From patchwork Sun Oct 31 16:42:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Taylor Simpson X-Patchwork-Id: 12595335 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3FF6C433EF for ; Sun, 31 Oct 2021 16:51:24 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7FBFA60F58 for ; Sun, 31 Oct 2021 16:51:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 7FBFA60F58 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=quicinc.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:34836 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mhE3H-00066q-Dk for qemu-devel@archiver.kernel.org; Sun, 31 Oct 2021 12:51:23 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35644) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mhDvl-0001YB-Ui for qemu-devel@nongnu.org; Sun, 31 Oct 2021 12:43:37 -0400 Received: from alexa-out-sd-02.qualcomm.com ([199.106.114.39]:21617) by eggs.gnu.org with esmtps (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1mhDvj-0008Bi-HU for qemu-devel@nongnu.org; Sun, 31 Oct 2021 12:43:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1635698615; x=1667234615; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=KzxKZ/0Ni1ktOdqJ9ABgsTZKs3Zxbp/6oRoRM0oa4mw=; b=Esi377OAqHhLdkNtxMuzDNqJArhSQzYjFBargTETegkzvglJFJtMezwO E0iiRK2sqSKV2jpWF3NJzYtp/Qjcj3Nrprh/zWWIVCFd8RzFJNDQnSMbi 8WPgMxqcujUznVKgngRDh3EWl1vbN6Y1X6CSIm4gOVamYWn3ZnAs1+LHn Q=; Received: from unknown (HELO ironmsg03-sd.qualcomm.com) ([10.53.140.143]) by alexa-out-sd-02.qualcomm.com with ESMTP; 31 Oct 2021 09:43:30 -0700 X-QCInternal: smtphost Received: from vu-tsimpson-aus.qualcomm.com (HELO vu-tsimpson1-aus.qualcomm.com) ([10.222.150.1]) by ironmsg03-sd.qualcomm.com with ESMTP; 31 Oct 2021 09:43:29 -0700 Received: by vu-tsimpson1-aus.qualcomm.com (Postfix, from userid 47164) id 4C14D1B42; Sun, 31 Oct 2021 11:43:29 -0500 (CDT) From: Taylor Simpson To: qemu-devel@nongnu.org Subject: [PULL 01/30] Hexagon HVX (target/hexagon) README Date: Sun, 31 Oct 2021 11:42:40 -0500 Message-Id: <1635698589-31849-2-git-send-email-tsimpson@quicinc.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1635698589-31849-1-git-send-email-tsimpson@quicinc.com> References: <1635698589-31849-1-git-send-email-tsimpson@quicinc.com> MIME-Version: 1.0 Received-SPF: pass client-ip=199.106.114.39; envelope-from=tsimpson@qualcomm.com; helo=alexa-out-sd-02.qualcomm.com X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=0.248, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, tsimpson@quicinc.com, richard.henderson@linaro.org, f4bug@amsat.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Reviewed-by: Richard Henderson Signed-off-by: Taylor Simpson --- target/hexagon/README | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 80 insertions(+), 1 deletion(-) diff --git a/target/hexagon/README b/target/hexagon/README index b0b2435..372e247 100644 --- a/target/hexagon/README +++ b/target/hexagon/README @@ -1,9 +1,13 @@ Hexagon is Qualcomm's very long instruction word (VLIW) digital signal -processor(DSP). +processor(DSP). We also support Hexagon Vector eXtensions (HVX). HVX +is a wide vector coprocessor designed for high performance computer vision, +image processing, machine learning, and other workloads. The following versions of the Hexagon core are supported Scalar core: v67 https://developer.qualcomm.com/downloads/qualcomm-hexagon-v67-programmer-s-reference-manual + HVX extension: v66 + https://developer.qualcomm.com/downloads/qualcomm-hexagon-v66-hvx-programmer-s-reference-manual We presented an overview of the project at the 2019 KVM Forum. https://kvmforum2019.sched.com/event/Tmwc/qemu-hexagon-automatic-translation-of-the-isa-manual-pseudcode-to-tiny-code-instructions-of-a-vliw-architecture-niccolo-izzo-revng-taylor-simpson-qualcomm-innovation-center @@ -124,6 +128,71 @@ There are also cases where we brute force the TCG code generation. Instructions with multiple definitions are examples. These require special handling because qemu helpers can only return a single value. +For HVX vectors, the generator behaves slightly differently. The wide vectors +won't fit in a TCGv or TCGv_i64, so we pass TCGv_ptr variables to pass the +address to helper functions. Here's an example for an HVX vector-add-word +istruction. + static void generate_V6_vaddw( + CPUHexagonState *env, + DisasContext *ctx, + Insn *insn, + Packet *pkt) + { + const int VdN = insn->regno[0]; + const intptr_t VdV_off = + ctx_future_vreg_off(ctx, VdN, 1, true); + TCGv_ptr VdV = tcg_temp_local_new_ptr(); + tcg_gen_addi_ptr(VdV, cpu_env, VdV_off); + const int VuN = insn->regno[1]; + const intptr_t VuV_off = + vreg_src_off(ctx, VuN); + TCGv_ptr VuV = tcg_temp_local_new_ptr(); + const int VvN = insn->regno[2]; + const intptr_t VvV_off = + vreg_src_off(ctx, VvN); + TCGv_ptr VvV = tcg_temp_local_new_ptr(); + tcg_gen_addi_ptr(VuV, cpu_env, VuV_off); + tcg_gen_addi_ptr(VvV, cpu_env, VvV_off); + TCGv slot = tcg_constant_tl(insn->slot); + gen_helper_V6_vaddw(cpu_env, VdV, VuV, VvV, slot); + tcg_temp_free(slot); + gen_log_vreg_write(ctx, VdV_off, VdN, EXT_DFL, insn->slot, false); + ctx_log_vreg_write(ctx, VdN, EXT_DFL, false); + tcg_temp_free_ptr(VdV); + tcg_temp_free_ptr(VuV); + tcg_temp_free_ptr(VvV); + } + +Notice that we also generate a variable named _off for each operand of +the instruction. This makes it easy to override the instruction semantics with +functions from tcg-op-gvec.h. Here's the override for this instruction. + #define fGEN_TCG_V6_vaddw(SHORTCODE) \ + tcg_gen_gvec_add(MO_32, VdV_off, VuV_off, VvV_off, \ + sizeof(MMVector), sizeof(MMVector)) + +Finally, we notice that the override doesn't use the TCGv_ptr variables, so +we don't generate them when an override is present. Here is what we generate +when the override is present. + static void generate_V6_vaddw( + CPUHexagonState *env, + DisasContext *ctx, + Insn *insn, + Packet *pkt) + { + const int VdN = insn->regno[0]; + const intptr_t VdV_off = + ctx_future_vreg_off(ctx, VdN, 1, true); + const int VuN = insn->regno[1]; + const intptr_t VuV_off = + vreg_src_off(ctx, VuN); + const int VvN = insn->regno[2]; + const intptr_t VvV_off = + vreg_src_off(ctx, VvN); + fGEN_TCG_V6_vaddw({ fHIDE(int i;) fVFOREACH(32, i) { VdV.w[i] = VuV.w[i] + VvV.w[i] ; } }); + gen_log_vreg_write(ctx, VdV_off, VdN, EXT_DFL, insn->slot, false); + ctx_log_vreg_write(ctx, VdN, EXT_DFL, false); + } + In addition to instruction semantics, we use a generator to create the decode tree. This generation is also a two step process. The first step is to run target/hexagon/gen_dectree_import.c to produce @@ -140,6 +209,7 @@ runtime information for each thread and contains stuff like the GPR and predicate registers. macros.h +mmvec/macros.h The Hexagon arch lib relies heavily on macros for the instruction semantics. This is a great advantage for qemu because we can override them for different @@ -203,6 +273,15 @@ During runtime, the following fields in CPUHexagonState (see cpu.h) are used pred_written boolean indicating if predicate was written mem_log_stores record of the stores (indexed by slot) +For Hexagon Vector eXtensions (HVX), the following fields are used + VRegs Vector registers + future_VRegs Registers to be stored during packet commit + tmp_VRegs Temporary registers *not* stored during commit + VRegs_updated Mask of predicated vector writes + QRegs Q (vector predicate) registers + future_QRegs Registers to be stored during packet commit + QRegs_updated Mask of predicated vector writes + *** Debugging *** You can turn on a lot of debugging by changing the HEX_DEBUG macro to 1 in