From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 4725D42A79F; Mon, 6 Jul 2026 06:46:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.242.206.163 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783320392; cv=none; b=PCpAXvgDgJc4smpSi7g19NNsu8lvHSh9m50MtgAk8k3cf2V7slVZ4HqKkbg28OAF9rhomcmW8+Px0z2tHweBAPcgJIu8lmkUtIr3Po7fyS2LBQ9cmTmtb8wtdH2E7YdXQb1AB1dtrez3SWPE7eL5jnovKtyDHVth+VJ5Mmyptmw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783320392; c=relaxed/simple; bh=e83rGfsw7ahDdPokrwquGPwhn58FshJu2zDl5WGH2nE=; h=Subject:To:Cc:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=gI8lB2VaJc8Q50Vv51Lb3nAX+6Jfk0mLMzf5WAfRxgLhGgQBPeg7ByaJg0/nfuJJ1rMJhxovJ3jJwMlIt2E28WeN4VyJVfALpXuY85HVgrDcMKS614Jc7NmP/OWFf6xEtPk338rbgf9vfPsMQyVNSwMVKSQqFO31P7D83fhdGv8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn; spf=pass smtp.mailfrom=loongson.cn; arc=none smtp.client-ip=114.242.206.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=loongson.cn Received: from loongson.cn (unknown [113.200.148.30]) by gateway (Coremail) with SMTP id _____8Axx+o2T0tq9FAAAA--.1537S3; Mon, 06 Jul 2026 14:46:14 +0800 (CST) Received: from [10.130.40.83] (unknown [113.200.148.30]) by front1 (Coremail) with SMTP id qMiowJCxLcUyT0tqa+kBAA--.234S3; Mon, 06 Jul 2026 14:46:11 +0800 (CST) Subject: Re: [PATCH bpf-next v2 02/11] LoongArch: BPF: Support internal-only MOV to resolve per-CPU addrs To: George Guo , Huacai Chen , Hengqi Chen , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: WANG Xuerui , Martin KaFai Lau , Eduard Zingerman , Kumar Kartikeya Dwivedi , Song Liu , Yonghong Song , Jiri Olsa , George Guo , bpf@vger.kernel.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org References: <20260702022322.51033-1-dongtai.guo@linux.dev> <20260702022322.51033-3-dongtai.guo@linux.dev> From: Tiezhu Yang Message-ID: Date: Mon, 6 Jul 2026 14:46:10 +0800 User-Agent: Mozilla/5.0 (X11; Linux loongarch64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20260702022322.51033-3-dongtai.guo@linux.dev> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-CM-TRANSID:qMiowJCxLcUyT0tqa+kBAA--.234S3 X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ X-Coremail-Antispam: 1Uk129KBj93XoW7Aw1DCr4xuw1fKFyxAFW7WrX_yoW8ZFy8pF nrArs5GFWvgr13Gwsrtw43Wr15Can3Cr4agr9FkrWUAr9xZry8XF10k3sxWF95Jw4rWryS grsakw1a9F1DXabCm3ZEXasCq-sJn29KB7ZKAUJUUUUx529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUPqb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Gr0_Xr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AK xVWxJr0_GcWln4kS14v26r126r1DM2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6xkI12 xvs2x26I8E6xACxx1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1q 6rW5McIj6I8E87Iv67AKxVWxJVW8Jr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcVAKI4 8JMxk0xIA0c2IEe2xFo4CEbIxvr21lc7CjxVAaw2AFwI0_Jw0_GFyl42xK82IYc2Ij64vI r41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1l4IxYO2xFxVAFwI0_JF0_Jw1lx2IqxVAqx4xG67 AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MIIY rxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Gr0_Xr1lIxAIcVC0I7IYx2IY6xkF7I0E14 v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWxJVW8 Jr1lIxAIcVC2z280aVCY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x07jjLv tUUUUU= On 2026/7/2 上午10:23, George Guo wrote: > From: George Guo > > Support the internal-only BPF_MOV instruction that resolves the absolute > address of per-CPU data from its per-CPU offset. This instruction is used > only for internal inlining optimizations between the BPF verifier and the > JITs (e.g. inlining bpf_get_smp_processor_id() and per-CPU map lookups). > > LoongArch keeps the per-CPU offset of the current CPU in $r21 > (__my_cpu_offset), so resolving a per-CPU address only requires adding > $r21 to the source register holding the per-CPU offset. Advertise the > capability via bpf_jit_supports_percpu_insn(). > > Signed-off-by: George Guo > --- > arch/loongarch/include/asm/inst.h | 1 + > arch/loongarch/net/bpf_jit.c | 14 ++++++++++++++ > 2 files changed, 15 insertions(+) > > diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h > index 76b723590023..44fb5ad26d1a 100644 > --- a/arch/loongarch/include/asm/inst.h > +++ b/arch/loongarch/include/asm/inst.h > @@ -404,6 +404,7 @@ enum loongarch_gpr { > LOONGARCH_GPR_T6, > LOONGARCH_GPR_T7, > LOONGARCH_GPR_T8, > + LOONGARCH_GPR_U0 = 21, /* Kernel per-CPU base register ($r21) */ > LOONGARCH_GPR_FP = 22, > LOONGARCH_GPR_S0 = 23, > LOONGARCH_GPR_S1, > diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c > index 5e34e9e3f508..b4208fa3a242 100644 > --- a/arch/loongarch/net/bpf_jit.c > +++ b/arch/loongarch/net/bpf_jit.c > @@ -759,6 +759,15 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext > move_reg(ctx, dst, t1); > break; > } > + if (insn_is_mov_percpu_addr(insn)) { > + if (dst != src) > + move_reg(ctx, dst, src); > +#ifdef CONFIG_SMP > + /* dst += __my_cpu_offset, held in $r21 */ > + emit_insn(ctx, addd, dst, dst, LOONGARCH_GPR_U0); > +#endif How to test? Did you test under !CONFIG_SMP? Thanks, Tiezhu