From mboxrd@z Thu Jan 1 00:00:00 1970 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 9662DC433FE for ; Sat, 19 Nov 2022 01:08:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229762AbiKSBIE (ORCPT ); Fri, 18 Nov 2022 20:08:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43576 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233029AbiKSBHq (ORCPT ); Fri, 18 Nov 2022 20:07:46 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 710D8E5B3C; Fri, 18 Nov 2022 16:04:41 -0800 (PST) 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 0B0E96280C; Sat, 19 Nov 2022 00:04:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 68162C4314A; Sat, 19 Nov 2022 00:04:39 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="ER3bEm+Y" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1668816277; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=lmwBk/Gz2TqSzFgUZDAtaG0xzco/3QDbfEsP3AkA5Y8=; b=ER3bEm+YxSIY1yg4IKdwrGVBIvMx0EUlVXTUxMfaRCCgXiSGPO3attbX+RwqWHBJrgV2cn ZJmdFuHQ1uBoWlbelNruvYJZnmHu3eQOW/QrN3q5as703nDtvrbRGN8cnioaYY4cjYuFsM oi8VLJg/bH3Xf/sK2zJfv/b7h6cibek= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id ca956244 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Sat, 19 Nov 2022 00:04:37 +0000 (UTC) Date: Sat, 19 Nov 2022 01:04:35 +0100 From: "Jason A. Donenfeld" To: Christophe Leroy Cc: "linux-kernel@vger.kernel.org" , "patches@lists.linux.dev" , "linux-crypto@vger.kernel.org" , "x86@kernel.org" , Thomas Gleixner , Greg Kroah-Hartman , Adhemerval Zanella Netto , Carlos O'Donell Subject: Re: [PATCH v4 2/3] random: introduce generic vDSO getrandom() implementation Message-ID: References: <20221118172839.2653829-1-Jason@zx2c4.com> <20221118172839.2653829-3-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Nov 19, 2022 at 12:55:02AM +0100, Jason A. Donenfeld wrote: > Sorry if I'm a bit slow here to grok what's up. Okay, I think I see it now. That's a complicated patch for a simple idea because gettime is more complicated than getrandom. I suspect what you want is something like the below, correct? Seems easy enough. diff --git a/lib/vdso/getrandom.c b/lib/vdso/getrandom.c index b253e9247706..b3282d7cfb53 100644 --- a/lib/vdso/getrandom.c +++ b/lib/vdso/getrandom.c @@ -41,10 +41,10 @@ static void memcpy_and_zero(void *dst, void *src, size_t len) } static __always_inline ssize_t -__cvdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state) +__cvdso_getrandom_data(const struct vdso_rng_data *rng_info, void *buffer, size_t len, + unsigned int flags, void *opaque_state) { struct vgetrandom_state *state = opaque_state; - const struct vdso_rng_data *rng_info = __arch_get_vdso_rng_data(); u32 chacha_state[CHACHA_STATE_WORDS]; ssize_t ret = min_t(size_t, MAX_RW_COUNT, len); unsigned long current_generation; @@ -107,3 +107,9 @@ __cvdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_sta memzero_explicit(chacha_state, sizeof(chacha_state)); goto more_batch; } + +static __always_inline ssize_t +__cvdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state) +{ + return __cvdso_getrandom_data(__arch_get_vdso_rng_data(), buffer, len, flags, opaque_state); +}