powerpc/perf: Core EBB support for 64-bit book3s
Add support for EBB (Event Based Branches) on 64-bit book3s. See the
included documentation for more details.
EBBs are a feature which allows the hardware to branch directly to a
specified user space address when a PMU event overflows. This can be
used by programs for self-monitoring with no kernel involvement in the
inner loop.
Most of the logic is in the generic book3s code, primarily to avoid a
proliferation of PMU callbacks.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index b0f3e3f..f8a76e6 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -916,7 +916,11 @@
flush_altivec_to_thread(src);
flush_vsx_to_thread(src);
flush_spe_to_thread(src);
+
*dst = *src;
+
+ clear_task_ebb(dst);
+
return 0;
}