Description LeoLiu-oc 2022-10-27 17:00:38 UTC

Description of problem:
When resume from S4 on Zhaoxin 2 packages platform that support X86_FEATURE_TSC_ADJUST,
the following warning messages appear:

[  327.445302] [Firmware Bug]: TSC ADJUST differs: CPU15 45960750 --> 78394770. Restoring
[  329.209120] [Firmware Bug]: TSC ADJUST differs: CPU14 45960750 --> 78394770. Restoring
[  329.209128] [Firmware Bug]: TSC ADJUST differs: CPU13 45960750 --> 78394770. Restoring
[  329.209138] [Firmware Bug]: TSC ADJUST differs: CPU12 45960750 --> 78394770. Restoring
[  329.209151] [Firmware Bug]: TSC ADJUST differs: CPU11 45960750 --> 78394770. Restoring
[  329.209160] [Firmware Bug]: TSC ADJUST differs: CPU10 45960750 --> 78394770. Restoring
[  329.209169] [Firmware Bug]: TSC ADJUST differs: CPU9 45960750 --> 78394770. Restoring

How reproducible:

Steps to Reproduce:
Step 1: Bring up.
        TSC is sync after bring up with following settings:
                                MSR 0x3b        cur->adjusted
        Package#0 CPU 0-7         0               0
        Package#1 first CPU       value1          value1
        Package#1 non-first CPU   value1          value1

Step 2: Suspend to S4.
        Settings in Step 1 are not changed in this Step.

Step 3: Bring up caused by S4 wake up event.
        TSC is sync when bring up with following settings:
                                MSR 0x3b        cur->adjusted
        Package#0 CPU 0-7         0               0
        Package#1 first CPU       value2          value2
        Package#1 non-first CPU   value2          value2

Step 4: Resume from S4.
        When resuming from S4, Current TSC synchronous mechanism
        cause following settings:
                                MSR 0x3b        cur->adjusted
        Package#0 CPU 0-7         0               0
        Package#1 first CPU       value2          value2
        Package#1 non-first CPU   value2          value1

In these Steps, value1 != 0 and value2 != value1.

In Step4, as function tsc_store_and_check_tsc_adjust() do, when the value
of MSR 0x3b on the non-first online CPU in package#1 is equal to the value
of cur->adjusted on the first online CPU in the same package,
the cur->adjusted value on this non-first online CPU will hold the old value1.
This cause function tsc_verify_tsc_adjust() set the value of MSR 0x3b on the
non-first online CPUs in the package#1 to the old value1 and print the
beginning warning messages.

Expected results:
Fix it by setting cur->adjusted value on the non-first online CPU in a package
to the value of MSR 0x3b on the same CPU when they are not equal.