symbols build files added to gitignore

.gitignore

@@ -8,3 +8,5 @@ iso_root
 */*.gch
 */*/*.gch
 .gdb_history
+symbols.map
+symbols.S

Makefile

@@ -1,4 +1,4 @@
-SOURCES = src/boot/boot.c src/sched/scheduler.c src/sched/process.c src/mem/heap/kheap.c src/mem/paging/vmm.c src/mem/paging/paging.c src/mem/paging/pmm.c src/string/string.c src/io/kbd/ps2.c src/io/serial/serial.c src/io/term/printf.c src/io/term/term.c src/idt/idt.c src/mem/gdt/gdt.c src/mem/misc/utils.c src/time/timer.c src/kmain.c
+SOURCES = src/debug/panic.c src/debug/stacktrace.c src/boot/boot.c src/sched/scheduler.c src/sched/process.c src/mem/heap/kheap.c src/mem/paging/vmm.c src/mem/paging/paging.c src/mem/paging/pmm.c src/string/string.c src/io/kbd/ps2.c src/io/serial/serial.c src/io/term/printf.c src/io/term/term.c src/idt/idt.c src/mem/gdt/gdt.c src/mem/misc/utils.c src/time/timer.c src/kmain.c
 
 PROBLEMATIC_FLAGS=-Wno-unused-parameter -Wno-unused-variable
 
@@ -9,6 +9,10 @@ build:
 	nasm -f elf64 src/idt/idt.S -o idt_stub.o
 	nasm -f elf64 src/entry.S -o entry.o
 	x86_64-elf-ld -o pepperk -T linker.ld *.o
+	nm -n pepperk | awk '$$2 ~ /[TtDdBbRr]/ {print $$1, $$3}' > symbols.map
+	python3 symbols.py
+	nasm -f elf64 symbols.S -o symbols.o
+	x86_64-elf-ld -o pepperk -T linker.ld *.o
 
 limine/limine:
 	rm -rf limine
@@ -44,4 +48,4 @@ run: build-iso
 	/usr/bin/qemu-system-x86_64 -cdrom pepper.iso -serial stdio
 
 clean:
-	rm -rf *.o pepperk iso_root pepper.iso limine
+	rm -rf *.o symbols.map symbols.S pepperk iso_root pepper.iso limine

README.md

@@ -2,7 +2,7 @@
 
 ## Trying the kernel
 
-First install the dependencies: `sudo apt install xorriso make qemu-system`
+First install the dependencies: `sudo apt install python3 xorriso make qemu-system`
 
 Then, to compile the kernel and make an ISO image file: `make build-iso`
 To run it with QEMU, `make run`

src/config.h

@@ -10,7 +10,7 @@
 /* version */
 #define PEPPEROS_VERSION_MAJOR "0"
 #define PEPPEROS_VERSION_MINOR "0"
-#define PEPPEROS_VERSION_PATCH "1"
+#define PEPPEROS_VERSION_PATCH "58"
 #define PEPPEROS_SPLASH "pepperOS version "PEPPEROS_VERSION_MAJOR"."PEPPEROS_VERSION_MINOR"."PEPPEROS_VERSION_PATCH"\n"
 
 /* process */

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);
 

symbols.py

@@ -0,0 +1,33 @@
+# Make assembly file from ELF symbols map
+# Then link it to kernel so it's aware of symbol names
+# then we can use that for the stack trace.
+
+print("Extracting symbols from map file to assembly...")
+
+with open("symbols.map", "r") as f:
+    lines = f.readlines()
+
+    symbols = []
+    for line in lines:
+        parts = line.split()
+        # output is formed like "address name"
+        symbols.append((parts[0], parts[1]))
+
+with open("symbols.S", "w") as f:
+    f.write("section .rodata\n")
+    f.write("global symbol_table\n")
+    f.write("global symbol_count\n")
+    f.write("symbol_table:\n")
+
+    for i, (addr, name) in enumerate(symbols):
+        f.write(f"    dq 0x{addr}\n")
+        f.write(f"    dq sym_name_{i}\n")
+
+    f.write("\nsymbol_count: dq " + str(len(symbols)) + "\n\n")
+
+    for i, (addr, name) in enumerate(symbols):
+        # escaping quotes
+        safe_name = name.replace('"', '\\"')
+        f.write(f'sym_name_{i}: db "{safe_name}", 0\n')
+
+print("Done!")