From patchwork Mon Jan 13 17:22:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 206624 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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 D34A8C33CA9 for ; Mon, 13 Jan 2020 17:24:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AAC3321739 for ; Mon, 13 Jan 2020 17:24:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578936245; bh=ywnXyYx3AvLj1uPsyuEwdyOKRA+9azpuVDDX701x9FU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=FsQoDlNztoHklbGGoUeooyiCqMlZnq1R8SMmO6k3Lpdksa6PHG6f+arfqvHJQPHec CEn4HqSsDd0zh7sb9U82FMXaF7M3aH4PPVuzqlyXtBP0zSKlfNnUBiMU4QU9SRN2jV tE3KMHHzMcHYXZrrJhu5DS5HlHtZclTi8OD4lvhU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728804AbgAMRXK (ORCPT ); Mon, 13 Jan 2020 12:23:10 -0500 Received: from mail.kernel.org ([198.145.29.99]:41218 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728512AbgAMRXJ (ORCPT ); Mon, 13 Jan 2020 12:23:09 -0500 Received: from dogfood.home (amontpellier-657-1-18-247.w109-210.abo.wanadoo.fr [109.210.65.247]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C0C772081E; Mon, 13 Jan 2020 17:23:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578936188; bh=ywnXyYx3AvLj1uPsyuEwdyOKRA+9azpuVDDX701x9FU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Sm6BT1QpuPskrUhj/iXXK55XKmolJ7zOspIwbiFCSIX1ypWH0+jE1YjfiCyzhlXHb 5hTWc2SNKNPp9ureteaF+3cXnHSqVxTKjELOeBTepJ7bEhtnpO9qYq3wMhG5BkXyQ6 xeFHG2ackdA5eXgnOoMtBBVBSU0uMq9GPc9eNG6w= From: Ard Biesheuvel To: linux-efi@vger.kernel.org, Ingo Molnar , Thomas Gleixner Cc: Ard Biesheuvel , linux-kernel@vger.kernel.org, Anshuman Khandual , Arnd Bergmann , Dan Williams , Dave Young , Saravana Kannan Subject: [PATCH 01/13] efi/libstub/x86: use const attribute for efi_is_64bit() Date: Mon, 13 Jan 2020 18:22:33 +0100 Message-Id: <20200113172245.27925-2-ardb@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200113172245.27925-1-ardb@kernel.org> References: <20200113172245.27925-1-ardb@kernel.org> MIME-Version: 1.0 Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org Reshuffle the x86 stub code a bit so that we can tag the efi_is_64bit() function with the 'const' attribute, which permits the compiler to optimize away any redundant calls. Since we have two different entry points for 32 and 64 bit firmware in the startup code, this also simplifies the C code since we'll enter it with the efi_is64 variable already set. Signed-off-by: Ard Biesheuvel --- arch/x86/boot/compressed/eboot.c | 14 ++++++-------- arch/x86/boot/compressed/head_64.S | 7 +++---- arch/x86/include/asm/efi.h | 2 +- 3 files changed, 10 insertions(+), 13 deletions(-) diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c index 4afd29eb5b34..ab3a40283db7 100644 --- a/arch/x86/boot/compressed/eboot.c +++ b/arch/x86/boot/compressed/eboot.c @@ -21,16 +21,18 @@ #include "eboot.h" static efi_system_table_t *sys_table; -static bool efi_is64 = IS_ENABLED(CONFIG_X86_64); +extern const bool efi_is64; __pure efi_system_table_t *efi_system_table(void) { return sys_table; } -__pure bool efi_is_64bit(void) +__attribute_const__ bool efi_is_64bit(void) { - return efi_is64; + if (IS_ENABLED(CONFIG_EFI_MIXED)) + return efi_is64; + return IS_ENABLED(CONFIG_X64_64); } static efi_status_t @@ -710,8 +712,7 @@ static efi_status_t exit_boot(struct boot_params *boot_params, void *handle) */ struct boot_params *efi_main(efi_handle_t handle, efi_system_table_t *sys_table_arg, - struct boot_params *boot_params, - bool is64) + struct boot_params *boot_params) { struct desc_ptr *gdt = NULL; struct setup_header *hdr = &boot_params->hdr; @@ -721,9 +722,6 @@ struct boot_params *efi_main(efi_handle_t handle, sys_table = sys_table_arg; - if (IS_ENABLED(CONFIG_EFI_MIXED)) - efi_is64 = is64; - /* Check if we were booted by the EFI firmware */ if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) goto fail; diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 44a6bb6964b5..1f1f6c8139b3 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -211,10 +211,9 @@ SYM_FUNC_START(startup_32) movl efi32_boot_args(%ebp), %edi cmp $0, %edi jz 1f - leal handover_entry(%ebp), %eax + leal efi64_stub_entry(%ebp), %eax movl %esi, %edx movl efi32_boot_args+4(%ebp), %esi - movl $0x0, %ecx 1: #endif pushl %eax @@ -242,6 +241,7 @@ SYM_FUNC_START(efi32_stub_entry) movl %ecx, efi32_boot_args(%ebp) movl %edx, efi32_boot_args+4(%ebp) sgdtl efi32_boot_gdt(%ebp) + movb $0, efi_is64(%ebp) /* Disable paging */ movl %cr0, %eax @@ -452,8 +452,6 @@ SYM_CODE_END(startup_64) .org 0x390 SYM_FUNC_START(efi64_stub_entry) SYM_FUNC_START_ALIAS(efi_stub_entry) - movq $1, %rcx -SYM_INNER_LABEL(handover_entry, SYM_L_LOCAL) and $~0xf, %rsp /* realign the stack */ call efi_main movq %rax,%rsi @@ -632,6 +630,7 @@ SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end) #ifdef CONFIG_EFI_MIXED SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0) +SYM_DATA(efi_is64, .byte 1) #endif /* diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index 383f7a0fc170..0a58468a7203 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -221,7 +221,7 @@ efi_status_t efi_set_virtual_address_map(unsigned long memory_map_size, /* arch specific definitions used by the stub code */ -__pure bool efi_is_64bit(void); +__attribute_const__ bool efi_is_64bit(void); static inline bool efi_is_native(void) {