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 BE4D1C433F5 for ; Sat, 16 Apr 2022 14:45:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232307AbiDPOr3 (ORCPT ); Sat, 16 Apr 2022 10:47:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232287AbiDPOr2 (ORCPT ); Sat, 16 Apr 2022 10:47:28 -0400 Received: from angie.orcam.me.uk (angie.orcam.me.uk [IPv6:2001:4190:8020::34]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id A6E1516598; Sat, 16 Apr 2022 07:44:55 -0700 (PDT) Received: by angie.orcam.me.uk (Postfix, from userid 500) id EDBF792009E; Sat, 16 Apr 2022 16:44:53 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by angie.orcam.me.uk (Postfix) with ESMTP id E02D092009C; Sat, 16 Apr 2022 15:44:53 +0100 (BST) Date: Sat, 16 Apr 2022 15:44:53 +0100 (BST) From: "Maciej W. Rozycki" To: "Jason A. Donenfeld" cc: Thomas Bogendoerfer , LKML , Linux Crypto Mailing List , Thomas Gleixner , Arnd Bergmann , Theodore Ts'o , Dominik Brodowski , Russell King , Catalin Marinas , Will Deacon , Geert Uytterhoeven , 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 , linux-m68k , "open list:BROADCOM NVRAM DRIVER" , linux-riscv , sparclinux , linux-um@lists.infradead.org, X86 ML , linux-xtensa@linux-xtensa.org Subject: Re: [PATCH v4 04/11] mips: use fallback for random_get_entropy() instead of zero In-Reply-To: Message-ID: References: <20220413115411.21489-1-Jason@zx2c4.com> <20220413115411.21489-5-Jason@zx2c4.com> <20220413122546.GA11860@alpha.franken.de> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Hi Jason, > > There are two variants only of the CP0 Random register that we can ever > > encounter, as it's been de-facto standardised in early 1990s already and > > then written down in the MIPSr1 architecture specification ~2000. So I > > think it may make sense to actually handle them both explictitly with > > individual calculations, possibly conditionalised on a CONFIG setting or > > `cpu_has_3kex', because kernels that support the two variants of the MMU > > architecture are mutually incompatible. > > Okay, I can give this a shot, but this certainly isn't my forté. It > may ultimately wind up being simpler for you to just send some code of > what you envision for this, but if I understand your idea correctly, > what you're saying is something like: > > static inline unsigned long random_get_entropy(void) > { > unsigned int prid = read_c0_prid(); > unsigned int imp = prid & PRID_IMP_MASK; > unsigned int c0_random; > > if (can_use_mips_counter(prid)) > return read_c0_count(); > > if (cpu_has_3kex) > c0_random = (read_c0_random() >> 8) & 0x3f; > else > c0_random = read_c0_random() & 0x3f; > return (random_get_entropy_fallback() << 6) | (0x3f - c0_random); > } > > What do you think of that? Some tweak I'm missing? It certainly looks good to me. Do you have a way I could verify how this function performs? If so, then I could put it through my systems as I can cover all the cases handled here. Any improvements I previously discussed can then be made locally in the MIPS port as follow-up changes. > > Isn't it going to be an issue for an entropy source that the distribution > > of values obtained from the CP0 Random bit-field is not even, that is some > > values from the 6-bit range will never appear? > > It's the same situation without inverting the order: instead of some > bits on the top never happening, some bits on the bottom never happen > instead. In general, counters don't form uniform distributions anyway, > since the lower bits change faster, and neither are they independent, > since one sample in large part depends on the previous. This is just > sort of the nature of the beast, and the code that calls > random_get_entropy() deals with this appropriately (by, at the moment, > just hashing all the bits). OK then, thanks for your clarification. Maciej 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 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 DC3A1C433F5 for ; Sat, 16 Apr 2022 14:45:22 +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:Message-ID: In-Reply-To:Subject:cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Qa1365MM06+2zoQUqZJqm5KdGrRLRtj8sIwp74ZuBBo=; b=0X/lSGw3mcrNJA Omw91WhdUGJTzTBeY7GYTPSa86BSJVfgOwlyiF33AAc9nvU5w0/Irx9w4BvqQC0s+atJRrzwUBq+0 9OM9vkjx8othdZx/mgvulpJqxzWjBG18KrkXNO1XyO98Qkg/lR8ratnnxFoqid6JCJrmgdVw39Q7y /gtWzHhDPLaph2L2V0TgQ/66TceI0+2dPkMWSVwfMpEYDKZF4UDAY3pzSeUUwvWcJrdVLQgseOSs9 obt3fKeKQ2LM8OpmQIVpdBV2wkrnnHtRtxUCFup9swuUmQiQfMs8z2MB8byF1z01G7q23YBh37adY 7XePE6+mLGNo64woCvDA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nfjfk-00D81p-3F; Sat, 16 Apr 2022 14:45:12 +0000 Received: from angie.orcam.me.uk ([2001:4190:8020::34]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nfjfY-00D7yK-KY; Sat, 16 Apr 2022 14:45:02 +0000 Received: by angie.orcam.me.uk (Postfix, from userid 500) id EDBF792009E; Sat, 16 Apr 2022 16:44:53 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by angie.orcam.me.uk (Postfix) with ESMTP id E02D092009C; Sat, 16 Apr 2022 15:44:53 +0100 (BST) Date: Sat, 16 Apr 2022 15:44:53 +0100 (BST) From: "Maciej W. Rozycki" To: "Jason A. Donenfeld" cc: Thomas Bogendoerfer , LKML , Linux Crypto Mailing List , Thomas Gleixner , Arnd Bergmann , Theodore Ts'o , Dominik Brodowski , Russell King , Catalin Marinas , Will Deacon , Geert Uytterhoeven , 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 , linux-m68k , "open list:BROADCOM NVRAM DRIVER" , linux-riscv , sparclinux , linux-um@lists.infradead.org, X86 ML , linux-xtensa@linux-xtensa.org Subject: Re: [PATCH v4 04/11] mips: use fallback for random_get_entropy() instead of zero In-Reply-To: Message-ID: References: <20220413115411.21489-1-Jason@zx2c4.com> <20220413115411.21489-5-Jason@zx2c4.com> <20220413122546.GA11860@alpha.franken.de> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220416_074500_882406_8F641CD5 X-CRM114-Status: GOOD ( 27.61 ) 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: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org SGkgSmFzb24sCgo+ID4gIFRoZXJlIGFyZSB0d28gdmFyaWFudHMgb25seSBvZiB0aGUgQ1AwIFJh bmRvbSByZWdpc3RlciB0aGF0IHdlIGNhbiBldmVyCj4gPiBlbmNvdW50ZXIsIGFzIGl0J3MgYmVl biBkZS1mYWN0byBzdGFuZGFyZGlzZWQgaW4gZWFybHkgMTk5MHMgYWxyZWFkeSBhbmQKPiA+IHRo ZW4gd3JpdHRlbiBkb3duIGluIHRoZSBNSVBTcjEgYXJjaGl0ZWN0dXJlIHNwZWNpZmljYXRpb24g fjIwMDAuICBTbyBJCj4gPiB0aGluayBpdCBtYXkgbWFrZSBzZW5zZSB0byBhY3R1YWxseSBoYW5k bGUgdGhlbSBib3RoIGV4cGxpY3RpdGx5IHdpdGgKPiA+IGluZGl2aWR1YWwgY2FsY3VsYXRpb25z LCBwb3NzaWJseSBjb25kaXRpb25hbGlzZWQgb24gYSBDT05GSUcgc2V0dGluZyBvcgo+ID4gYGNw dV9oYXNfM2tleCcsIGJlY2F1c2Uga2VybmVscyB0aGF0IHN1cHBvcnQgdGhlIHR3byB2YXJpYW50 cyBvZiB0aGUgTU1VCj4gPiBhcmNoaXRlY3R1cmUgYXJlIG11dHVhbGx5IGluY29tcGF0aWJsZS4K PiAKPiBPa2F5LCBJIGNhbiBnaXZlIHRoaXMgYSBzaG90LCBidXQgdGhpcyBjZXJ0YWlubHkgaXNu J3QgbXkgZm9ydMOpLiBJdAo+IG1heSB1bHRpbWF0ZWx5IHdpbmQgdXAgYmVpbmcgc2ltcGxlciBm b3IgeW91IHRvIGp1c3Qgc2VuZCBzb21lIGNvZGUgb2YKPiB3aGF0IHlvdSBlbnZpc2lvbiBmb3Ig dGhpcywgYnV0IGlmIEkgdW5kZXJzdGFuZCB5b3VyIGlkZWEgY29ycmVjdGx5LAo+IHdoYXQgeW91 J3JlIHNheWluZyBpcyBzb21ldGhpbmcgbGlrZToKPiAKPiBzdGF0aWMgaW5saW5lIHVuc2lnbmVk IGxvbmcgcmFuZG9tX2dldF9lbnRyb3B5KHZvaWQpCj4gewo+ICAgICAgICAgdW5zaWduZWQgaW50 IHByaWQgPSByZWFkX2MwX3ByaWQoKTsKPiAgICAgICAgIHVuc2lnbmVkIGludCBpbXAgPSBwcmlk ICYgUFJJRF9JTVBfTUFTSzsKPiAgICAgICAgIHVuc2lnbmVkIGludCBjMF9yYW5kb207Cj4gCj4g ICAgICAgICBpZiAoY2FuX3VzZV9taXBzX2NvdW50ZXIocHJpZCkpCj4gICAgICAgICAgICAgICAg IHJldHVybiByZWFkX2MwX2NvdW50KCk7Cj4gCj4gICAgICAgICBpZiAoY3B1X2hhc18za2V4KQo+ ICAgICAgICAgICAgICAgICBjMF9yYW5kb20gPSAocmVhZF9jMF9yYW5kb20oKSA+PiA4KSAmIDB4 M2Y7Cj4gICAgICAgICBlbHNlCj4gICAgICAgICAgICAgICAgIGMwX3JhbmRvbSA9IHJlYWRfYzBf cmFuZG9tKCkgJiAweDNmOwo+ICAgICAgICAgcmV0dXJuIChyYW5kb21fZ2V0X2VudHJvcHlfZmFs bGJhY2soKSA8PCA2KSB8ICgweDNmIC0gYzBfcmFuZG9tKTsKPiB9Cj4gCj4gV2hhdCBkbyB5b3Ug dGhpbmsgb2YgdGhhdD8gU29tZSB0d2VhayBJJ20gbWlzc2luZz8KCiBJdCBjZXJ0YWlubHkgbG9v a3MgZ29vZCB0byBtZS4gIERvIHlvdSBoYXZlIGEgd2F5IEkgY291bGQgdmVyaWZ5IGhvdyB0aGlz IApmdW5jdGlvbiBwZXJmb3Jtcz8gIElmIHNvLCB0aGVuIEkgY291bGQgcHV0IGl0IHRocm91Z2gg bXkgc3lzdGVtcyBhcyBJIGNhbiAKY292ZXIgYWxsIHRoZSBjYXNlcyBoYW5kbGVkIGhlcmUuCgog QW55IGltcHJvdmVtZW50cyBJIHByZXZpb3VzbHkgZGlzY3Vzc2VkIGNhbiB0aGVuIGJlIG1hZGUg bG9jYWxseSBpbiB0aGUgCk1JUFMgcG9ydCBhcyBmb2xsb3ctdXAgY2hhbmdlcy4KCj4gPiAgSXNu J3QgaXQgZ29pbmcgdG8gYmUgYW4gaXNzdWUgZm9yIGFuIGVudHJvcHkgc291cmNlIHRoYXQgdGhl IGRpc3RyaWJ1dGlvbgo+ID4gb2YgdmFsdWVzIG9idGFpbmVkIGZyb20gdGhlIENQMCBSYW5kb20g Yml0LWZpZWxkIGlzIG5vdCBldmVuLCB0aGF0IGlzIHNvbWUKPiA+IHZhbHVlcyBmcm9tIHRoZSA2 LWJpdCByYW5nZSB3aWxsIG5ldmVyIGFwcGVhcj8KPiAKPiBJdCdzIHRoZSBzYW1lIHNpdHVhdGlv biB3aXRob3V0IGludmVydGluZyB0aGUgb3JkZXI6IGluc3RlYWQgb2Ygc29tZQo+IGJpdHMgb24g dGhlIHRvcCBuZXZlciBoYXBwZW5pbmcsIHNvbWUgYml0cyBvbiB0aGUgYm90dG9tIG5ldmVyIGhh cHBlbgo+IGluc3RlYWQuIEluIGdlbmVyYWwsIGNvdW50ZXJzIGRvbid0IGZvcm0gdW5pZm9ybSBk aXN0cmlidXRpb25zIGFueXdheSwKPiBzaW5jZSB0aGUgbG93ZXIgYml0cyBjaGFuZ2UgZmFzdGVy LCBhbmQgbmVpdGhlciBhcmUgdGhleSBpbmRlcGVuZGVudCwKPiBzaW5jZSBvbmUgc2FtcGxlIGlu IGxhcmdlIHBhcnQgZGVwZW5kcyBvbiB0aGUgcHJldmlvdXMuIFRoaXMgaXMganVzdAo+IHNvcnQg b2YgdGhlIG5hdHVyZSBvZiB0aGUgYmVhc3QsIGFuZCB0aGUgY29kZSB0aGF0IGNhbGxzCj4gcmFu ZG9tX2dldF9lbnRyb3B5KCkgZGVhbHMgd2l0aCB0aGlzIGFwcHJvcHJpYXRlbHkgKGJ5LCBhdCB0 aGUgbW9tZW50LAo+IGp1c3QgaGFzaGluZyBhbGwgdGhlIGJpdHMpLgoKIE9LIHRoZW4sIHRoYW5r cyBmb3IgeW91ciBjbGFyaWZpY2F0aW9uLgoKICBNYWNpZWoKCl9fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fCmxpbnV4LXJpc2N2IG1haWxpbmcgbGlzdApsaW51 eC1yaXNjdkBsaXN0cy5pbmZyYWRlYWQub3JnCmh0dHA6Ly9saXN0cy5pbmZyYWRlYWQub3JnL21h aWxtYW4vbGlzdGluZm8vbGludXgtcmlzY3YK 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 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 CA2CBC433EF for ; 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Sat, 16 Apr 2022 14:45:03 +0000 Received: from angie.orcam.me.uk ([2001:4190:8020::34]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nfjfY-00D7yK-KY; Sat, 16 Apr 2022 14:45:02 +0000 Received: by angie.orcam.me.uk (Postfix, from userid 500) id EDBF792009E; Sat, 16 Apr 2022 16:44:53 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by angie.orcam.me.uk (Postfix) with ESMTP id E02D092009C; Sat, 16 Apr 2022 15:44:53 +0100 (BST) Date: Sat, 16 Apr 2022 15:44:53 +0100 (BST) From: "Maciej W. Rozycki" To: "Jason A. Donenfeld" cc: Thomas Bogendoerfer , LKML , Linux Crypto Mailing List , Thomas Gleixner , Arnd Bergmann , Theodore Ts'o , Dominik Brodowski , Russell King , Catalin Marinas , Will Deacon , Geert Uytterhoeven , 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 , linux-m68k , "open list:BROADCOM NVRAM DRIVER" , linux-riscv , sparclinux , linux-um@lists.infradead.org, X86 ML , linux-xtensa@linux-xtensa.org Subject: Re: [PATCH v4 04/11] mips: use fallback for random_get_entropy() instead of zero In-Reply-To: Message-ID: References: <20220413115411.21489-1-Jason@zx2c4.com> <20220413115411.21489-5-Jason@zx2c4.com> <20220413122546.GA11860@alpha.franken.de> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220416_074500_882406_8F641CD5 X-CRM114-Status: GOOD ( 27.61 ) 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: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org SGkgSmFzb24sCgo+ID4gIFRoZXJlIGFyZSB0d28gdmFyaWFudHMgb25seSBvZiB0aGUgQ1AwIFJh bmRvbSByZWdpc3RlciB0aGF0IHdlIGNhbiBldmVyCj4gPiBlbmNvdW50ZXIsIGFzIGl0J3MgYmVl biBkZS1mYWN0byBzdGFuZGFyZGlzZWQgaW4gZWFybHkgMTk5MHMgYWxyZWFkeSBhbmQKPiA+IHRo ZW4gd3JpdHRlbiBkb3duIGluIHRoZSBNSVBTcjEgYXJjaGl0ZWN0dXJlIHNwZWNpZmljYXRpb24g fjIwMDAuICBTbyBJCj4gPiB0aGluayBpdCBtYXkgbWFrZSBzZW5zZSB0byBhY3R1YWxseSBoYW5k bGUgdGhlbSBib3RoIGV4cGxpY3RpdGx5IHdpdGgKPiA+IGluZGl2aWR1YWwgY2FsY3VsYXRpb25z LCBwb3NzaWJseSBjb25kaXRpb25hbGlzZWQgb24gYSBDT05GSUcgc2V0dGluZyBvcgo+ID4gYGNw dV9oYXNfM2tleCcsIGJlY2F1c2Uga2VybmVscyB0aGF0IHN1cHBvcnQgdGhlIHR3byB2YXJpYW50 cyBvZiB0aGUgTU1VCj4gPiBhcmNoaXRlY3R1cmUgYXJlIG11dHVhbGx5IGluY29tcGF0aWJsZS4K PiAKPiBPa2F5LCBJIGNhbiBnaXZlIHRoaXMgYSBzaG90LCBidXQgdGhpcyBjZXJ0YWlubHkgaXNu J3QgbXkgZm9ydMOpLiBJdAo+IG1heSB1bHRpbWF0ZWx5IHdpbmQgdXAgYmVpbmcgc2ltcGxlciBm b3IgeW91IHRvIGp1c3Qgc2VuZCBzb21lIGNvZGUgb2YKPiB3aGF0IHlvdSBlbnZpc2lvbiBmb3Ig dGhpcywgYnV0IGlmIEkgdW5kZXJzdGFuZCB5b3VyIGlkZWEgY29ycmVjdGx5LAo+IHdoYXQgeW91 J3JlIHNheWluZyBpcyBzb21ldGhpbmcgbGlrZToKPiAKPiBzdGF0aWMgaW5saW5lIHVuc2lnbmVk IGxvbmcgcmFuZG9tX2dldF9lbnRyb3B5KHZvaWQpCj4gewo+ICAgICAgICAgdW5zaWduZWQgaW50 IHByaWQgPSByZWFkX2MwX3ByaWQoKTsKPiAgICAgICAgIHVuc2lnbmVkIGludCBpbXAgPSBwcmlk ICYgUFJJRF9JTVBfTUFTSzsKPiAgICAgICAgIHVuc2lnbmVkIGludCBjMF9yYW5kb207Cj4gCj4g ICAgICAgICBpZiAoY2FuX3VzZV9taXBzX2NvdW50ZXIocHJpZCkpCj4gICAgICAgICAgICAgICAg IHJldHVybiByZWFkX2MwX2NvdW50KCk7Cj4gCj4gICAgICAgICBpZiAoY3B1X2hhc18za2V4KQo+ ICAgICAgICAgICAgICAgICBjMF9yYW5kb20gPSAocmVhZF9jMF9yYW5kb20oKSA+PiA4KSAmIDB4 M2Y7Cj4gICAgICAgICBlbHNlCj4gICAgICAgICAgICAgICAgIGMwX3JhbmRvbSA9IHJlYWRfYzBf cmFuZG9tKCkgJiAweDNmOwo+ICAgICAgICAgcmV0dXJuIChyYW5kb21fZ2V0X2VudHJvcHlfZmFs bGJhY2soKSA8PCA2KSB8ICgweDNmIC0gYzBfcmFuZG9tKTsKPiB9Cj4gCj4gV2hhdCBkbyB5b3Ug dGhpbmsgb2YgdGhhdD8gU29tZSB0d2VhayBJJ20gbWlzc2luZz8KCiBJdCBjZXJ0YWlubHkgbG9v a3MgZ29vZCB0byBtZS4gIERvIHlvdSBoYXZlIGEgd2F5IEkgY291bGQgdmVyaWZ5IGhvdyB0aGlz IApmdW5jdGlvbiBwZXJmb3Jtcz8gIElmIHNvLCB0aGVuIEkgY291bGQgcHV0IGl0IHRocm91Z2gg bXkgc3lzdGVtcyBhcyBJIGNhbiAKY292ZXIgYWxsIHRoZSBjYXNlcyBoYW5kbGVkIGhlcmUuCgog QW55IGltcHJvdmVtZW50cyBJIHByZXZpb3VzbHkgZGlzY3Vzc2VkIGNhbiB0aGVuIGJlIG1hZGUg bG9jYWxseSBpbiB0aGUgCk1JUFMgcG9ydCBhcyBmb2xsb3ctdXAgY2hhbmdlcy4KCj4gPiAgSXNu J3QgaXQgZ29pbmcgdG8gYmUgYW4gaXNzdWUgZm9yIGFuIGVudHJvcHkgc291cmNlIHRoYXQgdGhl IGRpc3RyaWJ1dGlvbgo+ID4gb2YgdmFsdWVzIG9idGFpbmVkIGZyb20gdGhlIENQMCBSYW5kb20g Yml0LWZpZWxkIGlzIG5vdCBldmVuLCB0aGF0IGlzIHNvbWUKPiA+IHZhbHVlcyBmcm9tIHRoZSA2 LWJpdCByYW5nZSB3aWxsIG5ldmVyIGFwcGVhcj8KPiAKPiBJdCdzIHRoZSBzYW1lIHNpdHVhdGlv biB3aXRob3V0IGludmVydGluZyB0aGUgb3JkZXI6IGluc3RlYWQgb2Ygc29tZQo+IGJpdHMgb24g dGhlIHRvcCBuZXZlciBoYXBwZW5pbmcsIHNvbWUgYml0cyBvbiB0aGUgYm90dG9tIG5ldmVyIGhh cHBlbgo+IGluc3RlYWQuIEluIGdlbmVyYWwsIGNvdW50ZXJzIGRvbid0IGZvcm0gdW5pZm9ybSBk aXN0cmlidXRpb25zIGFueXdheSwKPiBzaW5jZSB0aGUgbG93ZXIgYml0cyBjaGFuZ2UgZmFzdGVy LCBhbmQgbmVpdGhlciBhcmUgdGhleSBpbmRlcGVuZGVudCwKPiBzaW5jZSBvbmUgc2FtcGxlIGlu IGxhcmdlIHBhcnQgZGVwZW5kcyBvbiB0aGUgcHJldmlvdXMuIFRoaXMgaXMganVzdAo+IHNvcnQg b2YgdGhlIG5hdHVyZSBvZiB0aGUgYmVhc3QsIGFuZCB0aGUgY29kZSB0aGF0IGNhbGxzCj4gcmFu ZG9tX2dldF9lbnRyb3B5KCkgZGVhbHMgd2l0aCB0aGlzIGFwcHJvcHJpYXRlbHkgKGJ5LCBhdCB0 aGUgbW9tZW50LAo+IGp1c3QgaGFzaGluZyBhbGwgdGhlIGJpdHMpLgoKIE9LIHRoZW4sIHRoYW5r cyBmb3IgeW91ciBjbGFyaWZpY2F0aW9uLgoKICBNYWNpZWoKCl9fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fCmxpbnV4LWFybS1rZXJuZWwgbWFpbGluZyBsaXN0 CmxpbnV4LWFybS1rZXJuZWxAbGlzdHMuaW5mcmFkZWFkLm9yZwpodHRwOi8vbGlzdHMuaW5mcmFk ZWFkLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2xpbnV4LWFybS1rZXJuZWwK