i don't know what i'm doing anymore

5 files changed, 207 insertions, 106 deletions

diff --git a/lib/component.ld b/lib/component.ld
new file mode 100644
index 0000000..3a48ae8
--- /dev/null
+++ b/lib/component.ld
@@ -0,0 +1,75 @@
+ENTRY(kc_entry)
+
+SECTIONS
+{
+    PROVIDE(kc_image_base = .);
+
+    . = sizeof_headers;
+
+    .rel :
+    {
+        *(.rel)
+        *(.rel.*)
+    }
+
+    .rela :
+    {
+        *(.rel)
+        *(.rela.*)
+    }
+
+    .hash :
+    {
+        *(.hash)
+    }
+    
+    .dynsym :
+    {
+        *(.dynsym)
+    }
+
+    .dynstr :
+    {
+        *(.dynstr)
+    }
+
+    .text : ALIGN(4K)
+    {
+        PROVIDE(kc_text_begin = .);
+        *(.text.start)
+        *(.text)
+        . = ALIGN(4K);
+        PROVIDE(kc_text_end = .);
+    } =0xcc
+
+    .dynamic : ALIGN(4K)
+    {
+        *(.dynamic)
+    }
+
+    .data :
+    {
+        PROVIDE(kc_data_begin = .);
+        *(.rodata)
+        *(.data)
+    }
+
+    .data.rel :
+    {
+        *(.data.rel)
+        *(.data.rel.*)
+    }
+
+    .bss :
+    {
+        *(.bss)
+        PROVIDE(kc_data_end = .);
+    }
+
+    /DISCARD/ :
+    {
+        *(.eh_frame)
+        *(.comment)
+    }
+}
+
diff --git a/lib/elf.c b/lib/elf.c
deleted file mode 100644
index 551a5a5..0000000
--- a/lib/elf.c
+++ /dev/null
@@ -1,106 +0,0 @@
-#include "elf.h"
-
-bool elf64_validate(Elf64_Ehdr *ehdr, unsigned type, unsigned machine)
-{
-    if (ehdr->e_ident[EI_MAG0] != ELFMAG0 ||
-            ehdr->e_ident[EI_MAG1] != ELFMAG1 ||
-            ehdr->e_ident[EI_MAG2] != ELFMAG2 ||
-            ehdr->e_ident[EI_MAG3] != ELFMAG3 ||
-            ehdr->e_ident[EI_CLASS] != ELFCLASS64 ||
-            ehdr->e_ident[EI_DATA] != ELFDATA2LSB ||
-            ehdr->e_ident[EI_VERSION] != EV_CURRENT ||
-            ehdr->e_machine != machine ||
-            ehdr->e_type != type)
-    {
-        return false;
-    }
-
-    return true;
-}
-
-size_t elf64_size(Elf64_Ehdr *ehdr, Elf64_Phdr *phdrs)
-{
-    size_t size = 0;
-
-    for (int i = 0; i < ehdr->e_phnum; i++)
-    {
-        if (phdrs[i].p_type != PT_LOAD)
-        {
-            continue;
-        }
-
-        if (phdrs[i].p_paddr + phdrs[i].p_memsz > size)
-        {
-            size = phdrs[i].p_paddr + phdrs[i].p_memsz;
-            if (phdrs[i].p_align > 1)
-            {
-                size = (size + phdrs[i].p_align - 1) &
-                    ~(phdrs[i].p_align - 1);
-            }
-        }
-    }
-
-    return size;
-}
-
-void elf64_reloc(Elf64_Ehdr *ehdr)
-{
-    // locate the dynamic segment
-    Elf64_Phdr *phdrs = (Elf64_Phdr *)(ehdr->e_phoff + (uintptr_t)ehdr);
-    Elf64_Dyn *dyn = NULL;
-    Elf64_Rela *rela = NULL;
-    size_t rela_size;
-    int rela_count;
-
-    for (int i = 0; i < ehdr->e_phnum; i++)
-    {
-        if (phdrs[i].p_type != PT_DYNAMIC) continue;
-
-        dyn = (Elf64_Dyn *)(phdrs[i].p_offset + (uintptr_t)ehdr);
-    }
-
-    // parse the dynamic segment
-    while (dyn->d_tag != DT_NULL)
-    {
-        switch (dyn->d_tag)
-        {
-            case DT_RELA:
-                rela = (Elf64_Rela *)(dyn->d_ptr + (uintptr_t)ehdr);
-                break;
-            case DT_RELASZ:
-                rela_size = dyn->d_val;
-                break;
-            case DT_RELAENT:
-                rela_count = rela_size / dyn->d_val;
-                break;
-            default:
-                break;
-        }
-        dyn++;
-    }
-
-    // perform the actual relocations
-
-    for (int i; i < rela_count; i++)
-    {
-        union
-        {
-            Elf_Byte word8;
-            Elf64_Half word16;
-            Elf64_Word word32;
-            Elf64_Xword word64;
-        }
-        *reloc_ptr = NULL;
-
-        switch (ELF64_R_TYPE(rela[i].r_info))
-        {
-            case R_AMD64_RELATIVE:
-                reloc_ptr = (void *)(rela[i].r_offset + (uintptr_t)ehdr);
-                reloc_ptr->word64 = (rela[i].r_addend + (uintptr_t)ehdr);
-                break;
-            default:
-                break;
-        }
-    }
-}
-
diff --git a/lib/elf64.c b/lib/elf64.c
new file mode 100644
index 0000000..2dee395
--- /dev/null
+++ b/lib/elf64.c
@@ -0,0 +1,45 @@
+#include "elf.h"
+
+bool elf64_validate(Elf64_Ehdr *ehdr, unsigned type, unsigned machine)
+{
+    if (ehdr->e_ident[EI_MAG0] != ELFMAG0 ||
+            ehdr->e_ident[EI_MAG1] != ELFMAG1 ||
+            ehdr->e_ident[EI_MAG2] != ELFMAG2 ||
+            ehdr->e_ident[EI_MAG3] != ELFMAG3 ||
+            ehdr->e_ident[EI_CLASS] != ELFCLASS64 ||
+            ehdr->e_ident[EI_DATA] != ELFDATA2LSB ||
+            ehdr->e_ident[EI_VERSION] != EV_CURRENT ||
+            ehdr->e_machine != machine ||
+            ehdr->e_type != type)
+    {
+        return false;
+    }
+
+    return true;
+}
+
+size_t elf64_size(Elf64_Ehdr *ehdr, Elf64_Phdr *phdrs)
+{
+    size_t size = 0;
+
+    for (int i = 0; i < ehdr->e_phnum; i++)
+    {
+        if (phdrs[i].p_type != PT_LOAD)
+        {
+            continue;
+        }
+
+        if (phdrs[i].p_offset + phdrs[i].p_memsz > size)
+        {
+            size = phdrs[i].p_offset + phdrs[i].p_memsz;
+            if (phdrs[i].p_align > 1)
+            {
+                size = (size + phdrs[i].p_align - 1) &
+                    ~(phdrs[i].p_align - 1);
+            }
+        }
+    }
+
+    return size;
+}
+
diff --git a/lib/entry_x86_64.S b/lib/entry_x86_64.S
new file mode 100644
index 0000000..231953a
--- /dev/null
+++ b/lib/entry_x86_64.S
@@ -0,0 +1,18 @@
+.section .text.start
+.extern kc_reloc
+.extern kc_main
+.extern _DYNAMIC
+.extern kc_image_base
+
+.global kc_entry
+.type kc_entry, @function
+kc_entry:
+    push %rdi
+    lea _DYNAMIC(%rip), %rdi
+    lea kc_image_base(%rip), %rsi
+    call kc_reloc
+    pop %rdi
+    call kc_main
+    ret
+.size kc_entry, . - kc_entry
+    
diff --git a/lib/reloc_x86_64.c b/lib/reloc_x86_64.c
new file mode 100644
index 0000000..0204700
--- /dev/null
+++ b/lib/reloc_x86_64.c
@@ -0,0 +1,69 @@
+#include <kernel/component.h>
+
+#include <elf/elf64.h>
+
+#include <stddef.h>
+
+#define STARTCODE __attribute__((section(".text.start")))
+
+STARTCODE 
+static void do_rela(Elf64_Rela *rela, void *base)
+{
+    union
+    {
+        Elf_Byte word8;
+        Elf64_Half word16;
+        Elf64_Word word32;
+        Elf64_Xword word64;
+    }
+    *fixup;
+
+    switch (ELF64_R_TYPE(rela->r_info))
+    {
+        case R_AMD64_RELATIVE:
+            fixup = (void *)(rela->r_offset + (uintptr_t)base);
+            fixup->word64 = (rela->r_addend + (uintptr_t)base);
+            break;
+        default:
+            break;
+    }
+}
+
+STARTCODE
+void kc_reloc(Elf64_Dyn *dyn, void *base)
+{
+    struct
+    {
+        Elf64_Rela *entries;
+        size_t *size;
+        size_t *entsize;
+    }
+    rela = {NULL, NULL, NULL};
+
+    // parse the dynamic segment
+    while (dyn && dyn++->d_tag != DT_NULL)
+    {
+        switch (dyn->d_tag)
+        {
+            case DT_RELA:
+                rela.entries = (Elf64_Rela *)(dyn->d_ptr + (uintptr_t)base);
+                break;
+            case DT_RELASZ:
+                rela.size = &dyn->d_val;
+                break;
+            case DT_RELAENT:
+                rela.entsize = &dyn->d_val;
+                break;
+            default:
+                break;
+        }
+    }
+
+    // perform the actual relocation
+
+    for (size_t i = 0; rela.entries && (i < *rela.size / *rela.entsize); i++)
+    {
+        do_rela(&rela.entries[i], base);
+    }
+}
+