On Mon, Oct 27, 2025 at 09:49:39AM +0000, Suzuki Kuruppassery Poulose wrote:
On 24/10/2025 17:45, Leo Yan wrote:
As recommended in section 4.3.7 "Synchronization of register updates" of ARM IHI0064H.b, a self-hosted trace analyzer should always executes an ISB instruction after programming the trace unit registers.
An ISB works as a context synchronization event; a DSB is not required. Removes the redundant barrier in the enabling flow.
It is required for MMIO based instances and must be retained.
Sorry I did not give details in commit log so caused confusion (and thanks a lot for Levi's supplement info!)
I will amend in next spin.
The ISB was placed at the end of the enable and disable functions. However, this does not guarantee a context synchronization event in the calling code, which may speculatively execute across function boundaries.
It is not allowed to commit though, right ? I don't think this change is required TBH.
Correct, I will drop this part.
Thanks, Leo