Re: [dpdk-dev] [PATCH 3/4] mk: allow kernel artifacts to be located in output directory

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 4/6/2018 11:32 PM, Scott Branden wrote:
> 
> 
> On 18-04-06 02:31 PM, Ferruh Yigit wrote:
>> On 4/6/2018 7:10 PM, Scott Branden wrote:
>>> Hi Ferruh,
>>>
>>> Somehow I did not receive your other email so Ajit fowarded it to me.  So I am
>>> responding to it here.
>>>
>>> Sorry for the previous confusion:  RTE_KERNELDIR_OUT specifies the location of
>>> the output of the kernel artifacts, not the output of the DPDK build artifacts.
>> Ahh, this makes more sense now J Thanks.
>>
>>> Here is an example to use RTE_KERNELDIR_OUT:
>>>
>>> export ARCH=arm64
>>> export CROSS_COMPILE=~/gcc-linaro-aarch64-linux-gnu/bin/aarch64-linux-gnu-
>>> export CROSS=aarch64-linux-gnu-
>>>
>>> export RTE_KERNELDIR_OUT=~/test/linux-out
>>> export RTE_KERNELDIR=~/test/linux
>>> cd $RTE_KERNELDIR
>>> make defconfig O=$RTE_KERNELDIR_OUT
>>> make -j 8 O=$RTE_KERNELDIR_OUT
>>>
>>> cd ~/test/dpdk
>>> make config T=arm64-stingray-linuxapp-gcc
>>> make
>> I guess using "~/test/linux-out" as RTE_KERNELDIR also works (because of
>> "source" link), but your patch looks more proper way.
> Actually, you may be correct.
> Perhaps all this requires is a documentation change.
> Does any of DPDK build system actually require to know where the kernel 
> source directory is?
> Or, does DPDK only require to know where the kernel artifacts exist (ie. 
> generated headers)

Both are required, kernel source is required because of some headers, there are
multiple components depends on kernel headers, also kernel artifacts are
required like kernel config mainly for building kernel modules.

> 
> Looking at the documentation it is a little confusing.  Each one 
> describes something different.
> guides/linux_gsg/build_dpdk.rst
> 99:    the ``RTE_KERNELDIR`` environment variable should be used to 
> point the compilation at a copy of the kernel version to be used on the 
> target machine.
> 
> guides/prog_guide/dev_kit_build_system.rst
> 297:*   RTE_KERNELDIR: This variable contains the absolute path to the 
> kernel sources that will be used to compile the kernel modules.
> 
> build-sdk-quick.txt
> 24:    RTE_KERNELDIR    linux headers path
> 
> In guides/prog_guide/dev_kit_build_system.rst.  If "kernel sources" was 
> changed to "linux headers" my change may not be needed.  I'm doing some 
> more testing now with RTE_KERNELDIR set to linux-out in other DPDK builds.

I believe it is not just "linux headers", it is more like "compiled kernel source"

> 
>> There are a few documents for build parameters, can you please update them too:
>> doc/guides/prog_guide/dev_kit_build_system.rst
>> doc/guides/linux_gsg/build_dpdk.rst <-- not sure about this one, please check
>> doc/build-sdk-quick.txt  <-- this is "make help" output
>>
>>
>>> Note:
>>>
>>> With this example you will likely hit a few compile errors as latest dpdk has
>>> compile bugs with unused variables/type mismatches in the code.
>> I didn't get the error, if you observe build error please report or better a
>> patch to fix is always welcome :)
> Yes - we have patches being created for 64-bit build warnings/errors 
> that we will submit.
>>
>>> Regards,
>>>
>>>   Scott
>>>
>>>
>>> On 18-04-05 11:58 AM, Ajit Khaparde wrote:
>>>> Scott, are you looking at this?
>>>>
>>>> ---------- Forwarded message ----------
>>>> From: *Ferruh Yigit* <ferruh.yigit@intel.com <mailto:ferruh.yigit@intel.com>>
>>>> Date: Tue, Apr 3, 2018 at 7:18 AM
>>>> Subject: Re: [PATCH 3/4] mk: allow kernel artifacts to be located in output
>>>> directory
>>>> To: Scott Branden <scott.branden@broadcom.com
>>>> <mailto:scott.branden@broadcom.com>>, Ajit Khaparde
>>>> <ajit.khaparde@broadcom.com <mailto:ajit.khaparde@broadcom.com>>, dev@dpdk.org
>>>> <mailto:dev@dpdk.org>
>>>>
>>>>
>>>> On 3/30/2018 7:23 PM, Scott Branden wrote:
>>>>> Hi Ferruh,
>>>>>
>>>>>
>>>>> On 18-03-30 03:35 AM, Ferruh Yigit wrote:
>>>>>> On 3/21/2018 6:06 PM, Ajit Khaparde wrote:
>>>>>>> From: Scott Branden <scott.branden@broadcom.com
>>>> <mailto:scott.branden@broadcom.com>>
>>>>>>> Allow kernel artifacts to be located in output directory specific
>>>>>>> by RTE_KERNELDIR_OUT.
>>>>>> How to use this variable, I tried following but kernel modules are still in
>>>> same
>>>>>> place:
>>>>> export RTE_KERNELDIR and RTE_KERNELDIR_OUT and it works fine.
>>>>> RTE_KERNELDIR already exists in Makefile.  Are you able to override it?
>>>> Please help me a little more, can you please list your commands?
>>>>
>>>> Before your patch, what I do:
>>>>
>>>> export RTE_KERNELDIR=~/development/linux/linux
>>>> make defconfig
>>>> make    <--- After this kernel modules in ./build/kmod/*.ko
>>>> make DESTDIR=/tmp/for-scott install
>>>>
>>>> kernel modules are installed into /tmp/for-scott/lib/modules/`uname
>>>> -r`/extra/dpdk/*.ko
>>>>
>>>> Here `uname -r` is wrong but your patch is not related this.
>>>>
>>>> I am using RTE_KERNELDIR a lot since I am compiling with various kernel
>>>> versions, not seen .ko files goes into source folder, what is your command line?
>>>>
>>>>
>>>>
>>>> Or _after_ your patch:
>>>> export RTE_KERNELDIR=~/development/linux/linux
>>>> export RTE_KERNELDIR_OUT=/tmp/kmod
>>>> make defconfig
>>>> make    <--- After this kernel modules in ./build/kmod/*.ko
>>>>
>>>> Getting following build error:
>>>> /bin/sh: scripts/mod/modpost: No such file or directory
>>>> make[7]: *** [.../development/linux/linux/scripts/Makefile.modpost:92:
>>>> __modpost] Error 127
>>>> make[6]: *** [.../development/linux/linux/Makefile:1558: modules] Error 2
>>>> make[5]: *** [Makefile:146: sub-make] Error 2
>>>> make[4]: *** [../mk/rte.module.mk:54 <http://rte.module.mk:54>: igb_uio.ko]
>>>> Error 2
>>>>
>>>> Can you please describe how this variable intended to be used?
>>>>
>>>>
>>>>>> - make RTE_KERNELDIR_OUT=/tmp/kmod O=ferruh DESTDIR=/tmp/ferruh
>>>>>> - make RTE_KERNELDIR_OUT=/tmp/kmod O=ferruh DESTDIR=/tmp/ferruh install
>>>>>> - make RTE_KERNELDIR_OUT=/tmp/kmod O=ferruh DESTDIR=/tmp/ferruh modules_install
>>>>>>
>>>>>> /tmp/kmod not created.
>>>>>>
>>>>>> And what we are fixing here, what was wrong with old code?
>>>>> Old code puts the intermediate object files in the kernel source
>>>>> directory.  This doesn't work when building an external module in
>>>>> openembedded recipes.  We need the Makefile change to be able to able to
>>>>> specify the kernel and output directories separately.
>>>>>>> If RTE_KERNELDIR_OUT not specified than
>>>>>>> source directory RTE_KERNEL is used.
>>>>>> ${RTE_KERNELDIR} is used as external Linux kernel source folder, why we are
>>>> want
>>>>>> to put artifacts into kernel source?
>>>>> I just kept the default behaviour the same as what it does today.
>>>>>>> Signed-off-by: Scott Branden <scott.branden@broadcom.com
>>>> <mailto:scott.branden@broadcom.com>>
>>>>>>> Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com
>>>> <mailto:ajit.khaparde@broadcom.com>>
>>>>>>> ---
>>>>>>>     mk/rte.module.mk <http://rte.module.mk> | 9 ++++++---
>>>>>>>     1 file changed, 6 insertions(+), 3 deletions(-)
>>>>>>>
>>>>>>> diff --git a/mk/rte.module.mk <http://rte.module.mk> b/mk/rte.module.mk
>>>> <http://rte.module.mk>
>>>>>>> index 1ada528a0..e2e1af716 100644
>>>>>>> --- a/mk/rte.module.mk <http://rte.module.mk>
>>>>>>> +++ b/mk/rte.module.mk <http://rte.module.mk>
>>>>>>> @@ -39,6 +39,9 @@ _postinstall: build
>>>>>>>     .PHONY: build
>>>>>>>     build: _postbuild
>>>>>>>
>>>>>>> +# Allow kernel artifacts to be located in a different location that source
>>>>>>> +RTE_KERNELDIR_OUT ?= ${RTE_KERNELDIR}
>>>>>>> +
>>>>>>>     # Link all sources in build directory
>>>>>>>     %_link: FORCE
>>>>>>>       $(if $(call compare,$(notdir $*),$*),\
>>>>>>> @@ -48,7 +51,7 @@ build: _postbuild
>>>>>>>     # build module
>>>>>>>     $(MODULE).ko: $(SRCS_LINKS)
>>>>>>>       @if [ ! -f $(notdir Makefile) ]; then ln -nfs $(SRCDIR)/Makefile . ; fi
>>>>>>> -   @$(MAKE) -C $(RTE_KERNELDIR) M=$(CURDIR) O=$(RTE_KERNELDIR) \
>>>>>>> +   @$(MAKE) -C $(RTE_KERNELDIR) M=$(CURDIR) O=$(RTE_KERNELDIR_OUT) \
>>>>>>>               CC="$(KERNELCC)" CROSS_COMPILE=$(CROSS) V=$(if $V,1,0)
>>>>>>>
>>>>>>>     # install module in $(RTE_OUTPUT)/kmod
>>>>>>> @@ -59,7 +62,7 @@ $(RTE_OUTPUT)/kmod/$(MODULE).ko: $(MODULE).ko
>>>>>>>
>>>>>>>     # install module
>>>>>>>     modules_install:
>>>>>>> -   @$(MAKE) -C $(RTE_KERNELDIR) M=$(CURDIR) O=$(RTE_KERNELDIR) \
>>>>>>> +   @$(MAKE) -C $(RTE_KERNELDIR) M=$(CURDIR) O=$(RTE_KERNELDIR_OUT) \
>>>>>>>               modules_install
>>>>>>>
>>>>>>>     .PHONY: clean
>>>>>>> @@ -69,7 +72,7 @@ clean: _postclean
>>>>>>>     .PHONY: doclean
>>>>>>>     doclean:
>>>>>>>       @if [ ! -f $(notdir Makefile) ]; then ln -nfs $(SRCDIR)/Makefile . ; fi
>>>>>>> -   $(Q)$(MAKE) -C $(RTE_KERNELDIR) M=$(CURDIR) O=$(RTE_KERNELDIR) clean
>>>>>>> +   $(Q)$(MAKE) -C $(RTE_KERNELDIR) M=$(CURDIR) O=$(RTE_KERNELDIR_OUT) clean
>>>>>>>       @$(foreach FILE,$(SRCS-y) $(SRCS-n) $(SRCS-),\
>>>>>>>               if [ -h $(notdir $(FILE)) ]; then rm -f $(notdir $(FILE)) ; fi ;)
>>>>>>>       @if [ -h $(notdir Makefile) ]; then rm -f $(notdir Makefile) ; fi
>>>>>>>
>>>>> Regards,
>>>>>     Scott
>>>>>
>>>>
>