From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Tue, 29 Aug 2023 14:06:51 +0200 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1qaxUi-00DHdk-Ur for lore@lore.pengutronix.de; Tue, 29 Aug 2023 14:06:51 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qaxUg-0000Bp-Lj for lore@pengutronix.de; Tue, 29 Aug 2023 14:06:51 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=EDkWaBxxbPT1ZOmNHbD3iKYtrAZfICKKlQo8Qc6sSRM=; b=vFJeXwZi5zySB1MytUQ1bJWIeQ 7scj0YEmIf7O3zGybcWqExtu2+LlLFE+jn2ageBo8bSPwIcyGUPng+mjNfZbpFuGwWanP4ZpCLcbo I9Vd31Ey6b9gdBTiMB6Ctvgumbc5Qdm96tkpvc9D7FvkbSfIgi0SiyPmW7mFOGr/djFsKdo8vWFyh kBigq7iPBef3zCOkdUOg2GI94Z8d4AoB29NK1UcU41qw7WnKGEkcar5YiWqgar1rqdhIcvCLF1oAu YIHmJVhIHLkhHhbtQ9T0T/2nbrX61wbhokCn/CD1UHYCQzwXS1j8aV0ELEFimGfemdA8WzuCpA5Y9 edh33SkA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qaxTH-00BShj-0J; Tue, 29 Aug 2023 12:05:23 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qaxTD-00BSgq-26 for barebox@lists.infradead.org; Tue, 29 Aug 2023 12:05:21 +0000 Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[127.0.0.1]) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1qaxT9-0008GX-FR; Tue, 29 Aug 2023 14:05:15 +0200 Message-ID: <065ee7e7-cb0a-6651-8d24-e4a4be941956@pengutronix.de> Date: Tue, 29 Aug 2023 14:05:02 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.14.0 Content-Language: en-US, de-DE To: Ahmad Fatoum , patchwork-jzi@pengutronix.de Cc: Barebox Mailing List References: <20230829-crc32_in_pbl-v1-1-6a3e01a74c8d@pengutronix.de> <7101f4d9-9ebc-9d73-40a5-85a96c34589c@pengutronix.de> <44ee704c-8e28-a0a6-6627-c33f0bd56d3d@pengutronix.de> <80bc6b24-35c5-f895-ace2-887ceddaa542@pengutronix.de> <65dea589-e8f6-e5d3-76a6-7a966e498017@pengutronix.de> From: Johannes Zink In-Reply-To: <65dea589-e8f6-e5d3-76a6-7a966e498017@pengutronix.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230829_050519_685941_8C757835 X-CRM114-Status: GOOD ( 34.88 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.ext.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-5.5 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH] crypto: crc32: make crc32 available in PBL X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.ext.pengutronix.de) Hi Ahmad, On 8/29/23 13:08, Ahmad Fatoum wrote: > On 29.08.23 12:55, Johannes Zink wrote: >> On 8/29/23 12:45, Ahmad Fatoum wrote: >>>>> +lwl-$(CONFIG_CRC32_EARLY)        += crc32.o >>>> >>>> pbl-obj- is the correct prefix. lwl- means pbl- if we have PBL >>>> support at all and obj- otherwise (for legacy systems without PBL), >>>> while pbl-obj- is equivalent to duplicating the line once with pbl- >>>> and once with obj- >>> >>> s/pbl-obj-/obj-pbl-/ :) > > Sorry, had a small brain fart here. > > You didn't remove the original obj-, > so now lwl- either expands to and extra obj- or to pbl-. > > obj-pbl- makes sense when you use the same symbol for both PBL and > barebox proper, but as you're introducing a new symbol, you can > leave it as lwl- or make it pbl- for explicitness. > ok. I think I won't glob it in obj-pbl, as one might want to explicitly add crc32.o only for PBL or only for barebox-proper. >> ack, gonna fix this for v2. >> >>>> >>>>>   obj-$(CONFIG_DIGEST_SHA384_GENERIC)    += sha4.o >>>>>   obj-$(CONFIG_DIGEST_SHA512_GENERIC)    += sha4.o >>>>>   obj-y    += memneq.o >>>>> diff --git a/crypto/crc32.c b/crypto/crc32.c >>>>> index 95cb2212db2b..284d39351682 100644 >>>>> --- a/crypto/crc32.c >>>>> +++ b/crypto/crc32.c >>>>> @@ -22,7 +22,7 @@ >>>>>   #define STATIC static inline >>>>>   #endif >>>>>   -#ifdef CONFIG_DYNAMIC_CRC_TABLE >>>>> +#if defined(CONFIG_DYNAMIC_CRC_TABLE) && !defined(__PBL__) >>>> >>>> You could also replace the dynamic allocation with a static array initialized >>>> to zero. That way you can have a dynamic crc table even in PBL without affecting >>>> image size as the BSS is not part of the image. >> >> ack. Is this ok? >> >> #ifdef __PBL__ >>   static uint32_t _crc_table_memory[sizeof(uint32_t) * 256] = { 0 }; > > The array is 256 elements, not 1024 elements. Explicit intialization > is unnecessary. good catch. thanks. > >> #endif >> >> static void *alloc_crc_table() { >> #ifdef __PBL__ >>     return _crc_table_memory; >> #else >>     return xmalloc(sizeof(uint32_t) * 256); >> #endif >> } >> >> If so, I can change it for v2. > > My idea was to drop the allocation altogether by using BSS. > If you do this, you should not need any __PBL__ checking at all. I guess that should work indeed. Do I need to explicitly mark the array with a prefix to force it into BSS (sorry, I am not too familiar with the barebox linker scripts...)? > > Either you have CONFIG_DYNAMIC_CRC_TABLE and the table is dynamically > filled in bss on first access or you have CONFIG_DYNAMIC_CRC_TABLE=n > and the table is already there and need not be allocated. > > On a second thought, I am not sure if we want a table at all in PBL. > Do you do a lot of CRC32 computation? Maybe we should just not use > a table at all in PBL and just calculate a single crc32? > That's what Sascha did here: > > 2d13b856604b ("crc: Add PBL variant for crc_itu_t()") > For my specific usecase I need to check a single CRC32 once, so probably there is the same or even more overhead to dynamically filling the Table than just doing a single CRC32 computation. Maybe more overhead than using the precompiled, pre-filled table, but I fully acknowledge that size matters in PBL. I like Sascha's approach, so let me try to do a dynamic computation for the PBL implementation in my v2 patch. Best regards Johannes > Let me know what you think. > > Cheers, > Ahmad > >> >> Best regards >> Johannes >> >> >>>> >>>>>     static uint32_t *crc_table; >>>>>   @@ -145,7 +145,7 @@ STATIC uint32_t crc32(uint32_t crc, const void *_buf, unsigned int len) >>>>>   { >>>>>       const unsigned char *buf = _buf; >>>>>   -#ifdef CONFIG_DYNAMIC_CRC_TABLE >>>>> +#if defined(CONFIG_DYNAMIC_CRC_TABLE) && !defined(__PBL__) >>>>>       if (!crc_table) >>>>>           make_crc_table(); >>>>>   #endif >>>>> @@ -171,7 +171,7 @@ STATIC uint32_t crc32_no_comp(uint32_t crc, const void *_buf, unsigned int len) >>>>>   { >>>>>      const unsigned char *buf = _buf; >>>>>   -#ifdef CONFIG_DYNAMIC_CRC_TABLE >>>>> +#if defined(CONFIG_DYNAMIC_CRC_TABLE) && !defined(__PBL__) >>>>>       if (!crc_table) >>>>>           make_crc_table(); >>>>>   #endif >>>>> >>>>> --- >>>>> base-commit: bef38b18eeb5d2f1fac334fb8b831e47261e099c >>>>> change-id: 20230829-crc32_in_pbl-4d824629d4e2 >>>>> >>>>> Best regards, >>>> >>> >> > -- Pengutronix e.K. | Johannes Zink | Steuerwalder Str. 21 | https://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686| Fax: +49-5121-206917-5555 |