From patchwork Wed Apr 13 11:54:08 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: 12811963 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 2ADB7C433EF for ; Wed, 13 Apr 2022 12:01:08 +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=xuuLT3+N3IR/sEAbocjq3dkBjWbU+VzkNkC+Tk8ZV64=; b=I47xdJ2WLWjqFp /stUR/HiYdavfJQTDpLw82hGMTmyrGyO/X79Gtu4fI6rLW5y/ol1nrrk0Mvf9pc5Z2KUJlGW1h14U U7c//2d+/TUVJXUH7IKI4jE22mESFWm6llYxI9ein+sBvVTDBfrqEaDH0q6E/F3zbMY7Owq3SthZw u/xmUOMxBxoA9fTqkFlc7KS7EAAsSmSRFITav00HDGVAE/cmNUmL0Pypf1XYKsP7u7h7Do+V2Pvz3 2RtpQvvmK51KNGYTQc/u2u+tq3BIjx/5QOJIhhZoZOLzX7C9B26SHpJaVJr4XRgi2ms2aieRkiN1v utGZToIRj5Swzr1MEMIw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nebey-000rV2-VV; Wed, 13 Apr 2022 11:59:45 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nebbC-000pP1-DA; Wed, 13 Apr 2022 11:55:52 +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 EB5B561DFD; Wed, 13 Apr 2022 11:55:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77BE8C385A4; Wed, 13 Apr 2022 11:55:46 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="cNRrvj+O" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1649850945; 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=0AODITKYyJtEle+S4cX8w6pvyuCOHjrS7aFRmGybDo8=; b=cNRrvj+OHP8TIAgbpphFdAlGJ2gZ3RT0Y6msoDztzpSaAprtyjw1gUz6xAsym8KBCe9Boy aRAM7s86BDMOEcB+Q1VyRNgtz50crRDhmxMI3EkzGGt3A5meZ09jc9avxxwWdzTuu1kRB8 Fg2pO36e+u5qb7Uie3inGTl/9GCTM7E= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id becf7c91 (TLSv1.3:AEAD-AES256-GCM-SHA384:256:NO); Wed, 13 Apr 2022 11:55:45 +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 v4 08/11] um: use fallback for random_get_entropy() instead of zero Date: Wed, 13 Apr 2022 13:54:08 +0200 Message-Id: <20220413115411.21489-9-Jason@zx2c4.com> In-Reply-To: <20220413115411.21489-1-Jason@zx2c4.com> References: <20220413115411.21489-1-Jason@zx2c4.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220413_045550_609842_F4E6C194 X-CRM114-Status: GOOD ( 15.71 ) 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 random_get_entropy_fallback() would be preferable, because that always needs to return _something_, even falling back to jiffies eventually. It's not as though random_get_entropy_fallback() 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: Richard Weinberger Cc: Anton Ivanov Cc: Johannes Berg Signed-off-by: Jason A. Donenfeld --- arch/um/include/asm/timex.h | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/arch/um/include/asm/timex.h b/arch/um/include/asm/timex.h index e392a9a5bc9b..9f27176adb26 100644 --- a/arch/um/include/asm/timex.h +++ b/arch/um/include/asm/timex.h @@ -2,13 +2,8 @@ #ifndef __UM_TIMEX_H #define __UM_TIMEX_H -typedef unsigned long cycles_t; - -static inline cycles_t get_cycles (void) -{ - return 0; -} - #define CLOCK_TICK_RATE (HZ) +#include + #endif