Remove linuxkernel targets

These are not used by the actual Rust-for-Linux project, so they're mostly just confusing.

compiler/rustc_target/src/spec/linux_kernel_base.rs

@@ -1,18 +0,0 @@
-use crate::spec::TargetOptions;
-use crate::spec::{FramePointer, PanicStrategy, RelocModel, RelroLevel, StackProbeType};
-
-pub fn opts() -> TargetOptions {
-    TargetOptions {
-        env: "gnu".into(),
-        disable_redzone: true,
-        panic_strategy: PanicStrategy::Abort,
-        stack_probes: StackProbeType::X86,
-        frame_pointer: FramePointer::Always,
-        position_independent_executables: true,
-        needs_plt: true,
-        relro_level: RelroLevel::Full,
-        relocation_model: RelocModel::Static,
-
-        ..Default::default()
-    }
-}

compiler/rustc_target/src/spec/mod.rs

@@ -71,7 +71,6 @@ mod illumos_base;
 mod l4re_base;
 mod linux_base;
 mod linux_gnu_base;
-mod linux_kernel_base;
 mod linux_musl_base;
 mod linux_uclibc_base;
 mod msvc_base;
@@ -1003,7 +1002,7 @@ macro_rules! supported_targets {
             $(
                 #[test] // `#[test]`
                 fn $module() {
-                    tests_impl::test_target(super::$module::target(), $triple);
+                    tests_impl::test_target(super::$module::target());
                 }
             )+
         }
@@ -1071,8 +1070,6 @@ supported_targets! {
     ("thumbv7neon-linux-androideabi", thumbv7neon_linux_androideabi),
     ("aarch64-linux-android", aarch64_linux_android),
 
-    ("x86_64-unknown-none-linuxkernel", x86_64_unknown_none_linuxkernel),
-
     ("aarch64-unknown-freebsd", aarch64_unknown_freebsd),
     ("armv6-unknown-freebsd", armv6_unknown_freebsd),
     ("armv7-unknown-freebsd", armv7_unknown_freebsd),

compiler/rustc_target/src/spec/tests/tests_impl.rs

@@ -2,15 +2,15 @@ use super::super::*;
 use std::assert_matches::assert_matches;
 
 // Test target self-consistency and JSON encoding/decoding roundtrip.
-pub(super) fn test_target(mut target: Target, triple: &str) {
+pub(super) fn test_target(mut target: Target) {
     let recycled_target = Target::from_json(target.to_json()).map(|(j, _)| j);
     target.update_to_cli();
-    target.check_consistency(triple);
+    target.check_consistency();
     assert_eq!(recycled_target, Ok(target));
 }
 
 impl Target {
-    fn check_consistency(&self, triple: &str) {
+    fn check_consistency(&self) {
         assert_eq!(self.is_like_osx, self.vendor == "apple");
         assert_eq!(self.is_like_solaris, self.os == "solaris" || self.os == "illumos");
         assert_eq!(self.is_like_windows, self.os == "windows" || self.os == "uefi");
@@ -129,8 +129,7 @@ impl Target {
         if self.dynamic_linking && !(self.is_like_wasm && self.os != "emscripten") {
             assert_eq!(self.relocation_model, RelocModel::Pic);
         }
-        // PIEs are supported but not enabled by default with linuxkernel target.
-        if self.position_independent_executables && !triple.ends_with("-linuxkernel") {
+        if self.position_independent_executables {
             assert_eq!(self.relocation_model, RelocModel::Pic);
         }
         // The UEFI targets do not support dynamic linking but still require PIC (#101377).

compiler/rustc_target/src/spec/x86_64_unknown_none_linuxkernel.rs

@@ -1,28 +0,0 @@
-// This defines the amd64 target for the Linux Kernel. See the linux-kernel-base module for
-// generic Linux kernel options.
-
-use crate::spec::{Cc, CodeModel, LinkerFlavor, Lld, Target};
-
-pub fn target() -> Target {
-    let mut base = super::linux_kernel_base::opts();
-    base.cpu = "x86-64".into();
-    base.max_atomic_width = Some(64);
-    base.features =
-        "-mmx,-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-3dnow,-3dnowa,-avx,-avx2,+soft-float".into();
-    base.code_model = Some(CodeModel::Kernel);
-    base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m64"]);
-
-    Target {
-        // FIXME: Some dispute, the linux-on-clang folks think this should use
-        // "Linux". We disagree because running *on* Linux is nothing like
-        // running *as" linux, and historically the "os" component as has always
-        // been used to mean the "on" part.
-        llvm_target: "x86_64-unknown-none-elf".into(),
-        pointer_width: 64,
-        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
-            .into(),
-        arch: "x86_64".into(),
-
-        options: base,
-    }
-}

library/unwind/src/lib.rs

@@ -15,7 +15,6 @@ cfg_if::cfg_if! {
         target_os = "espidf",
     ))] {
         // These "unix" family members do not have unwinder.
-        // Note this also matches x86_64-unknown-none-linuxkernel.
     } else if #[cfg(any(
         unix,
         windows,

src/doc/rustc/src/platform-support.md

@@ -309,7 +309,6 @@ target | std | host | notes
 `x86_64-unknown-haiku` | ✓ | ✓ | 64-bit Haiku
 `x86_64-unknown-hermit` | ✓ |  | HermitCore
 `x86_64-unknown-l4re-uclibc` | ? |  |
-`x86_64-unknown-none-linuxkernel` | * |  | Linux kernel modules
 [`x86_64-unknown-openbsd`](platform-support/openbsd.md) | ✓ | ✓ | 64-bit OpenBSD
 [`x86_64-unknown-uefi`](platform-support/unknown-uefi.md) | * |  | 64-bit UEFI
 `x86_64-uwp-windows-gnu` | ✓ |  |