kernel: various changes.

+ kernel: replace sk-hello test executable with a test initramfs
+ panic: start implementing a proper kernel panic screen
+ lib: added a new string.h library for string manipulation.
+ kernel: replace all the strlen implementations with the strlen() function

CONTRIBUTING.MD

@@ -3,3 +3,7 @@ Do you want to improve Soaplin? You can by contributing to the project!
 
 ## Contributing guidelines
 * Before making a commit, please run `make format`. This will run clang-format over all the C source files in kernel/src.
+* Large language model-generated code is **allowed**, with the condition that you do extensive testing over that code.
+  You must also know how to make the LLM-generated code by yourself.
+
+  Note: Even if LLM-generated code is allowed, please try to not use it.

GNUmakefile

@@ -83,7 +83,6 @@ run-aarch64: ovmf/ovmf-code-$(ARCH).fd $(IMAGE_NAME).iso
 
 .PHONY: run-hdd-aarch64
 run-hdd-aarch64: ovmf/ovmf-code-$(ARCH).fd $(IMAGE_NAME).hdd
-	@echo "  Starting QEMU with $(IMAGE_NAME).hdd"
 	@qemu-system-$(ARCH) \
 		-M virt \
 		-cpu cortex-a72 \
@@ -204,8 +203,8 @@ $(IMAGE_NAME).iso: limine/limine kernel
 	@mkdir -p iso_root/boot/limine
 	@cp -v limine.conf iso_root/boot/limine/
 	@mkdir -p iso_root/EFI/BOOT
+	@cp -v initramfs.tar iso_root/
 ifeq ($(ARCH),x86_64)
-	@cp -v testing/sk-hello.elf iso_root/
 	@cp -v limine/limine-bios.sys limine/limine-bios-cd.bin limine/limine-uefi-cd.bin iso_root/boot/limine/
 	@cp -v limine/BOOTX64.EFI iso_root/EFI/BOOT/
 	@cp -v limine/BOOTIA32.EFI iso_root/EFI/BOOT/

initramfs/dir/subtest.txt

@@ -0,0 +1 @@
+Hello World from a subdirectory!

initramfs/test.txt

@@ -0,0 +1 @@
+Hello World!

kernel/src/fs/vfs.h

@@ -1,28 +0,0 @@
-#pragma once
-
-// btw fuck sun
-
-#include <stdint.h>
-
-#define VNODE_TYPE_FILE 0
-#define VNODE_TYPE_DIR 1
-#define VNODE_TYPE_DEV 2
-
-typedef struct __vnode {
-  char name[128];
-  int type;
-
-  struct __vnode *children;
-  struct __vnode *next;
-  struct __vnode *parent;
-
-  void (*write)(void *buffer, uint64_t off, uint64_t size);
-  void (*read)(void *buffer, uint64_t off, uint64_t size);
-} vnode;
-
-typedef struct __vfs_mount {
-  struct vfs_node
-      *mount_point; // The directory in the main VFS where this is mounted
-  struct vfs_node *mounted_root; // The root node of the mounted filesystem
-  struct vfs_mount *next;        // Pointer to next mount point
-} vfs_mount;

kernel/src/lib/string.c

@@ -0,0 +1,57 @@
+#include <lib/string.h>
+#include <stddef.h>
+
+int strlen(const char *str) {
+  int len = 0;
+  while (str[len])
+    len++;
+  return len;
+}
+
+int strcmp(const char *s1, const char *s2) {
+  while (*s1 && *s1 == *s2) {
+    s1++;
+    s2++;
+  }
+  return *s1 - *s2;
+}
+
+char *strcpy(char *dest, const char *src)
+{
+    if (dest == NULL || src == NULL)
+        return NULL;
+    
+    char *temp = dest;
+    while((*dest++ = *src++) != '\0'); 
+    return temp;
+}
+
+char *strchr(const char *s, int c) {
+  while (*s++) {
+    if (*s == c)
+      return (char *)s;
+  }
+  return NULL;
+}
+
+char *strrchr(const char *s, int c) {
+    const char *p = NULL;
+
+    for (;;) {
+        if (*s == (char)c)
+            p = s;
+        if (*s++ == '\0')
+            return (char *)p;
+    }
+}
+
+int oct2bin(unsigned char *str, int size) {
+    int n = 0;
+    unsigned char *c = str;
+    while (size-- > 0) {
+        n *= 8;
+        n += *c - '0';
+        c++;
+    }
+    return n;
+}

kernel/src/lib/string.h

@@ -0,0 +1,8 @@
+#pragma once
+
+int strlen(const char *str);
+int strcmp(const char *s1, const char *s2);
+char *strchr(const char *s, int c);
+char *strcpy(char *dest, const char *src);
+char *strrchr(const char *s, int c);
+int oct2bin(unsigned char *str, int size);

kernel/src/main.c

@@ -1,5 +1,7 @@
 #include "exec/elf.h"
 #include "exec/exec.h"
+#include "fs/tapefs.h"
+#include "fs/vfs.h"
 #include "mm/liballoc/liballoc.h"
 #include "mm/pmm.h"
 #include "mm/vma.h"
@@ -11,29 +13,22 @@
 #include "sys/syscall.h"
 #include <font.h>
 #include <limine.h>
+#include <mm/memop.h>
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <sys/arch/x86_64/fpu.h>
 #include <sys/arch/x86_64/gdt.h>
 #include <sys/arch/x86_64/idt.h>
+#include <sys/error_handling/panic.h>
 #include <sys/gfx/flanterm/backends/fb.h>
 #include <sys/gfx/flanterm/flanterm.h>
 #include <sys/log.h>
 #include <sys/printf.h>
 
-// Set the base revision to 3, this is recommended as this is the latest
-// base revision described by the Limine boot protocol specification.
-// See specification for further info.
-
 __attribute__((
     used, section(".limine_requests"))) static volatile LIMINE_BASE_REVISION(3);
 
-// The Limine requests can be placed anywhere, but it is important that
-// the compiler does not optimise them away, so, usually, they should
-// be made volatile or equivalent, _and_ they should be accessed at least
-// once or marked as used with the "used" attribute as done here.
-
 __attribute__((
     used,
     section(
@@ -45,14 +40,6 @@ __attribute__((
     section(".limine_requests"))) static volatile struct limine_module_request
     module_request = {.id = LIMINE_MODULE_REQUEST, .revision = 0};
 
-/*__attribute__((used, section(".limine_requests")))
-static volatile struct limine_entry_point_request entrypoint_request = {
-    .id = LIMINE_ENTRY_POINT_REQUEST,
-    .revision = 3
-};*/
-// Finally, define the start and end markers for the Limine requests.
-// These can also be moved anywhere, to any .c file, as seen fit.
-
 __attribute__((used,
                section(".limine_requests_"
                        "start"))) static volatile LIMINE_REQUESTS_START_MARKER;
@@ -62,38 +49,14 @@ __attribute__((
     section(
         ".limine_requests_end"))) static volatile LIMINE_REQUESTS_END_MARKER;
 
-// Halt and catch fire function.
-static void hcf(void) {
-  for (;;) {
-#if defined(__x86_64__)
-    asm("hlt");
-#elif defined(__aarch64__) || defined(__riscv)
-    asm("wfi");
-#elif defined(__loongarch64)
-    asm("idle 0");
-#endif
-  }
-}
-
 struct limine_framebuffer *fb;
 struct flanterm_context *ft_ctx;
-uint32_t fg = 0xFFFFFF;
 
 char kstack[8192];
 
-// The following will be our kernel's entry point.
-// If renaming kmain() to something else, make sure to change the
-// linker script accordingly.
 void kmain(void) {
-  // Ensure the bootloader actually understands our base revision (see spec).
-  /*if (LIMINE_BASE_REVISION_SUPPORTED == false) {
-      hcf();
-  }*/
-
-  // Ensure we got a framebuffer.
   if (framebuffer_request.response != NULL) {
 
-    // Fetch the first framebuffer.
     struct limine_framebuffer *framebuffer =
         framebuffer_request.response->framebuffers[0];
     fb = framebuffer;
@@ -103,12 +66,11 @@ void kmain(void) {
         framebuffer->height, framebuffer->pitch, framebuffer->red_mask_size,
         framebuffer->red_mask_shift, framebuffer->green_mask_size,
         framebuffer->green_mask_shift, framebuffer->blue_mask_size,
-        framebuffer->blue_mask_shift, NULL, NULL, NULL, NULL, &fg, NULL, NULL,
+        framebuffer->blue_mask_shift, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
         VGA8, 8, 16, 0, 0, 0, 0);
   }
 
   printf("\n  Soaplin 1.0-sild is booting up your computer...\n\n");
-  // printf("Physical kernel EP: %p", entrypoint_request.entry);
 
   gdt_init(&kstack[8192]);
   idt_init();
@@ -125,21 +87,13 @@ void kmain(void) {
       asm("hlt");
   }
 
-  // acpi_init();
   syscall_init();
   pit_init(1000);
   sched_init();
-  // user_init();
-
-  struct limine_file *f = module_request.response->modules[0];
-  log("kmain - %s\n", f->path);
-
-  program_t *prog = elf_load((char *)f->address, 1);
-
-  sched_create("Init", prog->entry, prog->pm, SCHED_USER_PROCESS);
 
   log("kernel - Soaplin initialized sucessfully.\n");
+
   while (1)
     ;
-  ; //__asm__ volatile ("hlt");
+  ;
 }

kernel/src/mm/vmm.c

@@ -211,8 +211,8 @@ void vmm_map_user(pagemap_t *pm, uint64_t vaddr, uint64_t paddr,
   uint64_t pml2_entry = (vaddr >> 21) & 0x1ff;
   uint64_t pml1_entry = (vaddr >> 12) & 0x1ff;
 
-
-  uint64_t *pml3 = __vmm_get_next_lvl(pm->toplevel, pml4_entry, flags | VMM_WRITABLE,
+  uint64_t *pml3 =
+      __vmm_get_next_lvl(pm->toplevel, pml4_entry, flags | VMM_WRITABLE,
                          true); // PML3 / Page Directory Pointer Entry
   uint64_t *pml2 = __vmm_get_next_lvl(pml3, pml3_entry, flags | VMM_WRITABLE,
                                       true); // PML2 / Page Directory Entry

kernel/src/sched/sched.c

@@ -4,6 +4,7 @@
 #include "mm/vmm.h"
 #include "sys/arch/x86_64/idt.h"
 #include "sys/log.h"
+#include <lib/string.h>
 #include <stddef.h>
 
 sched_process *proc_list;
@@ -47,16 +48,11 @@ void sched_init() {
 
 sched_process *sched_create(char *name, uint64_t entry_point, pagemap_t *pm,
                             uint32_t flags) {
-  // TODO: implement a separate strlen function
-  // as there's like 4 strlen impls in the kernel.
-  int i = 0;
-  while (name[i] != 0)
-    i++;
 
   sched_process *proc = pmm_request_page();
   memset(proc, 0, sizeof(sched_process));
 
-  memcpy(proc->name, name, i);
+  memcpy(proc->name, name, strlen(name) > 128 ? 128 : strlen(name));
   proc->pid = current_pid;
   proc->type = SCHED_RUNNING;
   proc->flags = flags;
@@ -141,7 +137,6 @@ void schedule(registers_t *regs) {
 
     prev_proc->next = curr_proc->next;
 
-    // Now, it is safe to free the process's memory.
     vmm_release_pm(curr_proc->pm);
     pmm_free_page(curr_proc->stack_base_physical);
 
@@ -155,15 +150,7 @@ void schedule(registers_t *regs) {
   if (curr_proc == NULL)
     curr_proc = proc_list;
 
-  //log("sched - I choosed process %d\n", curr_proc->pid);
-
-  //log("sched - I choosed process %d (pm: %s, rip: %p)\n", curr_proc->pid, curr_proc->pm == vmm_kernel_pm ? "kernel" : "user", curr_proc->regs.rip);
   memcpy(regs, &curr_proc->regs, sizeof(registers_t));
 
-  // Finally, load our pagemap
-  // if (memcmp(curr_proc->name, "Init", 4)== 0) {
   vmm_load_pagemap(curr_proc->pm);
-  // asm("cli");
-  // while (1)
-  //     asm("hlt");}
 }

kernel/src/sys/arch/x86_64/interrupts.c

@@ -1,5 +1,3 @@
-// #include "mm/pmm.h"
-// #include "mm/vmm.h"
 #include "mm/pmm.h"
 #include "mm/vmm.h"
 #include "sched/sched.h"
@@ -7,39 +5,20 @@
 #include "sys/arch/x86_64/rtc.h"
 #include "sys/log.h"
 #include "sys/syscall.h"
-// #include "sys/sched.h"
 #include <stdint.h>
 #include <sys/arch/x86_64/idt.h>
 #include <sys/arch/x86_64/io.h>
-// #include <sys/errhand/panic.h>
 
 int pit_millis = 0;
 int pit_secs = 0;
 extern int vmm_kernel_pm_exists;
 
-struct Idt_StackFrame {
-  struct Idt_StackFrame *rbp;
-  uint64_t rip;
-} __attribute__((packed));
-
-void dump_backtrace(registers_t *r) {
-  log("ints - backtrace : \n");
-  struct Idt_StackFrame *frame = (struct Idt_StackFrame *)r->rbp;
-
-  while (frame) {
-    log("ints -   %s (ip: %p)\n", frame->rip);
-    frame = frame->rbp;
-  }
-  log("ints -   <end of backtrace>\n");
-}
-
 void pit_handler(registers_t *regs);
 
 void exception_handler(registers_t *regs) {
   vmm_load_pagemap(vmm_kernel_pm);
 
   if (regs->int_no < 32) {
-    // panic(kmode_cpu_exception, regs);
     log("ints - %d (RIP: %p, ERR: %d)\n", regs->int_no, regs->rip,
         regs->err_code);
 
@@ -53,7 +32,6 @@ void exception_handler(registers_t *regs) {
       log("ints - PF: Faulting page map: %p\n", PHYSICAL(vmm_current_pm));
     }
 
-    // dump_backtrace(regs);
     asm("cli");
     while (1)
       asm("hlt");
@@ -73,7 +51,6 @@ void exception_handler(registers_t *regs) {
   } else if (regs->int_no == 0x80) {
     syscall_handle(regs);
   }
-  // logln(info, "arch/ints", "Received interrupt %d\n", regs->int_no);
-  //vmm_load_pagemap(curr_proc->pm);
+
   pic_ack(regs->int_no - 32);
 }

kernel/src/sys/error_handling/panic.c

@@ -1 +1,75 @@
-void panic_ctx() {}
+#include "sys/arch/x86_64/idt.h"
+#include <sys/log.h>
+
+static registers_t __panic_regdump;
+
+static void __panic_dump_regs() {
+  asm volatile(
+      // Save general purpose registers
+      "movq %%r15, %0\n\t"
+      "movq %%r14, %1\n\t"
+      "movq %%r13, %2\n\t"
+      "movq %%r12, %3\n\t"
+      "movq %%r11, %4\n\t"
+      "movq %%r10, %5\n\t"
+      "movq %%r9,  %6\n\t"
+      "movq %%r8,  %7\n\t"
+      "movq %%rdi, %8\n\t"
+      "movq %%rsi, %9\n\t"
+      "movq %%rbp, %10\n\t"
+      "movq %%rbx, %11\n\t"
+      "movq %%rdx, %12\n\t"
+      "movq %%rcx, %13\n\t"
+      "movq %%rax, %14\n\t"
+
+      // The rest of the registers (rip, cs, rflags, rsp, ss) would typically
+      // be captured in the interrupt/exception handler context and passed in
+      // We'll zero them out here since we don't have direct access
+      : "=m"(__panic_regdump.r15), "=m"(__panic_regdump.r14),
+        "=m"(__panic_regdump.r13), "=m"(__panic_regdump.r12),
+        "=m"(__panic_regdump.r11), "=m"(__panic_regdump.r10),
+        "=m"(__panic_regdump.r9), "=m"(__panic_regdump.r8),
+        "=m"(__panic_regdump.rdi), "=m"(__panic_regdump.rsi),
+        "=m"(__panic_regdump.rbp), "=m"(__panic_regdump.rbx),
+        "=m"(__panic_regdump.rdx), "=m"(__panic_regdump.rcx),
+        "=m"(__panic_regdump.rax)
+      :
+      : "memory");
+
+  // Zero out the registers we can't directly access in this context
+  __panic_regdump.int_no = 0;
+  __panic_regdump.err_code = 0;
+  __panic_regdump.rip = 0;
+  __panic_regdump.cs = 0;
+  __panic_regdump.rflags = 0;
+  __panic_regdump.rsp = 0;
+  __panic_regdump.ss = 0;
+}
+
+void panic() {
+  __panic_dump_regs();
+
+  log(" _  __                 _   ___           _          \n");
+  log("| |/ /___ _ _ _ _  ___| | | _ \\__ _ _ _ (_)__       \n");
+  log("| ' </ -_) '_| ' \\/ -_) | |  _/ _` | ' \\| / _|_ _ _ \n");
+  log("|_|\\_\\___|_| |_||_\\___|_| |_| \\__,_|_||_|_\\__(_|_|_)\n");
+  log("\n");
+  log("Due to an error that can't be recovered from, Soaplin was needed to "
+      "halt the PC.\n");
+  log("Please report this error to the Soaplin developers, along with the "
+      "information provided below:\n");
+  log("-- REGISTER DUMP --\n");
+  log("RDI: %p, RSI: %p, RDX: %p, RCX: %p, R8: %p, R9: %p\n",
+      __panic_regdump.rdi, __panic_regdump.rsi, __panic_regdump.rdx,
+      __panic_regdump.rcx, __panic_regdump.r8, __panic_regdump.r9);
+  log("RAX: %p, RBP: %p, RBX: %p, R10: %p, R11: %p, R12: %p\n",
+      __panic_regdump.rax, __panic_regdump.rbp, __panic_regdump.rbx,
+      __panic_regdump.r10, __panic_regdump.r11, __panic_regdump.r12);
+  log("R13: %p, R14: %p, R15: %p\n", __panic_regdump.r13, __panic_regdump.r14,
+      __panic_regdump.r15);
+  log("System halted.");
+
+  asm("cli");
+  for (;;)
+    asm("hlt");
+}

kernel/src/sys/error_handling/panic.h

@@ -0,0 +1 @@
+void panic();

kernel/src/sys/gfx/flanterm/backends/fb.h

@@ -45,11 +45,11 @@ extern "C" {
 struct flanterm_context *flanterm_fb_init(
     /* If _malloc and _free are nulled, use the bump allocated instance (1 use
        only). */
-    void *(*_malloc)(size_t size),
-    void (*_free)(void *ptr, size_t size), uint32_t *framebuffer, size_t width,
-    size_t height, size_t pitch, uint8_t red_mask_size, uint8_t red_mask_shift,
-    uint8_t green_mask_size, uint8_t green_mask_shift, uint8_t blue_mask_size,
-    uint8_t blue_mask_shift, uint32_t *canvas, /* If nulled, no canvas. */
+    void *(*_malloc)(size_t size), void (*_free)(void *ptr, size_t size),
+    uint32_t *framebuffer, size_t width, size_t height, size_t pitch,
+    uint8_t red_mask_size, uint8_t red_mask_shift, uint8_t green_mask_size,
+    uint8_t green_mask_shift, uint8_t blue_mask_size, uint8_t blue_mask_shift,
+    uint32_t *canvas, /* If nulled, no canvas. */
     uint32_t *ansi_colours,
     uint32_t *ansi_bright_colours,              /* If nulled, default. */
     uint32_t *default_bg, uint32_t *default_fg, /* If nulled, default. */

kernel/src/sys/log.c

@@ -1,6 +1,7 @@
 #include "sys/arch/x86_64/io.h"
 #include "sys/gfx/flanterm/flanterm.h"
 #include <lib/spinlock.h>
+#include <lib/string.h>
 #include <stdarg.h>
 #include <sys/printf.h>
 
@@ -14,12 +15,8 @@ void log(char *format, ...) {
   // TODO: replace this call with a call to printf() when the RTC is
   // implemented.
   char *date = "1970-01-01 00:00:00 | ";
-  int i2 = 0;
-  for (i2; date[i2] != 0; i2++)
-    ;
-  ;
   if (ft_ctx)
-    flanterm_write(ft_ctx, date, i2);
+    flanterm_write(ft_ctx, date, strlen(date));
 
   char buf[2048];
   va_list l;
@@ -27,14 +24,10 @@ void log(char *format, ...) {
   npf_vsnprintf(buf, 2048, format, l);
   va_end(l);
 
-  int i = 0;
-  for (i; buf[i] != 0; i++)
-    ;
-  ;
   if (ft_ctx)
-    flanterm_write(ft_ctx, buf, i);
+    flanterm_write(ft_ctx, buf, strlen(buf));
 
-  for (int i = 0;; i++) {
+  /*for (int i = 0;; i++) {
     if (date[i] == '\0')
       break;
 
@@ -46,7 +39,7 @@ void log(char *format, ...) {
       break;
 
     outb(0xE9, buf[i]);
-  }
+  }*/
 
   // spinlock_release(&log_lock);
 }

kernel/src/sys/printf.c

@@ -2,6 +2,7 @@
 // This code is part of the Soaplin kernel and is licensed under the terms of
 // the MIT License.
 #include "sys/gfx/flanterm/flanterm.h"
+#include <lib/string.h>
 #include <stdarg.h>
 
 #define NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS 1
@@ -25,11 +26,6 @@ void printf(char *format, ...) {
   va_end(lst);
 
   // rt_print(buf);
-  int i = 0;
-  for (i; buf[i] != 0; i++)
-    ;
-  ;
-
   if (ft_ctx)
-    flanterm_write(ft_ctx, buf, i);
+    flanterm_write(ft_ctx, buf, strlen(buf));
 }

limine.conf

@@ -6,4 +6,4 @@ verbose: yes
     protocol: limine
 
     path: boot():/boot/soaplin
-    module_path: boot():/sk-hello.elf
+    module_path: boot():/initramfs.tar