Native simulator - native_sim¶
Overview¶
The native_sim board is an evolution of native_posix. Just like with native_posix you can build your Zephyr application with the Zephyr kernel, creating a normal Linux executable with your host tooling, and can debug and instrument it like any other Linux program.
native_sim is based on the native simulator and the POSIX architecture.
Host system dependencies¶
Please check the Posix Arch Dependencies
Important limitations¶
Native_sim is based on the POSIX architecture, and therefore its limitations and considerations apply to it.
How to use it¶
To build, simply specify the native_sim board as target:
west build -b native_sim samples/hello_world
Now you have a Linux executable, ./build/zephyr/zephyr.exe, you can use just like any
other Linux program.
You can run, debug, build it with sanitizers or with coverage just like with native_posix. Please check native_posix’s how to for more info.
32 and 64bit versions¶
Just like native_posix, native_sim comes with two targets: A 32 bit and 64 bit version.
The 32 bit version, native_sim, is the default target, which will compile
your code for the ILP32 ABI (i386 in a x86 or x86_64 system) where pointers
and longs are 32 bits.
This mimics the ABI of most embedded systems Zephyr targets,
and is therefore normally best to test and debug your code, as some bugs are
dependent on the size of pointers and longs.
This target requires either a 64 bit system with multilib support installed or
one with a 32bit userspace.
The 64 bit version, native_sim_64, compiles your code targeting the
LP64 ABI (x86-64 in x86 systems), where pointers and longs are 64 bits.
You can use this target if you cannot compile or run 32 bit binaries.
C library choice¶
Unlike native_posix, native_sim may be compiled with a choice of C libraries.
By default it will be compiled with the host C library (CONFIG_EXTERNAL_LIBC),
but you can also select to build it with CONFIG_MINIMAL_LIBC or with
CONFIG_PICOLIBC.
When building with either MINIMAL or PICO libC you will build your code in a more similar way as when building for the embedded target, you will be able to test your code interacting with that C library, and there will be no conflicts with the POSIX OS abstraction shim, but, accessing the host for test purposes from your embedded code will be more difficult, and you will have a limited choice of drivers and backends to chose from.
Architecture¶
native_posix’s architecture description as well as the POSIX architecture description are directly applicable to native_sim.
If you are interested on the inner workigns of the native simulator itself, you can check its documentation.
Peripherals, subsystems backends and host based flash access¶
Today, native_sim supports the exact same
peripherals and backends as native_posix,
with the only caveat that some of these are, so far, only available when compiling with the
host libC (CONFIG_EXTERNAL_LIBC).
Driver class |
driver name |
driver kconfig |
libC choices |
|---|---|---|---|
adc |
ADC emul |
all |
|
bluetooth |
userchan |
host libC |
|
can |
can native posix |
host libC |
|
console backend |
POSIX arch console |
all |
|
display |
display SDL |
all |
|
entropy |
native posix entropy |
all |
|
eprom |
eprom emulator |
host libC |
|
ethernet |
eth native_posix |
host libC |
|
flash |
flash simulator |
all |
|
flash |
host based flash access |
host libC |
|
gpio |
GPIO emulator |
all |
|
gpio |
SDL GPIO emulator |
all |
|
i2c |
I2C emulator |
all |
|
input |
input SDL touch |
all |
|
log backend |
native backend |
all |
|
rtc |
RTC emul |
all |
|
serial |
uart native posix/PTTY |
all |
|
serial |
uart native TTY |
all |
|
spi |
SPI emul |
all |
|
system tick |
native_posix timer |
all |
|
tracing |
Posix tracing backend |
all |
|
usb |
USB native posix |
host libC |