Booting Linux with 2 cores - VCU128

[LorenzoCarletti]

I recently tried getting both CVA6 cores running at the same time under Linux, by changing the carfield_soc dtsi file.

Changes I implemented:

diff --git a/sw/boot/carfield_soc.dtsi b/sw/boot/carfield_soc.dtsi
index a8fd8a3..51bf185 100644
--- a/sw/boot/carfield_soc.dtsi
+++ b/sw/boot/carfield_soc.dtsi
@@ -24,6 +24,7 @@
       riscv,isa = "rv64imafdc";
       mmu-type = "riscv,sv39";
       tlb-split;
+      //Address: 0x08000000 -  0x00040000
       reg = <0>;
       CPU0_intc: interrupt-controller {
         #address-cells = <0>;
@@ -32,6 +33,23 @@
         compatible = "riscv,cpu-intc";
       };
     };
+    CPU1: cpu@1 {
+      device_type = "cpu";
+      status = "okay";
+      compatible = "eth,ariane", "riscv";
+      clock-frequency = <50000000>; // 50 MHz
+      riscv,isa = "rv64imafdc";
+      mmu-type = "riscv,sv39";
+      tlb-split;
+      //Address: 0x08040000 - 0x00040000
+      reg = <1>;
+      CPU1_intc: interrupt-controller {
+        #address-cells = <0>;
+        #interrupt-cells = <1>;
+        interrupt-controller;
+        compatible = "riscv,cpu-intc";
+      };
+    };
   };
 
   sysclk: virt_50mhz {
@@ -105,7 +123,7 @@
     };
     clint@2040000 {
       compatible = "riscv,clint0";
-      interrupts-extended = <&CPU0_intc 3 &CPU0_intc 7>;
+      interrupts-extended = <&CPU0_intc 3 &CPU0_intc 7 &CPU1_intc 3 &CPU1_intc 7>;
       reg-names = "control";
       reg = <0x0 0x2040000 0x0 0x040000>;
     };
@@ -114,7 +132,7 @@
       #address-cells = <0>;
       #interrupt-cells = <1>;
       interrupt-controller;
-      interrupts-extended = <&CPU0_intc 11 &CPU0_intc 9>;
+      interrupts-extended = <&CPU0_intc 11 &CPU0_intc 9 &CPU1_intc 11 &CPU1_intc 9>;
       riscv,max-priority = <7>;
       riscv,ndev = <51>;
       reg = <0x0 0x4000000 0x0 0x4000000>;

However, I now get the following error during the boot process:

[    0.411142] smp: Bringing up secondary CPUs ...
[    0.502259] CPU1: failed to start
[    0.504497] smp: Brought up 1 node, 1 CPU

I looked into it some more, and it seems to be related to the IPI_WAKEUP interrupt not being received by CPU 1 (or CPU 1 not signaling back). Related Linux kernel line: https://github.com/torvalds/linux/blob/cec1e6e5d1ab33403b809f79cd20d6aff124ccfe/arch/openrisc/kernel/smp.c#L103

Any clues what I am currently missing to get the second CPU online? Or what mistake I made with the above configuration change?
Thanks!