Kernel module build fails with "missing argument to -gdwarf-" - linux-kernel

Question

I am trying to build a Xilinx XDMA driver for Yocto, using their supplied makefile. When I run my recipe the build fails with the following errors:
DEBUG: Executing shell function do_compile
NOTE: make -j 32 KERNEL_SRC=./tmp/work-shared/intel-corei7-64/kernel-source
KERNEL_PATH=./tmp/work-shared/intel-corei7-64/kernel-source
KERNEL_VERSION=5.10.78-intel-pk-standard CC=x86_64-poky-linux-gcc
-fuse-ld=bfd
-fmacro-prefix-map=./tmp/work/intel_corei7_64-poky-linux/xdma-driver-mod/1.0+gitAUTOINC+8d75946900-r0=/usr/src/debug/xdma-driver-mod/1.0+gitAUTOINC+8d75946900-r0
-fdebug-prefix-map=./tmp/work/intel_corei7_64-poky-linux/xdma-driver-mod/1.0+gitAUTOINC+8d75946900-r0=/usr/src/debug/xdma-driver-mod/1.0+gitAUTOINC+8d75946900-r0
-fdebug-prefix-map=./tmp/work/intel_corei7_64-poky-linux/xdma-driver-mod/1.0+gitAUTOINC+8d75946900-r0/recipe-sysroot=
-fdebug-prefix-map=./tmp/work/intel_corei7_64-poky-linux/xdma-driver-mod/1.0+gitAUTOINC+8d75946900-r0/recipe-sysroot-native=
-fdebug-prefix-map=./tmp/work-shared/intel-corei7-64/kernel-source=/usr/src/kernel LD=x86_64-poky-linux-ld.bfd
AR=x86_64-poky-linux-ar
O=./tmp/work-shared/intel-corei7-64/kernel-build-artifacts KBUILD_EXTRA_SYMBOLS=
Makefile:17: XVC_FLAGS: .
make -C /lib/modules/5.13.0-40-generic/build
M=./tmp/work/intel_corei7_64-poky-linux/xdma-driver-mod/1.0+gitAUTOINC+8d75946900-r0/git/linux_driver/xdma modules
make[1]: Entering directory '/usr/src/linux-headers-5.13.0-40-generic'
make[2]: Entering directory './tmp/work-shared/intel-corei7-64/kernel-build-artifacts'
./tmp/work/intel_corei7_64-poky-linux/xdma-driver-mod/1.0+gitAUTOINC+8d75946900-r0/git/linux_driver/xdma/Makefile:17: XVC_FLAGS: .
CC [M] ./tmp/work/intel_corei7_64-poky-linux/xdma-driver-mod/1.0+gitAUTOINC+8d75946900-r0/git/linux_driver/xdma/libxdma.o
CC [M] ./tmp/work/intel_corei7_64-poky-linux/xdma-driver-mod/1.0+gitAUTOINC+8d75946900-r0/git/linux_driver/xdma/xdma_cdev.o
x86_64-poky-linux-gcc: error: missing argument to '-gdwarf-'
CC [M] ./tmp/work/intel_corei7_64-poky-linux/xdma-driver-mod/1.0+gitAUTOINC+8d75946900-r0/git/linux_driver/xdma/cdev_ctrl.o
make[3]: *** [/usr/src/linux-headers-5.13.0-40-generic/scripts/Makefile.build:281: ./tmp/work/intel_corei7_64-poky-linux/xdma-driver-mod/1.0+gitAUTOINC+8d75946900-r0/git/linux_driver/xdma/libxdma.o] Error 1
make[3]: *** Waiting for unfinished jobs....
x86_64-poky-linux-gcc: error: missing argument to '-gdwarf-'
ERROR: oe_runmake failed
WARNING: exit code 1 from a shell command.
I have no idea why this happens as it is not something I have specifically enabled. I have searched through the module.bbclass file but I couldn't see anything obvious. I believe that something needs to be configured such that the -gdwarf- actual ends up being set to a valid value (e.g. -gdwarf-2 or -gdwarf-4 etc.)
A grep through the poky repo for dwarf did not reveal anything neither did a search of /usr/src/linux-headers-5.13.0-40-generic/scripts/.
My bitbake recipe is as follows:
LICENSE = "MIT"
LIC_FILES_CHKSUM = "file://LICENSE;md5=441c1ecbc199a036abf37f3aa47c5f34"
SRC_URI += https://github.com/Xilinx/dma_ip_drivers.git;protocol=ssh;nobranch=1;branch=master"
# Modify these as desired
PV = "1.0+git${SRCPV}"
SRCREV = "8d7594690058dfa828accc02ac81348e416ffe38"
S = "${WORKDIR}/git/xdma/linux-driver/xdma"
RPROVIDES_${PN} += "xdma"
inherit module
EXTRA_OEMAKE_task-install:append = " -C ${STAGING_KERNEL_DIR} M=${S}"
EXTRA_OEMAKE += "KDIR=${STAGING_KERNEL_DIR}"
The makefile is the standard one from GitHub. The driver builds correctly for Ubuntu using make and I can also build the module if I change my recipe such that it does not include inherit module; this change will build the module (xdma.ko) but does to install it in the roofs. I am also not sure if inherit module includes additional functionality which may be rewired.
How to I either:
prevent / disable the -gdwarf flag being generated
configure the recipe that the -gdwarf- resolves to something valid
View the actual command being invoked that is causing the issue.
Attempts to build the xdma.ko module without the inherit module result in an invalid binary being built, i.e. when I try an load the module on the target I get:
insmod xdma.ko
insmod: ERROR: could not insert module xdma.ko: Invalid module format
Which indicates that the module is compiled from the wrong target.

Answer 1

inherit module is required when building kernel modules for Yocto. If it is omitted the build modules is not compatible with the target.
Workaround for the -gdwarf- error was to manually write a new makefile which is compatible with Yocto:
TARGET_MODULE:=xdma
topdir := $(shell cd $(src)/.. && pwd)
EXTRA_CFLAGS := -I$(topdir)/include
SRC := $(shell pwd)
$(TARGET_MODULE)-objs := libxdma.o xdma_cdev.o cdev_ctrl.o cdev_events.o cdev_sgdma.o cdev_xvc.o cdev_bypass.o xdma_mod.o xdma_thread.o
obj-m := $(TARGET_MODULE).o
all :
$(MAKE) -C $(KERNEL_SRC) M=$(SRC)
modules_install:
$(MAKE) -C $(KERNEL_SRC) M=$(SRC) modules_install
clean:
rm -f *.o *~ core .depend .*.cmd *.ko *.mod.c
rm -f Module.markers Module.symvers modules.order
rm -rf .tmp_versions Modules.symvers
This makefile correctly builds the Xilinx XDMA driver for Yocto. I can confirm that the driver works with Kintex-KC705 FPGA development card.