improve elf loader

anubis-rs · Feb 22, 2024 · e63feba · e63feba
1 parent f829996
commit e63feba
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Showing 3 changed files with 23 additions and 5 deletions.
diff --git a/xernel/kernel/src/main.rs b/xernel/kernel/src/main.rs
@@ -32,6 +32,7 @@ use alloc::string::ToString;
 use alloc::sync::Arc;
 use alloc::vec;
 use alloc::vec::Vec;
+use x86_64::VirtAddr;
 use core::arch::asm;
 use core::panic::PanicInfo;
 use libxernel::sync::Spinlock;
@@ -154,6 +155,13 @@ extern "C" fn kernel_main() -> ! {
     scheduler::init();
 
     let process = Arc::new(Spinlock::new(Process::new(Some(KERNEL_PROCESS.clone()))));
+    dbg!("before pt load");
+    unsafe {
+        process.lock().page_table.as_ref().unwrap().load_pt();
+        dbg!("ffffffff80016140 => {:x}", KERNEL_PAGE_MAPPER.lock().translate(VirtAddr::new(0xffffffff80016140)).unwrap().as_u64());
+        dbg!("ffffffff80016140 => {:x}", process.lock().page_table.as_ref().unwrap().translate(VirtAddr::new(0xffffffff80016140)).unwrap().as_u64());
+    }
+    dbg!("after pt load");
 
     let test_elf = include_bytes!("../test-elfloader");
     let user_task = Thread::new_user_thread_from_elf(process.clone(), test_elf);

diff --git a/xernel/kernel/src/mem/paging.rs b/xernel/kernel/src/mem/paging.rs
@@ -166,7 +166,6 @@ impl Pagemap {
                 self.flush(virt.start_address());
             }
         }
-        dbg!("end map");
     }
 
     pub fn flush(&self, addr: VirtAddr) {
@@ -296,7 +295,7 @@ impl Pagemap {
     }
 
     unsafe fn get_pt(pt: *mut PageTable, pt_index: PageTableIndex) -> *mut PageTable {
-        (*pt)[pt_index].addr().as_u64() as *mut PageTable
+        ((*pt)[pt_index].addr().as_u64() + *HIGHER_HALF_OFFSET) as *mut PageTable
     }
 
     /// Only works with 4KiB pages

diff --git a/xernel/kernel/src/sched/thread.rs b/xernel/kernel/src/sched/thread.rs
@@ -3,6 +3,7 @@ use elf::abi::{ET_EXEC, PT_LOAD};
 use elf::endian::LittleEndian;
 use elf::ElfBytes;
 use libxernel::sync::Spinlock;
+use x86_64::registers::control::Cr3;
 use x86_64::structures::paging::{Page, PageSize, PageTableFlags, PhysFrame, Size4KiB};
 
 use crate::allocator::align_up;
@@ -202,7 +203,7 @@ impl Thread {
 
         for segment in segments {
             if segment.p_type == PT_LOAD {
-                dbg!("{:#x?}", segment);
+                dbg!("{:x?}", segment);
                 let file_size = segment.p_filesz as usize;
                 let mem_size = segment.p_memsz as usize;
                 let vaddr = segment.p_vaddr as usize;
@@ -220,7 +221,11 @@ impl Thread {
                     let process = self.get_process().unwrap();
                     let process = process.lock();
 
-                    dbg!("before mapping");
+                    // we need to use the page table of the process to copy the content of the segment into the memory
+                    assert!(
+                        process.get_page_table().unwrap().pml4().as_u64() == Cr3::read().0.start_address().as_u64()
+                    );
+
                     process.get_page_table().unwrap().map(
                         frame,
                         page,
@@ -230,13 +235,19 @@ impl Thread {
                             | PageTableFlags::WRITABLE, // TODO: make this depend on the elf flags, currently we need it to write the content of the segment ==> make it read-only after writing
                         true,
                     );
-                    dbg!("after mapping");
 
                     unsafe {
                         write_bytes(page.start_address().as_mut_ptr::<u8>(), 0, Size4KiB::SIZE as usize);
                     }
                 }
 
+                dbg!(
+                    "{:x} - {:x}; executable: {}",
+                    vaddr,
+                    vaddr + file_size,
+                    segment.p_flags & 1 == 1
+                );
+
                 unsafe {
                     core::ptr::copy_nonoverlapping(
                         elf_data.as_ptr().add(segment.p_offset as usize),