cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

mmap.c (3462B)

      1/*
      2 * This file is subject to the terms and conditions of the GNU General Public
      3 * License.  See the file "COPYING" in the main directory of this archive
      4 * for more details.
      5 *
      6 * Copyright (C) 2011 Wind River Systems,
      7 *   written by Ralf Baechle <ralf@linux-mips.org>
      8 */
      9#include <linux/compiler.h>
     10#include <linux/elf-randomize.h>
     11#include <linux/errno.h>
     12#include <linux/mm.h>
     13#include <linux/mman.h>
     14#include <linux/export.h>
     15#include <linux/personality.h>
     16#include <linux/random.h>
     17#include <linux/sched/signal.h>
     18#include <linux/sched/mm.h>
     19
     20unsigned long shm_align_mask = PAGE_SIZE - 1;	/* Sane caches */
     21EXPORT_SYMBOL(shm_align_mask);
     22
     23#define COLOUR_ALIGN(addr, pgoff)				\
     24	((((addr) + shm_align_mask) & ~shm_align_mask) +	\
     25	 (((pgoff) << PAGE_SHIFT) & shm_align_mask))
     26
     27enum mmap_allocation_direction {UP, DOWN};
     28
     29static unsigned long arch_get_unmapped_area_common(struct file *filp,
     30	unsigned long addr0, unsigned long len, unsigned long pgoff,
     31	unsigned long flags, enum mmap_allocation_direction dir)
     32{
     33	struct mm_struct *mm = current->mm;
     34	struct vm_area_struct *vma;
     35	unsigned long addr = addr0;
     36	int do_color_align;
     37	struct vm_unmapped_area_info info;
     38
     39	if (unlikely(len > TASK_SIZE))
     40		return -ENOMEM;
     41
     42	if (flags & MAP_FIXED) {
     43		/* Even MAP_FIXED mappings must reside within TASK_SIZE */
     44		if (TASK_SIZE - len < addr)
     45			return -EINVAL;
     46
     47		/*
     48		 * We do not accept a shared mapping if it would violate
     49		 * cache aliasing constraints.
     50		 */
     51		if ((flags & MAP_SHARED) &&
     52		    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
     53			return -EINVAL;
     54		return addr;
     55	}
     56
     57	do_color_align = 0;
     58	if (filp || (flags & MAP_SHARED))
     59		do_color_align = 1;
     60
     61	/* requesting a specific address */
     62	if (addr) {
     63		if (do_color_align)
     64			addr = COLOUR_ALIGN(addr, pgoff);
     65		else
     66			addr = PAGE_ALIGN(addr);
     67
     68		vma = find_vma(mm, addr);
     69		if (TASK_SIZE - len >= addr &&
     70		    (!vma || addr + len <= vm_start_gap(vma)))
     71			return addr;
     72	}
     73
     74	info.length = len;
     75	info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0;
     76	info.align_offset = pgoff << PAGE_SHIFT;
     77
     78	if (dir == DOWN) {
     79		info.flags = VM_UNMAPPED_AREA_TOPDOWN;
     80		info.low_limit = PAGE_SIZE;
     81		info.high_limit = mm->mmap_base;
     82		addr = vm_unmapped_area(&info);
     83
     84		if (!(addr & ~PAGE_MASK))
     85			return addr;
     86
     87		/*
     88		 * A failed mmap() very likely causes application failure,
     89		 * so fall back to the bottom-up function here. This scenario
     90		 * can happen with large stack limits and large mmap()
     91		 * allocations.
     92		 */
     93	}
     94
     95	info.flags = 0;
     96	info.low_limit = mm->mmap_base;
     97	info.high_limit = TASK_SIZE;
     98	return vm_unmapped_area(&info);
     99}
    100
    101unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
    102	unsigned long len, unsigned long pgoff, unsigned long flags)
    103{
    104	return arch_get_unmapped_area_common(filp,
    105			addr0, len, pgoff, flags, UP);
    106}
    107
    108/*
    109 * There is no need to export this but sched.h declares the function as
    110 * extern so making it static here results in an error.
    111 */
    112unsigned long arch_get_unmapped_area_topdown(struct file *filp,
    113	unsigned long addr0, unsigned long len, unsigned long pgoff,
    114	unsigned long flags)
    115{
    116	return arch_get_unmapped_area_common(filp,
    117			addr0, len, pgoff, flags, DOWN);
    118}
    119
    120bool __virt_addr_valid(const volatile void *kaddr)
    121{
    122	unsigned long vaddr = (unsigned long)kaddr;
    123
    124	if ((vaddr < PAGE_OFFSET) || (vaddr >= MAP_BASE))
    125		return false;
    126
    127	return pfn_valid(PFN_DOWN(virt_to_phys(kaddr)));
    128}
    129EXPORT_SYMBOL_GPL(__virt_addr_valid);