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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
#include <linux/export.h>
#include <linux/io.h>
#include <linux/kfence.h>
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/mman.h>
#define SHM_ALIGN_MASK (SHMLBA - 1)
#define COLOUR_ALIGN(addr, pgoff) \
((((addr) + SHM_ALIGN_MASK) & ~SHM_ALIGN_MASK) \
+ (((pgoff) << PAGE_SHIFT) & SHM_ALIGN_MASK))
enum mmap_allocation_direction {UP, DOWN};
static unsigned long arch_get_unmapped_area_common(struct file *filp,
unsigned long addr0, unsigned long len, unsigned long pgoff,
unsigned long flags, enum mmap_allocation_direction dir)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long addr = addr0;
int do_color_align;
struct vm_unmapped_area_info info = {};
if (unlikely(len > TASK_SIZE))
return -ENOMEM;
if (flags & MAP_FIXED) {
/* Even MAP_FIXED mappings must reside within TASK_SIZE */
if (TASK_SIZE - len < addr)
return -EINVAL;
/*
* We do not accept a shared mapping if it would violate
* cache aliasing constraints.
*/
if ((flags & MAP_SHARED) &&
((addr - (pgoff << PAGE_SHIFT)) & SHM_ALIGN_MASK))
return -EINVAL;
return addr;
}
do_color_align = 0;
if (filp || (flags & MAP_SHARED))
do_color_align = 1;
/* requesting a specific address */
if (addr) {
if (do_color_align)
addr = COLOUR_ALIGN(addr, pgoff);
else
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (TASK_SIZE - len >= addr &&
(!vma || addr + len <= vm_start_gap(vma)))
return addr;
}
info.length = len;
info.align_mask = do_color_align ? (PAGE_MASK & SHM_ALIGN_MASK) : 0;
info.align_offset = pgoff << PAGE_SHIFT;
if (dir == DOWN) {
info.flags = VM_UNMAPPED_AREA_TOPDOWN;
info.low_limit = PAGE_SIZE;
info.high_limit = mm->mmap_base;
addr = vm_unmapped_area(&info);
if (!(addr & ~PAGE_MASK))
return addr;
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
}
info.low_limit = mm->mmap_base;
info.high_limit = TASK_SIZE;
return vm_unmapped_area(&info);
}
unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
unsigned long len, unsigned long pgoff, unsigned long flags,
vm_flags_t vm_flags)
{
return arch_get_unmapped_area_common(filp,
addr0, len, pgoff, flags, UP);
}
/*
* There is no need to export this but sched.h declares the function as
* extern so making it static here results in an error.
*/
unsigned long arch_get_unmapped_area_topdown(struct file *filp,
unsigned long addr0, unsigned long len, unsigned long pgoff,
unsigned long flags, vm_flags_t vm_flags)
{
return arch_get_unmapped_area_common(filp,
addr0, len, pgoff, flags, DOWN);
}
int __virt_addr_valid(volatile void *kaddr)
{
unsigned long vaddr = (unsigned long)kaddr;
if (is_kfence_address((void *)kaddr))
return 1;
if ((vaddr < PAGE_OFFSET) || (vaddr >= vm_map_base))
return 0;
return pfn_valid(PFN_DOWN(PHYSADDR(kaddr)));
}
EXPORT_SYMBOL_GPL(__virt_addr_valid);
/*
* You really shouldn't be using read() or write() on /dev/mem. This might go
* away in the future.
*/
int valid_phys_addr_range(phys_addr_t addr, size_t size)
{
/*
* Check whether addr is covered by a memory region without the
* MEMBLOCK_NOMAP attribute, and whether that region covers the
* entire range. In theory, this could lead to false negatives
* if the range is covered by distinct but adjacent memory regions
* that only differ in other attributes. However, few of such
* attributes have been defined, and it is debatable whether it
* follows that /dev/mem read() calls should be able traverse
* such boundaries.
*/
return memblock_is_region_memory(addr, size) && memblock_is_map_memory(addr);
}
/*
* Do not allow /dev/mem mappings beyond the supported physical range.
*/
int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
{
return !(((pfn << PAGE_SHIFT) + size) & ~(GENMASK_ULL(cpu_pabits, 0)));
}
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