145 lines
4.8 KiB
C
145 lines
4.8 KiB
C
/*
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* kernel.c – Kernel entry point and interactive shell loop.
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*
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* kmain() is called by the loader (main.c) after the ELF kernel has been
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* mapped into memory. It initialises subsystems (IDT, memory, tasks),
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* prints a welcome banner, and enters an interactive read-eval-print
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* loop that dispatches typed commands via commands.c.
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*
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* While waiting for keyboard input, the shell yields to the cooperative
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* scheduler so that background tasks can make progress.
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*/
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#include "kernel_types.h"
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#include "boot_info.h"
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#include "commands.h"
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#include "idt.h"
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#include "memory.h"
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#include "task.h"
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/* Null-safe print helper used throughout the kernel. */
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#define SAFE_PRINT(Boot, ...) \
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do { \
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if ((Boot) != NULL && (Boot)->print != NULL) { \
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(Boot)->print(__VA_ARGS__); \
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} \
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} while (0)
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/* Simple text attribute helper (modelled after UEFI TEXT_ATTR). */
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#define TEXT_ATTR(fg, bg) (UINTN)(((fg) & 0x0F) | (((bg) & 0x0F) << 4))
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/* Basic colour constants (compatible with UEFI's palette). */
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#define COLOR_BLACK 0x0
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#define COLOR_LIGHTGREEN 0xA
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/* ================================================================
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* Kernel entry point
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* ================================================================ */
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void kmain(BootInfo *Boot)
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{
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KeyEvent Key;
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KSTATUS Status;
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UINTN read_errors = 0;
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if (Boot == NULL) {
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return;
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}
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if (Boot->clear_screen != NULL) {
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Status = Boot->clear_screen();
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if (Status != 0) {
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SAFE_PRINT(Boot, L"clear_screen failed (status=%ld)\n\r",
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(UINT64)Status);
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}
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}
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if (Boot->set_attribute != NULL) {
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Status = Boot->set_attribute(TEXT_ATTR(COLOR_LIGHTGREEN, COLOR_BLACK));
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if (Status != 0) {
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SAFE_PRINT(Boot, L"set_attribute failed (status=%ld)\n\r",
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(UINT64)Status);
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}
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}
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/* ---- Subsystem initialisation ---- */
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idt_init(Boot);
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memory_init(Boot);
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task_init(Boot);
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/* ---- Welcome banner ---- */
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SAFE_PRINT(Boot, L" Welcome to Simple 64-bit Operating System!\n\r");
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SAFE_PRINT(Boot, L"================================================\n\r");
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SAFE_PRINT(Boot, L"\n\r");
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SAFE_PRINT(Boot, L"System Information:\n\r");
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if (Boot->firmware_vendor != NULL) {
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SAFE_PRINT(Boot, L" Firmware Vendor: %s\n\r", Boot->firmware_vendor);
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SAFE_PRINT(Boot, L" Firmware Revision: %d.%d\n\r",
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Boot->firmware_major, Boot->firmware_minor);
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} else {
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SAFE_PRINT(Boot, L" Firmware information: Unavailable\n\r");
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}
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SAFE_PRINT(Boot, L"\n\r");
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SAFE_PRINT(Boot, L"Available Services:\n\r");
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SAFE_PRINT(Boot, L" - Console Input/Output: %s\n\r",
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(Boot->read_key != NULL && Boot->print != NULL) ? L"Active" : L"Unavailable");
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SAFE_PRINT(Boot, L"\n\r");
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SAFE_PRINT(Boot, L"Type 'help' for a list of commands.\n\r\n\r");
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/* ---- Interactive shell loop ---- */
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CHAR16 line[128];
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UINTN len = 0;
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SAFE_PRINT(Boot, L"-> ");
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while (TRUE) {
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/* Try non-blocking read first; yield to other tasks while idle */
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if (Boot->try_read_key != NULL) {
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Status = Boot->try_read_key(&Key);
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if (Status != 0) {
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task_yield();
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continue;
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}
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} else if (Boot->read_key != NULL) {
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Status = Boot->read_key(&Key);
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} else {
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SAFE_PRINT(Boot, L"Console input unavailable.\n\r");
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break;
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}
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if (Status != 0) {
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read_errors++;
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if (read_errors == 1 || (read_errors % 64) == 0) {
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SAFE_PRINT(Boot, L"read_key failed (status=%ld)\n\r",
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(UINT64)Status);
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}
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continue;
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}
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read_errors = 0;
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if (Key.unicode_char == L'\r' || Key.unicode_char == L'\n') {
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/* Enter pressed: execute the buffered command */
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line[len] = L'\0';
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SAFE_PRINT(Boot, L"\n\r");
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execute_command(Boot, line);
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/* Reset for next command */
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len = 0;
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SAFE_PRINT(Boot, L"-> ");
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} else if (Key.scan_code == 0x08 || Key.unicode_char == L'\b' || Key.unicode_char == 0x7F) {
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/* Backspace */
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if (len > 0) {
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len--;
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SAFE_PRINT(Boot, L"\b \b");
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}
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} else if (Key.unicode_char >= 32 && Key.unicode_char < 127) {
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/* Printable ASCII */
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if (len < (sizeof(line) / sizeof(line[0]) - 1)) {
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line[len++] = Key.unicode_char;
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SAFE_PRINT(Boot, L"%c", Key.unicode_char);
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}
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}
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}
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}
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