From patchwork Thu Jun 15 13:32:37 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anshuman Khandual X-Patchwork-Id: 13281281 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 0F63EEB64D9 for ; Thu, 15 Jun 2023 13:34:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=2bimH6Aakkq1mZI5XTuduHCkBuGvUcIETcOp/rBcxHo=; b=dHeZLnESBFxPKC rLcLqHxWAhiqX6xiCS6nmKAyBL2mgcCEynubdU1aXIS7Gnp34/eLcqZLY80IficFnmcEnuiUFO7Xb 6c5NPo2kdCXh9k28BseTbmEcPxZN0IWzB5rVok8KeQqo5XhAr+i5DMvq3CMz44eunJuV3+EjXeRIl DMCiKOre6/4AgQK7jcqI7Z6wst+ro0dLTU4rPGiJs7kJMFh5VqJmthEl5Sv0jHFMeWcgotFJNflMU e82AP9bT+xTwedibH/o0R4PkNMZdyCWtNuAyQTqZgda3O8YgmParvWa2xZaZ3UHTgEyok+olr40a0 ML3UN5KhXWOb87+vXXmw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q9n6h-00F14V-35; Thu, 15 Jun 2023 13:33:47 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q9n6Y-00F0yX-0N for linux-arm-kernel@lists.infradead.org; Thu, 15 Jun 2023 13:33:40 +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 2F51A113E; Thu, 15 Jun 2023 06:34:21 -0700 (PDT) Received: from a077893.arm.com (unknown [10.163.46.86]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5C0E73F64C; Thu, 15 Jun 2023 06:33:32 -0700 (PDT) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com Cc: Anshuman Khandual , Mark Brown , James Clark , Rob Herring , Marc Zyngier , Suzuki Poulose , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , linux-perf-users@vger.kernel.org Subject: [PATCH V12 08/10] arm64/perf: Add struct brbe_regset helper functions Date: Thu, 15 Jun 2023 19:02:37 +0530 Message-Id: <20230615133239.442736-9-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230615133239.442736-1-anshuman.khandual@arm.com> References: <20230615133239.442736-1-anshuman.khandual@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230615_063338_253251_8818CBD9 X-CRM114-Status: GOOD ( 20.56 ) 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 The primary abstraction level for fetching branch records from BRBE HW has been changed as 'struct brbe_regset', which contains storage for all three BRBE registers i.e BRBSRC, BRBTGT, BRBINF. Whether branch record processing happens in the task sched out path, or in the PMU IRQ handling path, these registers need to be extracted from the HW. Afterwards both live and stored sets need to be stitched together to create final branch records set. This adds required helper functions for such operations. Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Tested-by: James Clark Signed-off-by: Anshuman Khandual Acked-by: Mark Rutland --- drivers/perf/arm_brbe.c | 127 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 127 insertions(+) diff --git a/drivers/perf/arm_brbe.c b/drivers/perf/arm_brbe.c index 4729cb49282b..f6693699fade 100644 --- a/drivers/perf/arm_brbe.c +++ b/drivers/perf/arm_brbe.c @@ -44,6 +44,133 @@ static void select_brbe_bank(int bank) isb(); } +static bool __read_brbe_regset(struct brbe_regset *entry, int idx) +{ + entry->brbinf = get_brbinf_reg(idx); + + /* + * There are no valid entries anymore on the buffer. + * Abort the branch record processing to save some + * cycles and also reduce the capture/process load + * for the user space as well. + */ + if (brbe_invalid(entry->brbinf)) + return false; + + entry->brbsrc = get_brbsrc_reg(idx); + entry->brbtgt = get_brbtgt_reg(idx); + return true; +} + +/* + * This scans over BRBE register banks and captures individual branch records + * [BRBSRC, BRBTGT, BRBINF] into a pre-allocated 'struct brbe_regset' buffer, + * until an invalid one gets encountered. The caller for this function needs + * to ensure BRBE is an appropriate state before the records can be captured. + */ +static int capture_brbe_regset(int nr_hw_entries, struct brbe_regset *buf) +{ + int idx = 0; + + select_brbe_bank(BRBE_BANK_IDX_0); + while (idx < nr_hw_entries && idx < BRBE_BANK0_IDX_MAX) { + if (!__read_brbe_regset(&buf[idx], idx)) + return idx; + idx++; + } + + select_brbe_bank(BRBE_BANK_IDX_1); + while (idx < nr_hw_entries && idx < BRBE_BANK1_IDX_MAX) { + if (!__read_brbe_regset(&buf[idx], idx)) + return idx; + idx++; + } + return idx; +} + +/* + * This function concatenates branch records from stored and live buffer + * up to maximum nr_max records and the stored buffer holds the resultant + * buffer. The concatenated buffer contains all the branch records from + * the live buffer but might contain some from stored buffer considering + * the maximum combined length does not exceed 'nr_max'. + * + * Stored records Live records + * ------------------------------------------------^ + * | S0 | L0 | Newest | + * --------------------------------- | + * | S1 | L1 | | + * --------------------------------- | + * | S2 | L2 | | + * --------------------------------- | + * | S3 | L3 | | + * --------------------------------- | + * | S4 | L4 | nr_max + * --------------------------------- | + * | | L5 | | + * --------------------------------- | + * | | L6 | | + * --------------------------------- | + * | | L7 | | + * --------------------------------- | + * | | | | + * --------------------------------- | + * | | | Oldest | + * ------------------------------------------------V + * + * + * S0 is the newest in the stored records, where as L7 is the oldest in + * the live records. Unless the live buffer is detected as being full + * thus potentially dropping off some older records, L7 and S0 records + * are contiguous in time for a user task context. The stitched buffer + * here represents maximum possible branch records, contiguous in time. + * + * Stored records Live records + * ------------------------------------------------^ + * | L0 | L0 | Newest | + * --------------------------------- | + * | L0 | L1 | | + * --------------------------------- | + * | L2 | L2 | | + * --------------------------------- | + * | L3 | L3 | | + * --------------------------------- | + * | L4 | L4 | nr_max + * --------------------------------- | + * | L5 | L5 | | + * --------------------------------- | + * | L6 | L6 | | + * --------------------------------- | + * | L7 | L7 | | + * --------------------------------- | + * | S0 | | | + * --------------------------------- | + * | S1 | | Oldest | + * ------------------------------------------------V + * | S2 | <----| + * ----------------- | + * | S3 | <----| Dropped off after nr_max + * ----------------- | + * | S4 | <----| + * ----------------- + */ +static int stitch_stored_live_entries(struct brbe_regset *stored, + struct brbe_regset *live, + int nr_stored, int nr_live, + int nr_max) +{ + int nr_move = min(nr_stored, nr_max - nr_live); + + /* Move the tail of the buffer to make room for the new entries */ + memmove(&stored[nr_live], &stored[0], nr_move * sizeof(*stored)); + + /* Copy the new entries into the head of the buffer */ + memcpy(&stored[0], &live[0], nr_live * sizeof(*stored)); + + /* Return the number of entries in the stitched buffer */ + return min(nr_live + nr_stored, nr_max); +} + /* * Generic perf branch filters supported on BRBE *