From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6828B271471 for ; Tue, 9 Jun 2026 04:15:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780978536; cv=none; b=XADSWOxEenZX7hJZLxIIirpl/zCeHy/PIhVExDnhMOR9TbnC4zVLtHzGYhbt5V+3M/12AGmY9KaJ/dzcx0jZxKrwxQxxCirKNwB4g+3JY0ClgyLOuZM3VQEZoVRVOKL4Y1AMA/Iun6EBHEEFqreinT+JygBI5Vvo/2aTxXnVmzc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780978536; c=relaxed/simple; bh=wpbJHpxad+7JGWSjJRRls0fRZwwrcJLgft4B7iXSC0k=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=klaUahqHeEwjza/VjyA4L+g7dyH5x4Z+zvXeLAcpeykpl2FEE5GuHgaUMxMBuXKtZTwIvqAWoezTmUwz9avosXyMPaxJ9Ft2apPdZkMZZGgA+4yYoCBOWgpCEirsQgg4EO2NDgZgfsWomnsT4t7XGXDtUymjU5VZ1xBytPrQgkY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=TOiHzgak; arc=none smtp.client-ip=91.218.175.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="TOiHzgak" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1780978533; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=RWpTHfWWZUVThXrKoJmnC/j3bJH8+PPCY8BiE0/Gy6Q=; b=TOiHzgakf1wOTnqrq+QC64QowG3xa3xpYnlFIwMXgfzIB6sQTyjNgooLBEpQjR+dvHcpKD RwRU28FwCD6ux6c4XLyQEBkjeFsIsEadW8c8Hu7JTFhbv7nueawqx68KpyduZ89sMfwpwc gnntFOxndwhsg3y1XOtlHfRld8ssIQQ= From: George Guo To: Huacai Chen , Tiezhu Yang , Hengqi Chen Cc: WANG Xuerui , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Kumar Kartikeya Dwivedi , Song Liu , Yonghong Song , Jiri Olsa , loongarch@lists.linux.dev, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, George Guo Subject: [PATCH v1 1/2] LoongArch: BPF: Support internal-only MOV to resolve per-CPU addrs Date: Tue, 9 Jun 2026 12:14:06 +0800 Message-Id: <20260609041407.122384-2-dongtai.guo@linux.dev> In-Reply-To: <20260609041407.122384-1-dongtai.guo@linux.dev> References: <20260609041407.122384-1-dongtai.guo@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 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), and is not exposed to BPF users. 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 24913dc7f4e8..20d5bf792108 100644 --- a/arch/loongarch/net/bpf_jit.c +++ b/arch/loongarch/net/bpf_jit.c @@ -728,6 +728,15 @@ 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 + break; + } switch (off) { case 0: move_reg(ctx, dst, src); @@ -2362,6 +2371,11 @@ bool bpf_jit_supports_fsession(void) return true; } +bool bpf_jit_supports_percpu_insn(void) +{ + return true; +} + /* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */ bool bpf_jit_supports_subprog_tailcalls(void) { -- 2.25.1