static glodf_t
mmap_fifo(int fd, int UNUSED(flags))
{
/* map the whole of stdin, attention this could cause RAM pressure */
/* we start out with one page of memory ... */
size_t iniz = sysconf(_SC_PAGESIZE);
glodf_t m;
if ((m = mmap_mem(iniz)).d == NULL) {
goto out;
}
{
ptrdiff_t off = 0;
for (ssize_t nrd, bz = m.z - off;
(nrd = read(fd, (char*)m.d + off, bz)) > 0;
off += nrd, bz = m.z - off) {
if (nrd == bz) {
/* enlarge and reread */
m = mremap_mem(m, 2U * m.z);
}
}
}
out:
return m;
}
static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
{
unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
unsigned long size = vma->vm_end - vma->vm_start;
/*
* If the user is not attempting to mmap a high memory address then
* the standard mmap_mem mechanism will work. High memory addresses
* need special handling, as remap_page_range expects a physically-
* contiguous range of kernel addresses (such as obtained in kmalloc).
*/
if ((offset + size) < (unsigned long) high_memory)
return mmap_mem(file, vma);
/*
* Accessing memory above the top the kernel knows about or
* through a file pointer that was marked O_SYNC will be
* done non-cached.
*/
if (noncached_address(offset) || (file->f_flags & O_SYNC))
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
/* Don't do anything here; "nopage" will fill the holes */
vma->vm_ops = &kmem_vm_ops;
/* Don't try to swap out physical pages.. */
vma->vm_flags |= VM_RESERVED;
/*
* Don't dump addresses that are not real memory to a core file.
*/
vma->vm_flags |= VM_IO;
return 0;
}
static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
{
unsigned long long val;
/*
* RED-PEN: on some architectures there is more mapped memory
* than available in mem_map which pfn_valid checks
* for. Perhaps should add a new macro here.
*
* RED-PEN: vmalloc is not supported right now.
*/
if (!pfn_valid(vma->vm_pgoff))
return -EIO;
val = (u64)vma->vm_pgoff << PAGE_SHIFT;
vma->vm_pgoff = __pa(val) >> PAGE_SHIFT;
return mmap_mem(file, vma);
}