From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cgTmR-0003EK-6q for barebox@lists.infradead.org; Wed, 22 Feb 2017 10:04:17 +0000 Date: Wed, 22 Feb 2017 11:03:50 +0100 From: Sascha Hauer Message-ID: <20170222100350.anjucafhspmwsa2c@pengutronix.de> References: <20170221144751.27760-1-yegorslists@googlemail.com> <0CEC428C-E1EE-48A7-85CF-6FC90A22F47C@jcrosoft.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH] lib: xz: add support for bcj filters To: Yegor Yefremov Cc: Falco Hyfing , barebox On Wed, Feb 22, 2017 at 09:15:36AM +0100, Yegor Yefremov wrote: > On Wed, Feb 22, 2017 at 5:29 AM, Jean-Christophe PLAGNIOL-VILLARD > wrote: > > > >> On Feb 21, 2017, at 10:47 PM, yegorslists@googlemail.com wrote: > >> > >> From: Yegor Yefremov > >> > >> Add missing configuration options for various bcj filters. Without > >> these options the lib/xz/xz_dec_bcj.c file will be compiled, but all > >> filters will be disabled. > >> > >> Signed-off-by: Yegor Yefremov > >> --- > >> lib/Kconfig | 28 ++++++++++++++++++++++++++++ > >> 1 file changed, 28 insertions(+) > >> > >> diff --git a/lib/Kconfig b/lib/Kconfig > >> index f9f25bdef..83dd8e0a4 100644 > >> --- a/lib/Kconfig > >> +++ b/lib/Kconfig > >> @@ -22,6 +22,34 @@ config XZ_DECOMPRESS > >> bool "include xz uncompression support" > >> select UNCOMPRESS > >> > >> +if XZ_DECOMPRESS > >> + > >> +config XZ_DEC_X86 > >> + bool "x86 BCJ filter decoder" > >> + default y > > this need to be ARCH dependant > > Why? In Linux kernel it is not arch dependent, because AFAIK it > describes only compression particularities. This way you can extract > sqaushfs images on your ARM machine, that were compressed on SPARK > etc. So xz uses the Sparc bcj filter even when compressing ARM binaries? That doesn't sound very mature to me. It is quite surprising to me that I have to enable XZ_DEC_X86 in barebox since this is the architecture the xz binary was most likely compressed on. Also it's surprising that XZ_DEC_X86 won't bring us any gain since the xz binary will most likely contain ARM instructions on a ARM build, except that without XZ_DEC_X86 enabled it will not work. Then in bcj_apply() we have: #ifdef XZ_DEC_X86 case BCJ_X86: filtered = bcj_x86(s, buf, size); break; #endif ... default: /* Never reached but silence compiler warnings. */ filtered = 0; This is simply not true when any of the ifdefs is not true. I think we should enable all the XZ_DEC_* options but without making them visible since if someone ever stumbles upon these options and changes them he will most likely do it wrong. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox