Backport Genoa/Turin UMC to OpenAnolis v23 Kernel 6.6 · Pull Request !6285 · anolis/cloud-kernel

bugzilla: https://bugzilla.openanolis.cn/show_bug.cgi?id=28936

**Backport Genoa/Turin UMC to OpenAnolis v23 Kernel 6.6**

* perf/x86/amd/uncore: Refactor uncore management

* perf/x86/amd/uncore: Move discovery and registration

* perf/x86/amd/uncore: Use rdmsr if rdpmc is unavailable

* perf/x86/amd/uncore: Add group exclusivity

* perf/x86/amd/uncore: Add memory controller support

* perf/x86/amd/uncore: Fix uninitialized return value in amd_uncore_init()

* perf/x86/amd/uncore: Pass through error code for initialization failures, instead of -ENODEV

* perf vendor events amd: Add Zen 4 memory controller events

* perf/x86/amd/uncore: Avoid PMU registration if counters are unavailable

* perf/x86/amd/uncore: Fix DF and UMC domain identification

This patch series contains 10 commits that enhance AMD uncore PMU support on x86 by introducing Unified Memory Controller (UMC) monitoring, refining discovery and registration logic, fixing domain identification, and improving error handling and robustness.

**Key Bug Fixes**

Corrected DF and UMC domain identification by using topology_logical_package_id() instead of topology_die_id() to ensure proper socket-level mapping on Zen 4 and later.

Avoided PMU registration when DF or L3 counters are unavailable, preventing invalid PMU setups.

Fixed uninitialized return value in amd_uncore_init() by defaulting to -ENODEV.

Passed through actual error codes for initialization failures instead of always returning -ENODEV.

**Feature Additions**

Added memory controller (UMC) support with perchannel PMUs and counter assignments based on CPUID leaf 0x80000022.

Introduced Zen 4 UMC vendor events (CAS, ACTIVATE, PRECHARGE, etc.) and derived metrics for bandwidth/utilization.

Implemented group exclusivity for PMUs to restrict event opening to CPUs on the same socket as the UMC.

Enabled fallback to RDMSR for counter reads when RDPMC is unavailable.

**Logic & Performance Improvements**

Refactored uncore management: split perCPU context (amd_uncore_ctx) from shared PMU attributes (amd_uncore_pmu) and modularized PMUspecific code.

Moved discovery and registration of uncore PMUs to hotplug startup (UNCORE_STARTING/UNCORE_ONLINE) for accurate persocket detection of active memory channels.

Simplified sibling context reuse and eliminated unnecessary tracking of unused contexts.

**Robustness & Safety**

Ensured proper MSR assignment per active UMC channel to avoid conflicts across sockets.

Restricted PMU cpumasks to reflect socketlevel exclusivity, preventing crosssocket event misuse.

Improved error reporting and initialization paths for more reliable hotplug handling.

**Unit test:**

**With backported patches**

[ perf]$ sudo ./perf stat -a -e amd_umc/umc_cas_cmd.all/ -- sleep 1

Performance counter stats for 'system wide':

1,314,906      amd_umc/umc_cas_cmd.all/

1.003616768 seconds time elapsed

[ perf]$ sudo ./perf stat -a  -e amd_umc_0/umc_cas_cmd.all/ \ 
  		-e amd_umc_4/umc_cas_cmd.all/ -- sleep 1

Performance counter stats for 'system wide':

93,364      amd_umc_0/umc_cas_cmd.all/ 
            	85,003      amd_umc_4/umc_cas_cmd.all/

1.003245951 seconds time elapsed

**Without backported patches (default)**

[ perf]$ sudo perf stat -a -e amd_umc/umc_cas_cmd.all/ -- sleep 1 
event syntax error: 'amd_umc/umc_cas_cmd.all/' 
                             \___ Bad event or PMU

Unable to find PMU or event on a PMU of 'amd_umc'

Initial error: 
event syntax error: 'amd_umc/umc_cas_cmd.all/' 
                     \___ Cannot find PMU `amd_umc'. Missing kernel support? 
Run 'perf list' for a list of valid events

Usage: perf stat [<options>] [<command>]

-e, --event <event>   event selector. use 'perf list' to list available events

[ perf]$ sudo perf stat -a  -e amd_umc_0/umc_cas_cmd.all/ \ 
 	 -e amd_umc_4/umc_cas_cmd.all/ -- sleep 1 
event syntax error: 'amd_umc_0/umc_cas_cmd.all/' 
                               \___ Bad event or PMU

Unable to find PMU or event on a PMU of 'amd_umc_0'

Initial error: 
event syntax error: 'amd_umc_0/umc_cas_cmd.all/' 
                               \___ unknown term 'umc_cas_cmd.all' for pmu 'amd_umc_0'

valid terms: event,rdwrmask,config,config1,config2,config3,name,period,percore,metric-id 
Run 'perf list' for a list of valid events

Usage: perf stat [<options>] [<command>]

-e, --event <event>   event selector. use 'perf list' to list available events

类型	指派人员	状态
审查	王鹏 xunlei 半叶枫尘 Artie Ding xueshuai 冯光辉 Guixin Liu kun-llfl Xuchun Shang	已完成 (0/0人)
测试	小龙已测试通过	已完成 (1/1人)

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