[U-Boot] [PATCH V2] spl: Weed out CONFIG_SYS_TEXT_BASE usage

[Marek Vasut]

On 08/14/2018 12:22 PM, Simon Goldschmidt wrote:
> On Tue, Aug 14, 2018 at 12:10 PM Marek Vasut <marex at denx.de> wrote:
>>
>> On 08/14/2018 11:51 AM, Simon Goldschmidt wrote:
>>> On Tue, Aug 14, 2018 at 11:27 AM Marek Vasut <marex at denx.de> wrote:
>>>>
>>>> The SPL loaders assume that the CONFIG_SYS_TEXT_BASE memory location
>>>> is available and can be corrupted by loading ie. uImage or fitImage
>>>> headers there. Sometimes it could be beneficial to load the headers
>>>> elsewhere, ie. if CONFIG_SYS_TEXT_BASE is not yet writable while we
>>>> still want to parse the image headers in some local onchip memory to
>>>> ie. extract firmware from that image.
>>>>
>>>> Add the possibility to override the location where the headers get
>>>> loaded by introducing new function, spl_get_load_buffer() which takes
>>>> two arguments -- offset from the CONFIG_SYS_TEXT_BASE and size of the
>>>> data that are to be loaded there -- and returns a valid buffer address
>>>> or hangs the system. The default behavior is the same as before, add
>>>> the offset to CONFIG_SYS_TEXT_BASE and return that address. User can
>>>> override the weak spl_get_load_buffer() function though.
>>>>
>>>> Signed-off-by: Marek Vasut <marex at denx.de>
>>>> Cc: Tom Rini <trini at konsulko.com>
>>>> ---
>>>> V2: Fix build issues on multiple boards due to incorrect pointer casting
>>
>> [...]
>>
>>>> diff --git a/common/spl/spl_ram.c b/common/spl/spl_ram.c
>>>> index e594beaeaa..619b39a537 100644
>>>> --- a/common/spl/spl_ram.c
>>>> +++ b/common/spl/spl_ram.c
>>>> @@ -63,8 +63,9 @@ static int spl_ram_load_image(struct spl_image_info *spl_image,
>>>>                          * No binman support or no information. For now, fix it
>>>>                          * to the address pointed to by U-Boot.
>>>>                          */
>>>> -                       u_boot_pos = CONFIG_SYS_TEXT_BASE -
>>>> -                                       sizeof(struct image_header);
>>>> +                       header = spl_get_load_buffer(-sizeof(*header),
>>>> +                                                    sizeof(*header));
>>>> +
>>>
>>> Using "spl_get_load_buffer()" here seems to be a bit misleading, as
>>> the address is used for "execute-in-place", not for loading.
>>
>> Do you have a better solution ? Instead of hard-coding the load buffer
>> address with some macro, this uses function which could be overridden.
>> Whether it's XIP or not has nothing to do with it.
> 
> I meant the name is a bit misleading as it implies loading. But since
> the preferred way to do this is using binman, it's probably not worth
> adding yet another weak function for RAM boot?

Do you have a better name that fits all the other usecases ? This
function just gets you buffer into which you can load the image.

>>>>                 }
>>>>                 header = (struct image_header *)map_sysmem(u_boot_pos, 0);
>>>>
>>>> diff --git a/common/spl/spl_spi.c b/common/spl/spl_spi.c
>>>> index ba60a3a3c5..e10cf0124f 100644
>>>> --- a/common/spl/spl_spi.c
>>>> +++ b/common/spl/spl_spi.c
>>>> @@ -88,8 +88,7 @@ static int spl_spi_load_image(struct spl_image_info *spl_image,
>>>>                 return -ENODEV;
>>>>         }
>>>>
>>>> -       /* use CONFIG_SYS_TEXT_BASE as temporary storage area */
>>>> -       header = (struct image_header *)(CONFIG_SYS_TEXT_BASE);
>>>> +       header = spl_get_load_buffer(-sizeof(*header), 0x40);
>>>
>>> Shouldn't the first argument be 0 here instead of -sizeof(*header)?
>>
>> No, because then the payload doesn't end up at CONFIG_SYS_TEXT_BASE .
> 
> Sorry, I haven't studied the code around the patch, only the patch.
> And I still think "header" has changed from "CONFIG_SYS_TEXT_BASE" to
> "CONFIG_SYS_TEXT_BASE - sizeof(*header)" with your patch. That might
> be a change required to get it work, I don't know that. But as this
> isn' mentioned in the commit message, to me it seemed like a copy and
> paste error or something.

I suspect it's the SPI that's weird. Look at the surrounding code, IMO
this is how it should be.

> Simon
> 


-- 
Best regards,
Marek Vasut