From patchwork Wed Jun 7 07:23:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 690331 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 6CC60C77B7A for ; Wed, 7 Jun 2023 07:26:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239254AbjFGH0t (ORCPT ); Wed, 7 Jun 2023 03:26:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53834 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239094AbjFGH0Q (ORCPT ); Wed, 7 Jun 2023 03:26:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BC637273E; Wed, 7 Jun 2023 00:25:02 -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 56A2F633AD; Wed, 7 Jun 2023 07:24:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2D84C4339C; Wed, 7 Jun 2023 07:24:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686122678; bh=RE5W68XPDnGbVeBBhzYfWFU/rF3D5/t2hy2u0mxg2G8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RWG4jlIZQdL1k+w4KLt2n/kvjWrWaov1+Y68sakYEaari1qauw2LHLEkufbWqKJFI xXZecxc/yF9QgJ7x5xSRqTQTNrYgDMNBKWtUACMwHvz1xNfZ2uIIvIGZAKyJxdnD6f QzDd3hVsung79G2vuB+KEnQ8vdvVA4eeSp8MIjQiyqfn5IK3bYtn21ej3dD0pyKVRO jgu+TNabvE4AuMSrLEyYS429uKN1pFGX9hx+APOEoG7hy9kQV+cI4xsWhzf55zHAv7 x9J/kE+wJ+is8vhZdyvvCTpKK16YjzflfQKM3bb7lj4kYN+TuGxcVMn+VwvdOvEkbT iXB5AEzrp16Ow== 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 , Joerg Roedel Subject: [PATCH v5 10/20] x86/decompressor: Call trampoline directly from C code Date: Wed, 7 Jun 2023 09:23:32 +0200 Message-Id: <20230607072342.4054036-11-ardb@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230607072342.4054036-1-ardb@kernel.org> References: <20230607072342.4054036-1-ardb@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4967; i=ardb@kernel.org; h=from:subject; bh=RE5W68XPDnGbVeBBhzYfWFU/rF3D5/t2hy2u0mxg2G8=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JIaXBoIDntVbaGYNZF05+sOFs4/9fbFG/J2ci3y7xstQHa wyWvNLqKGVhEONgkBVTZBGY/ffdztMTpWqdZ8nCzGFlAhnCwMUpABPZac/IcHT6wfvuCzqYQtm8 5p/yNOfat+FKT3SVjenlky/bb5Y2WTIyTDWK3W/aMfkuT+YFS/N1CWLtN1b8ZQu9cnz5srAnFZ4 nWQA= X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org Instead of returning to the asm calling code to invoke the trampoline, call it straight from the C code that sets the scene. That way, the struct return type is no longer needed for returning two values, and the call can be made conditional more cleanly in a subsequent patch. Acked-by: Kirill A. Shutemov Signed-off-by: Ard Biesheuvel --- arch/x86/boot/compressed/head_64.S | 20 +++----------- arch/x86/boot/compressed/pgtable_64.c | 28 ++++++++------------ 2 files changed, 15 insertions(+), 33 deletions(-) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index cdefafd456c70335..3d4da7e5270c8d4d 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -430,24 +430,12 @@ SYM_CODE_START(startup_64) #endif /* - * paging_prepare() sets up the trampoline and checks if we need to - * enable 5-level paging. - * - * paging_prepare() returns a two-quadword structure which lands - * into RDX:RAX: - * - Address of the trampoline is returned in RAX. - * - Non zero RDX means trampoline needs to enable 5-level - * paging. - * + * 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. */ movq %r15, %rdi /* pass struct boot_params pointer */ - call paging_prepare - - /* Pass the trampoline address and boolean flag as args #1 and #2 */ - movq %rax, %rdi - movq %rdx, %rsi - leaq TRAMPOLINE_32BIT_CODE_OFFSET(%rax), %rax - call *%rax + call set_paging_levels /* * cleanup_trampoline() would restore trampoline memory. diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c index d66639c961b8eeda..1d28ad95ea839531 100644 --- a/arch/x86/boot/compressed/pgtable_64.c +++ b/arch/x86/boot/compressed/pgtable_64.c @@ -16,11 +16,6 @@ unsigned int __section(".data") pgdir_shift = 39; unsigned int __section(".data") ptrs_per_p4d = 1; #endif -struct paging_config { - unsigned long trampoline_start; - unsigned long l5_required; -}; - /* Buffer to preserve trampoline memory */ static char trampoline_save[TRAMPOLINE_32BIT_SIZE]; @@ -106,10 +101,10 @@ static unsigned long find_trampoline_placement(void) return bios_start - TRAMPOLINE_32BIT_SIZE; } -struct paging_config paging_prepare(void *rmode) +asmlinkage void set_paging_levels(void *rmode) { - struct paging_config paging_config = {}; - void *tramp_code; + void (*toggle_la57)(void *trampoline, bool enable_5lvl); + bool l5_required = false; /* Initialize boot_params. Required for cmdline_find_option_bool(). */ boot_params = rmode; @@ -130,12 +125,10 @@ struct paging_config paging_prepare(void *rmode) !cmdline_find_option_bool("no5lvl") && native_cpuid_eax(0) >= 7 && (native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31)))) { - paging_config.l5_required = 1; + l5_required = true; } - paging_config.trampoline_start = find_trampoline_placement(); - - trampoline_32bit = (unsigned long *)paging_config.trampoline_start; + trampoline_32bit = (unsigned long *)find_trampoline_placement(); /* Preserve trampoline memory */ memcpy(trampoline_save, trampoline_32bit, TRAMPOLINE_32BIT_SIZE); @@ -144,7 +137,7 @@ struct paging_config paging_prepare(void *rmode) memset(trampoline_32bit, 0, TRAMPOLINE_32BIT_SIZE); /* Copy trampoline code in place */ - tramp_code = memcpy(trampoline_32bit + + toggle_la57 = memcpy(trampoline_32bit + TRAMPOLINE_32BIT_CODE_OFFSET / sizeof(unsigned long), &trampoline_32bit_src, TRAMPOLINE_32BIT_CODE_SIZE); @@ -154,7 +147,8 @@ struct paging_config paging_prepare(void *rmode) * immediate absolute address, which needs to be adjusted based on the * placement of the trampoline. */ - *(u32 *)(tramp_code + trampoline_ljmp_imm_offset) += (unsigned long)tramp_code; + *(u32 *)((u8 *)toggle_la57 + trampoline_ljmp_imm_offset) += + (unsigned long)toggle_la57; /* * The code below prepares page table in trampoline memory. @@ -170,10 +164,10 @@ 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 == !!(native_read_cr4() & X86_CR4_LA57)) + if (l5_required == !!(native_read_cr4() & X86_CR4_LA57)) goto out; - 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. @@ -196,7 +190,7 @@ struct paging_config paging_prepare(void *rmode) } out: - return paging_config; + toggle_la57(trampoline_32bit, l5_required); } void cleanup_trampoline(void *pgtable)