Processwatch: Add support for AMD Zen processors

src/kerninfo.h

@@ -6,10 +6,51 @@
 
 #include <stdio.h>
 
+void get_vendor(char *vendor) {
+  unsigned int a[4];
+
+  asm (
+    /* %rbx must be preserved. */
+    "mov %%rbx, %%rdi\n"
+    "cpuid\n"
+    "xchg %%rdi, %%rbx\n"
+    : "=a"(a[0]), "=D"(a[1]), "=c"(a[2]), "=d"(a[3])
+    : "a"(0)
+  );
+  strncpy(&vendor[0], (char *)&a[1], 4);
+  strncpy(&vendor[4], (char *)&a[3], 4);
+  strncpy(&vendor[8], (char *)&a[2], 4);
+}
+
+int is_amd_arch(void) {
+  static int amd = -1; /* -1: Unknown, 1: Yes, 0: No */
+  char vendor[13] = {0};
+
+  if (amd != -1)
+    return amd;
+
+  get_vendor(vendor);
+  amd = strcmp(vendor, "AuthenticAMD") ? 0 : 1;
+  return amd;
+}
+
 void get_pmu_string(char *pmu_name) {
   FILE *f;
   size_t retval;
 
+  if (is_amd_arch()) {
+    f = fopen("/sys/bus/event_source/devices/ibs_op", "r");
+    if (!f) {
+      fprintf(stderr, "WARNING: Unable to open '/sys/bus/event_source/devices/ibs_op'. "
+                      "Using software events.\n");
+      strcpy(pmu_name, "invalid");
+      return;
+    }
+    fclose(f);
+    strcpy(pmu_name, "ibs_op");
+    return;
+  }
+
   f = fopen("/sys/devices/cpu/caps/pmu_name", "r");
   if(!f) {
     fprintf(stderr, "WARNING: Unable to open '/sys/devices/cpu/caps/pmu_name'. Using software events.\n");

src/setup_bpf.h

@@ -147,6 +147,35 @@ static int single_tma_event(struct event *e, struct event *leader,
 
 #else
 
+/* Return value: >0: Valid, -1: Error */
+static int get_ibs_op_type(void) {
+  static int type = -1; /* -1 : Unknown, 0: Failed to read first time, >0: Valid */
+  FILE *fp;
+  int ret;
+
+  if (type != -1) {
+    if (!type)
+      return -1;
+    return type;
+  }
+
+  fp = fopen("/sys/bus/event_source/devices/ibs_op/type", "r");
+  if (!fp) {
+    fprintf(stderr, "Failed to find ibs_op// pmu sysfs. [%m]\n");
+    type = 0;
+    return -1;
+  }
+
+  ret = fscanf(fp, "%d", &type);
+  fclose(fp);
+  if (ret != 1) {
+    fprintf(stderr, "Failed to read ibs_op// type. [%m]\n");
+    type = 0;
+    return -1;
+  }
+  return type;
+}
+
 /**
   single_insn_event - Handles a single CPU, PMU, socket event.
   Returns:
@@ -177,6 +206,12 @@ static int single_insn_event(int cpu, int pid) {
   } else if(strncmp(bpf_info->pmu_name, "sapphire_rapids", 7) == 0) {
     attr.type = PERF_TYPE_RAW;
     attr.config = 0x00c0;
+  } else if(strncmp(bpf_info->pmu_name, "ibs_op", 6) == 0) {
+    attr.type = get_ibs_op_type();
+    if (attr.type < 0)
+	    return -1;
+    attr.config = 0x80000;
+    attr.exclude_guest = 0;
   } else {
     attr.type = PERF_TYPE_SOFTWARE;
     attr.config = PERF_COUNT_SW_CPU_CLOCK;