Move PAT initialization to rmm

Rmm needs to know the exact PAT configuration to produce the correct
bits in the page table.

src/arch/x86_shared/paging/mod.rs

@@ -3,8 +3,6 @@
 
 use core::fmt::Debug;
 
-use x86::msr;
-
 pub use super::CurrentRmmArch as RmmA;
 pub use rmm::{Arch as RmmArch, PageFlags, PhysicalAddress, TableKind, VirtualAddress};
 
@@ -21,46 +19,14 @@ pub mod mapper;
 pub const PAGE_SIZE: usize = RmmA::PAGE_SIZE;
 pub const PAGE_MASK: usize = RmmA::PAGE_OFFSET_MASK;
 
-/// Setup page attribute table
-#[cold]
-unsafe fn init_pat() {
-    unsafe {
-        let uncacheable = 0;
-        let write_combining = 1;
-        let write_through = 4;
-        //let write_protected = 5;
-        let write_back = 6;
-        let uncached = 7;
-
-        let pat0 = write_back;
-        let pat1 = write_through;
-        let pat2 = uncached;
-        let pat3 = uncacheable;
-
-        let pat4 = write_combining;
-        let pat5 = pat1;
-        let pat6 = pat2;
-        let pat7 = pat3;
-
-        msr::wrmsr(
-            msr::IA32_PAT,
-            (pat7 << 56)
-                | (pat6 << 48)
-                | (pat5 << 40)
-                | (pat4 << 32)
-                | (pat3 << 24)
-                | (pat2 << 16)
-                | (pat1 << 8)
-                | pat0,
-        );
-    }
-}
-
 /// Initialize PAT
 #[cold]
 pub unsafe fn init() {
     unsafe {
-        init_pat();
+        #[cfg(target_arch = "x86")]
+        rmm::x86::init_pat();
+        #[cfg(target_arch = "x86_64")]
+        rmm::x86_64::init_pat();
     }
 }