AMD pstate driver update patches for OpenAnolis 23.1 (6.6 kernel) - Phase2 - Part II · Pull Request !6124 · anolis/cloud-kernel

bugzilla: https://bugzilla.openanolis.cn/show_bug.cgi?id=26498

**AMD pstate driver update patches for OpenAnolis 23.1 (6.6 kernel) - Phase2 - Part II**

cpufreq/amd-pstate: Cache CPPC request in shared mem case too
cpufreq/amd-pstate: Move all EPP tracing into *_update_perf and *_set_epp functions
cpufreq/amd-pstate: Update cppc_req_cached for shared mem EPP writes
cpufreq/amd-pstate: Drop debug statements for policy setting
cpufreq/amd-pstate: Rework CPPC enabling
cpufreq/amd-pstate: Stop caching EPP
cpufreq/amd-pstate: Drop actions in amd_pstate_epp_cpu_offline()
cpufreq/amd-pstate: Fix min_limit perf and freq updation for performance governor
x86/sched: Add basic support for CPU capacity scaling
cpufreq: intel_pstate: Set asymmetric CPU capacity on hybrid systems
cpufreq: Consolidate some code in cpufreq_online()
cpufreq: Split cpufreq_online()
cpufreq: Add and use cpufreq policy locking guards
cpufreq: intel_pstate: Rearrange max frequency updates handling code
cpufreq: Pass policy pointer to ->update_limits()
cpufreq/amd-pstate: Enable ITMT support after initializing core rankings
sched/topology: Introduce sched_update_asym_prefer_cpu()
cpufreq/amd-pstate: Update asym_prefer_cpu when core rankings change
cpufreq/amd-pstate: Move max_perf limiting in amd_pstate_update
cpufreq/amd-pstate: Add offline, online and suspend callbacks for amd_pstate_driver
cpufreq/amd-pstate: Add support for the "Requested CPU Min frequency" BIOS option
ACPI: CPPC: Add IS_OPTIONAL_CPC_REG macro to judge if a cpc_reg is optional
ACPI: CPPC: Optimize cppc_get_perf()
ACPI: CPPC: Rename cppc_get_perf() to cppc_get_reg_val()

The AMD pstate driver support includes a total of 155 patches: 99 in Phase 1 and 56 in Phase 2. All Phase-1 patches have been reviewed and merged. The first 25 patches from Phase-2 have been reviewed and merged. The next 24 patches from Phase-2  have now been submitted in this PR for review.

This patch series contains 24 commits that improve the AMD P‑State cpufreq driver and related ACPI/CPPC infrastructure through bug fixes, code modernization, scheduler integration, and performance optimizations.

**Key Bug Fixes**
- Fixed min_limit perf/freq mismatch in the performance governor by updating both together.
- Dropped actions in amd_pstate_epp_cpu_offline() to prevent cached CPPC request corruption.
- Ensured CPPC request MSR values (like min_perf) are correctly restored after suspend/resume, offline, and kexec wakeups.
- Added missing NULL pointer checks and register support validation in CPPC register access functions.
- Improved error handling (no such device) when CPPC register IDs are invalid.

**Locking and Concurrency Improvements**
- Introduced cpufreq policy read/write locking guards for safer concurrency.
- Refactored cpufreq_online() into smaller functions (cpufreq_policy_online()) for clearer lock boundaries.
- Passed policy pointers directly to ->update_limits() callbacks, avoiding redundant cpufreq_cpu_get() calls.
- Rearranged Intel P‑State max frequency update handling with proper policy locking.

**Code Modernization**
- Renamed cppc_get_perf() → cppc_get_reg_val() to generalize CPPC register reads.
- Added IS_OPTIONAL_CPC_REG macro to align with ACPI 6.5 spec for optional CPC fields.
- Removed redundant debug prints in policy setting and online callbacks.
- Dropped unnecessary caching (EPP values, debug traces) in favor of direct CPPC request references.
- Reworked CPPC enabling logic (write‑once register) to avoid ineffective cleanup paths.

**Logic Improvements**
- Moved max_perf limiting earlier in amd_pstate_update() to clamp desired perf correctly.
- Updated cppc_req_cached handling for shared memory EPP writes.
- Consolidated code paths in cpufreq_online() for easier readability.
- Moved EPP tracing inside *_update_perf and *_set_epp functions to capture request changes accurately.

**Scheduler & Topology Enhancements**
- Introduced sched_update_asym_prefer_cpu() to dynamically recompute preferred cores when rankings change.
- Updated sg->asym_prefer_cpu in AMD systems when Preferred Core rankings shift at runtime.
- Enabled ITMT support only after all CPUs initialize asym priorities, ensuring correct sched domain rebuild.
- Added x86 hybrid CPU capacity scaling infrastructure (arch_scale_cpu_capacity()), with Intel P‑State using HWP values to set asymmetric capacity.

**Testing & Robustness**
- Added warnings when CPUs fail setup due to missing/unpopulated CPPC registers.
- Improved trace events to replace redundant debug statements, reducing overhead.
- Ensured unit tests and runtime paths handle CPUs with missing policies gracefully.

**Unit test**
---
```
$ cat /boot/config-6.6.102-pstate | grep PSTATE
CONFIG_X86_INTEL_PSTATE=y
CONFIG_X86_AMD_PSTATE=y
CONFIG_X86_AMD_PSTATE_DEFAULT_MODE=3
CONFIG_X86_AMD_PSTATE_UT=m

$ sudo cat /proc/cmdline
  amd_pstate=passive
 
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
  amd-pstate
 
$ cpupower frequency-info
 analyzing CPU 408:
 driver: amd-pstate
 CPUs which run at the same hardware frequency: 408
 CPUs which need to have their frequency coordinated by software: 408
 maximum transition latency: 20.0 us
 hardware limits: 1.20 GHz - 4.12 GHz
 available cpufreq governors: conservative ondemand userspace powersave performance schedutil
 current policy: frequency should be within 2.10 GHz and 4.12 GHz.
    The governor "conservative" may decide which speed to use
    within this range.
 current CPU frequency: Unable to call hardware
 current CPU frequency: 2.19 GHz (asserted by call to kernel)
 boost state support:
  Supported: yes
  Active: yes
  AMD PSTATE Highest Performance: 255. Maximum Frequency: 4.12 GHz.
  AMD PSTATE Nominal Performance: 167. Nominal Frequency: 2.70 GHz.
  AMD PSTATE Lowest Non-linear Performance: 130. Lowest Non-linear Frequency: 2.10 GHz.
  AMD PSTATE Lowest Performance: 75. Lowest Frequency: 1.20 GHz.
 
 
* Load amd_pstate_ut module
$ sudo modprobe amd_pstate_ut
$ sudo lsmod | grep amd_pstate_ut
  amd_pstate_ut          16384  0
  
* make selftest:
$ cd linux
$ make -C tools/testing/selftests
 
* make perf
$ cd tools/perf/
$ make

* Installation & Steps
$ cd linux
$ make -C tools/testing/selftests install INSTALL_PATH=~/kselftest
$ sudo cp tools/perf/perf /usr/bin/perf
$ sudo ~/kselftest/run_kselftest.sh -c amd-pstate
 
* Verify Results:
$ sudo dmesg | grep pstate
[  335.630200] kselftest: Running tests in amd-pstate
[  335.718885] amd_pstate_ut: 1    amd_pstate_ut_acpi_cpc_valid  success!
[  335.718893] amd_pstate_ut: 2    amd_pstate_ut_check_enabled   success!
[  335.727374] amd_pstate_ut: 3    amd_pstate_ut_check_perf      success!
[  335.727421] amd_pstate_ut: 4    amd_pstate_ut_check_freq      success!
[  340.437365] amd_pstate_ut: 5    amd_pstate_ut_check_driver    success!
[  692.825338] audit: type=1123 audit(1760887904.875:343): pid=32166 uid=1000 auid=1000 ses=3 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 msg='cwd="/home/amd/kselftest/amd-pstate" cmd=2E2F72756E2E7368202D74206261736963 exe="/usr/bin/sudo" terminal=pts/0 res=success'
 
* Specified test case:
$ cd ~/kselftest/amd-pstate
  
1. $ sudo ./run.sh -t basic
 Result:
  $ sudo dmesg | grep "amd_pstate_ut" | tee log.txt
  $ cat log.txt
  [  335.718885] amd_pstate_ut: 1    amd_pstate_ut_acpi_cpc_valid  success!
  [  335.718893] amd_pstate_ut: 2    amd_pstate_ut_check_enabled   success!
  [  335.727374] amd_pstate_ut: 3    amd_pstate_ut_check_perf      success!
  [  335.727421] amd_pstate_ut: 4    amd_pstate_ut_check_freq      success!
  [  340.437365] amd_pstate_ut: 5    amd_pstate_ut_check_driver    success!
  [  692.890559] amd_pstate_ut: 1    amd_pstate_ut_acpi_cpc_valid  success!
  [  692.890567] amd_pstate_ut: 2    amd_pstate_ut_check_enabled   success!
  [  692.896181] amd_pstate_ut: 3    amd_pstate_ut_check_perf      success!
  [  692.896229] amd_pstate_ut: 4    amd_pstate_ut_check_freq      success!
  [  697.455447] amd_pstate_ut: 5    amd_pstate_ut_check_driver    success!
  
2. $ sudo ./run.sh -t tbench
 Result:
  $ cat selftest.tbench.csv
  Governor, Round, Des-perf, Freq, Load, Performance, Energy, Performance Per Watt
  Unit, , , GHz, , MB/s, J, MB/J
  amd-pstate-ondemand, 1, 0, 0.29, 0.0000, , ,
  amd-pstate-ondemand, 2, 0, 0.27, 0.0000, , ,
  amd-pstate-ondemand, 3, 0, 0.26, 0.0000, , ,
  amd-pstate-ondemand, Average, 0, 0, 0, 0, 0.273333, 0.0000
  amd-pstate-schedutil, 1, 0, 0.4, 0.0000, , ,
  amd-pstate-schedutil, 2, 0, 0.26, 0.0000, , ,
  amd-pstate-schedutil, 3, 0, 0.27, 0.0000, , ,
  amd-pstate-schedutil, Average, 0, 0, 0, 0, 0.31, 0.0000
  amd-pstate-ondemand VS amd-pstate-schedutil, Comprison(%), , , , , 13.4147,
  
3. $ sudo ./run.sh -t gitsource
 Result:
  $ cat selftest.gitsource.csv
  Governor, Round, Des-perf, Freq, Load, Time, Energy, Performance Per Watt
  Unit, , , GHz, , s, J, 1/J
  amd-pstate-ondemand, 1, 0.09, 28.27, 0.035373187, , ,
  amd-pstate-ondemand, 2, 0.09, 27.68, 0.036127167, , ,
  amd-pstate-ondemand, 3, 0.09, 28.52, 0.035063113, , ,
  amd-pstate-ondemand, Average, 0, 0, 0, 0.09, 28.1567, 0.035515525
  amd-pstate-schedutil, 1, 0.11, 30.7, 0.032573289, , ,
  amd-pstate-schedutil, 2, 0.11, 29.17, 0.034281796, , ,
  amd-pstate-schedutil, 3, 0.11, 29.01, 0.034470872, , ,
  amd-pstate-schedutil, Average, 0, 0, 0, 0.11, 29.6267, 0.033753337
  amd-pstate-ondemand VS amd-pstate-schedutil, Comprison(%), , , , 22.2222, 5.2207, -4.9617

```
Note: Backporting P-state driver patches to the Anolis 6.6 kernel involves 150+ patches. The unit test cases will only work after all backported patches are merged into the kernel.

类型	指派人员	状态
审查	xunlei 半叶枫尘 Artie Ding winterddd xueshuai 赵鑫鹏陶义 dtc 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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