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@xxxxxxxxxxxxxxx # 6.1
Fixes: 5dc615520c4d ("LoongArch: Add BPF JIT support")
Reported-by: Colin King (gmail) <colin.i.king@xxxxxxxxx>
Closes: https://lore.kernel.org/all/bcf97046-e336-712a-ac68-7fd194f2953e@xxxxxxxxx/
Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
---
arch/loongarch/net/bpf_jit.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/loongarch/net/bpf_jit.h b/arch/loongarch/net/bpf_jit.h
index c335dc4..6858633 100644
--- 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_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);
--
2.1.0
