Set relocation-model=static

linkers/x86_64.ld

 ENTRY(kstart)
 OUTPUT_FORMAT(elf64-x86-64)
 
-KERNEL_OFFSET = 0xFFFFFF0000000000;
+KERNEL_OFFSET = 0xFFFFFFFF80000000;
 
 SECTIONS {
     . = KERNEL_OFFSET;

src/arch/x86_64/consts.rs

-// Because the memory map is so important to not be aliased, it is defined here, in one place
-// The lower 256 PML4 entries are reserved for userspace
-// Each PML4 entry references up to 512 GB of memory
-// The second from the top (510) PML4 is reserved for the kernel
-    /// The size of a single PML4
-    pub const PML4_SIZE: usize = 0x0000_0080_0000_0000;
-    pub const PML4_MASK: usize = 0x0000_ff80_0000_0000;
+// Because the memory map is so important to not be aliased, it is defined here, in one place.
+//
+// - The lower half (256 PML4 entries; 128 TiB) is reserved for userspace. These mappings are
+//   associated with _address spaces_, and change when context switching, unless the address spaces
+//   match.
+// - The upper half is reserved for the kernel. Kernel mappings are preserved across context
+//   switches.
+//
+// Each PML4 entry references 512 GiB of virtual memory.
 
-    /// Offset of recursive paging (deprecated, but still reserved)
-    pub const RECURSIVE_PAGE_OFFSET: usize = (-(PML4_SIZE as isize)) as usize;
-    pub const RECURSIVE_PAGE_PML4: usize = (RECURSIVE_PAGE_OFFSET & PML4_MASK)/PML4_SIZE;
+/// The size of a single PML4
+pub const PML4_SIZE: usize = 0x0000_0080_0000_0000;
+pub const PML4_MASK: usize = 0x0000_ff80_0000_0000;
 
-    /// Offset of kernel
-    pub const KERNEL_OFFSET: usize = RECURSIVE_PAGE_OFFSET - PML4_SIZE;
-    pub const KERNEL_PML4: usize = (KERNEL_OFFSET & PML4_MASK)/PML4_SIZE;
+/// Offset of kernel
+pub const KERNEL_MAX_SIZE: usize = 1_usize << 31;
+pub const KERNEL_OFFSET: usize = KERNEL_MAX_SIZE.wrapping_neg();
+pub const KERNEL_PML4: usize = (KERNEL_OFFSET & PML4_MASK)/PML4_SIZE;
 
-    /// Offset to kernel heap
-    pub const KERNEL_HEAP_OFFSET: usize = KERNEL_OFFSET - PML4_SIZE;
-    pub const KERNEL_HEAP_PML4: usize = (KERNEL_HEAP_OFFSET & PML4_MASK)/PML4_SIZE;
-    /// Size of kernel heap
-    pub const KERNEL_HEAP_SIZE: usize = 1 * 1024 * 1024; // 1 MB
+/// Offset to kernel heap
+pub const KERNEL_HEAP_OFFSET: usize = KERNEL_OFFSET - PML4_SIZE;
+pub const KERNEL_HEAP_PML4: usize = (KERNEL_HEAP_OFFSET & PML4_MASK)/PML4_SIZE;
+/// Size of kernel heap
+pub const KERNEL_HEAP_SIZE: usize = 1 * 1024 * 1024; // 1 MB
 
-    /// Offset of physmap
-    // This needs to match RMM's PHYS_OFFSET
-    pub const PHYS_OFFSET: usize = 0xFFFF_8000_0000_0000;
-    pub const PHYS_PML4: usize = (PHYS_OFFSET & PML4_MASK)/PML4_SIZE;
+/// Offset of physmap
+// This needs to match RMM's PHYS_OFFSET
+pub const PHYS_OFFSET: usize = 0xFFFF_8000_0000_0000;
+pub const PHYS_PML4: usize = (PHYS_OFFSET & PML4_MASK)/PML4_SIZE;
 
-    /// Offset to user image
-    pub const USER_OFFSET: usize = 0;
+/// Offset to user image
+pub const USER_OFFSET: usize = 0;
 
-    /// End offset of the user image, i.e. kernel start
-    pub const USER_END_OFFSET: usize = 256 * PML4_SIZE;
+/// End offset of the user image, i.e. kernel start
+pub const USER_END_OFFSET: usize = 256 * PML4_SIZE;

src/context/switch.rs

@@ -8,7 +8,6 @@ use spin::{RwLock, RwLockWriteGuard};
 
 use crate::context::signal::signal_handler;
 use crate::context::{arch, contexts, Context};
-use crate::gdt;
 use crate::interrupt;
 use crate::percpu::PercpuBlock;
 use crate::ptrace;
@@ -187,7 +186,7 @@ pub unsafe fn switch() -> bool {
         #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
         {
             if let Some(ref stack) = next_context.kstack {
-                gdt::set_tss_stack(stack.as_ptr() as usize + stack.len());
+                crate::gdt::set_tss_stack(stack.as_ptr() as usize + stack.len());
             }
         }
         let percpu = PercpuBlock::current();

targets/x86_64-unknown-kernel.json

@@ -16,7 +16,7 @@
     "features": "-mmx,-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-3dnow,-3dnowa,-avx,-avx2,+soft-float",
     "dynamic-linking": false,
     "executables": false,
-    "relocation-model": "pic",
+    "relocation-model": "static",
     "code-model": "kernel",
     "disable-redzone": true,
     "frame-pointer": "always",