diff options
| author | Hengqi Chen <hengqi.chen@gmail.com> | 2025-10-02 22:39:52 +0800 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2025-10-02 22:39:52 +0800 |
| commit | ea645cfd3d5f74a2bd40a60003f113b3c467975d (patch) | |
| tree | 808189c4c66143a67ab5f181830be7ed586464dd | |
| parent | a04731cbee6e981afa4263289a0c0059c8b2e7b9 (diff) | |
LoongArch: BPF: Make trampoline size stable
When attach fentry/fexit BPF programs, __arch_prepare_bpf_trampoline()
is called twice with different `struct bpf_tramp_image *im`:
bpf_trampoline_update()
-> arch_bpf_trampoline_size()
-> __arch_prepare_bpf_trampoline()
-> arch_prepare_bpf_trampoline()
-> __arch_prepare_bpf_trampoline()
Use move_imm() will emit unstable instruction sequences, so let's use
move_addr() instead to prevent subtle bugs.
(I observed this while debugging other issues with printk.)
Cc: stable@vger.kernel.org
Tested-by: Vincent Li <vincent.mc.li@gmail.com>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
| -rw-r--r-- | arch/loongarch/net/bpf_jit.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c index 8d5547014b2c..a941a9f4c337 100644 --- a/arch/loongarch/net/bpf_jit.c +++ b/arch/loongarch/net/bpf_jit.c @@ -1595,7 +1595,7 @@ static int __arch_prepare_bpf_trampoline(struct jit_ctx *ctx, struct bpf_tramp_i orig_call += LOONGARCH_BPF_FENTRY_NBYTES; if (flags & BPF_TRAMP_F_CALL_ORIG) { - move_imm(ctx, LOONGARCH_GPR_A0, (const s64)im, false); + move_addr(ctx, LOONGARCH_GPR_A0, (const u64)im); ret = emit_call(ctx, (const u64)__bpf_tramp_enter); if (ret) return ret; @@ -1645,7 +1645,7 @@ static int __arch_prepare_bpf_trampoline(struct jit_ctx *ctx, struct bpf_tramp_i if (flags & BPF_TRAMP_F_CALL_ORIG) { im->ip_epilogue = ctx->ro_image + ctx->idx; - move_imm(ctx, LOONGARCH_GPR_A0, (const s64)im, false); + move_addr(ctx, LOONGARCH_GPR_A0, (const u64)im); ret = emit_call(ctx, (const u64)__bpf_tramp_exit); if (ret) goto out; |