From patchwork Thu Nov 25 10:02:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tsukasa OI X-Patchwork-Id: 12638819 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 781CCC433FE for ; Thu, 25 Nov 2021 10:11:13 +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=5LIX1adSyLeGwHPPR41jxeKiU2sthiKfTg+YnHUTiAI=; b=ACW4uiURuuVtDd R1h9dLVxJ/pi3xuS96gsjz5eSHQL60xZKUkBn0u+IqxqiDyqVJAN6ZL65ZM8Cu/lPQC+H3q7Ek9oL XJGO/iNnYpmyO8EySYYtNwjkIwX3GpegGcZ7ije4DCU1boUEaVZhiz7u36p5MlWSX0cpUhiC2usqi 2eIf6T/ZIyWL5qJX1jhZhX7g1zZcwBXZYvwKCe3h++FHrlMmKXFj2Ogtk8g2P/Uq4PSQC/rj8mZXa 1b56PyzBXs/j2bukFIjQ6kEEEMj1fzvCizAXCZtg5EdWy0xn2BJuwfK0ejiddkRWD8qHMln1fDd6j CUH23x7HMvzcALrJPHTA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mqBib-0072Jb-7D; Thu, 25 Nov 2021 10:11:05 +0000 Received: from mail-sender.a4lg.com ([153.120.152.154] helo=mail-sender-0.a4lg.com) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mqBiR-0072E3-Pk for linux-riscv@lists.infradead.org; Thu, 25 Nov 2021 10:10:58 +0000 From: Tsukasa OI Authentication-Results: mail-sender-0.a4lg.com; dkim=permerror (bad message/signature format) To: Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: Tsukasa OI , linux-riscv@lists.infradead.org Subject: [RFC PATCH v2 2/4] riscv: cpufeature: Minimal parser for "riscv, isa" strings Date: Thu, 25 Nov 2021 19:02:53 +0900 Message-Id: <63b22e69b3089224ed2ff489af8b873bbb18ebb4.1637834060.git.research_trasio@irq.a4lg.com> In-Reply-To: References: Mime-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211125_021055_972410_41CDA2C3 X-CRM114-Status: GOOD ( 14.30 ) 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 Current hart ISA ("riscv,isa") parser don't correctly parse: 1. Multi-letter extensions 2. Version numbers If we don't have those in "riscv,isa", that's fine. However, many of standardized multi-letter extensions are being frozen and ratified. The current "riscv,isa" parser that is easily confused by multi-letter extensions and "p" in version numbers can be a huge problem for adding new extensions through the device tree. Leaving it would create incompatible hacks and would make "riscv,isa" value unreliable. This commit implements minimal parser for "riscv,isa" strings. With this, we can safely ignore multi-letter extensions and version numbers. Signed-off-by: Tsukasa OI --- arch/riscv/kernel/cpufeature.c | 62 ++++++++++++++++++++++++++++------ 1 file changed, 51 insertions(+), 11 deletions(-) diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index dd3d57eb4eea..93b436addd90 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -7,6 +7,7 @@ */ #include +#include #include #include #include @@ -66,7 +67,7 @@ void __init riscv_fill_hwcap(void) struct device_node *node; const char *isa; char print_str[NUM_ALPHA_EXTS + 1]; - size_t i, j, isa_len; + int i, j; static unsigned long isa2hwcap[256] = {0}; isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I; @@ -92,23 +93,62 @@ void __init riscv_fill_hwcap(void) continue; } - i = 0; - isa_len = strlen(isa); #if IS_ENABLED(CONFIG_32BIT) if (!strncmp(isa, "rv32", 4)) - i += 4; + isa += 4; #elif IS_ENABLED(CONFIG_64BIT) if (!strncmp(isa, "rv64", 4)) - i += 4; + isa += 4; #endif - for (; i < isa_len; ++i) { - this_hwcap |= isa2hwcap[(unsigned char)(isa[i])]; + for (; *isa; ++isa) { + const char *ext = isa++; + unsigned short ext_err = 0; + bool ext_long; + + switch (*ext) { + case 'h': + case 's': + case 'x': + case 'z': + ext_long = true; + /* Multi-letter extension must be delimited */ + for (; *isa && *isa != '_'; ++isa) + if (!islower(*isa) && !isdigit(*isa)) + ext_err = 1; + /* ... but must be ignored. */ + break; + default: + ext_long = false; + if (!islower(*ext)) { + ext_err = 1; + break; + } + /* Find next extension */ + if (!isdigit(*isa)) + break; + while (isdigit(*++isa)) + ; + if (*isa != 'p') + break; + if (!isdigit(*++isa)) { + --isa; + break; + } + while (isdigit(*++isa)) + ; + break; + } + if (*isa != '_') + --isa; /* - * TODO: X, Y and Z extension parsing for Host ISA - * bitmap will be added in-future. + * TODO: Full version-aware handling including + * multi-letter extensions will be added in-future. */ - if ('a' <= isa[i] && isa[i] < 'x') - this_isa |= (1UL << (isa[i] - 'a')); + if (!ext_long && !ext_err) { + this_hwcap |= isa2hwcap[(unsigned char)(*ext)]; + if (!ext_long) + this_isa |= (1UL << (*ext - 'a')); + } } /*