4 files changed, 92 insertions, 0 deletions
diff --git a/boards/default.nix b/boards/default.nix
new file mode 100644
index 0000000..dd09255
--- /dev/null
+++ b/boards/default.nix
@@ -0,0 +1,33 @@
+{ libkernel, pkgs }:
+
+let
+  mkKernel = { name, asmFile, linkerScript }:
+    pkgs.stdenvNoCC.mkDerivation {
+      pname = "${libkernel.pname}-${name}";
+      version = libkernel.version;
+      inherit asmFile linkerScript;
+
+      nativeBuildInputs = [ pkgs.stdenv.cc.bintools.bintools ];
+
+      dontUnpack = true;
+      buildPhase = ''
+        runHook preBuild
+
+        riscv64-unknown-none-elf-as -g -march=rv64gc -mabi=lp64d -o asm.o \
+          $asmFile
+
+        riscv64-unknown-none-elf-ld --gc-sections -T$linkerScript -o kernel.elf \
+          asm.o ${libkernel}/lib/libkernel.a
+
+        runHook postBuild
+      '';
+      installPhase = ''
+        runHook preInstall
+        install -Dt $out kernel.elf
+        runHook postInstall
+      '';
+    };
+
+in pkgs.lib.recurseIntoAttrs {
+  qemu-virt = pkgs.callPackage ./qemu-virt { inherit mkKernel; };
+}
diff --git a/boards/qemu-virt/default.nix b/boards/qemu-virt/default.nix
new file mode 100644
index 0000000..e41d924
--- /dev/null
+++ b/boards/qemu-virt/default.nix
@@ -0,0 +1,7 @@
+{ mkKernel }:
+
+mkKernel {
+  name = "qemu-virt";
+  asmFile = ./qemu-virt.s;
+  linkerScript = ./qemu-virt.ld;
+}
diff --git a/boards/qemu-virt/qemu-virt.ld b/boards/qemu-virt/qemu-virt.ld
new file mode 100644
index 0000000..9673637
--- /dev/null
+++ b/boards/qemu-virt/qemu-virt.ld
@@ -0,0 +1,29 @@
+OUTPUT("elf64-littleriscv")
+ENTRY(_start)
+
+SECTIONS {
+	. = 0x80000000;
+	.text : {
+		*(.text.start)
+		*(.text .text.*)
+		. = ALIGN(0x1000);
+	}
+
+	.rodata : {
+		*(.rodata)
+		. = ALIGN(0x1000);
+	}
+
+	.data : {
+		*(.data)
+	}
+	.bss : {
+		*(.bss)
+		. = ALIGN(0x1000);
+	}
+
+	.hart0_initial_stack : {
+		. += 0x1000;
+		PROVIDE(hart0_initial_stack_top = .);
+	}
+}
diff --git a/boards/qemu-virt/qemu-virt.s b/boards/qemu-virt/qemu-virt.s
new file mode 100644
index 0000000..4813b57
--- /dev/null
+++ b/boards/qemu-virt/qemu-virt.s
@@ -0,0 +1,23 @@
+.section .text.start
+
+.extern main
+
+.global _start
+_start:
+	# Have harts other than 0 spin until hart0 wakes them up.
+	csrr a0, mhartid
+	c.bnez a0, wait_for_hart0
+
+	# Set up hart0's stack.
+	la sp, hart0_initial_stack_top
+	call hart0_boot
+
+	# Fall through to a spin loop.
+halt:
+	j halt
+
+.section .text
+
+wait_for_hart0:
+	# TODO
+	j halt