diff options
| author | Chenghao Duan <duanchenghao@kylinos.cn> | 2025-12-31 15:19:21 +0800 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2025-12-31 15:19:21 +0800 |
| commit | 73721d8676771c6c7b06d4e636cc053fc76afefd (patch) | |
| tree | 6d780fc13cdbde85daf4da92984b9cb6f3b96c16 /arch | |
| parent | 26138762d9a27a7f1c33f467c4123c600f64a36e (diff) | |
LoongArch: BPF: Enhance the bpf_arch_text_poke() function
Enhance the bpf_arch_text_poke() function to enable accurate location
of BPF program entry points.
When modifying the entry point of a BPF program, skip the "move t0, ra"
instruction to ensure the correct logic and copy of the jump address.
Cc: stable@vger.kernel.org
Fixes: 677e6123e3d2 ("LoongArch: BPF: Disable trampoline for kernel module function trace")
Signed-off-by: Chenghao Duan <duanchenghao@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/loongarch/net/bpf_jit.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c index 9f6e93343b6e..d1d5a65308b9 100644 --- a/arch/loongarch/net/bpf_jit.c +++ b/arch/loongarch/net/bpf_jit.c @@ -1309,15 +1309,30 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type old_t, { int ret; bool is_call; + unsigned long size = 0; + unsigned long offset = 0; + void *image = NULL; + char namebuf[KSYM_NAME_LEN]; u32 old_insns[LOONGARCH_LONG_JUMP_NINSNS] = {[0 ... 4] = INSN_NOP}; u32 new_insns[LOONGARCH_LONG_JUMP_NINSNS] = {[0 ... 4] = INSN_NOP}; /* 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)) + if (!__bpf_address_lookup((unsigned long)ip, &size, &offset, namebuf)) return -ENOTSUPP; + image = ip - offset; + + /* zero offset means we're poking bpf prog entry */ + if (offset == 0) { + /* skip to the nop instruction in bpf prog entry: + * move t0, ra + * nop + */ + ip = image + LOONGARCH_INSN_SIZE; + } + is_call = old_t == BPF_MOD_CALL; ret = emit_jump_or_nops(old_addr, ip, old_insns, is_call); if (ret) |