[fix] Add used attr for function pointer

README.md

@@ -11,7 +11,7 @@ Module initialization functions for Rust (like __attribute__((constructor)) in C
 After registering a constructor function, a function pointer pointing to it will be stored in the `.init_array` section.
 
 
-It can support Linux, Windows, MacOS and other systems, and can be also used in `no_std` environments when developing your own kernel.
+It can support Linux, MacOS and other systems, and can be also used in `no_std` environments when developing your own kernel.
 
 
 In Linux, Windows, MacOS and other systems, the `.init_array` section is a default section to store initialization functions. When the program starts, the system will call all functions in the `.init_array` section in order.
@@ -43,18 +43,14 @@ fn main() {
 Because the `.init_array` section is a default section to store initialization functions in Linux and some other systems, it will be included in the linker script of compilers like GCC and Clang.
 
 
-**However**, if you are using a custom linker script, you need to **add the `.init_array` section to the `.text` section manually**, so that these functions can be mapped into the page table and executed correctly. You can add the following line to your linker script as a reference:
+**However**, if you are using a custom linker script, you need to **add the `.init_array` section and map them in the page table manually**, so that these functions can be executed correctly. You can add the following line to your linker script as a reference:
 
 ```test, ignore
-.text : ALIGN(4K) {
-    # other sections in the `.text` section
-
-    __init_array_start = .;
-    __init_array_end = __init_array_start + SIZEOF(.init_array);
+.init_array : ALIGN(4K) {
+    PROVIDE_HIDDEN (__init_array_start = .);
     *(.init_array .init_array.*)
-    . = __init_array_end;
-
-    # other sections in the `.text` section
+    PROVIDE_HIDDEN (__init_array_end = .);
+    . = ALIGN(4K);
 }
 ```
 

ctor_bare_macros/src/lib.rs

@@ -58,6 +58,7 @@ pub fn register_ctor(attr: TokenStream, function: TokenStream) -> TokenStream {
 
         quote! {
             #[link_section = ".init_array"]
+            #[used]
             #[allow(non_upper_case_globals)]
             static #name_ident: extern "C" fn() = #name;