powerpc/perf: Disable trace_imc pmu

When a root user or a user with CAP_SYS_ADMIN privilege uses any
trace_imc performance monitoring unit events, to monitor application
or KVM threads, it may result in a checkstop (System crash).

The cause is frequent switching of the "trace/accumulation" mode of
the In-Memory Collection hardware (LDBAR).

This patch disables the trace_imc PMU unit entirely to avoid
triggering the checkstop. A future patch will reenable it at a later
stage once a workaround has been developed.

Fixes: 012ae244845f ("powerpc/perf: Trace imc PMU functions")
Cc: [email protected] # v5.2+
Signed-off-by: Madhavan Srinivasan <[email protected]>
Tested-by: Hariharan T.S. <[email protected]>
[mpe: Add pr_info_once() so dmesg shows the PMU has been disabled]
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

0 files changed, 0 insertions, 0 deletions