Directly define __usercopy_{start,end} in the usercopy functions

As opposed to requiring a linker script

linkers/aarch64.ld

@@ -25,9 +25,6 @@ SECTIONS {
     .text : AT(ADDR(.text) - KERNEL_OFFSET) {
         __text_start = .;
         *(.text*)
-        __usercopy_start = .;
-        *(.usercopy-fns)
-        __usercopy_end = .;
 	. = ALIGN(4096);
         __text_end = .;
     }

linkers/i686.ld

@@ -23,9 +23,6 @@ SECTIONS {
     .text ALIGN(4K) : AT(ADDR(.text) - KERNEL_OFFSET) {
         __text_start = .;
         *(.text*)
-        __usercopy_start = .;
-        *(.usercopy-fns)
-        __usercopy_end = .;
     }
 
     .rodata ALIGN(4K) : AT(ADDR(.rodata) - KERNEL_OFFSET) {

linkers/riscv64.ld

@@ -27,9 +27,6 @@ SECTIONS {
 	*(.early_init.text*)
 	. = ALIGN(4096);
         *(.text*)
-        __usercopy_start = .;
-        *(.usercopy-fns)
-        __usercopy_end = .;
 	. = ALIGN(4096);
         __text_end = .;
     }

linkers/x86_64.ld

@@ -23,9 +23,6 @@ SECTIONS {
     .text ALIGN(4K) : AT(ADDR(.text) - KERNEL_OFFSET) {
         __text_start = .;
         *(.text*)
-        __usercopy_start = .;
-        *(.usercopy-fns)
-        __usercopy_end = .;
     }
 
     .rodata ALIGN(4K) : AT(ADDR(.rodata) - KERNEL_OFFSET) {

src/arch/aarch64/mod.rs

@@ -37,11 +37,12 @@ pub use ::rmm::AArch64Arch as CurrentRmmArch;
 pub use arch_copy_to_user as arch_copy_from_user;
 
 #[unsafe(naked)]
-#[unsafe(link_section = ".usercopy-fns")]
 pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -> u8 {
     // x0, x1, x2
     core::arch::naked_asm!(
         "
+    .global __usercopy_start
+    __usercopy_start:
         mov x4, x0
         mov x0, 0
     2:
@@ -58,6 +59,8 @@ pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -
         b 2b
     3:
         ret
+    .global __usercopy_end
+    __usercopy_end:
     "
     );
 }

src/arch/riscv64/mod.rs

@@ -15,11 +15,12 @@ use core::arch::naked_asm;
 
 pub use arch_copy_to_user as arch_copy_from_user;
 
-#[unsafe(link_section = ".usercopy-fns")]
 #[unsafe(naked)]
 pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -> u8 {
     naked_asm!(
         "
+    .global __usercopy_start
+    __usercopy_start:
         addi   sp, sp, -16
         sd     fp, 0(sp)
         sd     ra, 8(sp)
@@ -55,6 +56,8 @@ pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -
         bne    a2, x0, 4b
     5:  mv     a0, x0
         ret
+    .global __usercopy_end
+    __usercopy_end:
     "
     )
 }

src/arch/x86/mod.rs

@@ -17,10 +17,11 @@ pub mod flags {
 }
 
 #[unsafe(naked)]
-#[unsafe(link_section = ".usercopy-fns")]
 pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -> u8 {
     core::arch::naked_asm!(
         "
+    .global __usercopy_start
+    __usercopy_start:
         push edi
         push esi
 
@@ -34,6 +35,8 @@ pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -
 
         xor eax, eax
         ret
+    .global __usercopy_end
+    __usercopy_end:
     "
     );
 }

src/arch/x86_64/mod.rs

@@ -24,27 +24,32 @@ pub mod flags {
 // TODO: Maybe support rewriting relocations (using LD's --emit-relocs) when working with entire
 // functions?
 #[unsafe(naked)]
-#[unsafe(link_section = ".usercopy-fns")]
 pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -> u8 {
     // TODO: spectre_v1
 
-    core::arch::naked_asm!(alternative!(
-        feature: "smap",
-        then: ["
-        xor eax, eax
-        mov rcx, rdx
-        stac
-        rep movsb
-        clac
-        ret
-    "],
-        default: ["
-        xor eax, eax
-        mov rcx, rdx
-        rep movsb
-        ret
-    "]
-    ));
+    core::arch::naked_asm!(
+        ".global __usercopy_start
+        __usercopy_start:",
+        alternative!(
+            feature: "smap",
+            then: ["
+            xor eax, eax
+            mov rcx, rdx
+            stac
+            rep movsb
+            clac
+            ret
+        "],
+            default: ["
+            xor eax, eax
+            mov rcx, rdx
+            rep movsb
+            ret
+        "]
+        ),
+        ".global __usercopy_end
+        __usercopy_end:"
+    );
 }
 pub use arch_copy_to_user as arch_copy_from_user;