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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E29CDC43603 for ; Thu, 5 Dec 2019 18:56:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C05A32464E for ; Thu, 5 Dec 2019 18:56:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729426AbfLES4e (ORCPT ); Thu, 5 Dec 2019 13:56:34 -0500 Received: from mga05.intel.com ([192.55.52.43]:18412 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729290AbfLES4e (ORCPT ); Thu, 5 Dec 2019 13:56:34 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Dec 2019 10:56:33 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,282,1571727600"; d="scan'208";a="386274423" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by orsmga005.jf.intel.com with ESMTP; 05 Dec 2019 10:56:32 -0800 Received: from andy by smile with local (Exim 4.93-RC5) (envelope-from ) id 1icwIi-000422-AC; Thu, 05 Dec 2019 20:56:32 +0200 Date: Thu, 5 Dec 2019 20:56:32 +0200 From: Andy Shevchenko To: Ard Biesheuvel Cc: linux-efi@vger.kernel.org Subject: Re: [PATCH v4] efi/earlycon: Remap entire framebuffer after page initialization Message-ID: <20191205185632.GA32742@smile.fi.intel.com> References: <20191205164248.14511-1-ardb@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191205164248.14511-1-ardb@kernel.org> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org On Thu, Dec 05, 2019 at 04:42:48PM +0000, Ard Biesheuvel wrote: > From: Andy Shevchenko > > When commit 69c1f396f25b > > "efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation" > > moved the x86 specific EFI earlyprintk implementation to a shared location, > it also tweaked the behaviour. In particular, it dropped a trick with full > framebuffer remapping after page initialization, leading to two regressions: > 1) very slow scrolling after page initialization, > 2) kernel hang when the 'keep_bootcon' command line argument is passed. > > Putting the tweak back fixes #2 and mitigates #1, i.e., it limits the slow > behavior to the early boot stages, presumably due to eliminating heavy > map()/unmap() operations per each pixel line on the screen. > > Fixes: 69c1f396f25b ("efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation") > Signed-off-by: Andy Shevchenko > [ardb: ensure efifb is unmapped again unless keep_bootcon is in effect] > Signed-off-by: Ard Biesheuvel > --- > drivers/firmware/efi/earlycon.c | 40 +++++++++++++++++++++++++++++++++ > 1 file changed, 40 insertions(+) > > diff --git a/drivers/firmware/efi/earlycon.c b/drivers/firmware/efi/earlycon.c > index c9a0efca17b0..0bc4fe741415 100644 > --- a/drivers/firmware/efi/earlycon.c > +++ b/drivers/firmware/efi/earlycon.c > @@ -13,18 +13,57 @@ > > #include > > +static const struct console *earlycon_console __initdata; > static const struct font_desc *font; > static u32 efi_x, efi_y; > static u64 fb_base; > static pgprot_t fb_prot; > +static void *efi_fb; > + > +/* > + * efi earlycon needs to use early_memremap() to map the framebuffer. > + * But early_memremap() is not usable for 'earlycon=efifb keep_bootcon', > + * memremap() should be used instead. memremap() will be available after > + * paging_init() which is earlier than initcall callbacks. Thus adding this > + * early initcall function early_efi_map_fb() to map the whole efi framebuffer. > + */ > +static int __init efi_earlycon_remap_fb(void) > +{ > + /* bail if there is no bootconsole or it has been disabled already */ > + if (!earlycon_console || !(earlycon_console->flags & CON_ENABLED)) > + return 0; > + > + if (pgprot_val(fb_prot) == pgprot_val(PAGE_KERNEL)) > + efi_fb = memremap(fb_base, screen_info.lfb_size, MEMREMAP_WB); > + else > + efi_fb = memremap(fb_base, screen_info.lfb_size, MEMREMAP_WC); > + > + return efi_fb ? 0 : -ENOMEM; > +} > +early_initcall(efi_earlycon_remap_fb); > + > +static int __init efi_earlycon_unmap_fb(void) > +{ > + /* unmap the bootconsole fb unless keep_bootcon has left it enabled */ > + if (efi_fb && !(earlycon_console->flags & CON_ENABLED)) Isn't efi_fb test superfluous here? > + memunmap(efi_fb); > + return 0; > +} > +late_initcall(efi_earlycon_unmap_fb); I still think we need __exitcall() to clean up the stuff in any case. > > static __ref void *efi_earlycon_map(unsigned long start, unsigned long len) > { > + if (efi_fb) > + return efi_fb + start; > + > return early_memremap_prot(fb_base + start, len, pgprot_val(fb_prot)); > } > > static __ref void efi_earlycon_unmap(void *addr, unsigned long len) > { > + if (efi_fb) > + return; > + > early_memunmap(addr, len); > } > > @@ -201,6 +240,7 @@ static int __init efi_earlycon_setup(struct earlycon_device *device, > efi_earlycon_scroll_up(); > > device->con->write = efi_earlycon_write; > + earlycon_console = device->con; > return 0; > } > EARLYCON_DECLARE(efifb, efi_earlycon_setup); > -- > 2.17.1 > -- With Best Regards, Andy Shevchenko