From: Tiezhu Yang yangtiezhu@loongson.cn
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 --- arch/loongarch/net/bpf_jit.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/loongarch/net/bpf_jit.h +++ b/arch/loongarch/net/bpf_jit.h @@ -150,7 +150,7 @@ static inline void move_imm(struct jit_c * 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);