Intel: perf/x86/intel: Introduce the fourth fixed counter

mainline inclusion
from mainline-v5.10-rc1
commit 6f722509
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I47H3V
CVE: NA

--------------------------------

commit 6f722509 upstream
Backport summary: backport to kernel 4.19.57 for ICX perf topdown support

The fourth fixed counter, TOPDOWN.SLOTS, is introduced in Ice Lake to
measure the level 1 TopDown events.

Add MSR address and macros for the new fixed counter, which will be used
in a later patch.

Add comments to explain the event encoding rules for the fixed counters.
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200723171117.9918-4-kan.liang@linux.intel.comSigned-off-by: NYunying Sun <yunying.sun@intel.com>
Signed-off-by: NJackie Liu <liuyun01@kylinos.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Reviewed-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

arch/x86/include/asm/perf_event.h

@@ -146,12 +146,24 @@ struct x86_pmu_capability {
  */
 
 /*
- * All 3 fixed-mode PMCs are configured via this single MSR:
+ * All the fixed-mode PMCs are configured via this single MSR:
  */
 #define MSR_ARCH_PERFMON_FIXED_CTR_CTRL	0x38d
 
 /*
- * The counts are available in three separate MSRs:
+ * There is no event-code assigned to the fixed-mode PMCs.
+ *
+ * For a fixed-mode PMC, which has an equivalent event on a general-purpose
+ * PMC, the event-code of the equivalent event is used for the fixed-mode PMC,
+ * e.g., Instr_Retired.Any and CPU_CLK_Unhalted.Core.
+ *
+ * For a fixed-mode PMC, which doesn't have an equivalent event, a
+ * pseudo-encoding is used, e.g., CPU_CLK_Unhalted.Ref and TOPDOWN.SLOTS.
+ * The pseudo event-code for a fixed-mode PMC must be 0x00.
+ * The pseudo umask-code is 0xX. The X equals the index of the fixed
+ * counter + 1, e.g., the fixed counter 2 has the pseudo-encoding 0x0300.
+ *
+ * The counts are available in separate MSRs:
  */
 
 /* Instr_Retired.Any: */
@@ -162,11 +174,16 @@ struct x86_pmu_capability {
 #define MSR_ARCH_PERFMON_FIXED_CTR1	0x30a
 #define INTEL_PMC_IDX_FIXED_CPU_CYCLES	(INTEL_PMC_IDX_FIXED + 1)
 
-/* CPU_CLK_Unhalted.Ref: */
+/* CPU_CLK_Unhalted.Ref: event=0x00,umask=0x3 (pseudo-encoding) */
 #define MSR_ARCH_PERFMON_FIXED_CTR2	0x30b
 #define INTEL_PMC_IDX_FIXED_REF_CYCLES	(INTEL_PMC_IDX_FIXED + 2)
 #define INTEL_PMC_MSK_FIXED_REF_CYCLES	(1ULL << INTEL_PMC_IDX_FIXED_REF_CYCLES)
 
+/* TOPDOWN.SLOTS: event=0x00,umask=0x4 (pseudo-encoding) */
+#define MSR_ARCH_PERFMON_FIXED_CTR3	0x30c
+#define INTEL_PMC_IDX_FIXED_SLOTS	(INTEL_PMC_IDX_FIXED + 3)
+#define INTEL_PMC_MSK_FIXED_SLOTS	(1ULL << INTEL_PMC_IDX_FIXED_SLOTS)
+
 /*
  * We model BTS tracing as another fixed-mode PMC.
  *