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Change Yocto Project Kernel Compile Optimization Level

Question asked by James Burnworth on Dec 6, 2017
Latest reply on Dec 7, 2017 by James Burnworth

I'm trying to debug a kernel module and as such, need to compile it without optimizations.  I'm using the Yocto Project and can't get the module to compile with a -O0 flag despite trying several things.  So far I've tried adding the following to my local.conf.

EXTRA_IMAGE_FEATURES = "debug-tweaks tools-profile dbg-pkgs"

INHIBIT_PACKAGE_STRIP = "1"
DEBUG_BUILD = "1"

PACKAGE_DEBUG_SPLIT_STYLE = 'debug-file-directory'

I've also added the following to my kernel recipe in addition to the changes above.

DEBUG_FLAGS += "-O0"

None of this has worked.  If I run objdump -g on the .ko file in question I still find -O2 is being used.  This leads to the debugger jumping all around when I'm trying to step through source. 

 

Is there a way to override the kernel compile optimization level in the Yocto Project?

 

For kernel module debugging I'm following this guide from DS-MDK and the imx_rpmsg_tty module.

http://www2.keil.com/docs/default-source/default-document-library/gs_ds-mdk_5_27_r1.pdf?sfvrsn=2 

 

I'm working with this SOM.

CL-SOM-iMX7 | NXP (Freescale) i.MX 7 | System-on-Module | Computer-on-Module | CompuLab 

 

I've attached my local.conf, my kernel recipe, and my kernel .config.  Let me know if you need any more information.

 

Thanks for the help,

 

James

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