Re: [PATCH] perf/x86/intel: Add counter freezing quirk for Goldmont

Liang, Kan
2018-10-03T13:33:33Z

On 10/3/2018 2:10 AM, Thomas Gleixner wrote:
> On Tue, 2 Oct 2018, kan.liang@linux.intel.com wrote:
>> +static bool intel_atom_v4_counter_freezing_broken(int cpu)
>> {
>> u32 rev = UINT_MAX; /* default to broken for unknown stepping */
>>
>> - switch (cpu_data(cpu).x86_stepping) {
>> - case 1:
>> - rev = 0x28;
>> + switch (cpu_data(cpu).x86_model) {
>> + case INTEL_FAM6_ATOM_GOLDMONT:
>> + switch (cpu_data(cpu).x86_stepping) {
>> + case 2:
>> + rev = 0xe;
>> + break;
>> + case 9:
>> + rev = 0x2e;
>> + break;
>> + case 10:
>> + rev = 0x8;
>> + break;
>> + }
>> break;
>> - case 8:
>> - rev = 0x6;
>> +
>> + case INTEL_FAM6_ATOM_GOLDMONT_X:
>> + switch (cpu_data(cpu).x86_stepping) {
>> + case 1:
>> + rev = 0x1a;
>> + break;
>> + }
>> break;
>> +
>> + case INTEL_FAM6_ATOM_GOLDMONT_PLUS:
>> + switch (cpu_data(cpu).x86_stepping) {
>> + case 1:
>> + rev = 0x28;
>> + break;
>> + case 8:
>> + rev = 0x6;
>> + break;
>> + }
>> }
>>
>> return (cpu_data(cpu).microcode < rev);
>
> There is another variant of model/stepping micro code verification code in
> intel_snb_pebs_broken(). Can we please make this table based and use a
> common function? That's certainly not the last quirk we're going to have.
>
> We already have a table based variant of ucode checking in
> bad_spectre_microcode(). It's trivial enough to generalize that.
>

Sure, I will generalize the bad_spectre_microcode(), rename it to
is_bad_intel_microcode(), and move it to
arch\x86\kernel\cpu\microcode\intel.c.
The spectre code and perf code will share the generalized function.

Thanks,
Kan