[PATCH v1 0/6] TIMESTAMP output section command

[Jan Beulich]

On 09.10.2025 11:39, Ulf Samuelsson wrote:
> Den 2025-10-09 kl. 08:03, skrev Hans-Peter Nilsson:
>> On Wed, 8 Oct 2025, Ulf Samuelsson wrote:
>>> Den 2025-10-08 kl. 10:17, skrev Alan Modra:
>>>> You can of course already insert a quad-word entry with the current
>>>> time, so this is really just syntactic sugar.  One way is
>>>> INCLUDE timestamp.ld
>>>> in your script somewhere, then just before running the linker, run
>>>> echo ".QUAD `date '+%s'`" > timestamp.ld
>> I'll one-up Alan's suggestion: for your definition of a
>> timestamp, use the ld command-line option
>>   "--defsym my_timestamp=`date '+%s'`"
>> and use
>>   "QUAD(my_timestamp)" in the
>> linker script.  Works with today's version.
>> And yesterday's, and ten years ago: I checked.
> It is possible to do it this way. That does not mean that it is a good 
> way to implement it this way.
> The current linker decides on timestamp without having to specify 
> something as a command line
> option when you generate the timestamp for an ELF header or similar.

Just to mention - I'm unaware of ELF headers carrying timestamps. PE
and COFF headers do, yes.

>> That it works with today's (and yester-year's) linker version,
>> not requiring any functionality, is important to embedded
>> developers.
> 
> Assume that 10,000 projects implements timestamp this way.
> Then, they are forced by regulations to use "SOURCE_DATE_EPOCH" to 
> implement timestamps.
> Now you have 10,000 project with a technical debt.

Surely a fair part of them would have found a way to embed timestamps,
and hence ...

> With the suggestion implemented, you have a much smaller technical debt

... it would be extra effort for them to convert to the new linker
script syntax you suggest.

Jan