On 03/06/2013 02:58 PM, Jerome Poncin wrote:
> Gilles,
>
> I don't know, perhaps I missed some remarks, it's possible (by error or
> by misunderstanding) .
Again, that is because you seem to be used to top-posting, which is the
opposite way this mailing list (and many others) work.
> +static ssize_t cifx_pci_write(struct rtdm_dev_context *context,
> + rtdm_user_info_t *user_info, const void *buf,
> + size_t nbyte)
> +{
> + struct io_map_mem map_mem;
> + int ret;
> +
> + switch (nbyte) {
> + case sizeof(map_mem):
> + /* Copy data information for Kernel */
> + if (rtdm_safe_copy_from_user(user_info, &map_mem, buf, nbyte))
> + return 0;
> +
> + if (*map_mem.virt_addr == NULL) {
> + /* Map physical on virtual memory */
> + ret = rtdm_iomap_to_user(user_info,
> + map_mem.
> + phys_addr,
> + map_mem.length,
> + (PROT_READ | PROT_WRITE),
> + map_mem.virt_addr,
> + NULL,
> + NULL);
> +
> + if (ret != 0)
> + return 0;
> + } else {
> + /* Unap virtual memory */
> + ret = rtdm_munmap(user_info,
> + *map_mem.virt_addr,
> + map_mem.length);
> +
> + if (ret != 0)
> + return 0;
> + }
> + break;
> +
> + default:
> + /* Error */
> + return 0;
> + }
> +
> + return nbyte;
Again, left alone the fact that this function should not be a "write"
method, this should be:
if (nbyte != sizeof(mmap_mem))
return -EINVAL;
if (rtdm_safe_copy_from_user(user_info, &map_mem, buf, nbyte))
return -EFAULT;
if (*map_mem.virt_addr)
return rtdm_munmap(user_info, *map_mem.virt_addr, map_mem.length);
return rtdm_iomap_to_user(user_info, map_mem.phys_addr, map_mem.length,
(PROT_READ | PROT_WRITE), map_mem.virt_addr, NULL,
NULL);
And I am wondering, if this is even correct: if map_mem.virt_addr is a
user-space address, it is forbidden to dereference it directly in
kernel-space, we should use another copy_from/to_user, even if it appears
to work on some (most in fact) architectures. It is probably better to
put the virtual address directly in the map_mem structure instead of
a pointer requiring more contorsions.
--
Gilles.
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