Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3DCCBC4332F for ; Tue, 7 Dec 2021 22:45:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242297AbhLGWsw (ORCPT ); Tue, 7 Dec 2021 17:48:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51458 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237927AbhLGWst (ORCPT ); Tue, 7 Dec 2021 17:48:49 -0500 Received: from mail-lj1-x22f.google.com (mail-lj1-x22f.google.com [IPv6:2a00:1450:4864:20::22f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 50F17C061746 for ; Tue, 7 Dec 2021 14:45:18 -0800 (PST) Received: by mail-lj1-x22f.google.com with SMTP id e11so792838ljo.13 for ; Tue, 07 Dec 2021 14:45:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=FfinXtX3pmHa/EUUC93k09Uk+YA+ByZT/QN2YQh9LnM=; b=SX0898V2BkLrf2j5XUD1me/vuYO6CEp1PtmpC/3pxyZZCA8eTR1ACIhiHcmQpcQ/kn A0aacoNS1mXyUX3+jxmT1ZHOSVcFQk/uk2UUEIuGU4GwNyq9Nb0ix8rK9Z8saVWzwxt+ 1bkK9QFxr7TKVMAQyy6bbJl72f1A80MrgD2RFHknUDceGn/ihLZSfahKU9qkDR7ydLM9 tJ4Y8CUaYyj/cD6jlsrTjCEH4Az8S2I4qx93wbCI53on5SueyxV0wU56txOcziQMuy8b RrzUpYAgUtpyHXn85iSiWySQU2onqFDswQuOzgior1CCjyh9bFlA2kvg8n9JAC99v1FP GHUQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=FfinXtX3pmHa/EUUC93k09Uk+YA+ByZT/QN2YQh9LnM=; b=TmzBlijZ4zMv++wkF6xGI2Yc6SyOUt+NgvGnknwPK1bxpgrMnGHI0SvZvwFDRvyyNZ 7cJcLimxOzLxG/eU9vMwOJpUROQMc2b7anHsBRsFiU5Gb6S7ynD1/hHpaAgT5T5X0kEf 1iPEkJvFVnqI8NvBlRurtGvFh4/s5mI6B2TvnkWpoR0x9FTY2o4kTQSt2PrtcE5Qnh54 b5GwD6SHhgjcsDqvoBBXW4xYNfjLHkp5skXMeO4hQxiOi7vxrhjoXCH6U0VoupDfV+Sk sKt1YNVOK3p4thqv2PKqfMjoQh4m246HfyLLRS9flUwMBoiSMo/uCALzQSO1Jr6nASUy bOuQ== X-Gm-Message-State: AOAM530FGX7uerNrVgrx9UqRYA/4RoTvPY08D7r/rKFNwi33OrvlMlIB jWwpZvr7jrAHHygImiD1pEKvZ78eZHKapKNk5skceA== X-Google-Smtp-Source: ABdhPJw/BIP/oWPstMBy7rbYPjebc0W77X1H8PNj6OtRLBN9a/B58hVNurQf+Lwi2uctgQemyeOhgGHLeSLRlAP4D8E= X-Received: by 2002:a05:651c:292:: with SMTP id b18mr46269530ljo.220.1638917115681; Tue, 07 Dec 2021 14:45:15 -0800 (PST) MIME-Version: 1.0 References: <20211206140313.5653-1-ojeda@kernel.org> <20211206140313.5653-16-ojeda@kernel.org> In-Reply-To: <20211206140313.5653-16-ojeda@kernel.org> From: Nick Desaulniers Date: Tue, 7 Dec 2021 14:45:03 -0800 Message-ID: Subject: Re: [PATCH 15/19] Kbuild: add Rust support To: Miguel Ojeda , Masahiro Yamada , linux-kbuild@vger.kernel.org Cc: Linus Torvalds , Greg Kroah-Hartman , rust-for-linux@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Alex Gaynor , Finn Behrens , Adam Bratschi-Kaye , Wedson Almeida Filho , Michael Ellerman , Sven Van Asbroeck , Gary Guo , Boris-Chengbiao Zhou , Boqun Feng , Douglas Su , Dariusz Sosnowski , Antonio Terceiro , Daniel Xu Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "(/.On Mon, Dec 6, 2021 at 6:07 AM Miguel Ojeda wrote: > ... snip ... Miguel and team, I'm happy to see progress here! Just some quick notes after a first pass. Testing this series applied on mainline, I see: $ make LLVM=1 -j72 defconfig $ grep RUST .config CONFIG_HAS_RUST=y CONFIG_RUSTC_VERSION=14000 # CONFIG_RUST is not set ... $ make LLVM=1 -j72 menuconfig # enable CONFIG_RUST $ make LLVM=1 ... CALL scripts/checksyscalls.sh error: @path is unstable - use -Z unstable-options to enable its use error: @path is unstable - use -Z unstable-options to enable its use $ rustc --version rustc 1.40.0 (73528e339 2019-12-16) Can we update some Kconfig checks to fix that? > --- a/Makefile > +++ b/Makefile > @@ -120,6 +120,13 @@ endif > > export KBUILD_CHECKSRC > > +# Enable "clippy" (a linter) as part of the Rust compilation. > +# > +# Use 'make CLIPPY=1' to enable it. > +ifeq ("$(origin CLIPPY)", "command line") > + KBUILD_CLIPPY := $(CLIPPY) > +endif > + KBUILD_CLIPPY isn't used until ... > # Use make M=dir or set the environment variable KBUILD_EXTMOD to specify the > # directory of external module to build. Setting M= takes precedence. > ifeq ("$(origin M)", "command line") > @@ -267,7 +274,7 @@ no-dot-config-targets := $(clean-targets) \ > cscope gtags TAGS tags help% %docs check% coccicheck \ > $(version_h) headers headers_% archheaders archscripts \ > %asm-generic kernelversion %src-pkg dt_binding_check \ > - outputmakefile > + outputmakefile rustfmt rustfmtcheck > # Installation targets should not require compiler. Unfortunately, vdso_install > # is an exception where build artifacts may be updated. This must be fixed. > no-compiler-targets := $(no-dot-config-targets) install dtbs_install \ > @@ -461,6 +468,12 @@ OBJDUMP = $(CROSS_COMPILE)objdump > READELF = $(CROSS_COMPILE)readelf > STRIP = $(CROSS_COMPILE)strip > endif > +RUSTC = rustc > +RUSTDOC = rustdoc > +RUSTFMT = rustfmt > +CLIPPY_DRIVER = clippy-driver > +BINDGEN = bindgen > +CARGO = cargo > PAHOLE = pahole > RESOLVE_BTFIDS = $(objtree)/tools/bpf/resolve_btfids/resolve_btfids > LEX = flex > @@ -486,9 +499,11 @@ CHECKFLAGS := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \ > -Wbitwise -Wno-return-void -Wno-unknown-attribute $(CF) > NOSTDINC_FLAGS := > CFLAGS_MODULE = > +RUSTFLAGS_MODULE = > AFLAGS_MODULE = > LDFLAGS_MODULE = > CFLAGS_KERNEL = > +RUSTFLAGS_KERNEL = > AFLAGS_KERNEL = > LDFLAGS_vmlinux = > > @@ -517,15 +532,46 @@ KBUILD_CFLAGS := -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs \ > -Werror=return-type -Wno-format-security \ > -std=gnu89 > KBUILD_CPPFLAGS := -D__KERNEL__ > +KBUILD_RUST_TARGET := $(srctree)/arch/$(SRCARCH)/rust/target.json > +KBUILD_RUSTFLAGS := --emit=dep-info,obj,metadata --edition=2021 \ > + -Cpanic=abort -Cembed-bitcode=n -Clto=n -Crpath=n \ > + -Cforce-unwind-tables=n -Ccodegen-units=1 \ > + -Zbinary_dep_depinfo=y -Zsymbol-mangling-version=v0 \ > + -Dunsafe_op_in_unsafe_fn -Drust_2018_idioms \ > + -Dunreachable_pub -Dnon_ascii_idents \ > + -Wmissing_docs \ > + -Drustdoc::missing_crate_level_docs \ > + -Dclippy::correctness -Dclippy::style -Dclippy::suspicious \ > + -Dclippy::complexity -Dclippy::perf -Dclippy::float_arithmetic \ > + -Dclippy::let_unit_value -Dclippy::mut_mut \ > + -Dclippy::needless_bitwise_bool -Dclippy::needless_continue \ > + -Wclippy::dbg_macro Consider putting clippy specific flags in their own variable, and/or just adding them to KBUILD_RUSTFLAGS only when clippy is actually being used. > KBUILD_AFLAGS_KERNEL := > KBUILD_CFLAGS_KERNEL := > +KBUILD_RUSTFLAGS_KERNEL := > KBUILD_AFLAGS_MODULE := -DMODULE > KBUILD_CFLAGS_MODULE := -DMODULE > +KBUILD_RUSTFLAGS_MODULE := --cfg MODULE > KBUILD_LDFLAGS_MODULE := > KBUILD_LDFLAGS := > CLANG_FLAGS := > > +ifeq ($(KBUILD_CLIPPY),1) > + RUSTC_OR_CLIPPY_QUIET := CLIPPY > + RUSTC_OR_CLIPPY = $(CLIPPY_DRIVER) > +else > + RUSTC_OR_CLIPPY_QUIET := RUSTC > + RUSTC_OR_CLIPPY = $(RUSTC) > +endif ... here. Should we sink the check for origin CLIPPY? Can we also match how we check for LLVM=1 rather than checking the variables origin? Especially since KBUILD_CLIPPY isn't exported, it seems it's not used outside of this file, IIUC? > + > +ifdef RUST_LIB_SRC > + export RUST_LIB_SRC > +endif > + > +export RUSTC_BOOTSTRAP := 1 Is this used in a different patch in the series? ^ > + > export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC > +export RUSTC RUSTDOC RUSTFMT RUSTC_OR_CLIPPY_QUIET RUSTC_OR_CLIPPY BINDGEN CARGO > export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL > export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX > export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD > @@ -533,9 +579,10 @@ export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE > > export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS > export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE > +export KBUILD_RUST_TARGET KBUILD_RUSTFLAGS RUSTFLAGS_KERNEL RUSTFLAGS_MODULE > export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE > -export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE > -export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL > +export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_RUSTFLAGS_MODULE KBUILD_LDFLAGS_MODULE > +export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL KBUILD_RUSTFLAGS_KERNEL > export PAHOLE_FLAGS > > # Files to ignore in find ... statements > @@ -727,7 +774,7 @@ $(KCONFIG_CONFIG): > # > # Do not use $(call cmd,...) here. That would suppress prompts from syncconfig, > # so you cannot notice that Kconfig is waiting for the user input. > -%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h: $(KCONFIG_CONFIG) > +%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h %/generated/rustc_cfg: $(KCONFIG_CONFIG) > $(Q)$(kecho) " SYNC $@" > $(Q)$(MAKE) -f $(srctree)/Makefile syncconfig > else # !may-sync-config > @@ -756,11 +803,27 @@ KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) > > ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE > KBUILD_CFLAGS += -O2 > +KBUILD_RUSTFLAGS_OPT_LEVEL_MAP := 2 > else ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3 > KBUILD_CFLAGS += -O3 > +KBUILD_RUSTFLAGS_OPT_LEVEL_MAP := 3 > else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE > KBUILD_CFLAGS += -Os > -endif > +KBUILD_RUSTFLAGS_OPT_LEVEL_MAP := z If z and s are distinct opt levels, then rustc should really be using s rather than z. IME, z has created larger images than s due to LLVM aggressively emitting libcalls, regardless of the cost of call setup. See also commit a75bb4eb9e56 ("Revert "kbuild: use -Oz instead of -Os when using clang") > +endif > + > +# Always set `debug-assertions` and `overflow-checks` because their default > +# depends on `opt-level` and `debug-assertions`, respectively. > +KBUILD_RUSTFLAGS += -Cdebug-assertions=$(if $(CONFIG_RUST_DEBUG_ASSERTIONS),y,n) > +KBUILD_RUSTFLAGS += -Coverflow-checks=$(if $(CONFIG_RUST_OVERFLOW_CHECKS),y,n) > +KBUILD_RUSTFLAGS += -Copt-level=$\ > + $(if $(CONFIG_RUST_OPT_LEVEL_SIMILAR_AS_CHOSEN_FOR_C),$(KBUILD_RUSTFLAGS_OPT_LEVEL_MAP))$\ > + $(if $(CONFIG_RUST_OPT_LEVEL_0),0)$\ > + $(if $(CONFIG_RUST_OPT_LEVEL_1),1)$\ > + $(if $(CONFIG_RUST_OPT_LEVEL_2),2)$\ > + $(if $(CONFIG_RUST_OPT_LEVEL_3),3)$\ > + $(if $(CONFIG_RUST_OPT_LEVEL_S),s)$\ > + $(if $(CONFIG_RUST_OPT_LEVEL_Z),z) I'm still not a fan of this separate configurability for optimization level differing from C. > > # Tell gcc to never replace conditional load with a non-conditional one > ifdef CONFIG_CC_IS_GCC > @@ -791,6 +854,9 @@ KBUILD_CFLAGS += $(stackp-flags-y) > KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror > KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH) > > +KBUILD_RUSTFLAGS-$(CONFIG_WERROR) += -Dwarnings > +KBUILD_RUSTFLAGS += $(KBUILD_RUSTFLAGS-y) > + > ifdef CONFIG_CC_IS_CLANG > KBUILD_CPPFLAGS += -Qunused-arguments > # The kernel builds with '-std=gnu89' so use of GNU extensions is acceptable. > @@ -812,6 +878,7 @@ KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable) > > ifdef CONFIG_FRAME_POINTER > KBUILD_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls > +KBUILD_RUSTFLAGS += -Cforce-frame-pointers=y > else > # Some targets (ARM with Thumb2, for example), can't be built with frame > # pointers. For those, we don't have FUNCTION_TRACER automatically > @@ -1022,10 +1089,11 @@ include $(addprefix $(srctree)/, $(include-y)) > # Do not add $(call cc-option,...) below this line. When you build the kernel > # from the clean source tree, the GCC plugins do not exist at this point. > > -# Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments > +# Add user supplied CPPFLAGS, AFLAGS, CFLAGS and RUSTFLAGS as the last assignments > KBUILD_CPPFLAGS += $(KCPPFLAGS) > KBUILD_AFLAGS += $(KAFLAGS) > KBUILD_CFLAGS += $(KCFLAGS) > +KBUILD_RUSTFLAGS += $(KRUSTFLAGS) > > KBUILD_LDFLAGS_MODULE += --build-id=sha1 > LDFLAGS_vmlinux += --build-id=sha1 > @@ -1095,6 +1163,11 @@ ifeq ($(KBUILD_EXTMOD),) > core-y += kernel/ certs/ mm/ fs/ ipc/ security/ crypto/ > core-$(CONFIG_BLOCK) += block/ > > +# Keep this one as an `ifdef` block since its `Makefile` runs `rustc`. > +ifdef CONFIG_RUST > +core-y += rust/ > +endif > + > vmlinux-dirs := $(patsubst %/,%,$(filter %/, \ > $(core-y) $(core-m) $(drivers-y) $(drivers-m) \ > $(libs-y) $(libs-m))) > @@ -1195,6 +1268,9 @@ archprepare: outputmakefile archheaders archscripts scripts include/config/kerne > prepare0: archprepare > $(Q)$(MAKE) $(build)=scripts/mod > $(Q)$(MAKE) $(build)=. > +ifdef CONFIG_RUST > + $(Q)$(MAKE) $(build)=rust > +endif > > # All the preparing.. > prepare: prepare0 > @@ -1495,7 +1571,7 @@ endif # CONFIG_MODULES > # Directories & files removed with 'make clean' > CLEAN_FILES += include/ksym vmlinux.symvers modules-only.symvers \ > modules.builtin modules.builtin.modinfo modules.nsdeps \ > - compile_commands.json .thinlto-cache > + compile_commands.json .thinlto-cache rust/test rust/doc > > # Directories & files removed with 'make mrproper' > MRPROPER_FILES += include/config include/generated \ > @@ -1506,7 +1582,8 @@ MRPROPER_FILES += include/config include/generated \ > certs/signing_key.pem certs/signing_key.x509 \ > certs/x509.genkey \ > vmlinux-gdb.py \ > - *.spec > + *.spec \ > + rust/*_generated.h rust/*_generated.rs rust/libmacros.so > > # clean - Delete most, but leave enough to build external modules > # > @@ -1618,6 +1695,17 @@ help: > @echo ' kselftest-merge - Merge all the config dependencies of' > @echo ' kselftest to existing .config.' > @echo '' > + @echo 'Rust targets:' > + @echo ' rustfmt - Reformat all the Rust code in the kernel' > + @echo ' rustfmtcheck - Checks if all the Rust code in the kernel' > + @echo ' is formatted, printing a diff otherwise.' > + @echo ' rustdoc - Generate Rust documentation' > + @echo ' (requires kernel .config)' > + @echo ' rusttest - Runs the Rust tests' > + @echo ' (requires kernel .config; downloads external repos)' > + @echo ' rust-analyzer - Generate rust-project.json rust-analyzer support file' > + @echo ' (requires kernel .config)' > + @echo '' > @$(if $(dtstree), \ > echo 'Devicetree:'; \ > echo '* dtbs - Build device tree blobs for enabled boards'; \ > @@ -1689,6 +1777,47 @@ PHONY += $(DOC_TARGETS) > $(DOC_TARGETS): > $(Q)$(MAKE) $(build)=Documentation $@ > > + > +# Rust targets > +# --------------------------------------------------------------------------- > + > +# Documentation target > +# > +# Using the singular to avoid running afoul of `no-dot-config-targets`. > +PHONY += rustdoc > +rustdoc: prepare0 > + $(Q)$(MAKE) $(build)=rust $@ > + > +# Testing target > +PHONY += rusttest > +rusttest: prepare0 > + $(Q)$(MAKE) $(build)=rust $@ > + > +# Formatting targets > +PHONY += rustfmt rustfmtcheck > + > +# We skip `rust/alloc` since we want to minimize the diff w.r.t. upstream. > +# > +# We match using absolute paths since `find` does not resolve them > +# when matching, which is a problem when e.g. `srctree` is `..`. > +# We `grep` afterwards in order to remove the directory entry itself. > +rustfmt: > + $(Q)find $(abs_srctree) -type f -name '*.rs' \ > + -o -path $(abs_srctree)/rust/alloc -prune \ > + -o -path $(abs_objtree)/rust/test -prune \ > + | grep -Fv $(abs_srctree)/rust/alloc \ > + | grep -Fv $(abs_objtree)/rust/test \ > + | grep -Fv generated \ > + | xargs $(RUSTFMT) $(rustfmt_flags) > + > +rustfmtcheck: rustfmt_flags = --check > +rustfmtcheck: rustfmt > + > +# IDE support targets > +PHONY += rust-analyzer > +rust-analyzer: prepare0 > + $(Q)$(MAKE) $(build)=rust $@ > + > # Misc > # --------------------------------------------------------------------------- > > @@ -1856,6 +1985,7 @@ clean: $(clean-dirs) > $(call cmd,rmfiles) > @find $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \ > \( -name '*.[aios]' -o -name '*.ko' -o -name '.*.cmd' \ > + -o -name '*.rmeta' \ > -o -name '*.ko.*' \ > -o -name '*.dtb' -o -name '*.dtbo' -o -name '*.dtb.S' -o -name '*.dt.yaml' \ > -o -name '*.dwo' -o -name '*.lst' \ > diff --git a/arch/arm/rust/target.json b/arch/arm/rust/target.json > new file mode 100644 > index 000000000000..3f845b8221dc > --- /dev/null > +++ b/arch/arm/rust/target.json > @@ -0,0 +1,27 @@ > +{ > + "arch": "arm", > + "crt-static-respected": true, > + "data-layout": "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64", > + "dynamic-linking": true, > + "env": "gnu", > + "executables": true, > + "features": "+strict-align,+v6", > + "function-sections": false, > + "has-elf-tls": true, > + "has-rpath": true, > + "linker-is-gnu": true, > + "llvm-target": "arm-unknown-linux-gnueabi", > + "max-atomic-width": 64, > + "os": "linux", > + "position-independent-executables": true, > + "pre-link-args": { > + "gcc": [ > + "-Wl,--as-needed", > + "-Wl,-z,noexecstack" > + ] > + }, > + "relocation-model": "static", > + "target-family": "unix", > + "target-mcount": "\u0001__gnu_mcount_nc", > + "target-pointer-width": "32" > +} oh boy. I wonder which configs change the above values? ;) Can rustc still override these via command line flags? > diff --git a/arch/arm64/rust/target.json b/arch/arm64/rust/target.json > new file mode 100644 > index 000000000000..09a264df26c7 > --- /dev/null > +++ b/arch/arm64/rust/target.json > @@ -0,0 +1,34 @@ > +{ > + "arch": "aarch64", > + "data-layout": "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128", > + "disable-redzone": true, > + "emit-debug-gdb-scripts": false, > + "env": "gnu", > + "features": "+strict-align,+neon,+fp-armv8", > + "frame-pointer": "always", > + "function-sections": false, > + "linker-flavor": "gcc", > + "linker-is-gnu": true, > + "llvm-target": "aarch64-unknown-none", > + "max-atomic-width": 128, > + "needs-plt": true, > + "os": "none", > + "panic-strategy": "abort", > + "position-independent-executables": true, > + "pre-link-args": { > + "gcc": [ > + "-Wl,--as-needed", > + "-Wl,-z,noexecstack", > + "-m64" > + ] > + }, > + "relocation-model": "static", > + "relro-level": "full", > + "stack-probes": { > + "kind": "none" > + }, > + "target-c-int-width": "32", > + "target-endian": "little", > + "target-pointer-width": "64", > + "vendor": "" > +} > diff --git a/arch/powerpc/rust/target.json b/arch/powerpc/rust/target.json > new file mode 100644 > index 000000000000..2420c8e6a520 > --- /dev/null > +++ b/arch/powerpc/rust/target.json > @@ -0,0 +1,29 @@ > +{ > + "arch": "powerpc64", > + "code-model": "large", > + "cpu": "ppc64le", > + "data-layout": "e-m:e-i64:64-n32:64", > + "env": "gnu", > + "features": "-altivec,-vsx,-hard-float", > + "function-sections": false, > + "linker-flavor": "gcc", > + "linker-is-gnu": true, > + "llvm-target": "powerpc64le-elf", > + "max-atomic-width": 64, > + "os": "none", > + "panic-strategy": "abort", > + "position-independent-executables": true, > + "pre-link-args": { > + "gcc": [ > + "-Wl,--as-needed", > + "-Wl,-z,noexecstack", > + "-m64" > + ] > + }, > + "relocation-model": "static", > + "relro-level": "full", > + "target-family": "unix", > + "target-mcount": "_mcount", > + "target-endian": "little", > + "target-pointer-width": "64" > +} > diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile > index 8a107ed18b0d..0487db1e54c6 100644 > --- a/arch/riscv/Makefile > +++ b/arch/riscv/Makefile > @@ -52,6 +52,7 @@ riscv-march-$(CONFIG_FPU) := $(riscv-march-y)fd > riscv-march-$(CONFIG_RISCV_ISA_C) := $(riscv-march-y)c > KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y)) > KBUILD_AFLAGS += -march=$(riscv-march-y) > +KBUILD_RUST_TARGET := $(srctree)/arch/riscv/rust/$(subst fd,,$(riscv-march-y)).json > > KBUILD_CFLAGS += -mno-save-restore > KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET) > diff --git a/arch/riscv/rust/rv32ima.json b/arch/riscv/rust/rv32ima.json > new file mode 100644 > index 000000000000..bcdda88c1604 > --- /dev/null > +++ b/arch/riscv/rust/rv32ima.json > @@ -0,0 +1,36 @@ > +{ > + "arch": "riscv32", > + "code-model": "medium", > + "cpu": "generic-rv32", > + "data-layout": "e-m:e-p:32:32-i64:64-n32-S128", > + "disable-redzone": true, > + "emit-debug-gdb-scripts": false, > + "env": "gnu", > + "features": "+m,+a", > + "frame-pointer": "always", > + "function-sections": false, > + "linker-flavor": "gcc", > + "linker-is-gnu": true, > + "llvm-target": "riscv32", > + "max-atomic-width": 32, > + "needs-plt": true, > + "os": "none", > + "panic-strategy": "abort", > + "position-independent-executables": true, > + "pre-link-args": { > + "gcc": [ > + "-Wl,--as-needed", > + "-Wl,-z,noexecstack", > + "-m32" > + ] > + }, > + "relocation-model": "static", > + "relro-level": "full", > + "stack-probes": { > + "kind": "none" > + }, > + "target-c-int-width": "32", > + "target-endian": "little", > + "target-pointer-width": "32", > + "vendor": "" > +} > diff --git a/arch/riscv/rust/rv32imac.json b/arch/riscv/rust/rv32imac.json > new file mode 100644 > index 000000000000..45873c10a5c3 > --- /dev/null > +++ b/arch/riscv/rust/rv32imac.json > @@ -0,0 +1,36 @@ > +{ > + "arch": "riscv32", > + "code-model": "medium", > + "cpu": "generic-rv32", > + "data-layout": "e-m:e-p:32:32-i64:64-n32-S128", > + "disable-redzone": true, > + "emit-debug-gdb-scripts": false, > + "env": "gnu", > + "features": "+m,+a,+c", > + "frame-pointer": "always", > + "function-sections": false, > + "linker-flavor": "gcc", > + "linker-is-gnu": true, > + "llvm-target": "riscv32", > + "max-atomic-width": 32, > + "needs-plt": true, > + "os": "none", > + "panic-strategy": "abort", > + "position-independent-executables": true, > + "pre-link-args": { > + "gcc": [ > + "-Wl,--as-needed", > + "-Wl,-z,noexecstack", > + "-m32" > + ] > + }, > + "relocation-model": "static", > + "relro-level": "full", > + "stack-probes": { > + "kind": "none" > + }, > + "target-c-int-width": "32", > + "target-endian": "little", > + "target-pointer-width": "32", > + "vendor": "" > +} > diff --git a/arch/riscv/rust/rv64ima.json b/arch/riscv/rust/rv64ima.json > new file mode 100644 > index 000000000000..853d758c5461 > --- /dev/null > +++ b/arch/riscv/rust/rv64ima.json > @@ -0,0 +1,36 @@ > +{ > + "arch": "riscv64", > + "code-model": "medium", > + "cpu": "generic-rv64", > + "data-layout": "e-m:e-p:64:64-i64:64-i128:128-n64-S128", > + "disable-redzone": true, > + "emit-debug-gdb-scripts": false, > + "env": "gnu", > + "features": "+m,+a", > + "frame-pointer": "always", > + "function-sections": false, > + "linker-flavor": "gcc", > + "linker-is-gnu": true, > + "llvm-target": "riscv64", > + "max-atomic-width": 64, > + "needs-plt": true, > + "os": "none", > + "panic-strategy": "abort", > + "position-independent-executables": true, > + "pre-link-args": { > + "gcc": [ > + "-Wl,--as-needed", > + "-Wl,-z,noexecstack", > + "-m64" > + ] > + }, > + "relocation-model": "static", > + "relro-level": "full", > + "stack-probes": { > + "kind": "none" > + }, > + "target-c-int-width": "32", > + "target-endian": "little", > + "target-pointer-width": "64", > + "vendor": "" > +} > diff --git a/arch/riscv/rust/rv64imac.json b/arch/riscv/rust/rv64imac.json > new file mode 100644 > index 000000000000..ce50ee8e8c93 > --- /dev/null > +++ b/arch/riscv/rust/rv64imac.json > @@ -0,0 +1,36 @@ > +{ > + "arch": "riscv64", > + "code-model": "medium", > + "cpu": "generic-rv64", > + "data-layout": "e-m:e-p:64:64-i64:64-i128:128-n64-S128", > + "disable-redzone": true, > + "emit-debug-gdb-scripts": false, > + "env": "gnu", > + "features": "+m,+a,+c", > + "frame-pointer": "always", > + "function-sections": false, > + "linker-flavor": "gcc", > + "linker-is-gnu": true, > + "llvm-target": "riscv64", > + "max-atomic-width": 64, > + "needs-plt": true, > + "os": "none", > + "panic-strategy": "abort", > + "position-independent-executables": true, > + "pre-link-args": { > + "gcc": [ > + "-Wl,--as-needed", > + "-Wl,-z,noexecstack", > + "-m64" > + ] > + }, > + "relocation-model": "static", > + "relro-level": "full", > + "stack-probes": { > + "kind": "none" > + }, > + "target-c-int-width": "32", > + "target-endian": "little", > + "target-pointer-width": "64", > + "vendor": "" > +} > diff --git a/arch/x86/rust/target.json b/arch/x86/rust/target.json > new file mode 100644 > index 000000000000..379cf39e8941 > --- /dev/null > +++ b/arch/x86/rust/target.json > @@ -0,0 +1,36 @@ > +{ > + "arch": "x86_64", > + "code-model": "kernel", > + "cpu": "x86-64", > + "data-layout": "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128", > + "disable-redzone": true, > + "emit-debug-gdb-scripts": false, > + "env": "gnu", > + "features": "-mmx,-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-3dnow,-3dnowa,-avx,-avx2,+soft-float", > + "frame-pointer": "always", > + "function-sections": false, > + "linker-flavor": "gcc", > + "linker-is-gnu": true, > + "llvm-target": "x86_64-elf", > + "max-atomic-width": 64, > + "needs-plt": true, > + "os": "none", > + "panic-strategy": "abort", > + "position-independent-executables": true, > + "pre-link-args": { > + "gcc": [ > + "-Wl,--as-needed", > + "-Wl,-z,noexecstack", > + "-m64" > + ] > + }, > + "relocation-model": "static", > + "relro-level": "full", > + "stack-probes": { > + "kind": "none" > + }, > + "target-c-int-width": "32", > + "target-endian": "little", > + "target-pointer-width": "64", > + "vendor": "unknown" > +} > diff --git a/init/Kconfig b/init/Kconfig > index 4b7bac10c72d..03d3c21e28a3 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -60,6 +60,15 @@ config LLD_VERSION > default $(ld-version) if LD_IS_LLD > default 0 > > +config HAS_RUST > + depends on ARM64 || CPU_32v6 || CPU_32v6K || (PPC64 && CPU_LITTLE_ENDIAN) || X86_64 || RISCV > + def_bool $(success,$(RUSTC) --version) > + > +config RUSTC_VERSION > + depends on HAS_RUST > + int > + default $(shell,$(srctree)/scripts/rust-version.sh $(RUSTC)) > + > config CC_CAN_LINK > bool > default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m64-flag)) if 64BIT > @@ -142,7 +151,8 @@ config WERROR > default COMPILE_TEST > help > A kernel build should not cause any compiler warnings, and this > - enables the '-Werror' flag to enforce that rule by default. > + enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags > + to enforce that rule by default. > > However, if you have a new (or very old) compiler with odd and > unusual warnings, or you have some architecture with problems, > @@ -2044,6 +2054,25 @@ config PROFILING > Say Y here to enable the extended profiling support mechanisms used > by profilers. > > +config RUST > + bool "Rust support" > + depends on HAS_RUST > + depends on !COMPILE_TEST > + depends on !MODVERSIONS > + default n > + help > + Enables Rust support in the kernel. > + > + This allows other Rust-related options, like drivers written in Rust, > + to be selected. > + > + It is also required to be able to load external kernel modules > + written in Rust. > + > + See Documentation/rust/ for more information. > + > + If unsure, say N. > + > # > # Place an empty function call at each tracepoint site. Can be > # dynamically changed for a probe function. > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 5c12bde10996..361379695f18 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -2650,6 +2650,150 @@ config HYPERV_TESTING > > endmenu # "Kernel Testing and Coverage" > > +menu "Rust hacking" > + > +config RUST_DEBUG_ASSERTIONS > + bool "Debug assertions" > + default n > + depends on RUST > + help > + Enables rustc's `-Cdebug-assertions` codegen option. > + > + This flag lets you turn `cfg(debug_assertions)` conditional > + compilation on or off. This can be used to enable extra debugging > + code in development but not in production. For example, it controls > + the behavior of the standard library's `debug_assert!` macro. > + > + Note that this will apply to all Rust code, including `core`. > + > + If unsure, say N. > + > +config RUST_OVERFLOW_CHECKS > + bool "Overflow checks" > + default y So this is like turning on -fsanitize=signed-integer-overflow and -fsanitize=unsigned-integer-overflow by default? > + depends on RUST > + help > + Enables rustc's `-Coverflow-checks` codegen option. > + > + This flag allows you to control the behavior of runtime integer > + overflow. When overflow-checks are enabled, a panic will occur > + on overflow. A rust panic or a kernel panic? > + > + Note that this will apply to all Rust code, including `core`. > + > + If unsure, say Y. > + > +choice > + prompt "Optimization level" > + default RUST_OPT_LEVEL_SIMILAR_AS_CHOSEN_FOR_C > + depends on RUST > + help > + Controls rustc's `-Copt-level` codegen option. > + > + This flag controls the optimization level. > + > + If unsure, say "Similar as chosen for C". > + > +config RUST_OPT_LEVEL_SIMILAR_AS_CHOSEN_FOR_C > + bool "Similar as chosen for C" > + help > + This choice will pick a similar optimization level as chosen in > + the "Compiler optimization level" for C: > + > + -O2 is currently mapped to -Copt-level=2 > + -O3 is currently mapped to -Copt-level=3 > + -Os is currently mapped to -Copt-level=z > + > + The mapping may change over time to follow the intended semantics > + of the choice for C as sensibly as possible. > + > + This is the default. This should really be the only option here. I still don't see the point of allowing wacky combinations of configs where we differ from C code. The more combinations will just frustrate randconfig builds. > + > +config RUST_OPT_LEVEL_0 > + bool "No optimizations (-Copt-level=0)" > + help > + Not recommended for most purposes. It may come in handy for debugging > + suspected optimizer bugs, unexpected undefined behavior, etc. > + > + Note that this level will *not* enable debug assertions nor overflow > + checks on its own (like it happens when interacting with rustc > + directly). Use the corresponding configuration options to control > + that instead, orthogonally. > + > + Note this level may cause excessive stack usage, which can lead to stack > + overflow and subsequent crashes. > + > +config RUST_OPT_LEVEL_1 > + bool "Basic optimizations (-Copt-level=1)" > + help > + Useful for debugging without getting too lost, but without > + the overhead and boilerplate of no optimizations at all. > + > + Note this level may cause excessive stack usage, which can lead to stack > + overflow and subsequent crashes. > + > +config RUST_OPT_LEVEL_2 > + bool "Some optimizations (-Copt-level=2)" > + help > + The sensible choice in most cases. > + > +config RUST_OPT_LEVEL_3 > + bool "All optimizations (-Copt-level=3)" > + help > + Yet more performance (hopefully). > + > +config RUST_OPT_LEVEL_S > + bool "Optimize for size (-Copt-level=s)" > + help > + Smaller kernel, ideally without too much performance loss. > + > +config RUST_OPT_LEVEL_Z > + bool "Optimize for size, no loop vectorization (-Copt-level=z)" > + help > + Like the previous level, but also turn off loop vectorization. > + > +endchoice > + > +choice > + prompt "Build-time assertions" > + default RUST_BUILD_ASSERT_ALLOW if RUST_OPT_LEVEL_0 > + default RUST_BUILD_ASSERT_DENY if !RUST_OPT_LEVEL_0 > + depends on RUST > + help > + Controls how are `build_error!` and `build_assert!` handled during build. > + > + If calls to them exist in the binary, it may indicate a violated invariant > + or that the optimizer failed to verify the invariant during compilation. > + You can choose to abort compilation or ignore them during build and let the > + check be carried to runtime. > + > + If optimizations are turned off, you cannot select "Deny". > + > + If unsure, say "Deny". > + > +config RUST_BUILD_ASSERT_ALLOW > + bool "Allow" > + help > + Unoptimized calls to `build_error!` will be converted to `panic!` > + and checked at runtime. > + > +config RUST_BUILD_ASSERT_WARN > + bool "Warn" > + help > + Unoptimized calls to `build_error!` will be converted to `panic!` > + and checked at runtime, but warnings will be generated when building. > + > +config RUST_BUILD_ASSERT_DENY > + bool "Deny" > + depends on !RUST_OPT_LEVEL_0 > + help > + Unoptimized calls to `build_error!` will abort compilation. > + > +endchoice > + > + > +endmenu # "Rust" > + > source "Documentation/Kconfig" > > endmenu # Kernel hacking > diff --git a/rust/.gitignore b/rust/.gitignore > new file mode 100644 > index 000000000000..168cb26a31b9 > --- /dev/null > +++ b/rust/.gitignore > @@ -0,0 +1,7 @@ > +# SPDX-License-Identifier: GPL-2.0 > + > +bindings_generated.rs > +bindings_helpers_generated.rs > +exports_*_generated.h > +doc/ > +test/ > diff --git a/rust/Makefile b/rust/Makefile > new file mode 100644 > index 000000000000..2d08314e7031 > --- /dev/null > +++ b/rust/Makefile > @@ -0,0 +1,353 @@ > +# SPDX-License-Identifier: GPL-2.0 > + > +obj-$(CONFIG_RUST) += core.o compiler_builtins.o helpers.o > +extra-$(CONFIG_RUST) += exports_core_generated.h > + > +extra-$(CONFIG_RUST) += libmacros.so > + > +extra-$(CONFIG_RUST) += bindings_generated.rs bindings_helpers_generated.rs > +obj-$(CONFIG_RUST) += alloc.o kernel.o > +extra-$(CONFIG_RUST) += exports_alloc_generated.h exports_kernel_generated.h > + > +ifdef CONFIG_RUST_BUILD_ASSERT_DENY > +extra-$(CONFIG_RUST) += build_error.o > +else > +obj-$(CONFIG_RUST) += build_error.o > +endif > + > +obj-$(CONFIG_RUST) += exports.o > + > +ifeq ($(quiet),silent_) > +cargo_quiet=-q > +rust_test_quiet=-q > +rustdoc_test_quiet=--test-args -q > +else ifeq ($(quiet),quiet_) > +rust_test_quiet=-q > +rustdoc_test_quiet=--test-args -q > +else > +cargo_quiet=--verbose > +endif > + > +core-cfgs = \ > + --cfg no_fp_fmt_parse > + > +alloc-cfgs = \ > + --cfg no_global_oom_handling \ > + --cfg no_rc \ > + --cfg no_sync > + > +quiet_cmd_rustdoc = RUSTDOC $(if $(rustdoc_host),H, ) $< > + cmd_rustdoc = \ > + OBJTREE=$(abspath $(objtree)) \ > + $(RUSTDOC) $(if $(rustdoc_host),,$(rust_cross_flags)) \ > + $(filter-out -Cpanic=abort, $(filter-out --emit=%, $(rust_flags))) \ > + $(rustc_target_flags) -L $(objtree)/rust \ > + --output $(objtree)/rust/doc --crate-name $(subst rustdoc-,,$@) \ > + @$(objtree)/include/generated/rustc_cfg $< > + > +rustdoc: rustdoc-core rustdoc-macros rustdoc-compiler_builtins rustdoc-alloc rustdoc-kernel > + $(Q)cp $(srctree)/Documentation/rust/assets/* $(objtree)/rust/doc > + > +rustdoc-macros: private rustdoc_host = yes > +rustdoc-macros: private rustc_target_flags = --crate-type proc-macro \ > + --extern proc_macro > +rustdoc-macros: $(srctree)/rust/macros/lib.rs FORCE > + $(call if_changed,rustdoc) > + > +rustdoc-compiler_builtins: $(srctree)/rust/compiler_builtins.rs rustdoc-core FORCE > + $(call if_changed,rustdoc) > + > +# We need to allow `rustdoc::broken_intra_doc_links` because some > +# `no_global_oom_handling` functions refer to non-`no_global_oom_handling` > +# functions. Ideally `rustdoc` would have a way to distinguish broken links > +# due to things that are "configured out" vs. entirely non-existing ones. > +rustdoc-alloc: private rustc_target_flags = $(alloc-cfgs) \ > + -Arustdoc::broken_intra_doc_links > +rustdoc-alloc: $(srctree)/rust/alloc/lib.rs rustdoc-core \ > + rustdoc-compiler_builtins FORCE > + $(call if_changed,rustdoc) > + > +rustdoc-kernel: private rustc_target_flags = --extern alloc \ > + --extern build_error \ > + --extern macros=$(objtree)/rust/libmacros.so > +rustdoc-kernel: $(srctree)/rust/kernel/lib.rs rustdoc-core \ > + rustdoc-macros rustdoc-compiler_builtins rustdoc-alloc \ > + $(objtree)/rust/libmacros.so $(objtree)/rust/bindings_generated.rs \ > + $(objtree)/rust/bindings_helpers_generated.rs FORCE > + $(call if_changed,rustdoc) > + > +quiet_cmd_rustc_test_library = RUSTC TL $< > + cmd_rustc_test_library = \ > + OBJTREE=$(abspath $(objtree)) \ > + $(RUSTC) $(filter-out --sysroot=%, $(filter-out -Cpanic=abort, $(filter-out --emit=%, $(rust_flags)))) \ > + $(rustc_target_flags) --crate-type $(if $(rustc_test_library_proc),proc-macro,rlib) \ > + --out-dir $(objtree)/rust/test/ --cfg testlib \ > + --sysroot $(objtree)/rust/test/sysroot \ > + -L $(objtree)/rust/test/ --crate-name $(subst rusttest-,,$(subst rusttestlib-,,$@)) $< > + > +rusttestlib-build_error: $(srctree)/rust/build_error.rs rusttest-prepare FORCE > + $(call if_changed,rustc_test_library) > + > +rusttestlib-macros: private rustc_target_flags = --extern proc_macro > +rusttestlib-macros: private rustc_test_library_proc = yes > +rusttestlib-macros: $(srctree)/rust/macros/lib.rs rusttest-prepare FORCE > + $(call if_changed,rustc_test_library) > + > +quiet_cmd_rustdoc_test = RUSTDOC T $< > + cmd_rustdoc_test = \ > + OBJTREE=$(abspath $(objtree)) \ > + $(RUSTDOC) --test $(filter-out --sysroot=%, $(filter-out -Cpanic=abort, $(filter-out --emit=%, $(rust_flags)))) \ Seeing repeated filter-out rules makes me wonder if we could DRY up some of these rules with function definitions? > + $(rustc_target_flags) $(rustdoc_test_target_flags) \ > + --sysroot $(objtree)/rust/test/sysroot $(rustdoc_test_quiet) \ > + -L $(objtree)/rust/test \ > + --output $(objtree)/rust/doc --crate-name $(subst rusttest-,,$@) \ > + @$(objtree)/include/generated/rustc_cfg $< > + > +# We cannot use `-Zpanic-abort-tests` because some tests are dynamic, > +# so for the moment we skip `-Cpanic=abort`. > +quiet_cmd_rustc_test = RUSTC T $< > + cmd_rustc_test = \ > + OBJTREE=$(abspath $(objtree)) \ > + $(RUSTC) --test $(filter-out --sysroot=%, $(filter-out -Cpanic=abort, $(filter-out --emit=%, $(rust_flags)))) \ > + $(rustc_target_flags) --out-dir $(objtree)/rust/test \ > + --sysroot $(objtree)/rust/test/sysroot \ > + -L $(objtree)/rust/test/ --crate-name $(subst rusttest-,,$@) $<; \ > + $(objtree)/rust/test/$(subst rusttest-,,$@) $(rust_test_quiet) \ > + $(rustc_test_run_flags) > + > +rusttest: rusttest-macros rusttest-kernel > + > +# This prepares a custom sysroot with our custom `alloc` instead of > +# the standard one. > +# > +# This requires several hacks: > +# - Unlike `core` and `alloc`, `std` depends on more than a dozen crates, > +# including third-party crates that need to be downloaded, plus custom > +# `build.rs` steps. Thus hardcoding things here is not maintainable. > +# - `cargo` knows how to build the standard library, but it is an unstable > +# feature so far (`-Zbuild-std`). > +# - `cargo` only considers the use case of building the standard library > +# to use it in a given package. Thus we need to create a dummy package > +# and pick the generated libraries from there. > +# - Since we only keep a subset of upstream `alloc` in-tree, we need > +# to recreate it on the fly by putting our sources on top. > +# - The usual ways of modifying the dependency graph in `cargo` do not seem > +# to apply for the `-Zbuild-std` steps, thus we have to mislead it > +# by modifying the sources in the sysroot. > +# - To avoid messing with the user's Rust installation, we create a clone > +# of the sysroot. However, `cargo` ignores `RUSTFLAGS` in the `-Zbuild-std` > +# steps, thus we use a wrapper binary passed via `RUSTC` to pass the flag. Are there links to corresponding feature requests upstream so that one day we can drop technical debt here? In particular, having to create a custom sysroot as is done here isn't particularly pretty. I'd be curious if we could remove the dependency on cargo for rust tests. > +# > +# In the future, we hope to avoid the whole ordeal by either: > +# - Making the `test` crate not depend on `std` (either improving upstream > +# or having our own custom crate). > +# - Making the tests run in kernel space (requires the previous point). > +# - Making `std` and friends be more like a "normal" crate, so that > +# `-Zbuild-std` and related hacks are not needed. > +quiet_cmd_rustsysroot = RUSTSYSROOT > + cmd_rustsysroot = \ > + rm -rf $(objtree)/rust/test; \ > + mkdir -p $(objtree)/rust/test; \ > + cp -a $(rustc_sysroot) $(objtree)/rust/test/sysroot; \ > + cp -r $(srctree)/rust/alloc/* \ > + $(objtree)/rust/test/sysroot/lib/rustlib/src/rust/library/alloc/src; \ > + echo '\#!/bin/sh' > $(objtree)/rust/test/rustc_sysroot; \ > + echo "$(RUSTC) --sysroot=$(abspath $(objtree)/rust/test/sysroot) \"\$$@\"" \ > + >> $(objtree)/rust/test/rustc_sysroot; \ > + chmod u+x $(objtree)/rust/test/rustc_sysroot; \ > + $(CARGO) -q new $(objtree)/rust/test/dummy; \ > + RUSTC=$(objtree)/rust/test/rustc_sysroot $(CARGO) $(cargo_quiet) \ > + test -Zbuild-std --target $(rustc_host_target) \ > + --manifest-path $(objtree)/rust/test/dummy/Cargo.toml; \ > + rm $(objtree)/rust/test/sysroot/lib/rustlib/$(rustc_host_target)/lib/*; \ > + cp $(objtree)/rust/test/dummy/target/$(rustc_host_target)/debug/deps/* \ > + $(objtree)/rust/test/sysroot/lib/rustlib/$(rustc_host_target)/lib > + > +rusttest-prepare: FORCE > + $(call if_changed,rustsysroot) > + > +rusttest-macros: private rustc_target_flags = --extern proc_macro > +rusttest-macros: private rustdoc_test_target_flags = --crate-type proc-macro > +rusttest-macros: $(srctree)/rust/macros/lib.rs rusttest-prepare FORCE > + $(call if_changed,rustc_test) > + $(call if_changed,rustdoc_test) > + > +rusttest-kernel: private rustc_target_flags = --extern alloc \ > + --extern build_error --extern macros > +rusttest-kernel: private rustc_test_run_flags = \ > + --skip bindgen_test_layout_ > +rusttest-kernel: $(srctree)/rust/kernel/lib.rs rusttest-prepare \ > + rusttestlib-build_error rusttestlib-macros FORCE > + $(call if_changed,rustc_test) > + $(call if_changed,rustc_test_library) > + $(call if_changed,rustdoc_test) > + > +ifdef CONFIG_CC_IS_CLANG > +bindgen_c_flags = $(c_flags) > +else > +# bindgen relies on libclang to parse C. Ideally, bindgen would support a GCC > +# plugin backend and/or the Clang driver would be perfectly compatible with GCC. > +# > +# For the moment, here we are tweaking the flags on the fly. Some config > +# options may not work (e.g. `GCC_PLUGIN_RANDSTRUCT` if we end up using one Do we denote the conflict in KCONFIG? > +# of those structs). > +bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \ > + -mskip-rax-setup -mgeneral-regs-only -msign-return-address=% \ > + -mindirect-branch=thunk-extern -mindirect-branch-register -mrecord-mcount \ > + -mabi=lp64 -mstack-protector-guard% -fconserve-stack -falign-jumps=% \ > + -falign-loops=% -femit-struct-debug-baseonly \ > + -fno-ipa-cp-clone -fno-ipa-sra -fno-partial-inlining \ > + -fplugin-arg-arm_ssp_per_task_plugin-% \ > + -fno-reorder-blocks -fno-allow-store-data-races -fasan-shadow-offset=% \ > + -Wno-packed-not-aligned -Wno-format-truncation -Wno-format-overflow \ > + -Wno-stringop-truncation -Wno-unused-but-set-variable \ > + -Wno-stringop-overflow -Wno-restrict -Wno-maybe-uninitialized \ > + -Werror=designated-init -Wno-zero-length-bounds \ > + -Wno-alloc-size-larger-than --param=% --param asan-% Why do we need to strip out all these warning flags when running bindgen? Should be just be using -w to silence all warnings from clang when invoking bindgen? > + > +# We need to keep the quotes for this one -- it comes from a `Kconfig` > +bindgen_skip_c_flags += "-Wimplicit-fallthrough=%" > + > +# PowerPC > +bindgen_skip_c_flags += -mtraceback=no -mno-pointers-to-nested-functions \ > + -mno-string -mno-strict-align I don't understand why the PowerPC specific flags are pulled out, but the x86 specific ones (like most of the -m flags in the initial defiition of bindgen_skip_c_flags) are not. > + > +# Derived from `scripts/Makefile.clang` > +BINDGEN_TARGET_arm := arm-linux-gnueabi > +BINDGEN_TARGET_arm64 := aarch64-linux-gnu > +BINDGEN_TARGET_powerpc := powerpc64le-linux-gnu > +BINDGEN_TARGET_riscv := riscv64-linux-gnu > +BINDGEN_TARGET_x86 := x86_64-linux-gnu > +BINDGEN_TARGET := $(BINDGEN_TARGET_$(SRCARCH)) > + > +bindgen_extra_c_flags = --target=$(BINDGEN_TARGET) \ > + -Wno-address-of-packed-member \ > + -Wno-gnu-variable-sized-type-not-at-end > +bindgen_c_flags = $(filter-out $(bindgen_skip_c_flags), $(c_flags)) \ > + $(bindgen_extra_c_flags) > +endif > + > +ifdef CONFIG_LTO > +bindgen_c_flags_lto = $(filter-out $(CC_FLAGS_LTO), $(bindgen_c_flags)) > +else > +bindgen_c_flags_lto = $(bindgen_c_flags) > +endif > + > +# To avoid several recompilations in PowerPC, which inserts `-D_TASK_CPU` > +bindgen_c_flags_final = $(filter-out -D_TASK_CPU=%, $(bindgen_c_flags_lto)) > + > +quiet_cmd_bindgen = BINDGEN $@ > + cmd_bindgen = \ > + $(BINDGEN) $< $(shell grep -v '^\#\|^$$' $(srctree)/rust/bindgen_parameters) \ > + --use-core --with-derive-default --ctypes-prefix c_types \ > + --no-debug '.*' \ > + --size_t-is-usize -o $@ -- $(bindgen_c_flags_final) -DMODULE > + > +$(objtree)/rust/bindings_generated.rs: $(srctree)/rust/kernel/bindings_helper.h \ > + $(srctree)/rust/bindgen_parameters FORCE > + $(call if_changed_dep,bindgen) > + > +quiet_cmd_bindgen_helper = BINDGEN $@ > + cmd_bindgen_helper = \ > + $(BINDGEN) $< --blacklist-type '.*' --whitelist-var '' \ > + --whitelist-function 'rust_helper_.*' \ > + --use-core --with-derive-default --ctypes-prefix c_types \ > + --no-debug '.*' \ > + --size_t-is-usize -o $@ -- $(bindgen_c_flags_final) \ > + -I$(objtree)/rust/ -DMODULE; \ > + sed -Ei 's/pub fn rust_helper_([a-zA-Z0-9_]*)/\#[link_name="rust_helper_\1"]\n pub fn \1/g' $@ > + > +$(objtree)/rust/bindings_helpers_generated.rs: $(srctree)/rust/helpers.c FORCE > + $(call if_changed_dep,bindgen_helper) > + > +quiet_cmd_exports = EXPORTS $@ > + cmd_exports = \ > + $(NM) -p --defined-only $< \ > + | grep -E ' (T|R|D) ' | cut -d ' ' -f 3 \ > + | xargs -Isymbol \ > + echo 'EXPORT_SYMBOL_RUST_GPL(symbol);' > $@ This doesn't accidentally export non-GPL symbols as GPL does it? ... snip ... -- Thanks, ~Nick Desaulniers