From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 0079DCA101F for ; Wed, 10 Sep 2025 20:45:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=DxWMGMReeBHdg3SrIjYD6TpjQtQBzWJa/kGxD+CzD6Y=; b=0WuIHAscJvUkZ+bZxCuS0WMQI4 RMWpP/WxxvaKGoqjwQw8G+odlrCw5Wb8NQZye0/WEXHPS53E2ECHsxYksqCFxVGFlSlHAQsjSLLFG oW4q9yAWjZ9wJUHPpOjIDNsDM6IiHf69MWfpyzVhOT+KU1nN38kIhbHYJsYO6i14NMsBxOhD2cEKQ CwcIukAPX1XMc//q2/CYM+lD2m9mhX/HnaPvH4tMsRtAmJh9PA1y2nyPlsqUPNcORcO/KMomiJgbi bL1fZuHER+8+v0/3KVB51NiaB+ivdTUOZgZCXSVzphADEJ/3gQRGittGh9AWi7fMmW5RRuRkG3yqS Z3JNTh2g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uwRhN-0000000Gevm-2hAW; Wed, 10 Sep 2025 20:45:49 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uwRhF-0000000GenH-4AGp for linux-arm-kernel@lists.infradead.org; Wed, 10 Sep 2025 20:45:48 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3B01E1C0A; Wed, 10 Sep 2025 13:45:33 -0700 (PDT) Received: from merodach.members.linode.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C7CED3F63F; Wed, 10 Sep 2025 13:45:36 -0700 (PDT) From: James Morse To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org Cc: James Morse , D Scott Phillips OS , carl@os.amperecomputing.com, lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, David Hildenbrand , Dave Martin , Koba Ko , Shanker Donthineni , fenghuay@nvidia.com, baisheng.gao@unisoc.com, Jonathan Cameron , Rob Herring , Rohit Mathew , Rafael Wysocki , Len Brown , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , Greg Kroah-Hartman , Danilo Krummrich , Ben Horgan Subject: [PATCH v2 26/29] arm_mpam: Use long MBWU counters if supported Date: Wed, 10 Sep 2025 20:43:06 +0000 Message-Id: <20250910204309.20751-27-james.morse@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20250910204309.20751-1-james.morse@arm.com> References: <20250910204309.20751-1-james.morse@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250910_134542_130944_5B93C614 X-CRM114-Status: GOOD ( 18.36 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Rohit Mathew If the 44 bit (long) or 63 bit (LWD) counters are detected on probing the RIS, use long/LWD counter instead of the regular 31 bit mbwu counter. Only 32bit accesses to the MSC are required to be supported by the spec, but these registers are 64bits. The lower half may overflow into the higher half between two 32bit reads. To avoid this, use a helper that reads the top half multiple times to check for overflow. Signed-off-by: Rohit Mathew [morse: merged multiple patches from Rohit] Signed-off-by: James Morse Reviewed-by: Ben Horgan --- Changes since v1: * Only clear OFLOW_STATUS_L on MBWU counters. Changes since RFC: * Commit message wrangling. * Refer to 31 bit counters as opposed to 32 bit (registers). --- drivers/resctrl/mpam_devices.c | 91 ++++++++++++++++++++++++++++++---- 1 file changed, 82 insertions(+), 9 deletions(-) diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index bae9fa9441dc..3080a81f0845 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -927,6 +927,48 @@ struct mon_read { int err; }; +static bool mpam_ris_has_mbwu_long_counter(struct mpam_msc_ris *ris) +{ + return (mpam_has_feature(mpam_feat_msmon_mbwu_63counter, &ris->props) || + mpam_has_feature(mpam_feat_msmon_mbwu_44counter, &ris->props)); +} + +static u64 mpam_msc_read_mbwu_l(struct mpam_msc *msc) +{ + int retry = 3; + u32 mbwu_l_low; + u64 mbwu_l_high1, mbwu_l_high2; + + mpam_mon_sel_lock_held(msc); + + WARN_ON_ONCE((MSMON_MBWU_L + sizeof(u64)) > msc->mapped_hwpage_sz); + WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility)); + + mbwu_l_high2 = __mpam_read_reg(msc, MSMON_MBWU_L + 4); + do { + mbwu_l_high1 = mbwu_l_high2; + mbwu_l_low = __mpam_read_reg(msc, MSMON_MBWU_L); + mbwu_l_high2 = __mpam_read_reg(msc, MSMON_MBWU_L + 4); + + retry--; + } while (mbwu_l_high1 != mbwu_l_high2 && retry > 0); + + if (mbwu_l_high1 == mbwu_l_high2) + return (mbwu_l_high1 << 32) | mbwu_l_low; + return MSMON___NRDY_L; +} + +static void mpam_msc_zero_mbwu_l(struct mpam_msc *msc) +{ + mpam_mon_sel_lock_held(msc); + + WARN_ON_ONCE((MSMON_MBWU_L + sizeof(u64)) > msc->mapped_hwpage_sz); + WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility)); + + __mpam_write_reg(msc, MSMON_MBWU_L, 0); + __mpam_write_reg(msc, MSMON_MBWU_L + 4, 0); +} + static void gen_msmon_ctl_flt_vals(struct mon_read *m, u32 *ctl_val, u32 *flt_val) { @@ -989,6 +1031,9 @@ static void read_msmon_ctl_flt_vals(struct mon_read *m, u32 *ctl_val, static void clean_msmon_ctl_val(u32 *cur_ctl) { *cur_ctl &= ~MSMON_CFG_x_CTL_OFLOW_STATUS; + + if (FIELD_GET(MSMON_CFG_x_CTL_TYPE, *cur_ctl) == MSMON_CFG_MBWU_CTL_TYPE_MBWU) + *cur_ctl &= ~MSMON_CFG_MBWU_CTL_OFLOW_STATUS_L; } static void write_msmon_ctl_flt_vals(struct mon_read *m, u32 ctl_val, @@ -1011,7 +1056,11 @@ static void write_msmon_ctl_flt_vals(struct mon_read *m, u32 ctl_val, case mpam_feat_msmon_mbwu: mpam_write_monsel_reg(msc, CFG_MBWU_FLT, flt_val); mpam_write_monsel_reg(msc, CFG_MBWU_CTL, ctl_val); - mpam_write_monsel_reg(msc, MBWU, 0); + if (mpam_ris_has_mbwu_long_counter(m->ris)) + mpam_msc_zero_mbwu_l(m->ris->vmsc->msc); + else + mpam_write_monsel_reg(msc, MBWU, 0); + mpam_write_monsel_reg(msc, CFG_MBWU_CTL, ctl_val | MSMON_CFG_x_CTL_EN); mbwu_state = &m->ris->mbwu_state[m->ctx->mon]; @@ -1026,8 +1075,13 @@ static void write_msmon_ctl_flt_vals(struct mon_read *m, u32 ctl_val, static u64 mpam_msmon_overflow_val(struct mpam_msc_ris *ris) { - /* TODO: scaling, and long counters */ - return GENMASK_ULL(30, 0); + /* TODO: implement scaling counters */ + if (mpam_has_feature(mpam_feat_msmon_mbwu_63counter, &ris->props)) + return GENMASK_ULL(62, 0); + else if (mpam_has_feature(mpam_feat_msmon_mbwu_44counter, &ris->props)) + return GENMASK_ULL(43, 0); + else + return GENMASK_ULL(30, 0); } /* Call with MSC lock held */ @@ -1069,10 +1123,24 @@ static void __ris_msmon_read(void *arg) now = FIELD_GET(MSMON___VALUE, now); break; case mpam_feat_msmon_mbwu: - now = mpam_read_monsel_reg(msc, MBWU); - if (mpam_has_feature(mpam_feat_msmon_mbwu_hw_nrdy, rprops)) - nrdy = now & MSMON___NRDY; - now = FIELD_GET(MSMON___VALUE, now); + /* + * If long or lwd counters are supported, use them, else revert + * to the 31 bit counter. + */ + if (mpam_ris_has_mbwu_long_counter(ris)) { + now = mpam_msc_read_mbwu_l(msc); + if (mpam_has_feature(mpam_feat_msmon_mbwu_hw_nrdy, rprops)) + nrdy = now & MSMON___NRDY_L; + if (mpam_has_feature(mpam_feat_msmon_mbwu_63counter, rprops)) + now = FIELD_GET(MSMON___LWD_VALUE, now); + else + now = FIELD_GET(MSMON___L_VALUE, now); + } else { + now = mpam_read_monsel_reg(msc, MBWU); + if (mpam_has_feature(mpam_feat_msmon_mbwu_hw_nrdy, rprops)) + nrdy = now & MSMON___NRDY; + now = FIELD_GET(MSMON___VALUE, now); + } if (nrdy) break; @@ -1360,8 +1428,13 @@ static int mpam_save_mbwu_state(void *arg) cur_ctl = mpam_read_monsel_reg(msc, CFG_MBWU_CTL); mpam_write_monsel_reg(msc, CFG_MBWU_CTL, 0); - val = mpam_read_monsel_reg(msc, MBWU); - mpam_write_monsel_reg(msc, MBWU, 0); + if (mpam_ris_has_mbwu_long_counter(ris)) { + val = mpam_msc_read_mbwu_l(msc); + mpam_msc_zero_mbwu_l(msc); + } else { + val = mpam_read_monsel_reg(msc, MBWU); + mpam_write_monsel_reg(msc, MBWU, 0); + } cfg->mon = i; cfg->pmg = FIELD_GET(MSMON_CFG_x_FLT_PMG, cur_flt); -- 2.39.5