From patchwork Fri Jul 28 09:09:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 707704 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 23118C04A94 for ; Fri, 28 Jul 2023 09:14:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235463AbjG1JOv (ORCPT ); Fri, 28 Jul 2023 05:14:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235364AbjG1JMq (ORCPT ); Fri, 28 Jul 2023 05:12:46 -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 0760F30F5; Fri, 28 Jul 2023 02:11:26 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8DF0162059; Fri, 28 Jul 2023 09:11:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D3E7C433CA; Fri, 28 Jul 2023 09:11:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690535485; bh=9nqOjVjBZ3zE1l42bBuMA0Csq7IH+kYnkE7djc9kifo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WF7Lktl0KpEzJgnl4afBrahr3D48l4W/kp4DpNLf63panQEJotm3M6fb41MenPj5C zuzvPk1es5x0+21HHeUiPfz+MpXKi8xQ6zeQqPEJxVOR9rIHsa5Yg/WhlTbUSfj1+8 7b/V88ZXUDQwxs2Rom5xQmW3zBTBBch2I6wKiDR2JyzH3m/cuA0KQl5GSjGKcF4nMT PrFPZcQKh0NBm0qU+zvZCA8gtPpnBMav6KhCsTiZKj8rNgiDwiZPF0iyJpe+R0/v7Z lIWpXRV43FK4u6CyOiwGJ9/RDX7deGVqzO+C9HNDwBIhNPnnEowjncWQ/WmMCFDCcH 9scChOsfuocXw== 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 v7 10/22] x86/decompressor: Use standard calling convention for trampoline Date: Fri, 28 Jul 2023 11:09:04 +0200 Message-Id: <20230728090916.1538550-11-ardb@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230728090916.1538550-1-ardb@kernel.org> References: <20230728090916.1538550-1-ardb@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3804; i=ardb@kernel.org; h=from:subject; bh=9nqOjVjBZ3zE1l42bBuMA0Csq7IH+kYnkE7djc9kifo=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JIeVw61qJxI3NPQe3vjTMKxFduZ79kuOr559WnPL8FnBrI pMpZ3h2RykLgxgHg6yYIovA7L/vdp6eKFXrPEsWZg4rE8gQBi5OAZiIaizDfx+j1SmZbhKNRY8f b0osWGdy0O+2oFRp8Nsek2iNZc/PLmFkmObF9/nWgo9VlroZva4ZR1fMj+ThkdrecCv1kPsiz94 ydgA= X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org Update the trampoline code so its arguments are passed via RDI and RSI, which matches the ordinary SysV calling convention for x86_64. This will allow this code to be called directly from C. Acked-by: Kirill A. Shutemov Signed-off-by: Ard Biesheuvel --- arch/x86/boot/compressed/head_64.S | 26 +++++++++----------- arch/x86/boot/compressed/pgtable.h | 2 +- 2 files changed, 12 insertions(+), 16 deletions(-) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 1892679be2b6897a..491d985be75fd5b0 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -443,9 +443,9 @@ SYM_CODE_START(startup_64) movq %r15, %rdi /* pass struct boot_params pointer */ call paging_prepare - /* Save the trampoline address in RCX */ - movq %rax, %rcx - + /* 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 @@ -534,15 +534,15 @@ SYM_FUNC_END(.Lrelocated) /* * This is the 32-bit trampoline that will be copied over to low memory. * - * ECX contains the base address of the trampoline memory. - * Non zero RDX means trampoline needs to enable 5-level paging. + * EDI contains the base address of the trampoline memory. + * Non-zero ESI means trampoline needs to enable 5-level paging. */ SYM_CODE_START(trampoline_32bit_src) /* Grab return address */ movq (%rsp), %rax /* Set up 32-bit addressable stack */ - leaq TRAMPOLINE_32BIT_STACK_END(%rcx), %rsp + leaq TRAMPOLINE_32BIT_STACK_END(%rdi), %rsp /* Preserve return address and other live 64-bit registers */ pushq %rax @@ -569,7 +569,7 @@ SYM_CODE_START(trampoline_32bit_src) movl %eax, %cr0 /* Check what paging mode we want to be in after the trampoline */ - testl %edx, %edx + testl %esi, %esi jz 1f /* We want 5-level paging: don't touch CR3 if it already points to 5-level page tables */ @@ -584,21 +584,17 @@ SYM_CODE_START(trampoline_32bit_src) jz 3f 2: /* Point CR3 to the trampoline's new top level page table */ - leal TRAMPOLINE_32BIT_PGTABLE_OFFSET(%ecx), %eax + leal TRAMPOLINE_32BIT_PGTABLE_OFFSET(%edi), %eax movl %eax, %cr3 3: /* Set EFER.LME=1 as a precaution in case hypervsior pulls the rug */ - pushl %ecx - pushl %edx movl $MSR_EFER, %ecx rdmsr btsl $_EFER_LME, %eax /* Avoid writing EFER if no change was made (for TDX guest) */ jc 1f wrmsr -1: popl %edx - popl %ecx - +1: #ifdef CONFIG_X86_MCE /* * Preserve CR4.MCE if the kernel will enable #MC support. @@ -615,14 +611,14 @@ SYM_CODE_START(trampoline_32bit_src) /* Enable PAE and LA57 (if required) paging modes */ orl $X86_CR4_PAE, %eax - testl %edx, %edx + testl %esi, %esi jz 1f orl $X86_CR4_LA57, %eax 1: movl %eax, %cr4 /* Calculate address of paging_enabled() once we are executing in the trampoline */ - leal .Lpaging_enabled - trampoline_32bit_src + TRAMPOLINE_32BIT_CODE_OFFSET(%ecx), %eax + leal .Lpaging_enabled - trampoline_32bit_src + TRAMPOLINE_32BIT_CODE_OFFSET(%edi), %eax /* Prepare the stack for far return to Long Mode */ pushl $__KERNEL_CS diff --git a/arch/x86/boot/compressed/pgtable.h b/arch/x86/boot/compressed/pgtable.h index 91dbb99203fbce2d..4e8cef135226bcbb 100644 --- a/arch/x86/boot/compressed/pgtable.h +++ b/arch/x86/boot/compressed/pgtable.h @@ -14,7 +14,7 @@ extern unsigned long *trampoline_32bit; -extern void trampoline_32bit_src(void *return_ptr); +extern void trampoline_32bit_src(void *trampoline, bool enable_5lvl); #endif /* __ASSEMBLER__ */ #endif /* BOOT_COMPRESSED_PAGETABLE_H */