feat: added debug traces and added support for booting using grub and

tftp

kernel/debug/debug.c

@@ -0,0 +1,113 @@
+//
+// Created by rick on 08-03-21.
+//
+
+#include "debug.h"
+#include <elf.h>
+#include <libk/libk.h>
+#include <libc/libc.h>
+#include <libc/kprintf.h>
+#include <libc/string.h>
+#include <libk/kprint.h>
+
+static struct elf32_section_header* elf_headers = NULL;
+static struct elf32_section_header* elf_shstrtab = NULL;
+static struct elf32_section_header* elf_symtab = NULL;
+static struct elf32_section_header* elf_strtab = NULL;
+static uint32_t elf_header_cnt;
+
+static const char* elf_name_symtab = ".symtab";
+static const char* elf_name_strtab = ".strtab";
+
+struct stackframe {
+    struct stackframe* ebp;
+    uint32_t eip;
+};
+
+char *debug_get_shstrtab_entry(uint32_t ndx) {
+    if (elf_shstrtab == NULL) {
+        return NULL;
+    }
+    if (ndx > elf_shstrtab->sh_size) {
+        return NULL;
+    }
+    return ((char*)elf_shstrtab->sh_addr + ndx);
+}
+
+char *debug_get_strtab_entry(uint32_t ndx) {
+    if (elf_strtab == NULL) {
+        return NULL;
+    }
+    if (ndx > elf_strtab->sh_size) {
+        return NULL;
+    }
+    return ((char*)elf_strtab->sh_addr + ndx);
+}
+
+void debug_find_sections(uint32_t shndx) {
+    elf_shstrtab = &elf_headers[shndx];
+    for (uint32_t i = 0; i < elf_header_cnt; ++i) {
+        struct elf32_section_header *current = &elf_headers[i];
+        char *name = debug_get_shstrtab_entry(current->sh_name);
+        if (name == NULL) {
+            printf("Name was NULL\n");
+            continue;
+        }
+        if (strcmp(name, elf_name_symtab) == 0) {
+            elf_symtab = current;
+            continue;
+        }
+        if (strcmp(name, elf_name_strtab) == 0) {
+            elf_strtab = current;
+            continue;
+        }
+    }
+}
+
+void debug_store_info(struct multiboot_info *info) {
+    if (!(info->flags & MULTIBOOT_INFO_ELF_SHDR)) {
+        return;
+    }
+    if (sizeof(struct elf32_section_header) != info->u.elf_sec.size) {
+        k_panics("ELF size not correct");
+    }
+    elf_headers = (struct elf32_section_header *) info->u.elf_sec.addr;
+    elf_header_cnt = info->u.elf_sec.num;
+    debug_find_sections(info->u.elf_sec.shndx);
+}
+
+struct elf32_symtab_entry* debug_get_entry_for_addr(uint32_t addr) {
+    if (elf_symtab == NULL) {
+        return NULL;
+    }
+    struct elf32_symtab_entry* first = (struct elf32_symtab_entry *) elf_symtab->sh_addr;
+    uint32_t num = elf_symtab->sh_size / sizeof(struct elf32_symtab_entry);
+    for (uint32_t i = 0; i < num; ++i) {
+        // only functions for now
+        if (ELF32_ST_TYPE(first[i].st_info) != STT_FUNC) {
+            continue;
+        }
+        if (addr >= first[i].st_value && addr < (first[i].st_value + first[i].st_size)) {
+            return &first[i];
+        }
+    }
+    return NULL;
+}
+
+void debug_backtrace(bool do_sync) {
+    struct stackframe *frame = __builtin_frame_address(0);
+    void (*printer)(const char*) = do_sync ? kprint_sync : kprint;
+    printer("\n\n## Stack Trace ##\n");
+    char msg[1024] = {0};
+    while (frame->ebp != NULL) {
+        struct elf32_symtab_entry *entry = debug_get_entry_for_addr(frame->eip);
+        if (entry == NULL) {
+            sprintf(msg, "#unknown (%x)\n", frame->eip);
+        } else {
+            sprintf(msg, "%s (%x)\n", debug_get_strtab_entry(entry->st_name), frame->eip);
+        };
+        printer(msg);
+        frame = frame->ebp;
+    }
+    printer("\n");
+}