Remove the shim kernel crate

kernel/src/syscall/arch_prctl.rs

@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use ostd::cpu::UserContext;
+
+use super::SyscallReturn;
+use crate::{cpu::LinuxAbi, prelude::*};
+
+#[allow(non_camel_case_types)]
+#[repr(u64)]
+#[derive(Debug, TryFromInt)]
+pub enum ArchPrctlCode {
+    ARCH_SET_GS = 0x1001,
+    ARCH_SET_FS = 0x1002,
+    ARCH_GET_FS = 0x1003,
+    ARCH_GET_GS = 0x1004,
+}
+
+pub fn sys_arch_prctl(
+    code: u64,
+    addr: u64,
+    _ctx: &Context,
+    user_ctx: &mut UserContext,
+) -> Result<SyscallReturn> {
+    let arch_prctl_code = ArchPrctlCode::try_from(code)?;
+    debug!(
+        "arch_prctl_code: {:?}, addr = 0x{:x}",
+        arch_prctl_code, addr
+    );
+    let res = do_arch_prctl(arch_prctl_code, addr, user_ctx).unwrap();
+    Ok(SyscallReturn::Return(res as _))
+}
+
+pub fn do_arch_prctl(code: ArchPrctlCode, addr: u64, ctx: &mut UserContext) -> Result<u64> {
+    match code {
+        ArchPrctlCode::ARCH_SET_FS => {
+            ctx.set_tls_pointer(addr as usize);
+            Ok(0)
+        }
+        ArchPrctlCode::ARCH_GET_FS => Ok(ctx.tls_pointer() as u64),
+        ArchPrctlCode::ARCH_GET_GS | ArchPrctlCode::ARCH_SET_GS => {
+            return_errno_with_message!(Errno::EINVAL, "GS cannot be accessed from the user space")
+        }
+    }
+}