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Commit f4f925da authored by Sandipan Das's avatar Sandipan Das Committed by Peter Zijlstra
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perf/x86/amd/lbr: Add LbrExtV2 hardware branch filter support



If AMD Last Branch Record Extension Version 2 (LbrExtV2) is detected,
convert the requested branch filter (PERF_SAMPLE_BRANCH_* flags) to the
corresponding hardware filter value and stash it in the event data when
a branch stack is requested. The hardware filter value is also saved in
per-CPU areas for use during event scheduling.

Hardware filtering is provided by the LBR Branch Select register. It has
bits which when set, suppress recording of the following types of branches:

  * CPL = 0 (Kernel only)
  * CPL > 0 (Userspace only)
  * Conditional Branches
  * Near Relative Calls
  * Near Indirect Calls
  * Near Returns
  * Near Indirect Jumps (excluding Near Indirect Calls and Near Returns)
  * Near Relative Jumps (excluding Near Relative Calls)
  * Far Branches

Signed-off-by: default avatarSandipan Das <sandipan.das@amd.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/9336af5c9785b8e14c62220fc0e6cfb10ab97de3.1660211399.git.sandipan.das@amd.com
parent ca5b7c0d
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