feat: stacktraces

Signed-off-by: Ry <ry.diffusion@proton.me>

Kernel/Arch/x86_64-pc/Asm/Asm.c

@@ -15,7 +15,7 @@ void sti(void) { asm("sti"); }
 void cli(void) { asm("cli"); }
 void halt(void) { asm("hlt"); }
 
-void hcf(void) {
+__attribute__((noreturn)) void hcf(void) {
     asm("cli");
     for (;;) {
         asm("hlt");

Kernel/Arch/x86_64-pc/Entry/Entry.c

@@ -1,3 +1,4 @@
+#include "Kernel/Panic.h"
 #include <Asm/Asm.h>
 #include <Framebuffer/Framebuffer.h>
 #include <LibK/stdio.h>
@@ -6,10 +7,7 @@
 #include <System/Interrupts.h>
 #include <System/PIC.h>
 #include <limine.h>
-
-#ifndef GIT_VERSION
-#define GIT_VERSION "Undefined"
-#endif
+#include <meta.h>
 
 extern void far_jump(void);
 
@@ -81,8 +79,7 @@ void Arch_entry(void) {
     asm("int $0");
     asm("int $0");
 
-#ifdef GIT_VERSION
     kprintf("Welcome to BlobOS!\nVersion: %s\n", GIT_VERSION);
-#endif
+
     halt();
 }

Kernel/Arch/x86_64-pc/Include/meta.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#ifndef GIT_VERSION
+#define GIT_VERSION "UNKNOWN"
+#endif

Kernel/Arch/x86_64-pc/System/GDTFarJump.asm

@@ -1,5 +1,6 @@
 [bits 64]
 [global reloadSegments]
+[global set_up_stack]
 
 reloadSegments:
     push 0x08 ; Push code segment to stack
@@ -15,3 +16,4 @@ reloadSegments:
     mov gs, ax
     mov ss, ax
     ret
+

Kernel/Include/Asm/Asm.h

@@ -6,6 +6,8 @@
 bool interrupts_enabled();
 void loadIDT(idtr_t *idtr);
 void halt(void);
-void hcf(void);
+__attribute__((noreturn)) void hcf(void);
 void sti(void);
 void cli(void);
+
+extern void reloadSegments(void);

Kernel/Include/Kernel/Panic.h

@@ -1,3 +1,7 @@
 #pragma once
 
-void panic(char *message);
+/**
+    @brief Panics the kernel
+    @param message The message to put in kernel panic, must be non null.
+*/
+__attribute__((noreturn)) void panic(char message[static 1]);

Kernel/Include/Kernel/Stack.h

@@ -0,0 +1,7 @@
+#pragma once
+#define DUMP_STACK_ENTRIES_MAX 20
+
+/**
+    @brief Dumps the stack into console
+*/
+void dumpStack(void);

Kernel/Kernel/Panic.c

@@ -2,22 +2,21 @@
 #include <Framebuffer/Framebuffer.h>
 #include <Kernel/Panic.h>
 #include <LibK/stdio.h>
-#include <stdint.h>
+#include <meta.h>
 
-struct stackframe {
-    struct stackframe *rbp;
-    uint64_t rip;
-};
+#include <Kernel/Stack.h>
 
-// TODO: Unwind the stack and get a cool stack trace :)
-void panic(char *message) {
+void panic(char message[static 1]) {
     framebuffer_clear(0xcccccc, 0xc40404);
     kprintf(
         "BlobOS encountered an error which it couldn't recover from.\nPlease "
         "file an issue to https://github.com/RedsonBr140/BlobOS/issues "
         "with detailed information.\nYou will need to restart your "
         "computer.\n");
 
-    kprintf("\nError message: %s\n", message);
+    kprintf("\nVersion: %s\n", GIT_VERSION);
+    kprintf("Error message: %s\n", message);
+
+    dumpStack();
     hcf();
 }

Kernel/Kernel/Stack.c

@@ -0,0 +1,39 @@
+#include <Kernel/Stack.h>
+#include <LibK/stdio.h>
+#include <stdint.h>
+
+#if defined(__x86_64__)
+void dumpStack(void) {
+    kprintf("Stacktrace:\n");
+    uint64_t rbp = 0;
+
+    __asm__ volatile("mov %%rbp, %0" : "=r"(rbp));
+
+    for (uint64_t frame = 0; rbp && frame < DUMP_STACK_ENTRIES_MAX; ++frame) {
+        kprintf(" [%p]\n", rbp);
+        rbp += sizeof(void *);
+    }
+}
+
+#elif defined(__i386__)
+/* NOTE: NOT TESTED. */
+
+struct stackframe {
+    struct stackframe *ebp;
+    uint64_t rip;
+};
+
+void dumpStack(void) {
+    kprintf("Stacktrace:\n");
+    struct stackframe *stackFrame;
+    asm("movl %%ebp,%0" : "=r"(stackFrame)::);
+    for (uint64_t frame = 0; stackFrame && frame < PANIC_STACK_ENTRIES_MAX;
+         ++frame) {
+
+        kprintf(" [%p]\n", stackFrame->rip);
+        stackFrame = stackFrame->ebp;
+    }
+}
+#else
+void dumpStack(void) { kprintf("Stacktrace unavaliable.\n"); }
+#endif