From: Daniel Borkmann <daniel@iogearbox•net>
To: Alexei Starovoitov <ast@fb•com>,
"Naveen N. Rao" <naveen.n.rao@linux•vnet.ibm.com>,
linux-kernel@vger•kernel.org, linuxppc-dev@lists•ozlabs.org
Cc: "David S . Miller" <davem@davemloft•net>,
Ananth N Mavinakayanahalli <ananth@in•ibm.com>,
Michael Ellerman <mpe@ellerman•id.au>,
netdev@vger•kernel.org
Subject: Re: [PATCH 2/4] samples/bpf: Use llc in PATH, rather than a hardcoded value
Date: Thu, 31 Mar 2016 20:19:24 +0200 [thread overview]
Message-ID: <56FD6A2C.2010506@iogearbox.net> (raw)
In-Reply-To: <56FD627D.5080405@fb.com>
On 03/31/2016 07:46 PM, Alexei Starovoitov wrote:
> On 3/31/16 4:25 AM, Naveen N. Rao wrote:
>> While at it, fix some typos in the comment.
>>
>> Cc: Alexei Starovoitov <ast@fb•com>
>> Cc: David S. Miller <davem@davemloft•net>
>> Cc: Ananth N Mavinakayanahalli <ananth@in•ibm.com>
>> Cc: Michael Ellerman <mpe@ellerman•id.au>
>> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux•vnet.ibm.com>
>> ---
>> samples/bpf/Makefile | 11 ++++-------
>> 1 file changed, 4 insertions(+), 7 deletions(-)
>>
>> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
>> index 502c9fc..88bc5a0 100644
>> --- a/samples/bpf/Makefile
>> +++ b/samples/bpf/Makefile
>> @@ -76,16 +76,13 @@ HOSTLOADLIBES_offwaketime += -lelf
>> HOSTLOADLIBES_spintest += -lelf
>> HOSTLOADLIBES_map_perf_test += -lelf -lrt
>>
>> -# point this to your LLVM backend with bpf support
>> -LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc
>> -
>> -# asm/sysreg.h inline assmbly used by it is incompatible with llvm.
>> -# But, ehere is not easy way to fix it, so just exclude it since it is
>> +# asm/sysreg.h - inline assembly used by it is incompatible with llvm.
>> +# But, there is no easy way to fix it, so just exclude it since it is
>> # useless for BPF samples.
>> $(obj)/%.o: $(src)/%.c
>> clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \
>> -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \
>> - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=obj -o $@
>> + -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=obj -o $@
>> clang $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) \
>> -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \
>> - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=asm -o $@.s
>> + -O2 -emit-llvm -c $< -o -| llc -march=bpf -filetype=asm -o $@.s
>
> that was a workaround when clang/llvm didn't have bpf support.
> Now clang 3.7 and 3.8 have bpf built-in, so make sense to remove
> manual calls to llc completely.
> Just use 'clang -target bpf -O2 -D... -c $< -o $@'
+1, the clang part in that Makefile should also more correctly be called
with '-target bpf' as it turns out (despite llc with '-march=bpf' ...).
Better to use clang directly as suggested by Alexei.
next prev parent reply other threads:[~2016-03-31 18:19 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <922f95fb5d16686367a66d2d4bd176149a87e9ad.1459423412.git.naveen.n.rao@linux.vnet.ibm.com>
2016-03-31 17:43 ` [PATCH 1/4] samples/bpf: Fix build breakage with map_perf_test_user.c Alexei Starovoitov
2016-03-31 18:46 ` Naveen N. Rao
2016-03-31 19:19 ` Alexei Starovoitov
[not found] ` <ba23d688b3550c3f22dd0dd6d5cb1233c2f34816.1459423412.git.naveen.n.rao@linux.vnet.ibm.com>
2016-03-31 17:46 ` [PATCH 2/4] samples/bpf: Use llc in PATH, rather than a hardcoded value Alexei Starovoitov
2016-03-31 18:19 ` Daniel Borkmann [this message]
2016-04-01 14:37 ` Naveen N. Rao
2016-04-01 17:56 ` Alexei Starovoitov
[not found] ` <0ce1c8bdff478db55490a90db6732c4db9de6f22.1459423412.git.naveen.n.rao@linux.vnet.ibm.com>
2016-03-31 17:49 ` [PATCH 3/4] samples/bpf: Simplify building BPF samples Alexei Starovoitov
2016-03-31 18:51 ` Naveen N. Rao
2016-03-31 19:20 ` Alexei Starovoitov
[not found] ` <28a3811d03f6e8f7dca989a4ade536bf9aa8c7ce.1459423412.git.naveen.n.rao@linux.vnet.ibm.com>
2016-03-31 17:52 ` [PATCH 4/4] samples/bpf: Enable powerpc support Alexei Starovoitov
2016-04-01 14:41 ` Naveen N. Rao
2016-04-01 17:58 ` Alexei Starovoitov
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