cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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mmap.c (1798B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * ARC700 mmap
      4 *
      5 * (started from arm version - for VIPT alias handling)
      6 *
      7 * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
      8 */
      9
     10#include <linux/fs.h>
     11#include <linux/mm.h>
     12#include <linux/mman.h>
     13#include <linux/sched/mm.h>
     14
     15#include <asm/cacheflush.h>
     16
     17#define COLOUR_ALIGN(addr, pgoff)			\
     18	((((addr) + SHMLBA - 1) & ~(SHMLBA - 1)) +	\
     19	 (((pgoff) << PAGE_SHIFT) & (SHMLBA - 1)))
     20
     21/*
     22 * Ensure that shared mappings are correctly aligned to
     23 * avoid aliasing issues with VIPT caches.
     24 * We need to ensure that
     25 * a specific page of an object is always mapped at a multiple of
     26 * SHMLBA bytes.
     27 */
     28unsigned long
     29arch_get_unmapped_area(struct file *filp, unsigned long addr,
     30		unsigned long len, unsigned long pgoff, unsigned long flags)
     31{
     32	struct mm_struct *mm = current->mm;
     33	struct vm_area_struct *vma;
     34	int do_align = 0;
     35	int aliasing = cache_is_vipt_aliasing();
     36	struct vm_unmapped_area_info info;
     37
     38	/*
     39	 * We only need to do colour alignment if D cache aliases.
     40	 */
     41	if (aliasing)
     42		do_align = filp || (flags & MAP_SHARED);
     43
     44	/*
     45	 * We enforce the MAP_FIXED case.
     46	 */
     47	if (flags & MAP_FIXED) {
     48		if (aliasing && flags & MAP_SHARED &&
     49		    (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
     50			return -EINVAL;
     51		return addr;
     52	}
     53
     54	if (len > TASK_SIZE)
     55		return -ENOMEM;
     56
     57	if (addr) {
     58		if (do_align)
     59			addr = COLOUR_ALIGN(addr, pgoff);
     60		else
     61			addr = PAGE_ALIGN(addr);
     62
     63		vma = find_vma(mm, addr);
     64		if (TASK_SIZE - len >= addr &&
     65		    (!vma || addr + len <= vm_start_gap(vma)))
     66			return addr;
     67	}
     68
     69	info.flags = 0;
     70	info.length = len;
     71	info.low_limit = mm->mmap_base;
     72	info.high_limit = TASK_SIZE;
     73	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
     74	info.align_offset = pgoff << PAGE_SHIFT;
     75	return vm_unmapped_area(&info);
     76}