moving files around

1 files changed, 69 insertions, 0 deletions

diff --git a/kc/reloc_x86_64.c b/kc/reloc_x86_64.c
new file mode 100644
index 0000000..0204700
--- /dev/null
+++ b/kc/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);
+    }
+}
+