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Run embedded Rust code on your STM32F4
Raw
00-README.md

Embedded Rust on STM32F4

My notes from implementing Job Vranish's excellent guide.

Follow along with the guide above, getting rustc from rustup or similar:

rustc 1.0.0-nightly (dcaeb6aa2 2015-01-18 11:28:53 +0000)
binary: rustc
commit-hash: dcaeb6aa23ecba2dc2af870668a9239136d20fa3
commit-date: 2015-01-18 11:28:53 +0000
host: x86_64-unknown-linux-gnu
release: 1.0.0-nightly

(I have a nightly just around alpha2).

Then we want a target spec. The two linked examples work but for hard float support (which my C tends to get built with) we need to swap the llvm-target to thumbv7em-none-eabihf, as in thumbv7em-none-eabihf in this gist.

Create a folder to work in, grab Rust, build libcore:

$ mkdir embedded-rust
$ cd embedded-rust
$ git clone [email protected]:rust-lang/rust.git
$ cd rust
$ git checkout dcaeb6aa23ecba2dc2af870668a9239136d20fa3
$ cd ..
$ vi thumbv7em-none-eabihf # Get thumbv7-none-eabihf from this gist
$ mkdir libcore-thumbv7em-none-eabihf
$ rustc -C opt-level=2 -Z no-landing-pads --target thumbv7em-none-eabihf -g rust/src/libcore/lib.rs --out-dir libcore-thumbv7em-none-eabihf

Now create a new STM32 project. Here I'll use libopencm3.

$ mkdir example
$ cd example
$ git clone https://github.com/libopencm3/libopencm3.git
$ cd libopencm3
$ make -j8
$ cd ..

Finally we write some C code (with our main function, though main could just as happily go in the Rust code), a sample Rust file with a single function we'll call from the C, and a Makefile (from the libopencm3 project). The Makefile is modified slightly to support rust code compilation (see Makefile-notable). Then we build it and try it out!

$ vi example.c # From this gist
$ vi test_rust.rs # From this gist
$ vi Makefile # From this gist
$ cp ../thumbv7em-none-eabihf . # There's probably a better way to reference this
$ make
$ make debug

(gdb) break main
Breakpoint 1 at 0x80001ae: file example.c, line 9.
(gdb) run
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /home/adam/Projects/embedded-rust/example/example.elf 
Note: automatically using hardware breakpoints for read-only addresses.

Breakpoint 1, main () at example.c:9
9	    volatile uint32_t a = 5;
(gdb) s
10	    volatile uint32_t b = 6;
(gdb) 
11	    volatile uint32_t c = test_add(a, b); 
(gdb) 
test_rust::test_add (a=5, b=6) at test_rust.rs:36
36	    return a + b;
(gdb) 
37	}
(gdb) 
main () at example.c:12
12	    (void)c;
(gdb) p c
$1 = 11
Raw
example.c
#include <stdint.h>
// Defined in Rust
uint32_t test_add(uint32_t a, uint32_t b);
int main(void);
int main() {
volatile uint32_t a = 5;
volatile uint32_t b = 6;
volatile uint32_t c = test_add(a, b);
(void)c;
for(;;);
return 0;
}
Raw
example.ld
MEMORY
{
rom (rx) : ORIGIN = 0x08000000, LENGTH = 1M
ram (rwx) : ORIGIN = 0x20000000, LENGTH = 128K
}
INCLUDE libopencm3_stm32f4.ld
Raw
Makefile
BINARY = example
##
## This file is part of the libopencm3 project.
##
## Copyright (C) 2009 Uwe Hermann <[email protected]>
## Copyright (C) 2010 Piotr Esden-Tempski <[email protected]>
## Copyright (C) 2011 Fergus Noble <[email protected]>
##
## This library is free software: you can redistribute it and/or modify
## it under the terms of the GNU Lesser General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## This library is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU Lesser General Public License for more details.
##
## You should have received a copy of the GNU Lesser General Public License
## along with this library. If not, see <http://www.gnu.org/licenses/>.
##
PREFIX ?= arm-none-eabi
CC = $(PREFIX)-gcc
LD = $(PREFIX)-gcc
OBJCOPY = $(PREFIX)-objcopy
OBJDUMP = $(PREFIX)-objdump
GDB = $(PREFIX)-gdb
FLASH = $(shell which st-flash)
TOOLCHAIN_DIR = ./libopencm3
CFLAGS += -Os -g \
-Wall -Wextra -Wimplicit-function-declaration \
-Wredundant-decls -Wmissing-prototypes -Wstrict-prototypes \
-Wundef -Wshadow \
-I$(TOOLCHAIN_DIR)/include \
-fno-common -mcpu=cortex-m4 -mthumb \
-mfloat-abi=hard -mfpu=fpv4-sp-d16 -MD -DSTM32F4
LDSCRIPT ?= $(BINARY).ld
LDFLAGS += --static -lc -lnosys -L$(TOOLCHAIN_DIR)/lib \
-L$(TOOLCHAIN_DIR)/lib/stm32/f4 \
-T$(LDSCRIPT) -nostartfiles -Wl,--gc-sections \
-mthumb -mcpu=cortex-m4 -mthumb -mfloat-abi=hard -mfpu=fpv4-sp-d16
OBJS = $(sort \
$(patsubst %.c,%.o,$(wildcard *.c)) \
$(patsubst %.s,%.o,$(wildcard *.s)) \
$(patsubst %.rs,%.o,$(wildcard *.rs)))
BMP_PORT ?= /dev/ttyACM0
# Be silent per default, but 'make V=1' will show all compiler calls.
ifneq ($(V),1)
Q := @
NULL := 2>/dev/null
else
LDFLAGS += -Wl,--print-gc-sections
endif
RUSTC = rustc
RUSTCFLAGS = -C opt-level=2 -Z no-landing-pads --target thumbv7em-none-eabihf \
-g --emit obj -L ../libcore-thumbv7em-none-eabihf
.SUFFIXES: .elf .bin .hex .srec .list .images
.SECONDEXPANSION:
.SECONDARY:
all: images
images: $(BINARY).images test_rust
flash: $(BINARY).flash
%.images: %.bin %.hex %.srec %.list
@#printf "*** $* images generated ***\n"
%.bin: %.elf
@#printf " OBJCOPY $(*).bin\n"
$(Q)$(OBJCOPY) -Obinary $(*).elf $(*).bin
%.hex: %.elf
@#printf " OBJCOPY $(*).hex\n"
$(Q)$(OBJCOPY) -Oihex $(*).elf $(*).hex
%.srec: %.elf
@#printf " OBJCOPY $(*).srec\n"
$(Q)$(OBJCOPY) -Osrec $(*).elf $(*).srec
%.list: %.elf
@#printf " OBJDUMP $(*).list\n"
$(Q)$(OBJDUMP) -S $(*).elf > $(*).list
%.elf: $(OBJS) $(LDSCRIPT) $(TOOLCHAIN_DIR)/lib/libopencm3_stm32f4.a
@#printf " LD $(subst $(shell pwd)/,,$(@))\n"
$(Q)$(LD) -o $(*).elf $(OBJS) -lopencm3_stm32f4 $(LDFLAGS)
%.o: %.c Makefile
@#printf " CC $(subst $(shell pwd)/,,$(@))\n"
$(Q)$(CC) $(CFLAGS) -o $@ -c $<
%.o: %.rs Makefile
@#printf " RUSTC $(subst $(shell pwd)/,,$(@))\n"
$(Q)$(RUSTC) $(RUSTCFLAGS) -o $@ $<
clean:
$(Q)rm -f *.o
$(Q)rm -f *.d
$(Q)rm -f *.elf
$(Q)rm -f *.bin
$(Q)rm -f *.hex
$(Q)rm -f *.srec
$(Q)rm -f *.list
%.stlink-flash: %.bin
@printf " FLASH $<\n"
$(Q)$(FLASH) write $(*).bin 0x8000000
ifeq ($(BMP_PORT),)
ifeq ($(OOCD_SERIAL),)
%.flash: %.hex
@printf " FLASH $<\n"
@# IMPORTANT: Don't use "resume", only "reset" will work correctly!
$(Q)$(OOCD) -f interface/$(OOCD_INTERFACE).cfg \
-f board/$(OOCD_BOARD).cfg \
-c "init" -c "reset init" \
-c "stm32x mass_erase 0" \
-c "flash write_image $(*).hex" \
-c "reset" \
-c "shutdown" $(NULL)
else
%.flash: %.hex
@printf " FLASH $<\n"
@# IMPORTANT: Don't use "resume", only "reset" will work correctly!
$(Q)$(OOCD) -f interface/$(OOCD_INTERFACE).cfg \
-f board/$(OOCD_BOARD).cfg \
-c "ft2232_serial $(OOCD_SERIAL)" \
-c "init" -c "reset init" \
-c "stm32x mass_erase 0" \
-c "flash write_image $(*).hex" \
-c "reset" \
-c "shutdown" $(NULL)
endif
else
%.flash: %.elf
@printf " GDB $(*).elf (flash)\n"
$(Q)$(GDB) --batch \
-ex 'target extended-remote $(BMP_PORT)' \
-x $(TOOLCHAIN_DIR)/scripts/black_magic_probe_flash.scr \
$(*).elf
endif
.PHONY: images clean
-include $(OBJS:.o=.d)
##############################################################################
# Black Magic Probe flashing via GDB
#
flash: $(BINARY).elf
arm-none-eabi-gdb --batch \
-ex 'target extended-remote /dev/ttyACM0' \
-ex 'monitor version' \
-ex 'monitor swdp_scan' \
-ex 'attach 1' \
-ex 'load' $(BINARY).elf
debug: $(BINARY).elf
arm-none-eabi-gdb -ex 'target extended-remote /dev/ttyACM0' \
-ex 'monitor swdp_scan' \
-ex 'attach 1' \
-ex "file $(BINARY).elf"
#
# End BMP flashing
##############################################################################
Raw
Makefile-notable
RUSTC = rustc
RUSTCFLAGS = -C opt-level=2 -Z no-landing-pads --target thumbv7em-none-eabihf \
-g --emit obj -L ../libcore-thumbv7em-none-eabihf
OBJS = $(sort \
$(patsubst %.c,%.o,$(wildcard *.c)) \
$(patsubst %.s,%.o,$(wildcard *.s)) \
$(patsubst %.rs,%.o,$(wildcard *.rs)))
%.o: %.rs Makefile
@#printf " RUSTC $(subst $(shell pwd)/,,$(@))\n"
$(Q)$(RUSTC) $(RUSTCFLAGS) -o $@ $<
Raw
test_rust.rs
// From http://spin.atomicobject.com/2015/02/20/rust-language-c-embedded/
#![no_std]
#![crate_type="staticlib"]
#![allow(unstable)]
// **************************************
// These are here just to make the linker happy
// These functions are just used for critical error handling so for now we just
// loop forever For more information see:
// https://github.com/rust-lang/rust/blob/master/src/doc/trpl/unsafe.md
#![feature(lang_items)]
extern crate core;
#[lang="stack_exhausted"] extern fn stack_exhausted() {}
#[lang="eh_personality"] extern fn eh_personality() {}
#[lang="panic_fmt"]
pub fn panic_fmt(_fmt: &core::fmt::Arguments, _file_line: &(&'static str, usize)) -> ! {
loop { }
}
#[no_mangle]
pub unsafe fn __aeabi_unwind_cpp_pr0() -> () {
loop {}
}
// **************************************
// **************************************
// And now we can write some Rust!
#[no_mangle]
pub fn test_add(a: u32, b: u32) -> u32 {
return a + b;
}
Raw
thumbv7-none-eabihf
{
"arch": "arm",
"cpu": "cortex-m4",
"data-layout": "e-m:e-p:32:32-i1:8:32-i8:8:32-i16:16:32-i64:64-v128:64:128-a:0:32-n32-S64",
"disable-redzone": true,
"executables": true,
"llvm-target": "thumbv7em-none-eabihf",
"morestack": false,
"os": "none",
"relocation-model": "static",
"target-endian": "little",
"target-word-size": "32"
}
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