Build System: More better

Split code into generic, arch, and platform

Made QEMU its own platform

Added shitty uart upload script for lichee board until I can get fel to
actually upload uboot payloads without hanging

TODO: Move platform selection out of build script

TODO: Move arch specific stuff from kernel to arch

TODO: Common linker script for arch instead of having a copy in each
platform

kernel/arch/riscv/meson.build

@@ -0,0 +1,9 @@
+arch_sources = [
+    files(
+        'entry.S'
+    ),
+    kernel_sources
+]
+
+subdir('platform/' + platform)
+

kernel/arch/riscv/platform/allwinner-d1/meson.build

@@ -0,0 +1,51 @@
+objcopy = find_program('riscv64-linux-gnu-objcopy')
+mkimage = find_program('mkimage')
+
+arch_sources += [
+
+]
+
+elf = executable(
+    'kernel.elf',
+    arch_sources,
+    link_args: [
+        '-Wl,-T,' + meson.current_source_dir() + '/platform.ld',
+        '-static'
+    ],
+    link_depends: files('platform.ld'),
+    install: true,
+    install_dir: meson.build_root()
+)
+
+bin = custom_target(
+    'kernel.bin',
+    command: [objcopy, '-O', 'binary', '@INPUT@', '@OUTPUT@'],
+    input: elf,
+    output: 'kernel.bin'
+)
+
+uboot_img = custom_target(
+    'kernel.uboot',
+    command: [
+        mkimage,
+        '-d', '@INPUT@',
+        '-A', 'riscv',
+        '-O', 'u-boot',
+        '-a', '0x45000000',
+        '-e', '0x45000000',
+        '-C', 'none',
+        '@OUTPUT@'
+    ],
+    input: bin,
+    output: 'kernel.uboot',
+    install: true,
+    install_dir: meson.build_root()
+)
+
+run_target('uart',
+    command: [
+        find_program(meson.source_root() + '/tools/uboot_upload'),
+        elf
+    ]
+)
+

kernel/arch/riscv/platform/qemu/meson.build

@@ -0,0 +1,27 @@
+elf = executable(
+    'kernel.elf',
+    arch_sources,
+    link_args: [
+        '-Wl,-T,' + meson.current_source_dir() + '/platform.ld',
+        '-static'
+    ],
+    link_depends: files('platform.ld'),
+    install: true,
+    install_dir: meson.build_root()
+)
+
+run_target('qemu',
+    command: [
+        find_program('qemu-system-riscv64'),
+        '-machine', 'virt',
+        '-cpu', 'rv64',
+        '-bios', 'opensbi-riscv64-generic-fw_dynamic.bin',
+        '-m', '256m',
+        '-serial', 'stdio',
+        '-s',
+        '-display', 'none',
+        # '-d', 'int',
+        '-kernel', elf
+    ]
+)
+

kernel/arch/riscv/platform/qemu/platform.ld

@@ -0,0 +1,25 @@
+OUTPUT_ARCH("riscv")
+OUTPUT_FORMAT("elf64-littleriscv")
+ENTRY(_start)
+SECTIONS {
+	/* R-X segment. */
+	. = 0x81000000;
+
+	.text : { *(.text) *(.text.*) }
+
+	/* R-- segment. */
+	. = ALIGN(0x1000) + (. & (0xFFF));
+	/* For some reason, ld does not emit a read-only segment without an additional gap. */
+	. += 0x1000;
+
+	.rodata : { *(.rodata) *(.rodata.*) }
+	.note.gnu.build-id : { *(.note.gnu.build-id) }
+
+	/* RW- segment. */
+	. = ALIGN(0x1000) + (. & (0xFFF));
+
+	.data : { *(.data) *(.data.*) }
+	.got : { *(.got) }
+	.got.plt : { *(.got.plt) }
+	.bss : { *(.bss) *(.bss.*) }
+}

kernel/kernel.cpp

@@ -281,11 +281,13 @@ extern "C" void kmain(unsigned long hart, void *dtb) {
 
     //fmt("test\n");
 
+    /*
     volatile uint32_t *cfg = (uint32_t *)0x2000060;
     volatile uint32_t *dat = (uint32_t *)0x2000070;
 
     *cfg = 0x10;
     *dat = 0xFF;
+    */
 
     fmt("y");
 
@@ -306,11 +308,11 @@ extern "C" void kmain(unsigned long hart, void *dtb) {
 	cli();
 
     unsigned long time;
-    volatile uint32_t *meme = (uint32_t *)0x6011010;
+    //volatile uint32_t *meme = (uint32_t *)0x6011010;
     //while(true) {
     time = read_csr("time");
     fmt("hello world {}\n", time);
-    *meme = *meme | (0xA57 << 1) | (1 << 0);
+    //*meme = *meme | (0xA57 << 1) | (1 << 0);
     //}
 
 	// Identity map the first 512GiB.
@@ -339,9 +341,9 @@ extern "C" void kmain(unsigned long hart, void *dtb) {
 	create_task(&task2, task2_main);
 
 	time = read_csr("time");
-	//sbi_call1(0x54494D45, 0, time + 100000);
+	sbi_call1(0x54494D45, 0, time + 100000);
 
-	//save_stack(switch_task, 0);
+	save_stack(switch_task, 0);
 
 	sbi_call1(8, 0, 0);
 

kernel/meson.build

@@ -0,0 +1,8 @@
+kernel_sources = [
+    files(
+        'kernel.cpp'
+    )
+]
+
+subdir('arch/' + arch)
+

meson.build

@@ -1,26 +1,18 @@
-project('riscv-qtech-os', ['c', 'cpp'])
+project('riscv-qtech-os', ['c', 'cpp'],
-
+    default_options: [
-kernel = executable('kernel',
+        'cpp_std=gnu++20',
-    'kernel/boot.S',
+        'c_std=gnu11',
-    'kernel/kernel.cpp',
+        'c_flags=-Wall -Werror -Wextra',
-    link_args: [
+        'cpp_flags=-Wall -Werror -Wextra'
-        '-Wl,-T,' + (meson.current_source_dir() / 'kernel/kernel.ld'),
-        '-static'
     ]
 )
 
-run_target('qemu',
+if not meson.is_cross_build()
-    command: [
+    error('Kernel must be cross compiled')
-        find_program('qemu-system-riscv64'),
+endif
-        '-machine', 'virt',
-        '-cpu', 'rv64',
-        '-bios', 'opensbi-riscv64-generic-fw_dynamic.bin',
-        '-m', '256m',
-        '-serial', 'stdio',
-        '-s',
-        '-display', 'none',
-        # '-d', 'int',
-        '-kernel', kernel
-    ]
-)
 
+arch = host_machine.cpu_family()
+platform = 'allwinner-d1'
+# platform = 'qemu'
+
+subdir('kernel')

tools/uboot_upload

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+stty -F /dev/ttyUSB0 115200 -echo -icrnl
+echo "loadx" > /dev/ttyUSB0
+sx -vv -X -k $1 < /dev/ttyUSB0 > /dev/ttyUSB0
+echo "bootelf" > /dev/ttyUSB0
+cat - < /dev/ttyUSB0