From patchwork Sun Apr 10 21:49:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jason A. Donenfeld" X-Patchwork-Id: 12808319 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 20E00C433EF for ; Sun, 10 Apr 2022 21:57:25 +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=vQTEDwBIIbp2YKMBKNLmR1IAMJl2oxdt8WXcMJR9Q9s=; b=tcIMZ4/9DA3rqr 6Z84sXD89bkJSrx5cu+SvZd4cirWQTV5XFtsAf+CT6lxAj2Tca2Z6Gl7SUZB3Rp+vwmoH31Be6lwd YNSi8dfhpCqkMr0xjUAK8i0LgjLqW6jDjoWmz5oQirrHEk8RnT+ZVwTho++PRDiVf32YOe5IMnTan 8MsF2G/hlRbaMOkIQLMXSzrGz4JeKRDW0wv8Wij/KzYT26j47VCHhfsJwlmguHVgZ/UDVpiU7wh5a EeCmXH/bzzN8NMvNC/PVdiaQ3MqER4i/RJI0hR8hh9aO+Dlo9AdverqkkHcWt3FnWxXEQWFTXNNeA NYJCRXBLej6ntdyEO5AQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ndfXW-005dww-T2; Sun, 10 Apr 2022 21:56:11 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ndfSk-005azE-UF; Sun, 10 Apr 2022 21:51:16 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 58F4A60B7F; Sun, 10 Apr 2022 21:51:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1256C385A4; Sun, 10 Apr 2022 21:51:10 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="HSRuLPF+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1649627469; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9Cu7QXRsL/z13xQn/GFGGfZ5O+ssd8ncuQpowmlC+V8=; b=HSRuLPF+VEh5X+14lNQIOIFMHoOjiZe3dSYDy4a6n3H8a3H9VkjOITzBcZyRFj//HRr2Mm t6DBVplsZGwsPuaoIOTCX9UmrGJTeMZzXbEOLZSVNNhNta5KvvLPw2gQ+dNWWnwBbEQ+wc 6Tt5kGdkQwkh5Zu4gPG1UBVc3RaNcBk= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 8bb042a8 (TLSv1.3:AEAD-AES256-GCM-SHA384:256:NO); Sun, 10 Apr 2022 21:51:09 +0000 (UTC) From: "Jason A. Donenfeld" To: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, tglx@linutronix.de, arnd@arndb.de Cc: "Jason A. Donenfeld" , Theodore Ts'o , Dominik Brodowski , Russell King , Catalin Marinas , Will Deacon , Geert Uytterhoeven , Thomas Bogendoerfer , Paul Walmsley , Palmer Dabbelt , Albert Ou , "David S . Miller" , Richard Weinberger , Anton Ivanov , Johannes Berg , Ingo Molnar , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Chris Zankel , Max Filippov , John Stultz , Stephen Boyd , Dinh Nguyen , linux-arm-kernel@lists.infradead.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, x86@kernel.org, linux-xtensa@linux-xtensa.org Subject: [PATCH v2 11/11] xtensa: use ktime_read_raw_clock() for random_get_entropy() instead of zero Date: Sun, 10 Apr 2022 23:49:51 +0200 Message-Id: <20220410214951.55294-12-Jason@zx2c4.com> In-Reply-To: <20220410214951.55294-1-Jason@zx2c4.com> References: <20220410214951.55294-1-Jason@zx2c4.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220410_145115_116297_64F3AE3E X-CRM114-Status: GOOD ( 16.65 ) 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 In the event that random_get_entropy() can't access a cycle counter or similar, falling back to returning 0 is really not the best we can do. Instead, at least calling ktime_read_raw_clock() would be preferable, because that always needs to return _something_, even falling back to jiffies eventually. It's not as though ktime_read_raw_clock() is super high precision or guaranteed to be entropic, but basically anything that's not zero all the time is better than returning zero all the time. This is accomplished by just including the asm-generic code like on other architectures, which means we can get rid of the empty stub function here. Cc: Thomas Gleixner Cc: Arnd Bergmann Cc: Max Filippov Signed-off-by: Jason A. Donenfeld --- arch/xtensa/include/asm/timex.h | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/xtensa/include/asm/timex.h b/arch/xtensa/include/asm/timex.h index 233ec75e60c6..3f2462f2d027 100644 --- a/arch/xtensa/include/asm/timex.h +++ b/arch/xtensa/include/asm/timex.h @@ -29,10 +29,6 @@ extern unsigned long ccount_freq; -typedef unsigned long long cycles_t; - -#define get_cycles() (0) - void local_timer_setup(unsigned cpu); /* @@ -59,4 +55,6 @@ static inline void set_linux_timer (unsigned long ccompare) xtensa_set_sr(ccompare, SREG_CCOMPARE + LINUX_TIMER); } +#include + #endif /* _XTENSA_TIMEX_H */