[PATCH 2/2] bsps/arm: Sort fast text/data sections

[Sebastian Huber]

On 21/10/2020 07:42, Chris Johns wrote:

> On 21/10/20 4:31 pm, Sebastian Huber wrote:
>> On 21/10/2020 02:25, Chris Johns wrote:
>>
>>> On 21/10/20 3:04 am, Sebastian Huber wrote:
>>>> ---
>>>>    bsps/arm/shared/start/linkcmds.base | 4 ++--
>>>>    1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/bsps/arm/shared/start/linkcmds.base
>>>> b/bsps/arm/shared/start/linkcmds.base
>>>> index d0663cf97e..8fa127ce08 100644
>>>> --- a/bsps/arm/shared/start/linkcmds.base
>>>> +++ b/bsps/arm/shared/start/linkcmds.base
>>>> @@ -290,7 +290,7 @@ SECTIONS {
>>>>          .fast_text : ALIGN_WITH_INPUT {
>>>>            bsp_section_fast_text_begin = .;
>>> What is `fast text` (and fast data)? I have not heard of this before and I
>>> cannot find anything on it?
>> I added this section 11 years ago as a section for code which could reside in a
>> faster memory. For example, normal code could reside on a 16-bit SDRAM and the
>> fast code on an internal 32-bit SRAM in a chip without a cache. In the recent
>> Cortex-M7 BSPs, the fast text is mapped to the ITCM.
> OK. Is anything written up about this?
No, maybe we should add something about this in the arm BSP section of 
the user manual.
> For example is allocating variables
> automatic or can I control allocation to it?

You just have to place a function or variable with the section attribute 
into these sections:

bsps/arm/include/bsp/linker-symbols.h:#define BSP_FAST_TEXT_SECTION \
bsps/arm/include/bsp/linker-symbols.h- RTEMS_SECTION(".bsp_fast_text")

bsps/arm/include/bsp/linker-symbols.h:#define BSP_FAST_DATA_SECTION \
bsps/arm/include/bsp/linker-symbols.h- RTEMS_SECTION(".bsp_fast_data")