Ported Marvell armhf build on amd64 for debian buster to use cross-comp…

[gregshpit]

…ilation instead of qemu emulation

…ilation instead of qemu emulation

Motivation:
Current armhf Sonic build on amd64 host uses qemu emulation. Due to the nature of the emulation it takes a very long time, about 22-24 hours to complete the build. The change I did to improve the building time ports Sonic armhf build on amd64 host for Marvell platform for debian buster to use cross-compilation on arm64 host for armhf target. The overall Sonic armhf building time using cross-compilation is about 6 hours.

The Sonic configure and build for the armhf cross-compilation is as following:
NOJESSIE=1 NOSTRETCH=1 BLDENV=buster CROSS_BLDENV=1 make configure PLATFORM=marvell-armhf PLATFORM_ARCH=armhf
NOJESSIE=1 NOSTRETCH=1 BLDENV=buster CROSS_BLDENV=1 make target/sonic-marvell-armhf.bin

Sonic module should check if $CROSS_BUILD_ENVIRON is 'y' to make sure that it is cross-compilation build.

[kcudnik]

CROSS_BUILD_ENVIRON is that your internal variable name?

[gregshpit]

This environment variable is set in Sonic slave.mk when Sonic build uses cross-complation.

[kcudnik]

i grepped sonic-buildimage and i could not find it, can you give a link in github where this is set up? it also names seems to be truncated, should be CROSS_BUILD_ENVIRONMENT or CROSS_BUILD_ENV, this make more sense, also google returns nothing for "CROSS_BUILD_ENVIRON" :(

[kcudnik]

also, im just wondering, normally when we have configure.ac and ./configure, to specify cross compiler paramst are used from --host=HOST, this is standalone Makefile, so maybe it make more sense to make it similar like here: https://lists.gnu.org/archive/html/help-make/2005-05/msg00029.html and then passing

$ make ARCH=xxx CROSS_COMPILE=yyy

or whoever would set CROSS_COMPILE, or it could be even set CC and CXX before make, instead of doing all those if/else across all makefiles on the entire sonic

please do research on variable "CROSS_COMPILE" as it seems it's most common method to update Makefiles
take a look here:

• https://raspberrypi.stackexchange.com/questions/192/how-do-i-cross-compile-the-kernel-on-a-ubuntu-host
• https://lists.gnu.org/archive/html/help-make/2005-05/msg00029.html
• https://wiki.gentoo.org/wiki/Embedded_Handbook/General/Cross-compiling_the_kernel
• https://wiki.ubuntu.com/KernelTeam/ARMKernelCrossCompile
• https://lists.gnu.org/archive/html/help-make/2005-05/msg00029.html

and take a look how CROSS_COMPILE is used, ** and i would advise to go that direction **, i would like you also to update/refactor other repos that you made PRs to use CROSS_COMPILE pattern in them too, adding @lguohan for visibility

[gregshpit]

This sonic-buildimage PR sonic-net/sonic-buildimage#8035 is part of of the overall PR. You can find CROSS_BUILD_ENVIRON environment variable set in slave.mk that I've modified. The naming convention is taken from another variable MULTIARCH_QEMU_ENVIRON defined in this file. CROSS_BUILD_ENVIRON env. variable is used in hundreds files in the PR. I'll check the rest of your request tomorrow. Thanks for your comments.

[kcudnik]

also, im just wondering, normally when we have configure.ac and ./configure, to specify cross compiler paramst are used from --host=HOST, this is standalone Makefile, so maybe it make more sense to make it similar like here: https://lists.gnu.org/archive/html/help-make/2005-05/msg00029.html and then passing

$ make ARCH=xxx CROSS_COMPILE=yyy

or whoever would set CROSS_COMPILE, or it could be even set CC and CXX before make, instead of doing all those if/else across all makefiles on the entire sonic

please do research on variable "CROSS_COMPILE" as it seems it's most common method to update Makefiles
take a look here:

• https://raspberrypi.stackexchange.com/questions/192/how-do-i-cross-compile-the-kernel-on-a-ubuntu-host
• https://lists.gnu.org/archive/html/help-make/2005-05/msg00029.html
• https://wiki.gentoo.org/wiki/Embedded_Handbook/General/Cross-compiling_the_kernel
• https://wiki.ubuntu.com/KernelTeam/ARMKernelCrossCompile
• https://lists.gnu.org/archive/html/help-make/2005-05/msg00029.html

and take a look how CROSS_COMPILE is used, ** and i would advise to go that direction **, i would like you also to update/refactor other repos that you made PRs to use CROSS_COMPILE pattern in them too, adding @lguohan for visibility

[gregshpit]

Hi,

I think do pass CROSS_COMPILE variable to the Makefile. If it is true (I'll check it) then instead of:
+ifeq ($(CROSS_BUILD_ENVIRON),y)

• CC=$(CROSS_CC)
• CXX=$(CROSS_CXX)
  +else
• CC=gcc
• CXX=g++
  +endif

I can just write as you suggested in all modified files:
CC = $(CROSS_COMPILE)gcc
CXX = $(CROSS_COMPILE)g++

Is it OK with you.

Gregory

[kcudnik]

I can just write as you suggested in all modified files:
CC = $(CROSS_COMPILE)gcc
CXX = $(CROSS_COMPILE)g++

Is it OK with you.

yes, this is exactly what i had in mind!