kjarna runtime

1 files changed, 42 insertions, 0 deletions

diff --git a/kjarna_runtime/reloc_x86_64.c b/kjarna_runtime/reloc_x86_64.c
new file mode 100644
index 0000000..63dc6e7
--- /dev/null
+++ b/kjarna_runtime/reloc_x86_64.c
@@ -0,0 +1,42 @@
+#include <kc.h>
+
+#define STARTCODE __attribute__((section(".text.start")))
+
+STARTCODE 
+static void do_rela(void *base, Elf64_Rela *rela)
+{
+    union
+    {
+        Elf_Byte word8;
+        Elf64_Half word16;
+        Elf64_Word word32;
+        Elf64_Xword word64;
+    }
+    *fixup;
+
+    switch (ELF64_R_TYPE(rela->r_info))
+    {
+        case R_X86_64_JUMP_SLOT:
+            fixup = (void *)(rela->r_offset + (uintptr_t)base);
+            fixup->word64 += (uintptr_t)base;
+            break;
+        case R_X86_64_RELATIVE:
+            fixup = (void *)(rela->r_offset + (uintptr_t)base);
+            fixup->word64 = (rela->r_addend + (uintptr_t)base);
+            break;
+        default:
+            break;
+    }
+}
+
+STARTCODE
+void kc_reloc(void *base, Elf64_Rela *entries, size_t size, size_t entsize)
+{
+    // perform the actual relocation
+
+    for (size_t i = 0; entries && (i < size / entsize); i++)
+    {
+        do_rela(base, &entries[i]);
+    }
+}
+