From patchwork Mon Oct 10 12:27:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Heiko Stuebner X-Patchwork-Id: 13002563 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 C4B56C433FE for ; Mon, 10 Oct 2022 12:27:51 +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=bnOBYYPG2OeuOTIUroegt0txT8eZuNGgE8oKwaO6eZs=; b=rK1JOrpPQiCsl+ EgByvHtS4puj1G/LUEll3JtequmHMalps5kkiHXCr+N/6aQibU/FQYIzkrQhT7zjit10bX0TN8GVD A9slW6RIbUJxmq5FBe9UkemAw+LgfEZiiDB/m0rAc9w2YlHW6Wz7ynK/xeDmtqr/jKvnfk/04wzWA 0PrnsesB8aF4mXcCivCQzqvN9GXmllXhjH1X/rvAmI9dCkK80DB5jBUCoWvPQGsTWio4r0k2IOBXO xG5Wbh/gGHw4W01vfuV5IrY/G3rfA8t2T6se1tTpI6cmI7+efXPpXK+qHfvCUspC8tgH5znYeTxa8 VT6a4N6HM0gZkn1N+4hw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ohrsl-000pi3-F1; Mon, 10 Oct 2022 12:27:43 +0000 Received: from gloria.sntech.de ([185.11.138.130]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ohrsi-000pgp-OC for linux-riscv@lists.infradead.org; Mon, 10 Oct 2022 12:27:41 +0000 Received: from p5b1274fa.dip0.t-ipconnect.de ([91.18.116.250] helo=phil.fritz.box) by gloria.sntech.de with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1ohrsX-0001kg-4d; Mon, 10 Oct 2022 14:27:29 +0200 From: Heiko Stuebner To: atishp@atishpatra.org, anup@brainfault.org, will@kernel.org, mark.rutland@arm.com, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Conor.Dooley@microchip.com, ajones@ventanamicro.com, Heiko Stuebner Subject: [PATCH v5 1/2] RISC-V: Cache SBI vendor values Date: Mon, 10 Oct 2022 14:27:25 +0200 Message-Id: <20221010122726.2405153-2-heiko@sntech.de> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221010122726.2405153-1-heiko@sntech.de> References: <20221010122726.2405153-1-heiko@sntech.de> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221010_052740_822399_5A2D8A0C X-CRM114-Status: GOOD ( 12.54 ) X-BeenThere: linux-riscv@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-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org sbi_get_mvendorid(), sbi_get_marchid() and sbi_get_mimpid() might get called multiple times, though the values of these CSRs should not change during the runtime of a specific machine. So cache the values in the functions and prevent multiple ecalls to read these values. As Andrew Jones noted, at least marchid and mimpid may be negative values when viewed as a long, so we use a separate static bool to indiciate the cached status. Suggested-by: Atish Patra Signed-off-by: Heiko Stuebner --- arch/riscv/kernel/sbi.c | 30 +++++++++++++++++++++++++++--- 1 file changed, 27 insertions(+), 3 deletions(-) diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index 775d3322b422..cc618aaa9d11 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -625,17 +625,41 @@ static inline long sbi_get_firmware_version(void) long sbi_get_mvendorid(void) { - return __sbi_base_ecall(SBI_EXT_BASE_GET_MVENDORID); + static long id; + static bool cached; + + if (!cached) { + id = __sbi_base_ecall(SBI_EXT_BASE_GET_MVENDORID); + cached = true; + } + + return id; } long sbi_get_marchid(void) { - return __sbi_base_ecall(SBI_EXT_BASE_GET_MARCHID); + static long id; + static bool cached; + + if (!cached) { + id = __sbi_base_ecall(SBI_EXT_BASE_GET_MARCHID); + cached = true; + } + + return id; } long sbi_get_mimpid(void) { - return __sbi_base_ecall(SBI_EXT_BASE_GET_MIMPID); + static long id; + static bool cached; + + if (!cached) { + id = __sbi_base_ecall(SBI_EXT_BASE_GET_MIMPID); + cached = true; + } + + return id; } static void sbi_send_cpumask_ipi(const struct cpumask *target)