From patchwork Mon Mar 7 20:53:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Heiko Stuebner X-Patchwork-Id: 12772387 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 65360C433F5 for ; Mon, 7 Mar 2022 20:56:58 +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=at2b/8dCsoMXH80oad+W8P2OAbPCCb4Jryudms884TY=; b=A1F+525ohwdj+B ty2e9OHUngeP5LRjdK/RKR+tDooIB9rVnWRT3fIJTf3mPoKcGrRZ4s12FZa6Z1TEPa+sTieeRrh3s WCAmBTs6eL1b1hZQu38XhmRNfxqFtFcwqu20iAjuHOoJsvD6eM8Ccx+fYUBxeoE/UsI6unATAcC7A A5HLDmSZs1boORxBAuDXWwsNfktDuphPGtTRItHlA3xb0Uf2a2TQL2n4ODPuo9cet+VUeMgmmps/s qMAz3sNm8FNuDpKCMkuOANAYZNT1wS/0yV747G+GlXzDann6maXsAa555cHRDE5UcTTSer3Ms3Zqa s35J8ok3Ye1pxF+VvIxg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nRKPP-001ZXd-Gv; Mon, 07 Mar 2022 20:56:47 +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 1nRKPM-001ZVl-E1 for linux-riscv@lists.infradead.org; Mon, 07 Mar 2022 20:56:45 +0000 Received: from ip5b412258.dynamic.kabel-deutschland.de ([91.65.34.88] helo=phil.lan) by gloria.sntech.de with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nRKM6-0002DJ-9K; Mon, 07 Mar 2022 21:53:22 +0100 From: Heiko Stuebner To: palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, wefu@redhat.com, liush@allwinnertech.com, guoren@kernel.org, atishp@atishpatra.org, anup@brainfault.org, drew@beagleboard.org, hch@lst.de, arnd@arndb.de, wens@csie.org, maxime@cerno.tech, gfavor@ventanamicro.com, andrea.mondelli@huawei.com, behrensj@mit.edu, xinhaoqu@huawei.com, mick@ics.forth.gr, allen.baum@esperantotech.com, jscheid@ventanamicro.com, rtrauben@gmail.com, samuel@sholland.org, cmuellner@linux.com, philipp.tomsich@vrull.eu, Heiko Stuebner Subject: [PATCH v7 10/13] riscv: add cpufeature handling via alternatives Date: Mon, 7 Mar 2022 21:53:07 +0100 Message-Id: <20220307205310.1905628-11-heiko@sntech.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220307205310.1905628-1-heiko@sntech.de> References: <20220307205310.1905628-1-heiko@sntech.de> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220307_125644_513244_F1A16007 X-CRM114-Status: GOOD ( 18.15 ) 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 Some cpufeatures should be handled via the alternatives mechanism to not incur penalties on unsupporting variants. So add a mechanism to handle these similar to cpu erratas. Signed-off-by: Heiko Stuebner --- arch/riscv/include/asm/alternative.h | 3 ++ arch/riscv/include/asm/errata_list.h | 2 + arch/riscv/kernel/alternative.c | 2 + arch/riscv/kernel/cpufeature.c | 57 +++++++++++++++++++++++++++- 4 files changed, 63 insertions(+), 1 deletion(-) diff --git a/arch/riscv/include/asm/alternative.h b/arch/riscv/include/asm/alternative.h index f0657b1b3174..cf3b22173834 100644 --- a/arch/riscv/include/asm/alternative.h +++ b/arch/riscv/include/asm/alternative.h @@ -39,5 +39,8 @@ struct errata_checkfunc_id { void sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end, unsigned long archid, unsigned long impid, unsigned int stage); + +void riscv_cpufeature_patch_func(struct alt_entry *begin, struct alt_entry *end, + unsigned int stage); #endif #endif diff --git a/arch/riscv/include/asm/errata_list.h b/arch/riscv/include/asm/errata_list.h index 5f1046e82d9f..6b95bd9aee82 100644 --- a/arch/riscv/include/asm/errata_list.h +++ b/arch/riscv/include/asm/errata_list.h @@ -14,6 +14,8 @@ #define ERRATA_SIFIVE_NUMBER 2 #endif +#define CPUFEATURE_NUMBER 0 + #ifdef __ASSEMBLY__ #define ALT_INSN_FAULT(x) \ diff --git a/arch/riscv/kernel/alternative.c b/arch/riscv/kernel/alternative.c index 223770b3945c..e6c9de9f9ba6 100644 --- a/arch/riscv/kernel/alternative.c +++ b/arch/riscv/kernel/alternative.c @@ -63,6 +63,8 @@ static void __init_or_module _apply_alternatives(struct alt_entry *begin, struct alt_entry *end, unsigned int stage) { + riscv_cpufeature_patch_func(begin, end, stage); + if (!vendor_patch_func) return; diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index f3a4b0619aa0..92d4b4c25d47 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -8,9 +8,14 @@ #include #include +#include #include -#include +#include +#include #include +#include +#include +#include #include #include @@ -237,3 +242,53 @@ void __init riscv_fill_hwcap(void) static_branch_enable(&cpu_hwcap_fpu); #endif } + +struct cpufeature_info { + char name[ERRATA_STRING_LENGTH_MAX]; + bool (*check_func)(unsigned int stage); +}; + +static const struct cpufeature_info __initdata_or_module cpufeature_list[CPUFEATURE_NUMBER] = { +}; + +static u32 __init_or_module cpufeature_probe(unsigned int stage) +{ + const struct cpufeature_info *info; + u32 cpu_req_feature = 0; + int idx; + + for (idx = 0; idx < CPUFEATURE_NUMBER; idx++) { + info = &cpufeature_list[idx]; + + if (info->check_func(stage)) + cpu_req_feature |= (1U << idx); + } + + return cpu_req_feature; +} + +void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin, + struct alt_entry *end, + unsigned int stage) +{ + u32 cpu_req_feature = cpufeature_probe(stage); + u32 cpu_apply_feature = 0; + struct alt_entry *alt; + u32 tmp; + + for (alt = begin; alt < end; alt++) { + if (alt->vendor_id != 0) + continue; + if (alt->errata_id >= CPUFEATURE_NUMBER) { + WARN(1, "This feature id:%d is not in kernel cpufeature list", + alt->errata_id); + continue; + } + + tmp = (1U << alt->errata_id); + if (cpu_req_feature & tmp) { + patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len); + cpu_apply_feature |= tmp; + } + } +}