Re: [PATCH v4] perf: bpf: Fix build breakage due to libbpf

From: Wangnan (F)
Date: Wed Dec 16 2015 - 20:31:20 EST




On 2015/12/17 3:42, Arnaldo Carvalho de Melo wrote:
Em Tue, Dec 15, 2015 at 05:10:46PM +0530, Naveen N. Rao escreveu:
On 2015/12/15 08:51AM, Wang Nan wrote:
From: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx>

perf build is currently (v4.4-rc5) broken on powerpc:

bpf.c:28:4: error: #error __NR_bpf not defined. libbpf does not support
your arch.
# error __NR_bpf not defined. libbpf does not support your arch.
^

Fix this by including tools/scripts/Makefile.arch for the proper
$ARCH macro. While at it, remove redundant LP64 macro definition.

Also, since libbpf require $(srctree) now, detect the path of
srctree like perf.

Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
---

v3 -> v4: Add srctree detector code so directly run 'make' in libbpf
directory would not cause error.
Good catch!

Tested-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
Trying to apply the patchkit:

[acme@zoo linux]$ make -C tools clean > /dev/null 2>&1
[acme@zoo linux]$ make -C tools/perf build-test
make: Entering directory '/home/git/linux/tools/perf'
Testing Makefile
tests/make:15: /scripts/Makefile.arch: No such file or directory
make[2]: *** No rule to make target '/scripts/Makefile.arch'. Stop.
tests/make:5: recipe for target 'all' failed
make[1]: *** [all] Error 2
Makefile:81: recipe for target 'build-test' failed
make: *** [build-test] Error 2
make: Leaving directory '/home/git/linux/tools/perf'
[acme@zoo linux]$

What am I doing wrong?

You need all 3 patches. This v4 patch is a fix for previous v3 3/3 and I send
this patch by replying that one. I thought your email client is sorted by thread
so you can easily find it but it seems I was wrong...

The whole thread is:

[PATCH v3 0/3] perf build: PowerPC: Fix build breakage due to libbpf:
http://lkml.kernel.org/g/1450150557-127942-1-git-send-email-wangnan0@xxxxxxxxxx

[PATCH v3 1/3] perf tools: Fix PowerPC native building
http://lkml.kernel.org/g/1450150557-127942-2-git-send-email-wangnan0@xxxxxxxxxx

[PATCH v3 2/3] tools: Move Makefile.arch from perf/config to tools/scripts
http://lkml.kernel.org/g/1450150557-127942-3-git-send-email-wangnan0@xxxxxxxxxx

[PATCH v3 3/3] perf: bpf: Fix build breakage due to libbpf
http://lkml.kernel.org/g/1450150557-127942-4-git-send-email-wangnan0@xxxxxxxxxx

and [PATCH v3 3/3] breaks local building because the usage of "srctree", and
I fix it in this one.

Thanks.


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