coretempd: Add AMD Zen temperature sensor support

Detect CPU vendor by probing MSRs (Intel IA32_THERM_STATUS vs AMD
TCTL MSR C0010293). Support both Intel Tjmax-based and AMD direct
temperature reading. Log detected vendor per CPU at startup.

local/recipes/system/coretempd/source/src/main.rs

@@ -1,13 +1,21 @@
 use std::fs;
 use std::io::{Read, Write};
 use std::os::unix::net::UnixListener;
-use std::path::Path;
 use std::thread;
 use std::time::Duration;
 
+const POLL_MS: u64 = 2000;
+
 const IA32_THERM_STATUS: u32 = 0x19c;
 const IA32_TEMPERATURE_TARGET: u32 = 0x1a2;
-const POLL_MS: u64 = 2000;
+const AMD_TCTL: u32 = 0xc0010293;
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+enum Vendor {
+    Intel,
+    Amd,
+    Unknown,
+}
 
 fn read_msr(cpu: u32, msr: u32) -> Option<u64> {
     let path = format!("/scheme/sys/msr/{}/{:x}", cpu, msr);
@@ -15,6 +23,16 @@ fn read_msr(cpu: u32, msr: u32) -> Option<u64> {
         .and_then(|s| u64::from_str_radix(s.trim(), 16).ok())
 }
 
+fn detect_vendor(cpu: u32) -> Vendor {
+    if read_msr(cpu, IA32_THERM_STATUS).is_some() {
+        Vendor::Intel
+    } else if read_msr(cpu, AMD_TCTL).is_some() {
+        Vendor::Amd
+    } else {
+        Vendor::Unknown
+    }
+}
+
 fn detect_cpus() -> Vec<u32> {
     let mut v = Vec::new();
     if let Ok(d) = fs::read_to_string("/scheme/sys/cpu") {
@@ -30,7 +48,7 @@ fn detect_cpus() -> Vec<u32> {
     v
 }
 
-fn read_temperature(cpu: u32, tjmax: u8) -> Option<i16> {
+fn read_temperature_intel(cpu: u32, tjmax: u8) -> Option<i16> {
     let raw = read_msr(cpu, IA32_THERM_STATUS)?;
     let digital_readout = ((raw >> 16) & 0x7F) as u8;
     if digital_readout == 0 { return None; }
@@ -38,7 +56,7 @@ fn read_temperature(cpu: u32, tjmax: u8) -> Option<i16> {
     Some(temp as i16)
 }
 
-fn read_tjmax(cpu: u32) -> u8 {
+fn read_tjmax_intel(cpu: u32) -> u8 {
     if let Some(raw) = read_msr(cpu, IA32_TEMPERATURE_TARGET) {
         let tj = ((raw >> 16) & 0xFF) as u8;
         if tj > 0 && tj < 150 { return tj; }
@@ -46,6 +64,21 @@ fn read_tjmax(cpu: u32) -> u8 {
     100
 }
 
+fn read_temperature_amd(cpu: u32) -> Option<i16> {
+    let raw = read_msr(cpu, AMD_TCTL)?;
+    let tctl = ((raw >> 21) & 0x3FF) as u16;
+    if tctl == 0 { return None; }
+    let temp = (tctl as f32) / 8.0;
+    Some(temp as i16)
+}
+
+#[derive(Clone)]
+struct CpuInfo {
+    id: u32,
+    vendor: Vendor,
+    tjmax: u8,
+}
+
 fn main() {
     let scheme_path = ":coretemp";
     let _ = fs::remove_file(scheme_path);
@@ -55,16 +88,29 @@ fn main() {
     let cpus = detect_cpus();
     eprintln!("[INFO] coretempd: detected {} CPU(s)", cpus.len());
 
-    let tjmax_values: Vec<u8> = cpus.iter().map(|&c| read_tjmax(c)).collect();
+    let cpu_infos: Vec<CpuInfo> = cpus.iter().map(|&id| {
+        let vendor = detect_vendor(id);
+        let tjmax = if vendor == Vendor::Intel {
+            read_tjmax_intel(id)
+        } else {
+            0
+        };
+        eprintln!("[INFO] coretempd: CPU {} = {:?}", id, vendor);
+        CpuInfo { id, vendor, tjmax }
+    }).collect();
 
-    let cpus_clone = cpus.clone();
-    let tjmax_clone = tjmax_values.clone();
+    let infos_clone = cpu_infos.clone();
     thread::spawn(move || {
         loop {
             thread::sleep(Duration::from_millis(POLL_MS));
-            for (&cpu, &tjmax) in cpus_clone.iter().zip(&tjmax_clone) {
-                if let Some(temp) = read_temperature(cpu, tjmax) {
-                    let _ = fs::write(format!("/tmp/coretemp_cpu{}", cpu), format!("{}\n", temp));
+            for info in &infos_clone {
+                let temp = match info.vendor {
+                    Vendor::Intel => read_temperature_intel(info.id, info.tjmax),
+                    Vendor::Amd => read_temperature_amd(info.id),
+                    Vendor::Unknown => None,
+                };
+                if let Some(t) = temp {
+                    let _ = fs::write(format!("/tmp/coretemp_cpu{}", info.id), format!("{}\n", t));
                 }
             }
         }
@@ -77,15 +123,20 @@ fn main() {
                 let req = String::from_utf8_lossy(&buf[..n]).trim().to_string();
                 let resp = if req == "/" {
                     let mut names = String::new();
-                    for &cpu in &cpus {
-                        names.push_str(&format!("cpu{}\n", cpu));
+                    for info in &cpu_infos {
+                        names.push_str(&format!("cpu{}\n", info.id));
                     }
                     names
                 } else if let Some(cpu_str) = req.strip_prefix("/cpu") {
                     if let Ok(cpu) = cpu_str.parse::<u32>() {
-                        if let Some(idx) = cpus.iter().position(|&c| c == cpu) {
-                            if let Some(temp) = read_temperature(cpu, tjmax_values[idx]) {
-                                format!("{}\n", temp)
+                        if let Some(info) = cpu_infos.iter().find(|i| i.id == cpu) {
+                            let temp = match info.vendor {
+                                Vendor::Intel => read_temperature_intel(info.id, info.tjmax),
+                                Vendor::Amd => read_temperature_amd(info.id),
+                                Vendor::Unknown => None,
+                            };
+                            if let Some(t) = temp {
+                                format!("{}\n", t)
                             } else {
                                 "N/A\n".to_string()
                             }

recipes/system/coretempd

@@ -0,0 +1 @@
+../../local/recipes/system/coretempd