| Message ID | 1690268708-5899-1-git-send-email-yangtiezhu@loongson.cn (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next] LoongArch: BPF: Fix check condition to call lu32id in move_imm() | expand |
Queued for loongarch-next, thanks. Huacai On Tue, Jul 25, 2023 at 3:05 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote: > > 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> > --- > 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 > >
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);
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> --- arch/loongarch/net/bpf_jit.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)