Commit 92437fba authored by James Clark's avatar James Clark
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Documentation: coresight: Expand branch broadcast documentation



Now that there is a way of enabling branch broadcast via perf, mention
the possible use cases and known limitations.
Signed-off-by: James Clark's avatarJames Clark <james.clark@arm.com>
parent 08706765
...@@ -656,7 +656,15 @@ Bit assignments shown below:- ...@@ -656,7 +656,15 @@ Bit assignments shown below:-
ETM_MODE_BB ETM_MODE_BB
**description:** **description:**
Set to enable branch broadcast if supported in hardware [IDR0]. Set to enable branch broadcast if supported in hardware [IDR0]. The primary use for this feature
is when code is patched dynamically at run time and the full program flow may not be able to be
reconstructed using only conditional branches.
Choosing this option will result in a significant increase in the amount of trace generated -
possible danger of overflows, or fewer instructions covered. Note, that this option also
overrides any setting of :ref:`ETM_MODE_RETURNSTACK <coresight-return-stack>`, so where a branch
broadcast range overlaps a return stack range, return stacks will not be available for that
range.
.. _coresight-cycle-accurate: .. _coresight-cycle-accurate:
......
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