From patchwork Mon May 8 07:03:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 680351 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 41960C77B73 for ; Mon, 8 May 2023 07:05:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232932AbjEHHFL (ORCPT ); Mon, 8 May 2023 03:05:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47058 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233143AbjEHHEo (ORCPT ); Mon, 8 May 2023 03:04:44 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1C23E1C0F7; Mon, 8 May 2023 00:04:15 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9322861F96; Mon, 8 May 2023 07:04:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4069FC433D2; Mon, 8 May 2023 07:04:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1683529454; bh=Cbgin3O3w5TrAUQhn3/olaZs0A4XgRk35uCUUkZRmeM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ENwWEqdCtVzf0zk6FhW1aJ99HkXt7BD5OjSafuLC9oHhpagtOXKtTghetJRs30NXs AH4NNjgyAufSkCxPa/060OQepjjrZSpiPmY2UWaOfGj73FAiHYvN8i/MhyHnJ0hsyV 5R+6Ocy4N1dbrLMbcPmBYAlCJ3yxdwytYS6+o5CGLbvuEQ3p943QppwiEetM6cRR2O yLuyDI9g+e+tsK57ufIJd1hWztDtOHC3NIVG+53/jw6ix+smS//QaX//nx5rX3TYrD 7c7oJKdB0e1BIz6jo9xPVmoiiJ6YRreRNoaZy6yUC7eiZYw5sPT1bRtc37BPunbBNm rZS7DICb36CbQ== From: Ard Biesheuvel To: linux-efi@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel , Evgeniy Baskov , Borislav Petkov , Andy Lutomirski , Dave Hansen , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Alexey Khoroshilov , Peter Jones , Gerd Hoffmann , Dave Young , Mario Limonciello , Kees Cook , Tom Lendacky , "Kirill A . Shutemov" , Linus Torvalds Subject: [PATCH v2 08/20] x86: decompressor: Merge trampoline cleanup with switching code Date: Mon, 8 May 2023 09:03:18 +0200 Message-Id: <20230508070330.582131-9-ardb@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230508070330.582131-1-ardb@kernel.org> References: <20230508070330.582131-1-ardb@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4104; i=ardb@kernel.org; h=from:subject; bh=Cbgin3O3w5TrAUQhn3/olaZs0A4XgRk35uCUUkZRmeM=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JISVi3ubiDVq+31j5S78ITuP8/KjtsUHPLWmfkgnW5QLuf Gq7TrB2lLIwiHEwyIopsgjM/vtu5+mJUrXOs2Rh5rAygQxh4OIUgIk8fsPwP7KoU8HwhMCMeQ+C fzKFZn3n2HKkWmNxvsSrpvwdfy8vv8bIcLujhnG+p/X94lkrLuSnqF5lnn58WYJA1BKtpSdyv99 R5AcA X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org Now that the trampoline setup code and the actual invocation of it are all done from the C routine, we can merge the trampoline cleanup into that as well, instead of returning to asm just to call another C function. Signed-off-by: Ard Biesheuvel --- arch/x86/boot/compressed/head_64.S | 13 +++------ arch/x86/boot/compressed/pgtable_64.c | 28 ++++++++------------ 2 files changed, 15 insertions(+), 26 deletions(-) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index ccdfe7e55c36a40f..21af9cfd0dd0afb7 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -440,19 +440,14 @@ SYM_CODE_START(startup_64) * set_paging_levels() updates the number of paging levels using a * trampoline in 32-bit addressable memory if the current number does * not match the desired number. + * + * RSI is the relocated address of the page table to use instead of + * page table in trampoline memory (if required). */ movq %r15, %rdi /* pass struct boot_params pointer */ + leaq rva(top_pgtable)(%rbx), %rsi call set_paging_levels - /* - * cleanup_trampoline() would restore trampoline memory. - * - * RDI is address of the page table to use instead of page table - * in trampoline memory (if required). - */ - leaq rva(top_pgtable)(%rbx), %rdi - call cleanup_trampoline - /* Zero EFLAGS */ pushq $0 popfq diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c index b92cf1d6e156d5f6..eeddad8c8335655e 100644 --- a/arch/x86/boot/compressed/pgtable_64.c +++ b/arch/x86/boot/compressed/pgtable_64.c @@ -101,9 +101,10 @@ static unsigned long find_trampoline_placement(void) return bios_start - TRAMPOLINE_32BIT_SIZE; } -asmlinkage void set_paging_levels(void *rmode) +asmlinkage void set_paging_levels(void *rmode, void *pgtable) { void (*toggle_la57)(void *trampoline, bool enable_5lvl); + void *trampoline_pgtable; bool l5_required = false; /* Initialize boot_params. Required for cmdline_find_option_bool(). */ @@ -133,7 +134,7 @@ asmlinkage void set_paging_levels(void *rmode) * are already in the desired paging mode. */ if (l5_required == !!(native_read_cr4() & X86_CR4_LA57)) - return; + goto out; trampoline_32bit = (unsigned long *)find_trampoline_placement(); @@ -163,6 +164,8 @@ asmlinkage void set_paging_levels(void *rmode) * The new page table will be used by trampoline code for switching * from 4- to 5-level paging or vice versa. */ + trampoline_pgtable = trampoline_32bit + + TRAMPOLINE_32BIT_PGTABLE_OFFSET / sizeof(unsigned long); if (l5_required) { /* @@ -182,31 +185,21 @@ asmlinkage void set_paging_levels(void *rmode) * may be above 4G. */ src = *(unsigned long *)__native_read_cr3() & PAGE_MASK; - memcpy(trampoline_32bit + TRAMPOLINE_32BIT_PGTABLE_OFFSET / sizeof(unsigned long), - (void *)src, PAGE_SIZE); + memcpy(trampoline_pgtable, (void *)src, PAGE_SIZE); } toggle_la57(trampoline_32bit, l5_required); -} - -void cleanup_trampoline(void *pgtable) -{ - void *trampoline_pgtable; - - trampoline_pgtable = trampoline_32bit + TRAMPOLINE_32BIT_PGTABLE_OFFSET / sizeof(unsigned long); /* - * Move the top level page table out of trampoline memory, - * if it's there. + * Move the top level page table out of trampoline memory. */ - if ((void *)__native_read_cr3() == trampoline_pgtable) { - memcpy(pgtable, trampoline_pgtable, PAGE_SIZE); - native_write_cr3((unsigned long)pgtable); - } + memcpy(pgtable, trampoline_pgtable, PAGE_SIZE); + native_write_cr3((unsigned long)pgtable); /* Restore trampoline memory */ memcpy(trampoline_32bit, trampoline_save, TRAMPOLINE_32BIT_SIZE); +out: /* Initialize variables for 5-level paging */ #ifdef CONFIG_X86_5LEVEL if (__read_cr4() & X86_CR4_LA57) { @@ -215,4 +208,5 @@ void cleanup_trampoline(void *pgtable) ptrs_per_p4d = 512; } #endif + return; }