On 11/5/2024 6:57 AM, Ville Juven wrote:
For direct user level access, one option is to move tg_envp to TLS /
task_info_s. This way the user could access the memory without boring a hole
into the kernel.
The same environ is used by all threads in a task group/process. If one
thread changes the environment, it effects all threads in group/process
It could be possible to put the environment in the TLS of the main
thread and other could the access indirectly through their TLS references.
In KERNEL mode this issue is very simple; every process has its own instance of
environ** anyway so there is no need to use TLS or anything.
Yep. Lots of things are simpler in true kernel mode. Just like the
designers of Unix intended! NuttX is more complex and requires some
trade-offs.
However, in FLAT mode having a per-process instance of environ** is going to be
more difficult. You could -in theory- make a reference to the TLS area and use
it like that. This reference would have to be updated on every context switch.
Whether or not this is even possible to implement in a multicore (SMP) system
is beyond me, the reference would need to be duplicated on every CPU and the
user would need to be able to query which CPU it is running on.
I think this is already done for a few group common things. But I don't
remember. I haven't been that active for awhile (I got too old! 74 in
three days).
