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From: Hou Tao <houtao1@huawei.com>
To: John Fastabend <john.fastabend@gmail.com>,
	Alexei Starovoitov <ast@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>, Yonghong Song <yhs@fb.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Song Liu <songliubraving@fb.com>,
	"David S . Miller" <davem@davemloft.net>,
	<netdev@vger.kernel.org>, <bpf@vger.kernel.org>,
	Zi Shen Lim <zlim.lnx@gmail.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Julien Thierry <jthierry@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH bpf-next 2/2] arm64, bpf: support more atomic operations
Date: Fri, 28 Jan 2022 17:18:35 +0800	[thread overview]
Message-ID: <cf4f75c9-dccb-913f-4527-d358cf653f93@huawei.com> (raw)
In-Reply-To: <61f35869ba5a_738dc20823@john.notmuch>

Hi,

On 1/28/2022 10:43 AM, John Fastabend wrote:
> Hou Tao wrote:
>> Hi,
>>
>> On 1/27/2022 2:06 PM, John Fastabend wrote:
>>> Hou Tao wrote:
>>>> Atomics for eBPF patch series adds support for atomic[64]_fetch_add,
>>>> atomic[64]_[fetch_]{and,or,xor} and atomic[64]_{xchg|cmpxchg}, but
>>>> it only add support for x86-64, so support these atomic operations
>>>> for arm64 as well.
snip
>>>> +
>>>> +	switch (insn->imm) {
>>> Diff'ing X86 implementation which has a BPF_SUB case how is it avoided
>>> here?
>> I think it is just left over from patchset [1], because according to the LLVM
>> commit [2]
>> __sync_fetch_and_sub(&addr, value) is implemented by __sync_fetch_and_add(&addr,
>> -value).
>> I will post a patch to remove it.
> OK in that case LGTM with the caveat not an ARM expert.
>
> Acked-by: John Fastabend <john.fastabend@gmail.com>
Thanks for your Acked-by.

Regards,
Tao

WARNING: multiple messages have this Message-ID (diff)
From: Hou Tao <houtao1@huawei.com>
To: John Fastabend <john.fastabend@gmail.com>,
	Alexei Starovoitov <ast@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>, Yonghong Song <yhs@fb.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Song Liu <songliubraving@fb.com>,
	"David S . Miller" <davem@davemloft.net>,
	<netdev@vger.kernel.org>, <bpf@vger.kernel.org>,
	Zi Shen Lim <zlim.lnx@gmail.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Julien Thierry <jthierry@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH bpf-next 2/2] arm64, bpf: support more atomic operations
Date: Fri, 28 Jan 2022 17:18:35 +0800	[thread overview]
Message-ID: <cf4f75c9-dccb-913f-4527-d358cf653f93@huawei.com> (raw)
In-Reply-To: <61f35869ba5a_738dc20823@john.notmuch>

Hi,

On 1/28/2022 10:43 AM, John Fastabend wrote:
> Hou Tao wrote:
>> Hi,
>>
>> On 1/27/2022 2:06 PM, John Fastabend wrote:
>>> Hou Tao wrote:
>>>> Atomics for eBPF patch series adds support for atomic[64]_fetch_add,
>>>> atomic[64]_[fetch_]{and,or,xor} and atomic[64]_{xchg|cmpxchg}, but
>>>> it only add support for x86-64, so support these atomic operations
>>>> for arm64 as well.
snip
>>>> +
>>>> +	switch (insn->imm) {
>>> Diff'ing X86 implementation which has a BPF_SUB case how is it avoided
>>> here?
>> I think it is just left over from patchset [1], because according to the LLVM
>> commit [2]
>> __sync_fetch_and_sub(&addr, value) is implemented by __sync_fetch_and_add(&addr,
>> -value).
>> I will post a patch to remove it.
> OK in that case LGTM with the caveat not an ARM expert.
>
> Acked-by: John Fastabend <john.fastabend@gmail.com>
Thanks for your Acked-by.

Regards,
Tao

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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2022-01-28  9:18 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-21 13:56 [PATCH bpf-next 0/2] arm64, bpf: support more atomic ops Hou Tao
2022-01-21 13:56 ` Hou Tao
2022-01-21 13:56 ` [PATCH bpf-next 1/2] selftests/bpf: use raw_tp program for atomic test Hou Tao
2022-01-21 13:56   ` Hou Tao
2022-01-21 17:43   ` Andrii Nakryiko
2022-01-21 17:43     ` Andrii Nakryiko
2022-01-21 13:56 ` [PATCH bpf-next 2/2] arm64, bpf: support more atomic operations Hou Tao
2022-01-21 13:56   ` Hou Tao
2022-01-27  6:06   ` John Fastabend
2022-01-27  6:06     ` John Fastabend
2022-01-27  8:10     ` Hou Tao
2022-01-27  8:10       ` Hou Tao
2022-01-28  2:43       ` John Fastabend
2022-01-28  2:43         ` John Fastabend
2022-01-28  9:18         ` Hou Tao [this message]
2022-01-28  9:18           ` Hou Tao
2022-01-28 10:06   ` Daniel Borkmann
2022-01-28 10:06     ` Daniel Borkmann
2022-01-28 10:16   ` Mark Rutland
2022-01-28 10:16     ` Mark Rutland
2022-01-28 16:15     ` Yonghong Song
2022-01-28 16:15       ` Yonghong Song

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