From 5ad6058bf94f953462aab91ede6c15d4d5784d82 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Sun, 12 Oct 2025 15:33:22 -0400
Subject: kern/amd64: cpu: Get processor family ID

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 src/sys/arch/amd64/cpu/cpu_conf.c  | 30 ++++++++++++++++++++++++++++++
 src/sys/include/arch/amd64/mdcpu.h |  2 ++
 2 files changed, 32 insertions(+)

(limited to 'src')

diff --git a/src/sys/arch/amd64/cpu/cpu_conf.c b/src/sys/arch/amd64/cpu/cpu_conf.c
index 16bd57d..f844cf7 100644
--- a/src/sys/arch/amd64/cpu/cpu_conf.c
+++ b/src/sys/arch/amd64/cpu/cpu_conf.c
@@ -131,6 +131,35 @@ cpu_vendor(struct mdcore *mdcore)
     mdcore->vendor = CPU_VENDOR_OTHER;
 }
 
+/*
+ * Acquire the CPU family ID - used by cpu_identify()
+ */
+static void
+cpu_family(struct mdcore *mdcore)
+{
+    uint32_t eax, dmmy;
+    uint32_t family, ext_family;
+
+    if (mdcore == NULL) {
+        return;
+    }
+
+    CPUID(0x01, eax, dmmy, dmmy, dmmy);
+
+    /*
+     * If the family ID is 15 then the actual result
+     * is the sum of the family ID and extended family
+     * ID.
+     */
+    family = (eax >> 8) & 0xF;
+    if (family == 15) {
+        ext_family = (eax >> 20) & 0xFF;
+        family += ext_family;
+    }
+
+    mdcore->family = family;
+}
+
 /*
  * Identify the CPU via a CPUID
  */
@@ -142,6 +171,7 @@ cpu_identify(struct mdcore *mdcore)
     }
 
     cpu_vendor(mdcore);
+    cpu_family(mdcore);
 }
 
 void
diff --git a/src/sys/include/arch/amd64/mdcpu.h b/src/sys/include/arch/amd64/mdcpu.h
index 8701a61..a7336bd 100644
--- a/src/sys/include/arch/amd64/mdcpu.h
+++ b/src/sys/include/arch/amd64/mdcpu.h
@@ -53,6 +53,7 @@
  * @apic_id: Local APIC ID
  * @cr3: CR3 register value (PML<n> phys)
  * @vendor: Processor vendor (CPU_VENDOR_*)
+ * @family: Processor family ID
  * @lapic_base: LAPIC register interface base
  * @x2apic: Has the x2APIC? Is 1 if true
  * @tss: Task state segment for this core
@@ -64,6 +65,7 @@ struct mdcore {
     uint32_t apic_id;
     uint64_t cr3;
     uint8_t vendor;
+    uint32_t family;
     void *lapic_base;
     uint8_t x2apic : 1;
     struct tss_entry tss;
-- 
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