From: Hou Tao <houtao1@huawei.com>
Date: Sun, 30 Jan 2022 17:29:15 +0800
Subject: bpf, arm64: Enable kfunc call
Patch-mainline: v5.18-rc1
Git-commit: b5e975d256dbfebd62413eb04fbff6803f02a43c
References: jsc#PED-1377

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@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220130092917.14544-2-hotforest@gmail.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 arch/arm64/net/bpf_jit_comp.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -1140,6 +1140,11 @@ out:
 	return prog;
 }
 
+bool bpf_jit_supports_kfunc_call(void)
+{
+	return true;
+}
+
 u64 bpf_jit_alloc_exec_limit(void)
 {
 	return BPF_JIT_REGION_SIZE;