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feat: added UART support with a basic kprint in kernel

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wip: DTB
This commit is contained in:
karina
2026-04-20 16:20:31 +04:00
parent ef9aa56d11
commit 635052c8dc
8 changed files with 158 additions and 13 deletions
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Kernel/CMakeLists.txt
+44 -9
View File
@@ -1,5 +1,6 @@
cmake_minimum_required(VERSION 3.10)
project(ksOSKernel LANGUAGES ASM C)
set(KERNEL_MODULE_NAME "Kernel")
# --- Locate Swift toolchain with Embedded Swift stdlib ---
# Priority: cmake var > env var > auto-detect
@@ -62,7 +63,11 @@ add_link_options(
-Wl,-T,${LINKER_SCRIPT}
)
set(SWIFT_SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/Source/kernel.swift)
set(SWIFT_SOURCES
${CMAKE_CURRENT_SOURCE_DIR}/Source/kernel.swift
${CMAKE_CURRENT_SOURCE_DIR}/Source/Arch/dtb.swift
${CMAKE_CURRENT_SOURCE_DIR}/Source/IO/uart.swift
)
set(SWIFT_OBJ ${CMAKE_CURRENT_BINARY_DIR}/kernel_swift.o)
add_custom_command(
@@ -75,7 +80,7 @@ add_custom_command(
-O
-Xcc -fno-stack-protector
-Xcc -I${CMAKE_CURRENT_SOURCE_DIR}/../Common
-import-bridging-header ${CMAKE_CURRENT_SOURCE_DIR}/Source/BridgingHeader.h
-import-bridging-header ${CMAKE_CURRENT_SOURCE_DIR}/Source/Support/BridgingHeader.h
-resource-dir ${SWIFT_RESOURCE_DIR}
-c ${SWIFT_SOURCES}
-o ${SWIFT_OBJ}
@@ -89,17 +94,47 @@ set_source_files_properties(${SWIFT_OBJ} PROPERTIES
GENERATED TRUE
)
add_executable(kernel.elf Source/entry.S Source/stubs.c ${SWIFT_OBJ})
add_executable(kernel.elf Source/Arch/entry.S Source/Support/stubs.c ${SWIFT_OBJ})
add_custom_command(TARGET kernel.elf POST_BUILD
COMMAND ${LLVM_OBJCOPY} -O binary kernel.elf kernel.bin
COMMENT "kernel.elf -> kernel.bin"
)
# --- SourceKit-LSP: generate compile_commands.json for Swift ---
set(_COMMON_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../Common")
set(_BRIDGING_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/Source/BridgingHeader.h")
# --- SourceKit-LSP: generate compile_commands.json for Swift (Dynamic) ---
set(_BRIDGING_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/Source/Support/BridgingHeader.h")
set(SWIFT_ARGS
"\"${SWIFTC}\""
"\"-target\"" "\"aarch64-none-none-elf\""
"\"-enable-experimental-feature\"" "\"Embedded\""
"\"-module-name\"" "\"${KERNEL_MODULE_NAME}\""
"\"-parse-as-library\""
"\"-import-bridging-header\"" "\"${_BRIDGING_HEADER}\""
)
foreach(_src IN LISTS SWIFT_SOURCES)
list(APPEND SWIFT_ARGS "\"${_src}\"")
endforeach()
string(JOIN ", " SWIFT_ARGS_JSON ${SWIFT_ARGS})
set(COMPDB_ENTRIES "")
list(LENGTH SWIFT_SOURCES _src_count)
math(EXPR _last_idx "${_src_count} - 1")
set(_idx 0)
foreach(_src IN LISTS SWIFT_SOURCES)
set(_entry " {\n \"file\": \"${_src}\",\n \"directory\": \"${CMAKE_CURRENT_BINARY_DIR}\",\n \"arguments\": [${SWIFT_ARGS_JSON}]\n }")
if(_idx LESS _last_idx)
string(APPEND _entry ",\n")
else()
string(APPEND _entry "\n")
endif()
string(APPEND COMPDB_ENTRIES "${_entry}")
math(EXPR _idx "${_idx} + 1")
endforeach()
file(GENERATE OUTPUT "${CMAKE_CURRENT_SOURCE_DIR}/compile_commands.json"
CONTENT "[\n {\n \"file\": \"${SWIFT_SOURCES}\",\n \"directory\": \"${CMAKE_CURRENT_BINARY_DIR}\",\n \"arguments\": [\n \"${SWIFTC}\",\n \"-target\", \"aarch64-none-none-elf\",\n \"-enable-experimental-feature\", \"Embedded\",\n \"-parse-as-library\",\n \"-wmo\",\n \"-O\",\n \"-Xcc\", \"-fno-stack-protector\",\n \"-Xcc\", \"-I${_COMMON_DIR}\",\n \"-import-bridging-header\", \"${_BRIDGING_HEADER}\",\n \"-resource-dir\", \"${SWIFT_RESOURCE_DIR}\",\n \"${SWIFT_SOURCES}\"\n ]\n }\n]\n"
)
CONTENT "[\n${COMPDB_ENTRIES}]\n"
)
Kernel/Source/Arch/dtb.swift
+81
View File
@@ -0,0 +1,81 @@
struct FDTHeader {
let magic: UInt32 // 0xd00dfeed
let totalsize: UInt32
let off_dt_struct: UInt32
let off_dt_strings: UInt32
let off_mem_rsvmap: UInt32
let version: UInt32
let last_comp_version: UInt32
let boot_cpuid_phys: UInt32
let size_dt_strings: UInt32
let size_dt_struct: UInt32
}
struct FDTProperty {
let len: UInt32
let nameoff: UInt32
}
enum FDTToken: UInt32 {
case beginNode = 0x1
case endNode = 0x2
case prop = 0x3
case nop = 0x4
case end = 0x9
}
extension UInt32 {
var fromBe: UInt32 {
return self.byteSwapped
}
}
func alignUp(_ value: Int, to: Int) -> Int {
return (value + to - 1) & ~(to - 1)
}
let kFDTHeaderMagic = 0xd00dfeed
func parseDTB(at pointer: UnsafeRawPointer) {
let header = pointer.bindMemory(to: FDTHeader.self, capacity: 1).pointee
guard header.magic.byteSwapped == kFDTHeaderMagic else {
return
}
let structOffset = Int(header.off_dt_struct.byteSwapped)
let stringOffset = Int(header.off_dt_strings.byteSwapped)
var structBase = pointer.advanced(by: structOffset)
let stringsBase = pointer.advanced(by: stringOffset)
var finished = false
while !finished {
let rawToken = structBase.load(as: UInt32.self).byteSwapped
structBase = structBase.advanced(by: 4)
if let token = FDTToken(rawValue: rawToken) {
switch token {
case .beginNode:
let namePointer = structBase.assumingMemoryBound(to: UInt8.self)
let name = String(cString: namePointer)
let nameLength = name.utf8.count + 1
structBase = structBase.advanced(by: alignUp(nameLength, to: 4))
case .prop:
let propertyHeader = structBase.load(as: FDTProperty.self)
let dataLength = Int(propertyHeader.len.byteSwapped)
let nameOffset = Int(propertyHeader.nameoff.byteSwapped)
let namePointer = stringsBase.advanced(by: nameOffset).assumingMemoryBound(to: UInt8.self)
structBase = structBase.advanced(by: 8) // skip header
structBase = structBase.advanced(by: alignUp(dataLength, to: 4)) // skip data for now
case .endNode:
continue
case .nop:
continue
case .end:
finished = true
}
}
}
}
Kernel/Source/entry.S → Kernel/Source/Arch/entry.S
View File
Kernel/Source/BridgingHeader.h
-1
View File
@@ -1 +0,0 @@
#include "bootinfo.h"
Kernel/Source/IO/uart.swift
+19
View File
@@ -0,0 +1,19 @@
let kUARTBaseAddress: UInt = 0x09000000 // TODO: Make it dynamic by parsion DTB
@_cdecl("putchar")
@discardableResult func _serialPutchar(_ char: Int32) -> Int32 {
let uartFR: UInt = kUARTBaseAddress + 0x18// TXFF -- TRansmit FIFO Full for PL011 is 5 bit of FR reg (0x18)
while (mmio_read32(uartFR) & (1 << 5)) != 0 {
// i love pizza btw
}
mmio_write32(UInt(kUARTBaseAddress), UInt32(char))
return char
}
public func kprint(_ message: StaticString) {
for i in 0..<message.utf8CodeUnitCount {
_serialPutchar(Int32(message.utf8Start[i]))
}
}
Kernel/Source/Support/BridgingHeader.h
+10
View File
@@ -0,0 +1,10 @@
#include "bootinfo.h"
#include <stdint.h>
static inline void mmio_write32(uintptr_t addr, uint32_t val) {
*(volatile uint32_t *)addr = val;
}
static inline uint32_t mmio_read32(uintptr_t addr) {
return *(volatile uint32_t *)addr;
}
Kernel/Source/stubs.c → Kernel/Source/Support/stubs.c
+1 -3
View File
@@ -1,4 +1,5 @@
#include <stddef.h>
#include <stdint.h>
void* memmove(void* dest, const void* src, unsigned long n) {
unsigned char* d = (unsigned char*)dest;
@@ -26,9 +27,6 @@ void* memset(void* dest, int c, unsigned long n) {
long __stack_chk_guard = (long)0xDEADBEEFCAFEBABEULL;
void __stack_chk_fail(void) { while (1); }
// Swift embedded uses putchar for print(); stub so it links but does nothing
int putchar(int c) { return c; }
// Swift runtime allocator stubs — should never be called in embedded mode
int posix_memalign(void** ptr, unsigned long align, unsigned long size) {
(void)ptr; (void)align; (void)size;
Kernel/Source/kernel.swift
+3
View File
@@ -1,7 +1,9 @@
@_cdecl("kmain")
public func kernelMain(_ bootInfo: UnsafeMutablePointer<Bootinfo>) {
let fb = bootInfo.pointee.framebuffer
let pixels = fb.base!
let width = Int(fb.width)
let height = Int(fb.height)
let total = width * height
@@ -17,4 +19,5 @@ public func kernelMain(_ bootInfo: UnsafeMutablePointer<Bootinfo>) {
pixels[i] = color
i &+= 1
}
kprint("Meow prrr meow nyaaa")
}