From patchwork Sat Apr 23 21:26:20 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: 12824702 X-Patchwork-Delegate: herbert@gondor.apana.org.au 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1359C433F5 for ; Sat, 23 Apr 2022 21:28:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237174AbiDWVbp (ORCPT ); Sat, 23 Apr 2022 17:31:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237284AbiDWVbU (ORCPT ); Sat, 23 Apr 2022 17:31:20 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3B73D4ECFC; Sat, 23 Apr 2022 14:27:43 -0700 (PDT) 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 82B1F61036; Sat, 23 Apr 2022 21:27:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2CB5BC385A5; Sat, 23 Apr 2022 21:27:42 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="BEZkpuLY" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1650749261; 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=LtsT1bg8rxvUBlF/kXwH98fwCiYSInDOUaZObg+GDzI=; b=BEZkpuLYc+kRzZgF0QhMewuWGSQIScrjfxolT94RPSCCw6AoQSDUHd29gRXQh5NxXn2tlu SA+kCYIyrCzHOguzPz/xF8xLO1nTG4i9m3kNrQvHoOjWXAgeJmoSqMD53vtaBmHU6x9kC8 io3ZvlAr+RgKr0GvRkJNhAQ4joo/ChU= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id ba2011b9 (TLSv1.3:AEAD-AES256-GCM-SHA384:256:NO); Sat, 23 Apr 2022 21:27:40 +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" , Richard Weinberger , Anton Ivanov , Johannes Berg Subject: [PATCH v6 14/17] um: use fallback for random_get_entropy() instead of zero Date: Sat, 23 Apr 2022 23:26:20 +0200 Message-Id: <20220423212623.1957011-15-Jason@zx2c4.com> In-Reply-To: <20220423212623.1957011-1-Jason@zx2c4.com> References: <20220423212623.1957011-1-Jason@zx2c4.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.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 Acked-by: 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