[PATCH bpf-next 1/2] bpf, arm64: Enable the inline of bpf_kptr_xchg()

From: Hou Tao <houtao@huaweicloud.com>
To: bpf@vger.kernel.org
Cc: Martin KaFai Lau <martin.lau@linux.dev>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Andrii Nakryiko <andrii@kernel.org>, Song Liu <song@kernel.org>,
	Hao Luo <haoluo@google.com>,
	Yonghong Song <yonghong.song@linux.dev>,
	Daniel Borkmann <daniel@iogearbox.net>,
	KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@google.com>, Jiri Olsa <jolsa@kernel.org>,
	John Fastabend <john.fastabend@gmail.com>,
	Zi Shen Lim <zlim.lnx@gmail.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	houtao1@huawei.com
Subject: [PATCH bpf-next 1/2] bpf, arm64: Enable the inline of bpf_kptr_xchg()
Date: Fri, 19 Jan 2024 18:25:28 +0800	[thread overview]
Message-ID: <20240119102529.99581-2-houtao@huaweicloud.com> (raw)
In-Reply-To: <20240119102529.99581-1-houtao@huaweicloud.com>

From: Hou Tao <houtao1@huawei.com>

ARM64 bpf jit satisfies the following two conditions:
1) support BPF_XCHG() on pointer-sized word.
2) the implementation of xchg is the same as atomic_xchg() on
   pointer-sized words. Both of these two functions use arch_xchg() to
   implement the exchange.

So enable the inline of bpf_kptr_xchg() for arm64 bpf jit.

Signed-off-by: Hou Tao <houtao1@huawei.com>
---
 arch/arm64/net/bpf_jit_comp.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 8955da5c47cf7..cfd5434de4832 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -2305,3 +2305,8 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type poke_type,
 
 	return ret;
 }
+
+bool bpf_jit_supports_ptr_xchg(void)
+{
+	return true;
+}
-- 
2.29.2

