Stack trace with double linking to get symbol names

src/debug/panic.c

@@ -0,0 +1,23 @@
+#include <stddef.h>
+#include "idt/idt.h"
+#include "io/serial/serial.h"
+#include "kernel.h"
+
+void panic(struct cpu_status_t* ctx, const char* str)
+{
+	CLEAR_INTERRUPTS;
+	if (ctx == NULL)
+	{
+		DEBUG("\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[0m Something went horribly wrong! (no cpu ctx)");
+		DIE_DEBUG(str);
+		skputc('\n');
+		DEBUG("\x1b[38;5;231m\x1b[48;5;196mend Kernel panic - halting...\x1b[0m");
+		hcf();
+	}
+	DEBUG("\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[0m at rip=%p\nSomething went horribly wrong! vect=0x%.2x errcode=0x%x\n\rrax=%p rbx=%p rcx=%p rdx=%p\n\rrsi=%p rdi=%p  r8=%p  r9=%p\n\rr10=%p r11=%p r12=%p r13=%p\n\rr14=%p r15=%p\n\n\rflags=%p\n\rHalting...",
+		ctx->iret_rip,
+		ctx->vector_number, ctx->error_code, ctx->rax, ctx->rbx, ctx->rcx, ctx->rdx, ctx->rsi, ctx->rdi,
+		ctx->r8, ctx->r9, ctx->r10, ctx->r11, ctx->r12, ctx->r13, ctx->r14, ctx->r15, ctx->iret_flags);
+	debug_stack_trace(100);
+	hcf();
+}

src/debug/stacktrace.c

@@ -0,0 +1,75 @@
+#include <stdint.h>
+#include "kernel.h"
+
+void debug_stack_trace(unsigned int max_frames)
+{
+    DEBUG("*** begin stack trace ***");
+    // Thanks GCC :)
+    uintptr_t* rbp = (uintptr_t*)__builtin_frame_address(0);
+
+    for (unsigned int frame=0; frame<max_frames && rbp != NULL; frame++)
+    {
+        // Return address, 1 word above saved rbp
+        uintptr_t rip = rbp[1];
+        uintptr_t offset = 0;
+        const char* name = debug_find_symbol(rip, &offset);
+        DEBUG("[%u] <0x%p> (%s+0x%x)", frame, (void*)rip, name, offset);
+
+        uintptr_t* next_rbp = (uintptr_t*)rbp[0];
+
+        // invalid rbp or we're at the end
+        if (next_rbp <= rbp || next_rbp == NULL)
+        {
+            break;
+        }
+
+        rbp = next_rbp;
+    }
+    DEBUG("*** end stack trace ***");
+}
+
+typedef struct
+{
+    uint64_t addr;
+    const char *name;
+} __attribute__((packed)) kernel_symbol_t;
+
+__attribute__((weak)) extern kernel_symbol_t symbol_table[];
+__attribute__((weak)) extern uint64_t symbol_count;
+
+// binary search
+const char* debug_find_symbol(uintptr_t rip, uintptr_t* offset)
+{
+    if (!symbol_table || symbol_count == 0)
+    {
+        if (offset) *offset = 0;
+        return "???";
+    }
+
+    int low = 0, high = (int)symbol_count - 1;
+    int best = -1;
+
+    while (low <= high)
+    {
+        int mid = (low + high) / 2;
+        if (symbol_table[mid].addr <= rip)
+        {
+            best = mid;
+            low = mid + 1;
+        } else {
+            high = mid - 1;
+        }
+    }
+
+    if (best != -1)
+    {
+        if (offset)
+        {
+            *offset = rip - symbol_table[best].addr;
+        }
+        return symbol_table[best].name;
+    }
+
+    if (offset) *offset = 0;
+    return "unknown";
+}

src/kernel.h

@@ -31,6 +31,10 @@ enum ErrorCodes
 void panic(struct cpu_status_t* ctx, const char* str);
 void hcf();
 void idle();
+
+void debug_stack_trace(unsigned int max_frames);
+const char* debug_find_symbol(uintptr_t rip, uintptr_t* offset);
+
 #define assert(check) do { if(!(check)) hcf(); } while(0)
 
 struct boot_context

src/kmain.c

@@ -39,25 +39,6 @@ void idle() {SET_INTERRUPTS; for(;;)asm("hlt");}
 
 uint8_t kernel_stack[KERNEL_STACK_SIZE] __attribute__((aligned(16)));
 
-void panic(struct cpu_status_t* ctx, const char* str)
-{
-	CLEAR_INTERRUPTS;
-	if (ctx == NULL)
-	{
-		DEBUG("\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[0m Something went horribly wrong! (no cpu ctx)");
-		DIE_DEBUG(str);
-		skputc('\n');
-		DEBUG("\x1b[38;5;231m\x1b[48;5;196mend Kernel panic - halting...\x1b[0m");
-		hcf();
-	}
-	DEBUG("\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[0m at rip=%p\nSomething went horribly wrong! vect=0x%.2x errcode=0x%x\n\rrax=%p rbx=%p rcx=%p rdx=%p\n\rrsi=%p rdi=%p  r8=%p  r9=%p\n\rr10=%p r11=%p r12=%p r13=%p\n\rr14=%p r15=%p\n\n\rflags=%p\n\rstack at rbp=%p\n\rHalting...",
-		ctx->iret_rip,
-		ctx->vector_number, ctx->error_code, ctx->rax, ctx->rbx, ctx->rcx, ctx->rdx, ctx->rsi, ctx->rdi,
-		ctx->r8, ctx->r9, ctx->r10, ctx->r11, ctx->r12, ctx->r13, ctx->r14, ctx->r15, ctx->iret_flags,
-		ctx->rbp);
-	hcf();
-}
-
 struct boot_context boot_ctx;
 
 extern volatile struct limine_framebuffer_request framebuffer_request;
@@ -71,7 +52,11 @@ extern struct process_t* current_process;
 void pedicel_main(void* arg)
 {
 	printf("Hello, world from a KERNEL PROCESS!");
-	//panic(NULL, "WE DID IT! Hello, world from a PROCESS!!!!");
+}
+
+void two_main(void* arg)
+{
+	printf("...process 2 speaking!!!");
 }
 
 void idle_main(void* arg)
@@ -112,6 +97,7 @@ void kmain()
 	
 	struct process_t* idle_proc = process_create("idle", (void*)idle_main, 0);
 	struct process_t* pedicel = process_create("pedicel", (void*)pedicel_main, 0);
+	struct process_t* two = process_create("two", (void*)two_main, 0);
 	
 	process_display_list(processes_list);