runtimer_loader/arm: implement relocations

Change-Id: Ibda978e37d6dbdaf33ac054adbbda70768fe0d97
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4975
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: waddlesplash <[email protected]>

src/system/runtime_loader/arch/arm/arch_relocate.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012, Haiku, Inc.
+ * Copyright 2012-2022, Haiku, Inc.
  * Distributed under the terms of the MIT License.
  *
  * Authors:
@@ -16,15 +16,92 @@
 
 //#define TRACE_RLD
 #ifdef TRACE_RLD
-#	define TRACE(x) dprintf x
+#	define TRACE(x...) dprintf(x)
 #else
-#	define TRACE(x) ;
+#	define TRACE(x...) ;
 #endif
 
+
+static int
+relocate_rel(image_t *rootImage, image_t *image, Elf32_Rel *rel, int rel_len,
+	SymbolLookupCache* cache)
+{
+# define P	((addr_t *)(image->regions[0].delta + rel[i].r_offset))
+# define A	(*(P))
+# define B	(image->regions[0].delta)
+
+	for (int i = 0; i * (int)sizeof(Elf32_Rel) < rel_len; i++) {
+		unsigned type = ELF32_R_TYPE(rel[i].r_info);
+		unsigned symbolIndex = ELF32_R_SYM(rel[i].r_info);
+		addr_t final_val;
+		addr_t S;
+
+		image_t* symbolImage = NULL;
+		if (symbolIndex != 0) {
+			Elf32_Sym* sym = SYMBOL(image, symbolIndex);
+			status_t status = resolve_symbol(rootImage, image, sym, cache, &S,
+					&symbolImage);
+			if (status < B_OK) {
+				TRACE("resolve symbol \"%s\" returned: %ld\n",
+					SYMNAME(image, sym), status);
+				return status;
+			}
+		}
+
+		switch (type) {
+			case R_ARM_NONE:
+				continue;
+			case R_ARM_RELATIVE:
+				final_val = B + A;
+				break;
+			case R_ARM_JMP_SLOT:
+			case R_ARM_GLOB_DAT:
+				final_val = S;
+				break;
+			case R_ARM_ABS32:
+				final_val = S + A;
+				break;
+			default:
+				TRACE("unhandled relocation type %d\n", ELF32_R_TYPE(rel[i].r_info));
+				return B_NOT_ALLOWED;
+		}
+
+		*P = final_val;
+	}
+
+# undef P
+# undef A
+# undef B
+
+	return B_NO_ERROR;
+}
+
+
 status_t
 arch_relocate_image(image_t *rootImage, image_t *image,
 	SymbolLookupCache* cache)
 {
-	debugger("arch_relocate_image: Not Yet Implemented!");
+	status_t status;
+
+	// deal with the rels first
+	if (image->rel) {
+		status = relocate_rel(rootImage, image, image->rel, image->rel_len,
+			cache);
+		if (status < B_OK)
+			return status;
+	}
+
+	if (image->pltrel) {
+		status = relocate_rel(rootImage, image, image->pltrel,
+			image->pltrel_len, cache);
+		if (status < B_OK)
+			return status;
+	}
+
+	if (image->rela) {
+		TRACE("RELA relocations not supported\n");
+		return EOPNOTSUPP;
+	}
+
 	return B_OK;
 }