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Integrate compiler_builtins
This simplifies onboarding, it is smaller, faster to compile and it is one less dependency to worry about. It also simplifies the build system a tiny bit since now everything uses the 2018 edition. Fixes #69. Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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+135
-27
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6 files changed

+135
-27
lines changed

‎.github/workflows/ci.yaml

-3
Original file line numberDiff line numberDiff line change
@@ -131,9 +131,6 @@ jobs:
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git checkout $(rustc -vV | grep -F 'commit-hash' | awk '{print $2}')
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git submodule update --init library
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# Setup: compiler-builtins source
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- run: git clone --depth 1 -b 0.1.39 https://github.com/rust-lang/compiler-builtins.git $(rustc ${{ env.RUSTC_SYSROOT }} --print sysroot)/lib/rustlib/src/compiler-builtins
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# Setup: bindgen
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- run: cargo install --version 0.56.0 bindgen
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‎Documentation/rust/quick-start.rst

-12
Original file line numberDiff line numberDiff line change
@@ -49,18 +49,6 @@ repository into the installation folder of your nightly toolchain::
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git clone --recurse-submodules https://github.com/rust-lang/rust $(rustc --print sysroot)/lib/rustlib/src/rust
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compiler-builtins source
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************************
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The source for ``compiler-builtins`` (a Rust port of LLVM's ``compiler-rt``)
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is required.
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The build system expects the sources alongside the Rust ones we just installed,
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so you can clone it into the installation folder of your nightly toolchain::
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git clone https://github.com/rust-lang/compiler-builtins $(rustc --print sysroot)/lib/rustlib/src/compiler-builtins
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bindgen
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*******
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‎Makefile

+2-2
Original file line numberDiff line numberDiff line change
@@ -502,10 +502,10 @@ KBUILD_CFLAGS := -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs \
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-Werror=return-type -Wno-format-security \
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-std=gnu89
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KBUILD_CPPFLAGS := -D__KERNEL__
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KBUILD_RUSTCFLAGS := --emit=dep-info,obj,metadata -Zbinary_dep_depinfo=y \
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KBUILD_RUSTCFLAGS := --emit=dep-info,obj,metadata --edition=2018 \
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-Cpanic=abort -Cembed-bitcode=n -Clto=n -Crpath=n \
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-Cforce-unwind-tables=n -Ccodegen-units=1 \
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-Zsymbol-mangling-version=v0
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-Zbinary_dep_depinfo=y -Zsymbol-mangling-version=v0
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KBUILD_AFLAGS_KERNEL :=
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KBUILD_CFLAGS_KERNEL :=
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KBUILD_RUSTCFLAGS_KERNEL :=

‎rust/Makefile

+4-9
Original file line numberDiff line numberDiff line change
@@ -64,7 +64,7 @@ $(objtree)/rust/exports_kernel_generated.h: $(objtree)/rust/kernel.o FORCE
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quiet_cmd_rustc_procmacro = RUSTC P $@
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cmd_rustc_procmacro = \
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$(RUSTC) $(rustc_flags) --emit=dep-info,link --edition 2018 --extern proc_macro \
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$(RUSTC) $(rustc_flags) --emit=dep-info,link --extern proc_macro \
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--crate-type proc-macro --out-dir $(objtree)/rust/ \
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--crate-name $(patsubst lib%.so,%,$(notdir $@)) $<; \
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mv $(objtree)/rust/$(patsubst lib%.so,%,$(notdir $@)).d $(depfile); \
@@ -86,27 +86,22 @@ quiet_cmd_rustc_library = RUSTC L $@
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# `$(rustc_flags)` is passed in case the user added `--sysroot`.
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rustc_sysroot = $(shell $(RUSTC) $(rustc_flags) --print sysroot)
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rustc_src = $(rustc_sysroot)/lib/rustlib/src/rust
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compiler_builtins_src = $(rustc_sysroot)/lib/rustlib/src/compiler-builtins
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.SECONDEXPANSION:
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$(objtree)/rust/core.o: rustc_target_flags = --edition 2018
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$(objtree)/rust/core.o: $$(rustc_src)/library/core/src/lib.rs FORCE
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$(call if_changed_dep,rustc_library)
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$(objtree)/rust/compiler_builtins.o: rustc_objcopy = -w -W '__*' -W '!__rust*'
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$(objtree)/rust/compiler_builtins.o: rustc_target_flags = --edition 2015 \
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--cfg 'feature="compiler-builtins"' --cfg 'feature="default"'
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$(objtree)/rust/compiler_builtins.o: $$(compiler_builtins_src)/src/lib.rs \
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$(objtree)/rust/compiler_builtins.o: rustc_objcopy = -w -W '__*'
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$(objtree)/rust/compiler_builtins.o: $(srctree)/rust/compiler_builtins.rs \
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$(objtree)/rust/core.o FORCE
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$(call if_changed_dep,rustc_library)
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$(objtree)/rust/alloc.o: rustc_target_flags = --edition 2018
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$(objtree)/rust/alloc.o: $$(rustc_src)/library/alloc/src/lib.rs \
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$(objtree)/rust/compiler_builtins.o FORCE
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$(call if_changed_dep,rustc_library)
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# ICE on `--extern module`: https://github.com/rust-lang/rust/issues/56935
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$(objtree)/rust/kernel.o: rustc_target_flags = --edition 2018 --extern alloc \
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$(objtree)/rust/kernel.o: rustc_target_flags = --extern alloc \
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--extern module=$(objtree)/rust/libmodule.so
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$(objtree)/rust/kernel.o: $(srctree)/rust/kernel/lib.rs $(objtree)/rust/alloc.o \
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$(objtree)/rust/libmodule.so $(objtree)/rust/bindings_generated.rs FORCE

‎rust/compiler_builtins.rs

+128
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@@ -0,0 +1,128 @@
1+
// SPDX-License-Identifier: GPL-2.0
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//! Our `compiler_builtins`.
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//!
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//! Rust provides `compiler_builtins` as a port of LLVM's `compiler-rt`.
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//! Since we don't need the vast majority of them, we avoid the dependency
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//! by providing this file.
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//!
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//! At the moment, some builtins are required that shouldn't be. For instance,
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//! `core` has floating-point functionality which we shouldn't be compiling in.
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//! For the moment, we define them to `panic!` at runtime for simplicity.
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//! These are actually a superset of the ones we actually need to define,
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//! but it seems simpler to ban entire categories at once. In the future,
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//! we might be able to remove all this by providing our own custom `core` etc.,
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//! or perhaps `core` itself might provide `cfg` options to disable enough
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//! functionality to avoid requiring some of these.
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//!
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//! In any case, all these symbols are weakened to ensure we don't override
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//! those that may be provided by the rest of the kernel.
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#![feature(compiler_builtins)]
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#![compiler_builtins]
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#![no_builtins]
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#![no_std]
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macro_rules! define_panicking_intrinsics(
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($reason: tt, { $($ident: ident, )* }) => {
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$(
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#[no_mangle]
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pub extern "C" fn $ident() {
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panic!($reason);
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}
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)*
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}
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);
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define_panicking_intrinsics!("non-inline stack probes should not be used", {
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__rust_probestack,
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});
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define_panicking_intrinsics!("`f32` should not be used", {
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__addsf3,
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__addsf3vfp,
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__divsf3,
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__divsf3vfp,
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__eqsf2,
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__eqsf2vfp,
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__fixsfdi,
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__fixsfsi,
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__fixsfti,
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__fixunssfdi,
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__fixunssfsi,
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__fixunssfti,
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__floatdisf,
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__floatsisf,
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__floattisf,
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__floatundisf,
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__floatunsisf,
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__floatuntisf,
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__gesf2,
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__gesf2vfp,
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__gtsf2,
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__gtsf2vfp,
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__lesf2,
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__lesf2vfp,
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__ltsf2,
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__ltsf2vfp,
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__mulsf3,
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__mulsf3vfp,
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__nesf2,
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__nesf2vfp,
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__powisf2,
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__subsf3,
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__subsf3vfp,
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__unordsf2,
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});
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define_panicking_intrinsics!("`f64` should not be used", {
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__adddf3,
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__adddf3vfp,
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__divdf3,
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__divdf3vfp,
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__eqdf2,
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__eqdf2vfp,
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__fixdfdi,
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__fixdfsi,
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__fixdfti,
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__fixunsdfdi,
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__fixunsdfsi,
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__fixunsdfti,
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__floatdidf,
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__floatsidf,
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__floattidf,
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__floatundidf,
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__floatunsidf,
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__floatuntidf,
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__gedf2,
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__gedf2vfp,
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__gtdf2,
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__gtdf2vfp,
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__ledf2,
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__ledf2vfp,
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__ltdf2,
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__ltdf2vfp,
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__muldf3,
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__muldf3vfp,
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__nedf2,
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__nedf2vfp,
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__powidf2,
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__subdf3,
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__subdf3vfp,
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__unorddf2,
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});
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define_panicking_intrinsics!("`i128` should not be used", {
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__ashrti3,
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__muloti4,
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__multi3,
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});
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122+
define_panicking_intrinsics!("`u128` should not be used", {
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__ashlti3,
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__lshrti3,
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__udivmodti4,
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__udivti3,
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__umodti3,
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});

‎scripts/Makefile.build

+1-1
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@@ -304,7 +304,7 @@ rustc_cross_flags := --target=$(srctree)/arch/$(SRCARCH)/rust/target.json
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quiet_cmd_rustc_o_rs = RUSTC $(quiet_modtag) $@
305305
cmd_rustc_o_rs = \
306306
RUST_MODFILE=$(modfile) \
307-
$(RUSTC) $(rustc_flags) $(rustc_cross_flags) --edition 2018 \
307+
$(RUSTC) $(rustc_flags) $(rustc_cross_flags) \
308308
--extern alloc --extern kernel \
309309
--crate-type rlib --out-dir $(obj) -L $(objtree)/rust/ \
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--crate-name $(patsubst %.o,%,$(notdir $@)) $<; \

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