vm: object: zero-initialise pages allocated for vm-object

this patch must now be done by the wider OS build system, to avoid
interference with any bootloaders that don't support this kind of
patching (e.g GRUB i386-pc)

arch/x86_64/config.cmake

@@ -2,9 +2,3 @@ target_compile_options(${kernel_exe_name} PRIVATE
 	-z max-page-size=0x1000 -m64 -mcmodel=large -mno-red-zone -mno-mmx
 	-mno-sse -mno-sse2 -D_64BIT -DBYTE_ORDER=1234)
 target_link_libraries(${kernel_exe_name} "-z max-page-size=0x1000" "-T ${CMAKE_CURRENT_SOURCE_DIR}/arch/x86_64/layout.ld")
-
-add_custom_command(TARGET ${kernel_exe_name} POST_BUILD
-	COMMAND ${BUILD_TOOLS_DIR}/e64patch $<TARGET_FILE:${kernel_exe_name}>
-	WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
-	COMMENT "Patching kernel elf64 image"
-)

kernel/object.c

@@ -50,8 +50,6 @@ struct object *object_create(struct object_type *type)
 		return NULL;
 	}
 
-	memset(obj_buf, 0x00, type->ob_size);
-
 	struct object *obj = (struct object *)((unsigned char *)obj_buf
 	                                       + type->ob_header_offset);
 

vm/cache.c

@@ -198,6 +198,8 @@ void *vm_cache_alloc(struct vm_cache *cache, enum vm_flags flags)
 	}
 
 	spin_unlock_irqrestore(&cache->c_lock, irq_flags);
+
+	memset(p, 0x0, cache->c_obj_size);
 	return p;
 }
 

vm/vm-object.c

@@ -286,6 +286,8 @@ extern struct vm_page *vm_object_alloc_page(
 			return NULL;
 		}
 
+		void *page_buf = vm_page_get_vaddr(page);
+		memset(page_buf, 0x0, vm_page_get_size_bytes(page));
 		tracek("vm-object: [%s] alloc offset %zx -> page %zx",
 		       vo->vo_name,
 		       offset,