_VM_GET_PAGE_PROT