x86: Reload cpuid after loading microcode for the BSP

Right now, we're doing very early init - then parsing boot modules -
and only then doing the microcode load for the BSP. This results in
having possibly stale cpuid info that doesn't correspond to the current
microcode. Fix that by reloading if cpu 0. This also handles re-running
jump labels and alternatives.

Signed-off-by: Pedro Falcato <[email protected]>

kernel/arch/x86_64/cpu.cpp

@@ -84,13 +84,25 @@ uint64_t x86_get_tsc_rate(void)
 
 extern "C" void intel_ucode_load(void);
 
+static void __cpu_identify(void);
+
 void x86_load_ucode(void)
 {
     if (bootcpu_info.manufacturer == X86_CPU_MANUFACTURER_INTEL)
         intel_ucode_load();
+
+    if (get_cpu_nr() == 0)
+    {
+        /* If we're cpu 0, try to reload cpuid bits, since we might be loading ucode a little after
+         * the initial cpu_identify. */
+        __cpu_identify();
+    }
 }
 
-void __cpu_identify(void)
+static char *cpu_get_name(void);
+static void cpu_get_sign(void);
+
+static void __cpu_identify(void)
 {
     uint32_t eax = 0;
     uint32_t ebx = 0;
@@ -134,9 +146,14 @@ void __cpu_identify(void)
 		halt();
 	}
 #endif
+
+    cpu_get_name();
+    cpu_get_sign();
+    x86_do_alternatives();
+    jump_label_init();
 }
 
-char *cpu_get_name(void)
+static char *cpu_get_name(void)
 {
     uint32_t eax = 0;
     uint32_t ebx = 0;
@@ -193,7 +210,7 @@ char *cpu_get_name(void)
     return &bootcpu_info.manuid[0];
 }
 
-void cpu_get_sign(void)
+static void cpu_get_sign(void)
 {
     uint32_t eax, ebx, edx, ecx;
     if (__get_cpuid(CPUID_SIGN, &eax, &ebx, &ecx, &edx) == 0)
@@ -213,24 +230,20 @@ void cpu_get_sign(void)
     if (family == 15)
         cpu_family = family + extended_family;
 
-    pr_info("CPUID: %04x:%04x:%04x:%04x\n", cpu_family, cpu_model, stepping, processor_type);
     bootcpu_info.model = cpu_model;
     bootcpu_info.family = cpu_family;
     bootcpu_info.stepping = stepping;
+    (void) processor_type;
 }
 
 void cpu_identify(void)
 {
-    pr_info("Detected x86_64 %s cpu\n", cpu_get_name());
+    __cpu_identify();
+    pr_info("Detected x86_64 %s cpu\n", bootcpu_info.manuid);
     if (bootcpu_info.brandstr[0] != '\0')
         pr_info("Name: %s\n", bootcpu_info.brandstr);
-    cpu_get_sign();
-    pr_info("Stepping %i, Model %i, Family %i\n", bootcpu_info.stepping, bootcpu_info.model,
-            bootcpu_info.family);
-    __cpu_identify();
-
-    x86_do_alternatives();
-    jump_label_init();
+    pr_info("Family %x, model %x, stepping %x\n", bootcpu_info.family, bootcpu_info.model,
+            bootcpu_info.stepping);
 }
 
 extern "C" void syscall_ENTRY64(void);