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

[Liang, Kan]

On 10/3/2018 2:10 AM, Thomas Gleixner wrote:
On Tue, 2 Oct 2018, kan.li...@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