From: Hengqi Chen Date: Thu, 2 Oct 2025 14:39:52 +0000 (+0800) Subject: LoongArch: BPF: No text_poke() for kernel text X-Git-Tag: v6.18-rc1~56^2~6 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3d770bd11b943066db11dba7be0b6f0d81cb5d50;p=thirdparty%2Fkernel%2Fstable.git LoongArch: BPF: No text_poke() for kernel text The current implementation of bpf_arch_text_poke() requires 5 nops at patch site which is not applicable for kernel/module functions. Because LoongArch reserves ONLY 2 nops at the function entry. With CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS=y, this can be done by ftrace instead. See the following commit for details: * commit b91e014f078e ("bpf: Make BPF trampoline use register_ftrace_direct() API") * commit 9cdc3b6a299c ("LoongArch: ftrace: Add direct call support") Cc: stable@vger.kernel.org Tested-by: Vincent Li Signed-off-by: Hengqi Chen Signed-off-by: Huacai Chen --- diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c index bee2e8e340e7..33e8942cc961 100644 --- a/arch/loongarch/net/bpf_jit.c +++ b/arch/loongarch/net/bpf_jit.c @@ -1292,8 +1292,10 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type poke_type, u32 old_insns[LOONGARCH_LONG_JUMP_NINSNS] = {[0 ... 4] = INSN_NOP}; u32 new_insns[LOONGARCH_LONG_JUMP_NINSNS] = {[0 ... 4] = INSN_NOP}; - if (!is_kernel_text((unsigned long)ip) && - !is_bpf_text_address((unsigned long)ip)) + /* Only poking bpf text is supported. Since kernel function entry + * is set up by ftrace, we rely on ftrace to poke kernel functions. + */ + if (!is_bpf_text_address((unsigned long)ip)) return -ENOTSUPP; ret = emit_jump_or_nops(old_addr, ip, old_insns, is_call);