netdev - [PATCH bpf-next] bpf, arm64: enable kfunc call

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Date:   Wed, 19 Jan 2022 22:49:42 +0800
From:   Hou Tao <houtao1@...wei.com>
To:     Alexei Starovoitov <ast@...nel.org>,
        Ard Biesheuvel <ard.biesheuvel@....com>
CC:     Martin KaFai Lau <kafai@...com>, Yonghong Song <yhs@...com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Zi Shen Lim <zlim.lnx@...il.com>,
        Will Deacon <will@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        <netdev@...r.kernel.org>, <bpf@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>, <houtao1@...wei.com>
Subject: [PATCH bpf-next] bpf, arm64: enable kfunc call

Since commit b2eed9b58811 ("arm64/kernel: kaslr: reduce module
randomization range to 2 GB"), for arm64 whether KASLR is enabled
or not, the module is placed within 2GB of the kernel region, so
s32 in bpf_kfunc_desc is sufficient to represente the offset of
module function relative to __bpf_call_base. The only thing needed
is to override bpf_jit_supports_kfunc_call().

Signed-off-by: Hou Tao <houtao1@...wei.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 e96d4d87291f..74f9a9b6a053 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -1143,6 +1143,11 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 	return prog;
 }
 
+bool bpf_jit_supports_kfunc_call(void)
+{
+	return true;
+}
+
 u64 bpf_jit_alloc_exec_limit(void)
 {
 	return VMALLOC_END - VMALLOC_START;
-- 
2.27.0