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[188.22.218.164]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-36075114e09sm12117931f8f.117.2024.06.17.09.03.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 Jun 2024 09:03:16 -0700 (PDT) Message-ID: <2dbd1491-149d-443c-9802-75786a6a3b73@gmail.com> Date: Mon, 17 Jun 2024 18:03:11 +0200 Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Christian Schrefl Subject: [PATCH v2] arm: rust: Enable Rust support for ARMv7 To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, rust-for-linux@vger.kernel.org Cc: Miguel Ojeda , Jamie Cunliffe , Sven Van Asbroeck , Geert Stappers , Andrew Lunn Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit This commit allows building ARMv7 kernels with Rust support. The rust core library expects some __eabi_... functions that are not implemented in the kernel. Those functions are some float operations and __aeabi_uldivmod. For now those are implemented with define_panicking_intrinsics!. This is based on the code by Sven Van Asbroeck from the original rust branch and inspired by the AArch64 version by Jamie Cunliffe. I have tested the rust samples and a custom simple MMIO module on hardware (De1SoC FPGA + Arm A9 CPU). This only includes support for ARMv7, but supporting other sub-architectures in the future should be as simple as setting the correct rustc target. Signed-off-by: Christian Schrefl --- Changes since V1 [1]: - Removed unrelated whitespace change. - Added target name to panic message in scripts/generate_rust_target.rs. - Fixed the comment in rust/bindgen_parameters. [1]: https://lore.kernel.org/rust-for-linux/4e0f5932-c7bc-4878-862c-1186cbecd71d@gmail.com -- Documentation/rust/arch-support.rst | 1 + arch/arm/Kconfig | 1 + arch/arm/Makefile | 1 + rust/Makefile | 8 ++++++++ rust/bindgen_parameters | 4 ++++ rust/compiler_builtins.rs | 24 ++++++++++++++++++++++++ scripts/generate_rust_target.rs | 4 +++- 7 files changed, 42 insertions(+), 1 deletion(-) diff --git a/Documentation/rust/arch-support.rst b/Documentation/rust/arch-support.rst index b13e19d84744..4bf5205f526d 100644 --- a/Documentation/rust/arch-support.rst +++ b/Documentation/rust/arch-support.rst @@ -15,6 +15,7 @@ support corresponds to ``S`` values in the ``MAINTAINERS`` file. ============= ================ ============================================== Architecture Level of support Constraints ============= ================ ============================================== +``arm`` Maintained ARMv7 Little Endian only. ``arm64`` Maintained Little Endian only. ``loongarch`` Maintained \- ``riscv`` Maintained ``riscv64`` only. diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index ee5115252aac..f07149fe078b 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -126,6 +126,7 @@ config ARM select MMU_GATHER_RCU_TABLE_FREE if SMP && ARM_LPAE select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_RSEQ + select HAVE_RUST if CPU_LITTLE_ENDIAN && CPU_32v7 select HAVE_STACKPROTECTOR select HAVE_SYSCALL_TRACEPOINTS select HAVE_UID16 diff --git a/arch/arm/Makefile b/arch/arm/Makefile index 71afdd98ddf2..9cc10e32e8be 100644 --- a/arch/arm/Makefile +++ b/arch/arm/Makefile @@ -150,6 +150,7 @@ endif KBUILD_CPPFLAGS +=$(cpp-y) KBUILD_CFLAGS +=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -msoft-float -Uarm KBUILD_AFLAGS +=$(CFLAGS_ABI) $(AFLAGS_ISA) -Wa,$(arch-y) $(tune-y) -include asm/unified.h -msoft-float +KBUILD_RUSTFLAGS += --target=arm-unknown-linux-gnueabi CHECKFLAGS += -D__arm__ diff --git a/rust/Makefile b/rust/Makefile index f70d5e244fee..8214a6f378e3 100644 --- a/rust/Makefile +++ b/rust/Makefile @@ -287,6 +287,7 @@ bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \ # Derived from `scripts/Makefile.clang`. BINDGEN_TARGET_x86 := x86_64-linux-gnu BINDGEN_TARGET_arm64 := aarch64-linux-gnu +BINDGEN_TARGET_arm := arm-linux-gnueabi BINDGEN_TARGET := $(BINDGEN_TARGET_$(SRCARCH)) # All warnings are inhibited since GCC builds are very experimental, @@ -413,6 +414,13 @@ redirect-intrinsics = \ __muloti4 __multi3 \ __udivmodti4 __udivti3 __umodti3 +ifdef CONFIG_ARM + # Add eabi initrinsics for ARM 32-bit + redirect-intrinsics += \ + __aeabi_fadd __aeabi_fmul __aeabi_fcmpeq __aeabi_fcmple __aeabi_fcmplt __aeabi_fcmpun \ + __aeabi_dadd __aeabi_dmul __aeabi_dcmple __aeabi_dcmplt __aeabi_dcmpun \ + __aeabi_uldivmod +endif ifneq ($(or $(CONFIG_ARM64),$(and $(CONFIG_RISCV),$(CONFIG_64BIT))),) # These intrinsics are defined for ARM64 and RISCV64 redirect-intrinsics += \ diff --git a/rust/bindgen_parameters b/rust/bindgen_parameters index a721d466bee4..83f28ae4bb2b 100644 --- a/rust/bindgen_parameters +++ b/rust/bindgen_parameters @@ -24,3 +24,7 @@ # These functions use the `__preserve_most` calling convention, which neither bindgen # nor Rust currently understand, and which Clang currently declares to be unstable. --blocklist-function __list_.*_report + +# Depending on how the architecture defines `ARCH_SLAB_MINALIGN`, `bindgen` might generate a binding. +# Disable this here as there is a `const` item that will always be generated in `bindings_helper.h` +--blocklist-item ARCH_SLAB_MINALIGN diff --git a/rust/compiler_builtins.rs b/rust/compiler_builtins.rs index bba2922c6ef7..c37142b16a45 100644 --- a/rust/compiler_builtins.rs +++ b/rust/compiler_builtins.rs @@ -70,5 +70,29 @@ pub extern "C" fn $ident() { __umodti3, }); +#[cfg(target_arch = "arm")] +define_panicking_intrinsics!("`f32` should not be used", { + __aeabi_fadd, + __aeabi_fmul, + __aeabi_fcmpeq, + __aeabi_fcmple, + __aeabi_fcmplt, + __aeabi_fcmpun, +}); + +#[cfg(target_arch = "arm")] +define_panicking_intrinsics!("`f64` should not be used", { + __aeabi_dadd, + __aeabi_dmul, + __aeabi_dcmple, + __aeabi_dcmplt, + __aeabi_dcmpun, +}); + +#[cfg(target_arch = "arm")] +define_panicking_intrinsics!("`u64` division/modulo should not be used", { + __aeabi_uldivmod, +}); + // NOTE: if you are adding a new intrinsic here, you should also add it to // `redirect-intrinsics` in `rust/Makefile`. diff --git a/scripts/generate_rust_target.rs b/scripts/generate_rust_target.rs index 641b713a033a..c3a6058fdf30 100644 --- a/scripts/generate_rust_target.rs +++ b/scripts/generate_rust_target.rs @@ -148,7 +148,9 @@ fn main() { let mut ts = TargetSpec::new(); // `llvm-target`s are taken from `scripts/Makefile.clang`. - if cfg.has("ARM64") { + if cfg.has("ARM") { + panic!("arm uses the builtin rustc arm-unknown-linux-gnueabi target"); + } else if cfg.has("ARM64") { panic!("arm64 uses the builtin rustc aarch64-unknown-none target"); } else if cfg.has("RISCV") { if cfg.has("64BIT") { base-commit: 1613e604df0cd359cf2a7fbd9be7a0bcfacfabd0 -- 2.45.2