LoongArch: BPF: Fix check condition to call lu32id in move_imm()

commit 4eece7e6de94d833c8aeed2f438faf487cbf94ff upstream.

As the code comment says, the initial aim is to reduce one instruction
in some corner cases, if bit[51:31] is all 0 or all 1, no need to call
lu32id. That is to say, it should call lu32id only if bit[51:31] is not
all 0 and not all 1. The current code always call lu32id, the result is
right but the logic is unexpected and wrong, fix it.

Cc: stable@vger.kernel.org # 6.1
Fixes: 5dc615520c4d ("LoongArch: Add BPF JIT support")
Reported-by: Colin King (gmail) <colin.i.king@gmail.com>
Closes: https://lore.kernel.org/all/bcf97046-e336-712a-ac68-7fd194f2953e@gmail.com/
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/loongarch/net/bpf_jit.h b/arch/loongarch/net/bpf_jit.h
index 093885539e701d0822aa2279368460cf4f0af911..684b22f54ccc63dc47d2d6e02dd02e7f64e7e30c 100644 (file)
--- a/arch/loongarch/net/bpf_jit.h
+++ b/arch/loongarch/net/bpf_jit.h
@@ -148,7 +148,7 @@ static inline void move_imm(struct jit_ctx *ctx, enum loongarch_gpr rd, long imm
                         * no need to call lu32id to do a new filled operation.
                         */
                        imm_51_31 = (imm >> 31) & 0x1fffff;
-                       if (imm_51_31 != 0 || imm_51_31 != 0x1fffff) {
+                       if (imm_51_31 != 0 && imm_51_31 != 0x1fffff) {
                                /* lu32id rd, imm_51_32 */
                                imm_51_32 = (imm >> 32) & 0xfffff;
                                emit_insn(ctx, lu32id, rd, imm_51_32);