Bootargs
Overview
This sample demonstrates use of bootargs passed to Zephyr by printing each main argument to the console. Zephyr support both dynamic bootargs, received from supported bootloader, and static bootargs embedded in the binary.
Requirements
Static bootargs don’t have special requirements. Dynamic bootargs work on platforms where Zephyr is booted by multiboot or efi.
Building and Running
Static bootargs
Static bootargs can be configured using CONFIG_BOOTARGS_STRING.
west build -b qemu_x86 samples/kernel/bootargs -- -DCONF_FILE=prj_static_bootargs.conf
west build -t run
Output:
*** Booting Zephyr OS build v3.7.0-514-gd4490bc739d1 ***
argv[0] = appname
argv[1] = This
argv[2] = is
argv[3] = a list of
argv[4] = arguments
Multiboot
west build -b qemu_x86 samples/kernel/bootargs -- -DCONF_FILE=prj_multiboot.conf
west build -t run
Output:
*** Booting Zephyr OS build v3.7.0-rc2-421-g3cf718e6dabc ***
argv[0] = /home/user/zephyr/samples/kernel/bootargs/build/zephyr/zephyr.elf
To pass your own arguments you can manually invoke qemu with -append "your args", for example:
qemu-system-x86_64 -kernel ./build/zephyr/zephyr.elf -nographic -append "This is 'a list of' arguments"
Which will result in the following output:
*** Booting Zephyr OS build v3.7.0-rc2-421-g3cf718e6dabc ***
argv[0] = ./build/zephyr/zephyr.elf
argv[1] = This
argv[2] = is
argv[3] = a list of
argv[4] = arguments
Efi
west build -b qemu_x86_64 samples/kernel/bootargs -- -DCONF_FILE=prj_efi.conf
west build -t run
Output:
*** Zephyr EFI Loader ***
RSDP found at 0xbf7e014
Zeroing 501792 bytes of memory at 0x163000
Copying 16384 data bytes to 0x1000 from image offset
Copying 405504 data bytes to 0x100000 from image offset 16384
Copying 30688 data bytes to 0x1dd820 from image offset 421888
Jumping to Entry Point: 0x1137 (48 31 c0 48 31 d2 48)
*** Booting Zephyr OS build v3.7.0-rc2-421-g3cf718e6dabc ***
argv[0] = run.efi
To pass your own arguments you can press ESC and write your arguments after name of the Zephyr efi binary, for example:
Press ESC in 5 seconds to skip startup.nsh or any other key to continue.
Shell> run.efi This is 'a list of' arguments
*** Zephyr EFI Loader ***
RSDP found at 0xbf7e014
Zeroing 501792 bytes of memory at 0x163000
Copying 16384 data bytes to 0x1000 from image offset
Copying 405504 data bytes to 0x100000 from image offset 16384
Copying 30688 data bytes to 0x1dd820 from image offset 421888
Jumping to Entry Point: 0x1137 (48 31 c0 48 31 d2 48)
*** Booting Zephyr OS build v3.7.0-rc2-421-g3cf718e6dabc ***
argv[0] = run.efi
argv[1] = This
argv[2] = is
argv[3] = a list of
argv[4] = arguments