Directly read the bootstrap entry point from the initfs header

src/arch/aarch64/start.rs

@@ -48,8 +48,8 @@ pub struct KernelArgs {
     bootstrap_base: usize,
     /// Size of contiguous bootstrap/initfs physical region, not necessarily page aligned.
     bootstrap_size: usize,
-    /// Entry point the kernel will jump to.
-    bootstrap_entry: usize,
+    /// Entry point the kernel will jump to. (deprecated)
+    _bootstrap_entry: usize,
 }
 
 /// The entry to Rust, all things must be initialized
@@ -125,7 +125,6 @@ pub unsafe extern "C" fn kstart(args_ptr: *const KernelArgs) -> ! {
             { args.bootstrap_base },
             args.bootstrap_base + args.bootstrap_size
         );
-        info!("Bootstrap entry point: {:X}", { args.bootstrap_entry });
 
         // Setup interrupt handlers
         core::arch::asm!(
@@ -202,7 +201,6 @@ pub unsafe extern "C" fn kstart(args_ptr: *const KernelArgs) -> ! {
                 args.bootstrap_base,
             )),
             page_count: args.bootstrap_size / crate::memory::PAGE_SIZE,
-            entry: args.bootstrap_entry,
             env,
         }
     };

src/arch/x86/start.rs

@@ -60,8 +60,8 @@ pub struct KernelArgs {
     bootstrap_base: u64,
     /// Size of contiguous bootstrap/initfs physical region, not necessarily page aligned.
     bootstrap_size: u64,
-    /// Entry point the kernel will jump to.
-    bootstrap_entry: u64,
+    /// Entry point the kernel will jump to. (deprecated)
+    _bootstrap_entry: u64,
 }
 
 /// The entry to Rust, all things must be initialized
@@ -135,7 +135,6 @@ pub unsafe extern "C" fn kstart(args_ptr: *const KernelArgs) -> ! {
             { args.bootstrap_base },
             { args.bootstrap_base } + { args.bootstrap_size }
         );
-        info!("Bootstrap entry point: {:X}", { args.bootstrap_entry });
 
         // Set up GDT before paging
         gdt::init();
@@ -224,7 +223,6 @@ pub unsafe extern "C" fn kstart(args_ptr: *const KernelArgs) -> ! {
                 args.bootstrap_base as usize,
             )),
             page_count: (args.bootstrap_size as usize) / crate::memory::PAGE_SIZE,
-            entry: args.bootstrap_entry as usize,
             env,
         }
     };

src/arch/x86_64/start.rs

@@ -60,8 +60,8 @@ pub struct KernelArgs {
     bootstrap_base: u64,
     /// Size of contiguous bootstrap/initfs physical region, not necessarily page aligned.
     bootstrap_size: u64,
-    /// Entry point the kernel will jump to.
-    bootstrap_entry: u64,
+    /// Entry point the kernel will jump to. (deprecated)
+    _bootstrap_entry: u64,
 }
 
 /// The entry to Rust, all things must be initialized
@@ -135,7 +135,6 @@ pub unsafe extern "C" fn kstart(args_ptr: *const KernelArgs) -> ! {
             { args.bootstrap_base },
             { args.bootstrap_base } + { args.bootstrap_size }
         );
-        info!("Bootstrap entry point: {:X}", { args.bootstrap_entry });
 
         // Set up GDT before paging
         gdt::init();
@@ -233,7 +232,6 @@ pub unsafe extern "C" fn kstart(args_ptr: *const KernelArgs) -> ! {
                 args.bootstrap_base as usize,
             )),
             page_count: (args.bootstrap_size as usize) / crate::memory::PAGE_SIZE,
-            entry: args.bootstrap_entry as usize,
             env,
         }
     };

src/main.rs

@@ -172,7 +172,6 @@ extern "C" fn userspace_init() {
 struct Bootstrap {
     base: crate::memory::Frame,
     page_count: usize,
-    entry: usize,
     env: &'static [u8],
 }
 static BOOTSTRAP: spin::Once<Bootstrap> = spin::Once::new();

src/syscall/process.rs

@@ -594,13 +594,18 @@ pub unsafe fn usermode_bootstrap(bootstrap: &Bootstrap) -> ! {
     }
 
     // TODO: Not all arches do linear mapping
+    let bootstrap_slice = unsafe { bootstrap_mem(bootstrap) };
     UserSliceWo::new(PAGE_SIZE, bootstrap.page_count * PAGE_SIZE)
         .expect("failed to create bootstrap user slice")
-        .copy_from_slice(unsafe { bootstrap_mem(bootstrap) })
+        .copy_from_slice(bootstrap_slice)
         .expect("failed to copy memory to bootstrap");
 
+    let bootstrap_entry = u64::from_le_bytes(bootstrap_slice[0x1a..0x22].try_into().unwrap());
+    log::info!("Bootstrap entry point: {:X}", bootstrap_entry);
+    assert_ne!(bootstrap_entry, 0);
+
     // Start in a minimal environment without any stack.
-    usermode(bootstrap.entry, 0, 0, 0);
+    usermode(bootstrap_entry.try_into().unwrap(), 0, 0, 0);
 }
 
 pub unsafe fn bootstrap_mem(bootstrap: &crate::Bootstrap) -> &'static [u8] {