From patchwork Mon Sep 4 09:06:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?C=C3=A9dric_Le_Goater?= X-Patchwork-Id: 13373623 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 0F130C83F3F for ; Mon, 4 Sep 2023 09:10:12 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qd5Xw-0001MJ-W8; Mon, 04 Sep 2023 05:07:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qd5Xt-0001Hw-Tm; Mon, 04 Sep 2023 05:06:58 -0400 Received: from gandalf.ozlabs.org ([150.107.74.76]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qd5Xr-0003da-Ef; Mon, 04 Sep 2023 05:06:57 -0400 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by gandalf.ozlabs.org (Postfix) with ESMTP id 4RfN6y6F2Bz4wy9; Mon, 4 Sep 2023 19:06:50 +1000 (AEST) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4RfN6x0KsFz4wxN; Mon, 4 Sep 2023 19:06:48 +1000 (AEST) From: =?utf-8?q?C=C3=A9dric_Le_Goater?= To: qemu-ppc@nongnu.org, qemu-devel@nongnu.org Cc: Daniel Henrique Barboza , Nicholas Piggin , =?utf-8?q?C=C3=A9dric_Le_Goater?= Subject: [PULL 05/35] target/ppc: Suppress single step interrupts on rfi-type instructions Date: Mon, 4 Sep 2023 11:06:00 +0200 Message-ID: <20230904090630.725952-6-clg@kaod.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230904090630.725952-1-clg@kaod.org> References: <20230904090630.725952-1-clg@kaod.org> MIME-Version: 1.0 Received-SPF: pass client-ip=150.107.74.76; envelope-from=SRS0=kZzc=EU=kaod.org=clg@ozlabs.org; helo=gandalf.ozlabs.org X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Nicholas Piggin BookS does not take single step interrupts on completion of rfi and similar (rfid, hrfid, rfscv). This is not a completely clean way to do it, but in general non-branch instructions that change NIP on completion are excluded. Signed-off-by: Nicholas Piggin Signed-off-by: Cédric Le Goater --- target/ppc/translate.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/target/ppc/translate.c b/target/ppc/translate.c index 505159667083..6e8f1797ac95 100644 --- a/target/ppc/translate.c +++ b/target/ppc/translate.c @@ -338,7 +338,7 @@ static void gen_ppc_maybe_interrupt(DisasContext *ctx) * The exception can be either POWERPC_EXCP_TRACE (on most PowerPCs) or * POWERPC_EXCP_DEBUG (on BookE). */ -static void gen_debug_exception(DisasContext *ctx) +static void gen_debug_exception(DisasContext *ctx, bool rfi_type) { #if !defined(CONFIG_USER_ONLY) if (ctx->flags & POWERPC_FLAG_DE) { @@ -357,10 +357,12 @@ static void gen_debug_exception(DisasContext *ctx) tcg_constant_i32(POWERPC_EXCP_DEBUG)); ctx->base.is_jmp = DISAS_NORETURN; } else { - TCGv t0 = tcg_temp_new(); - tcg_gen_movi_tl(t0, ctx->cia); - gen_helper_book3s_trace(cpu_env, t0); - ctx->base.is_jmp = DISAS_NORETURN; + if (!rfi_type) { /* BookS does not single step rfi type instructions */ + TCGv t0 = tcg_temp_new(); + tcg_gen_movi_tl(t0, ctx->cia); + gen_helper_book3s_trace(cpu_env, t0); + ctx->base.is_jmp = DISAS_NORETURN; + } } #endif } @@ -7412,6 +7414,8 @@ static void ppc_tr_tb_stop(DisasContextBase *dcbase, CPUState *cs) /* Honor single stepping. */ if (unlikely(ctx->singlestep_enabled & CPU_SINGLE_STEP)) { + bool rfi_type = false; + switch (is_jmp) { case DISAS_TOO_MANY: case DISAS_EXIT_UPDATE: @@ -7420,12 +7424,19 @@ static void ppc_tr_tb_stop(DisasContextBase *dcbase, CPUState *cs) break; case DISAS_EXIT: case DISAS_CHAIN: + /* + * This is a heuristic, to put it kindly. The rfi class of + * instructions are among the few outside branches that change + * NIP without taking an interrupt. Single step trace interrupts + * do not fire on completion of these instructions. + */ + rfi_type = true; break; default: g_assert_not_reached(); } - gen_debug_exception(ctx); + gen_debug_exception(ctx, rfi_type); return; }