From nobody Wed Sep 17 22:23:51 2025 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 86D4CC3DA79 for ; Thu, 15 Dec 2022 12:42:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229588AbiLOMm0 (ORCPT ); Thu, 15 Dec 2022 07:42:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54870 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229906AbiLOMl0 (ORCPT ); Thu, 15 Dec 2022 07:41:26 -0500 Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3BE792F01A; Thu, 15 Dec 2022 04:40:26 -0800 (PST) Received: from localhost.localdomain (unknown [83.149.199.65]) by mail.ispras.ru (Postfix) with ESMTPSA id 421B540737A3; Thu, 15 Dec 2022 12:40:24 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru 421B540737A3 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ispras.ru; s=default; t=1671108024; bh=M3naYL3GGl+5q+XfB9vebSxsQoc+3D3N13eyKPThq2o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IWyIGJFBnzJsQIQrSjOaeMbZjo7sAJtUMyNo3yquaylA6gq0bJVAr4PeNJJC3Jf0Q URAETK1ahqEnAouSJpMiIC15NDt4Iz03atawHNbkIDkRhcOds6fkCvObHGM7TMrytA OrSu2IqbhBN+5RdqIF3TUrfTF9ihM+NdoLGTvBVo= From: Evgeniy Baskov To: Ard Biesheuvel Cc: Evgeniy Baskov , Borislav Petkov , Andy Lutomirski , Dave Hansen , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Alexey Khoroshilov , Peter Jones , "Limonciello, Mario" , joeyli , lvc-project@linuxtesting.org, x86@kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH v4 13/26] x86/boot: Split trampoline and pt init code Date: Thu, 15 Dec 2022 15:38:04 +0300 Message-Id: <9f951d6332eea6e46ebd46ca919ed5b1b85c0ba3.1671098103.git.baskov@ispras.ru> X-Mailer: git-send-email 2.37.4 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When allocating trampoline from libstub trampoline allocation is performed separately, so it needs to be skipped. Split trampoline initialization and allocation code into two functions to make them invokable separately. Tested-by: Mario Limonciello Tested-by: Peter Jones Signed-off-by: Evgeniy Baskov --- arch/x86/boot/compressed/pgtable_64.c | 73 +++++++++++++++++---------- 1 file changed, 46 insertions(+), 27 deletions(-) diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compress= ed/pgtable_64.c index c7cf5a1059a8..1f7169248612 100644 --- a/arch/x86/boot/compressed/pgtable_64.c +++ b/arch/x86/boot/compressed/pgtable_64.c @@ -106,12 +106,8 @@ static unsigned long find_trampoline_placement(void) return bios_start - TRAMPOLINE_32BIT_SIZE; } =20 -struct paging_config paging_prepare(void *rmode) +bool trampoline_pgtable_init(struct boot_params *boot_params) { - struct paging_config paging_config =3D {}; - - /* Initialize boot_params. Required for cmdline_find_option_bool(). */ - boot_params =3D rmode; =20 /* * Check if LA57 is desired and supported. @@ -125,26 +121,10 @@ struct paging_config paging_prepare(void *rmode) * * That's substitute for boot_cpu_has() in early boot code. */ - if (IS_ENABLED(CONFIG_X86_5LEVEL) && - !cmdline_find_option_bool("no5lvl") && - native_cpuid_eax(0) >=3D 7 && - (native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31)))) { - paging_config.l5_required =3D 1; - } - - paging_config.trampoline_start =3D find_trampoline_placement(); - - trampoline_32bit =3D (unsigned long *)paging_config.trampoline_start; - - /* Preserve trampoline memory */ - memcpy(trampoline_save, trampoline_32bit, TRAMPOLINE_32BIT_SIZE); - - /* Clear trampoline memory first */ - memset(trampoline_32bit, 0, TRAMPOLINE_32BIT_SIZE); - - /* Copy trampoline code in place */ - memcpy(trampoline_32bit + TRAMPOLINE_32BIT_CODE_OFFSET / sizeof(unsigned = long), - &trampoline_32bit_src, TRAMPOLINE_32BIT_CODE_SIZE); + bool l5_required =3D IS_ENABLED(CONFIG_X86_5LEVEL) && + !cmdline_find_option_bool("no5lvl") && + native_cpuid_eax(0) >=3D 7 && + (native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31))); =20 /* * The code below prepares page table in trampoline memory. @@ -160,10 +140,10 @@ struct paging_config paging_prepare(void *rmode) * We are not going to use the page table in trampoline memory if we * are already in the desired paging mode. */ - if (paging_config.l5_required =3D=3D !!(native_read_cr4() & X86_CR4_LA57)) + if (l5_required =3D=3D !!(native_read_cr4() & X86_CR4_LA57)) goto out; =20 - if (paging_config.l5_required) { + if (l5_required) { /* * For 4- to 5-level paging transition, set up current CR3 as * the first and the only entry in a new top-level page table. @@ -185,6 +165,45 @@ struct paging_config paging_prepare(void *rmode) (void *)src, PAGE_SIZE); } =20 +out: + return l5_required; +} + +struct paging_config paging_prepare(void *rmode) +{ + struct paging_config paging_config =3D {}; + bool early_trampoline_alloc =3D 0; + + /* Initialize boot_params. Required for cmdline_find_option_bool(). */ + boot_params =3D rmode; + + /* + * We only need to find trampoline placement, if we have + * not already done it from libstub. + */ + + paging_config.trampoline_start =3D find_trampoline_placement(); + trampoline_32bit =3D (unsigned long *)paging_config.trampoline_start; + early_trampoline_alloc =3D 0; + + /* + * Preserve trampoline memory. + * When trampoline is located in memory + * owned by us, i.e. allocated in EFISTUB, + * we don't care about previous contents + * of this memory so copying can also be skipped. + */ + memcpy(trampoline_save, trampoline_32bit, TRAMPOLINE_32BIT_SIZE); + + /* Clear trampoline memory first */ + memset(trampoline_32bit, 0, TRAMPOLINE_32BIT_SIZE); + + /* Copy trampoline code in place */ + memcpy(trampoline_32bit + TRAMPOLINE_32BIT_CODE_OFFSET / sizeof(unsigned = long), + &trampoline_32bit_src, TRAMPOLINE_32BIT_CODE_SIZE); + + paging_config.l5_required =3D trampoline_pgtable_init(boot_params); + out: return paging_config; } --=20 2.37.4