From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C6E0917727; Mon, 27 May 2024 19:30:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716838242; cv=none; b=bhPskBFm5fIIk4k+1gSG+i+6PfxvRXy40gqp85yLX+ArSGUMHBZvybO/89SzScpZ6YzyOqbHL8efB1D/KlUAj9VqS63uMYZqyI9j6B6E+9KxNID0D/H6msG32qQOB+Vq+9HB1sM5VXoVHaWXmhToOW7oyB4u9UOp1vgbNG06Grg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716838242; c=relaxed/simple; bh=Ynj7gzcMHwIorxOSzXhZa1/ASWNG270OzG7BKaLPbRw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oKKZS8oVfBJ1b218JszbCBnppyn5hL6myKEr2sCK47kWavVzGmg01ZbdjxooCTnsaO755DswBomes/V/1EPBdD9eHkkRQah33MVTmhbU4zfFwvSaC3zJF2/PO+LP3GtQo2MkhWM+x32b/7w9KEWNBE5c43bgMZYpYeFW99JEoqE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=NDW3oliQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="NDW3oliQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 562AAC2BBFC; Mon, 27 May 2024 19:30:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1716838242; bh=Ynj7gzcMHwIorxOSzXhZa1/ASWNG270OzG7BKaLPbRw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NDW3oliQ7ULC06LS+a1jAQCWxttAL1JpWpRnoWSyXtNzGDQ/oxp2uy5+Ivj//yx0H wxyi7cpsTbyhSAhK8bxX/lFLNLCPYEKFY1rDRKvv6ClGQ24/w8d08l45NtPCYNZ8wE WfG2J7vrAYVcEtWhWW4bKrV0/3y6v20Tv/AA7tes= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Puranjay Mohan , Pu Lehui , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.8 320/493] riscv, bpf: make some atomic operations fully ordered Date: Mon, 27 May 2024 20:55:22 +0200 Message-ID: <20240527185640.748055457@linuxfoundation.org> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240527185626.546110716@linuxfoundation.org> References: <20240527185626.546110716@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Puranjay Mohan [ Upstream commit 20a759df3bba35bf5c3ddec0c02ad69b603b584c ] The BPF atomic operations with the BPF_FETCH modifier along with BPF_XCHG and BPF_CMPXCHG are fully ordered but the RISC-V JIT implements all atomic operations except BPF_CMPXCHG with relaxed ordering. Section 8.1 of the "The RISC-V Instruction Set Manual Volume I: Unprivileged ISA" [1], titled, "Specifying Ordering of Atomic Instructions" says: | To provide more efficient support for release consistency [5], each | atomic instruction has two bits, aq and rl, used to specify additional | memory ordering constraints as viewed by other RISC-V harts. and | If only the aq bit is set, the atomic memory operation is treated as | an acquire access. | If only the rl bit is set, the atomic memory operation is treated as a | release access. | | If both the aq and rl bits are set, the atomic memory operation is | sequentially consistent. Fix this by setting both aq and rl bits as 1 for operations with BPF_FETCH and BPF_XCHG. [1] https://riscv.org/wp-content/uploads/2017/05/riscv-spec-v2.2.pdf Fixes: dd642ccb45ec ("riscv, bpf: Implement more atomic operations for RV64") Signed-off-by: Puranjay Mohan Reviewed-by: Pu Lehui Link: https://lore.kernel.org/r/20240505201633.123115-1-puranjay@kernel.org Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- arch/riscv/net/bpf_jit_comp64.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 0bd747d1d00fc..29f031f68f480 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -516,33 +516,33 @@ static void emit_atomic(u8 rd, u8 rs, s16 off, s32 imm, bool is64, break; /* src_reg = atomic_fetch_(dst_reg + off16, src_reg) */ case BPF_ADD | BPF_FETCH: - emit(is64 ? rv_amoadd_d(rs, rs, rd, 0, 0) : - rv_amoadd_w(rs, rs, rd, 0, 0), ctx); + emit(is64 ? rv_amoadd_d(rs, rs, rd, 1, 1) : + rv_amoadd_w(rs, rs, rd, 1, 1), ctx); if (!is64) emit_zext_32(rs, ctx); break; case BPF_AND | BPF_FETCH: - emit(is64 ? rv_amoand_d(rs, rs, rd, 0, 0) : - rv_amoand_w(rs, rs, rd, 0, 0), ctx); + emit(is64 ? rv_amoand_d(rs, rs, rd, 1, 1) : + rv_amoand_w(rs, rs, rd, 1, 1), ctx); if (!is64) emit_zext_32(rs, ctx); break; case BPF_OR | BPF_FETCH: - emit(is64 ? rv_amoor_d(rs, rs, rd, 0, 0) : - rv_amoor_w(rs, rs, rd, 0, 0), ctx); + emit(is64 ? rv_amoor_d(rs, rs, rd, 1, 1) : + rv_amoor_w(rs, rs, rd, 1, 1), ctx); if (!is64) emit_zext_32(rs, ctx); break; case BPF_XOR | BPF_FETCH: - emit(is64 ? rv_amoxor_d(rs, rs, rd, 0, 0) : - rv_amoxor_w(rs, rs, rd, 0, 0), ctx); + emit(is64 ? rv_amoxor_d(rs, rs, rd, 1, 1) : + rv_amoxor_w(rs, rs, rd, 1, 1), ctx); if (!is64) emit_zext_32(rs, ctx); break; /* src_reg = atomic_xchg(dst_reg + off16, src_reg); */ case BPF_XCHG: - emit(is64 ? rv_amoswap_d(rs, rs, rd, 0, 0) : - rv_amoswap_w(rs, rs, rd, 0, 0), ctx); + emit(is64 ? rv_amoswap_d(rs, rs, rd, 1, 1) : + rv_amoswap_w(rs, rs, rd, 1, 1), ctx); if (!is64) emit_zext_32(rs, ctx); break; -- 2.43.0