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 480E7C433EF for ; Wed, 8 Dec 2021 02:26:53 +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:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=VLPpZNYweggcZjldQkp0fB1V1fRN9K8GNKGHrlIZd0w=; b=fg/9gvtSjRbo4h yHqfruxGbmxtKlHu/jzbOD6NvmXF+zjQKz1aS4RFixuJZD1qxqNnKWvfyoCt07OhpBCJSrArtWhWU reDhUHEhpPYYnEu9ikl1qM3AVPtiyErzhGqx13sTPBAj/g0D+nVxcJ8mQDxges5D46camm5XmAa8o N/OXqEuUFmjQp28SIH0RRWftRWZsmd1sseoMYOcqOCY2f/ej0YKlrxB1Pv9yDanj15XUfr92RhYQK 0LpjVNXAoQMndZ79ilt+Tw9jcYj/0LFnX2n05JvV+75fU3uOIgUFloIRugn9UeJN3DSzzHFuDHMt0 LYB4MM4/xXSTWhQIYw5Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mumfI-00Agl7-52; Wed, 08 Dec 2021 02:26:40 +0000 Received: from mailgw01.mediatek.com ([216.200.240.184]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mumfD-00Agk9-Nm; Wed, 08 Dec 2021 02:26:38 +0000 X-UUID: 5708fc8db9794601878249352476e52a-20211207 X-UUID: 5708fc8db9794601878249352476e52a-20211207 Received: from mtkcas67.mediatek.inc [(172.29.193.45)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 887743112; Tue, 07 Dec 2021 19:26:26 -0700 Received: from MTKMBS07N2.mediatek.inc (172.21.101.141) by MTKMBS62N1.mediatek.inc (172.29.193.41) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 7 Dec 2021 18:26:24 -0800 Received: from mtkcas10.mediatek.inc (172.21.101.39) by mtkmbs07n2.mediatek.inc (172.21.101.141) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 8 Dec 2021 10:26:23 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas10.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Wed, 8 Dec 2021 10:26:23 +0800 From: Mark-PK Tsai To: CC: , , , , , , , , , , , Subject: Re: [PATCH] arm: remove [_text, _stext) from kernel code resource Date: Wed, 8 Dec 2021 10:26:23 +0800 Message-ID: <20211208022623.15103-1-mark-pk.tsai@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: References: MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211207_182635_808177_B723AE58 X-CRM114-Status: GOOD ( 25.43 ) X-BeenThere: linux-mediatek@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="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org > On Fri, Dec 03, 2021 at 10:14:16PM +0800, Mark-PK Tsai wrote: > > Remove the [_text, _stext) from Kernel Code. > > Although there are some startup code in head.text, they > > are freed to the buddy system after kernel boot. > > Hmm, I don't see it is being freed anywhere. Can you elaborate when and how > the range [_text, _stext) is freed? arm_memblock_init() reserve [KERNEL_START, KERNEL_END) which are defined as following. #define KERNEL_START _stext #define KERNEL_END _end free_low_memory_core_early() free all the non-reserved range in lowmem, so the range [_text, _stext) is also freed here. > > > And we have memory protection mechanism use this > > which have false alarm when some other IPs doing dma > > if the dma page frame is in the [_text, _stext). > > > > Below are my iomem resource and reserved memory information: > > console:/ # grep Kernel /proc/iomem > > 20208000-219fffff : Kernel code > > 21b00000-21c2e76f : Kernel data > > > > console:/ # cat /sys/kernel/debug/memblock/reserved > > 0: 0x20201000..0x20207fff > > 1: 0x20300000..0x21c2e76f > > What are the addresses of _text and _stext in your configuration? va pa c0008000 20208000 _text c0100000 20300000 _stext > > What these dumps are supposed to show here? > Below is the dump info after applied this patch. console:/ # grep Kernel /proc/iomem 20300000-219fffff : Kernel code 21b00000-21c2e76f : Kernel data console:/ # cat /sys/kernel/debug/memblock/reserved 0: 0x20201000..0x20207fff 1: 0x20300000..0x21c2e76f The difference is that Kernel Code resource match the reserved memblock 1 which is reserved in arm_memblock_init(). > > > Signed-off-by: Mark-PK Tsai > > --- > > arch/arm/kernel/setup.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c > > index 284a80c0b6e1..85ffc9501e38 100644 > > --- a/arch/arm/kernel/setup.c > > +++ b/arch/arm/kernel/setup.c > > @@ -851,7 +851,7 @@ static void __init request_standard_resources(const struct machine_desc *mdesc) > > struct resource *res; > > u64 i; > > > > - kernel_code.start = virt_to_phys(_text); > > + kernel_code.start = virt_to_phys(_stext); > > kernel_code.end = virt_to_phys(__init_begin - 1); > > kernel_data.start = virt_to_phys(_sdata); > > kernel_data.end = virt_to_phys(_end - 1); > > -- > > 2.18.0 > > > > -- > Sincerely yours, > Mike. _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek