Re: [PATCH 14/17] dt: Consolidate __dtb_start declarations in <linux/of_fdt.h>

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On Wed, Nov 13, 2013 at 6:34 PM, Rob Herring <robherring2@xxxxxxxxx> wrote:
>>> +       if (!initial_boot_params ||
>>> +           (be32_to_cpu(initial_boot_params->magic) != OF_DT_HEADER))
>>> +               initial_boot_params = &__dtb_start;
>>> +
>>>         /* check device tree validity */
>>> -       if (be32_to_cpu(initial_boot_params->magic) != OF_DT_HEADER) {
>>> +       if (!initial_boot_params ||
>>
>> initial_boot_params cannot be NULL here, so no need to check.
>
> What about the case of no built-in dtb like on arm?

Even then the symbol exists, as all architectures put INIT_DATA or
INIT_DATA_SECTION in their vmlinux.lds.S.
But the section will be empty, cfr. the case __dtb_end == __dtb_start below.

>>
>>> +           (be32_to_cpu(initial_boot_params->magic) != OF_DT_HEADER)) {
>>
>> However, if __dtb_end == __dtb_start, you may be reading random
>> data here from the next section. The OF_DT_HEADER check should cover
>> this, but better safe than sorry?
>
> Then we should also check that (__dtb_end != __dtb_start).

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]
  Powered by Linux