kernel/drivers/perf/arm-cmn.c, branch linux-6.1.y

perf/arm-cmn: Reject unsupported hardware configurations

2026-03-04T12:20:51Z

[ Upstream commit 36c0de02575ce59dfd879eb4ef63d53a68bbf9ce ] So far we've been fairly lax about accepting both unknown CMN models (at least with a warning), and unknown revisions of those which we do know, as although things do frequently change between releases, typically enough remains the same to be somewhat useful for at least some basic bringup checks. However, we also make assumptions of the maximum supported sizes and numbers of things in various places, and there's no guarantee that something new might not be bigger and lead to nasty array overflows. Make sure we only try to run on things that actually match our assumptions and so will not risk memory corruption. We have at least always failed on completely unknown node types, so update that error message for clarity and consistency too. Cc: stable@vger.kernel.org Fixes: 7819e05a0dce ("perf/arm-cmn: Revamp model detection") Reviewed-by: Ilkka Koskinen Signed-off-by: Robin Murphy Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

perf/arm-cmn: Support CMN-600AE

2026-03-04T12:20:13Z

[ Upstream commit 12a94953c37e834c3eabb839ce057094946fe67a ] The functional safety features of CMN-600AE have little to no impact on the PMU relative to the base CMN-600 design, so for simplicity we can reasonably just treat it as the same thing. The only obvious difference is that the revision numbers aren't aligned, so we may hide some aliases for events which do actually exist, but those can still be specified via the underlying "type,eventid" format so it's not too big a deal. Signed-off-by: Robin Murphy Reviewed-by: Ilkka Koskinen Tested-by: Michal Simek Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

perf/arm-cmn: Initialise cmn->cpu earlier

2025-06-04T12:40:25Z

commit 597704e201068db3d104de3c7a4d447ff8209127 upstream. For all the complexity of handling affinity for CPU hotplug, what we've apparently managed to overlook is that arm_cmn_init_irqs() has in fact always been setting the *initial* affinity of all IRQs to CPU 0, not the CPU we subsequently choose for event scheduling. Oh dear. Cc: stable@vger.kernel.org Fixes: 0ba64770a2f2 ("perf: Add Arm CMN-600 PMU driver") Signed-off-by: Robin Murphy Reviewed-by: Ilkka Koskinen Link: https://lore.kernel.org/r/b12fccba6b5b4d2674944f59e4daad91cd63420b.1747069914.git.robin.murphy@arm.com Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman

perf/arm-cmn: Fix REQ2/SNP2 mixup

2025-06-04T12:40:25Z

commit 11b0f576e0cbde6a12258f2af6753b17b8df342b upstream. Somehow the encodings for REQ2/SNP2 channels in XP events got mixed up... Unmix them. CC: stable@vger.kernel.org Fixes: 23760a014417 ("perf/arm-cmn: Add CMN-700 support") Signed-off-by: Robin Murphy Link: https://lore.kernel.org/r/087023e9737ac93d7ec7a841da904758c254cb01.1746717400.git.robin.murphy@arm.com Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman

perf/arm-cmn: Ensure port and device id bits are set properly

2024-12-14T18:54:09Z

[ Upstream commit dfdf714fed559c09021df1d2a4bb64c0ad5f53bc ] The portid_bits and deviceid_bits were set only for XP type nodes in the arm_cmn_discover() and it confused other nodes to find XP nodes. Copy the both bits from the XP nodes directly when it sets up a new node. Fixes: e79634b53e39 ("perf/arm-cmn: Refactor node ID handling. Again.") Signed-off-by: Namhyung Kim Acked-by: Will Deacon Reviewed-by: Robin Murphy Link: https://lore.kernel.org/r/20241121001334.331334-1-namhyung@kernel.org Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin

perf/arm-cmn: Fail DTC counter allocation correctly

2024-10-17T13:21:28Z

commit 1892fe103c3a20fced306c8dafa74f7f6d4ea0a3 upstream. Calling arm_cmn_event_clear() before all DTC indices are allocated is wrong, and can lead to arm_cmn_event_add() erroneously clearing live counters from full DTCs where allocation fails. Since the DTC counters are only updated by arm_cmn_init_counter() after all DTC and DTM allocations succeed, nothing actually needs cleaning up in this case anyway, and it should just return directly as it did before. Fixes: 7633ec2c262f ("perf/arm-cmn: Rework DTC counters (again)") Signed-off-by: Robin Murphy Reviewed-by: Ilkka Koskinen Acked-by: Will Deacon Link: https://lore.kernel.org/r/ed589c0d8e4130dc68b8ad1625226d28bdc185d4.1702322847.git.robin.murphy@arm.com Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman

perf/arm-cmn: Ensure dtm_idx is big enough

2024-10-17T13:20:40Z

[ Upstream commit 359414b33e00bae91e4eabf3e4ef8e76024c7673 ] While CMN_MAX_DIMENSION was bumped to 12 for CMN-650, that only supports up to a 10x10 mesh, so bumping dtm_idx to 256 bits at the time worked out OK in practice. However CMN-700 did finally support up to 144 XPs, and thus needs a worst-case 288 bits of dtm_idx for an aggregated XP event on a maxed-out config. Oops. Fixes: 23760a014417 ("perf/arm-cmn: Add CMN-700 support") Signed-off-by: Robin Murphy Link: https://lore.kernel.org/r/e771b358526a0d7fc06efee2c3a2fdc0c9f51d44.1725296395.git.robin.murphy@arm.com Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

perf/arm-cmn: Refactor node ID handling. Again.

2024-10-17T13:20:40Z

[ Upstream commit e79634b53e398966c49f803c49701bc74dc3ccf8 ] The scope of the "extra device ports" configuration is not made clear by the CMN documentation - so far we've assumed it applies globally, based on the sole example which suggests as much. However it transpires that this is incorrect, and the format does in fact vary based on each individual XP's port configuration. As a consequence, we're currenly liable to decode the port/device indices from a node ID incorrectly, thus program the wrong event source in the DTM leading to bogus event counts, and also show device topology on the wrong ports in debugfs. To put this right, rework node IDs yet again to carry around the additional data necessary to decode them properly per-XP. At this point the notion of fully decomposing an ID becomes more impractical than it's worth, so unabstracting the XY mesh coordinates (where 2/3 users were just debug anyway) ends up leaving things a bit simpler overall. Fixes: 60d1504070c2 ("perf/arm-cmn: Support new IP features") Acked-by: Mark Rutland Signed-off-by: Robin Murphy Link: https://lore.kernel.org/r/5195f990152fc37adba5fbf5929a6b11063d9f09.1725296395.git.robin.murphy@arm.com Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

perf/arm-cmn: Improve debugfs pretty-printing for large configs

2024-10-17T13:20:40Z

[ Upstream commit a1083ee717e9bde012268782e084d343314490a4 ] The debugfs pretty-printer was written for the CMN-600 assumptions of a maximum 8x8 mesh, but CMN-700 now allows coordinates and ID values up to 12 and 128 respectively, which can overflow the format strings, mess up the alignment of the table and hurt overall readability. This table does prove useful for double-checking that the driver is picking up the topology of new systems correctly and for verifying user expectations, so tweak the formatting to stay nice and readable with wider values. Signed-off-by: Robin Murphy Link: https://lore.kernel.org/r/1d1517eadd1bac5992fab679c9dc531b381944da.1702484646.git.robin.murphy@arm.com Signed-off-by: Will Deacon Stable-dep-of: e79634b53e39 ("perf/arm-cmn: Refactor node ID handling. Again.") Signed-off-by: Sasha Levin

perf/arm-cmn: Rework DTC counters (again)

2024-10-17T13:20:40Z

[ Upstream commit 7633ec2c262fab3e7c5bf3cd3876b5748f584a57 ] The bitmap-based scheme for tracking DTC counter usage turns out to be a complete dead-end for its imagined purpose, since by the time we have to keep track of a per-DTC counter index anyway, we already have enough information to make the bitmap itself redundant. Revert the remains of it back to almost the original scheme, but now expanded to track per-DTC indices, in preparation for making use of them in anger. Note that since cycle count events always use a dedicated counter on a single DTC, we reuse the field to encode their DTC index directly. Signed-off-by: Robin Murphy Reviewed-by: Ilkka Koskinen Link: https://lore.kernel.org/r/5f6ade76b47f033836d7a36c03555da896dfb4a3.1697824215.git.robin.murphy@arm.com Signed-off-by: Will Deacon Stable-dep-of: e79634b53e39 ("perf/arm-cmn: Refactor node ID handling. Again.") Signed-off-by: Sasha Levin