From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 ECEC9C43331 for ; Thu, 5 Sep 2019 23:44:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1B99C206CD for ; Thu, 5 Sep 2019 23:44:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=codeweavers.com header.i=@codeweavers.com header.b="TjzIp1x/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389339AbfIEXoF (ORCPT ); Thu, 5 Sep 2019 19:44:05 -0400 Received: from mail.codeweavers.com ([50.203.203.244]:33980 "EHLO mail.codeweavers.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725921AbfIEXoF (ORCPT ); Thu, 5 Sep 2019 19:44:05 -0400 X-Greylist: delayed 964 seconds by postgrey-1.27 at vger.kernel.org; Thu, 05 Sep 2019 19:44:05 EDT DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=codeweavers.com; s=6377696661; h=Message-Id:Date:Subject:Cc:To:From:Sender: Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=rASns3U+6Oa/LoIG4M+RXQqZmudbbKPab+NbWJxo+g0=; b=TjzIp1x/oChw/7uIFnctLEQNYP 29PS6hDMe4HNArik8U+9zc2IChTbjg4v1emSxDQZGgVhPh/go6t1DcUVc7gnOg2zNK5WbQpUOjLpq 0MKbE0eYl3+hfF/RIgR+0FOS+dZX2RxoErfR0yYxunUupCclVkfFI8y8DbKLUTrCVj4k=; Received: from cpe-107-184-2-226.socal.res.rr.com ([107.184.2.226] helo=brendan-dell.bslabs.net) by mail.codeweavers.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1i61AR-0004DI-Re; Thu, 05 Sep 2019 18:27:57 -0500 From: Brendan Shanks To: linux-kernel@vger.kernel.org Cc: Ricardo Neri , Brendan Shanks , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , x86@kernel.org, "Eric W. Biederman" Subject: [PATCH] x86/umip: Add emulation for 64-bit processes Date: Thu, 5 Sep 2019 16:22:21 -0700 Message-Id: <20190905232222.14900-1-bshanks@codeweavers.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add emulation of the sgdt, sidt, and smsw instructions for 64-bit processes. Wine users have encountered a number of 64-bit Windows games that use these instructions (particularly sgdt), and were crashing when run on UMIP-enabled systems. Originally-by: Ricardo Neri Signed-off-by: Brendan Shanks --- arch/x86/kernel/umip.c | 55 +++++++++++++++++++++++++----------------- 1 file changed, 33 insertions(+), 22 deletions(-) diff --git a/arch/x86/kernel/umip.c b/arch/x86/kernel/umip.c index 5b345add550f..1812e95d2f55 100644 --- a/arch/x86/kernel/umip.c +++ b/arch/x86/kernel/umip.c @@ -51,9 +51,7 @@ * The instruction smsw is emulated to return the value that the register CR0 * has at boot time as set in the head_32. * - * Also, emulation is provided only for 32-bit processes; 64-bit processes - * that attempt to use the instructions that UMIP protects will receive the - * SIGSEGV signal issued as a consequence of the general protection fault. + * Emulation is provided for both 32-bit and 64-bit processes. * * Care is taken to appropriately emulate the results when segmentation is * used. That is, rather than relying on USER_DS and USER_CS, the function @@ -63,17 +61,18 @@ * application uses a local descriptor table. */ -#define UMIP_DUMMY_GDT_BASE 0xfffe0000 -#define UMIP_DUMMY_IDT_BASE 0xffff0000 +#define UMIP_DUMMY_GDT_BASE 0xfffffffffffe0000ULL +#define UMIP_DUMMY_IDT_BASE 0xffffffffffff0000ULL /* * The SGDT and SIDT instructions store the contents of the global descriptor * table and interrupt table registers, respectively. The destination is a * memory operand of X+2 bytes. X bytes are used to store the base address of - * the table and 2 bytes are used to store the limit. In 32-bit processes, the - * only processes for which emulation is provided, X has a value of 4. + * the table and 2 bytes are used to store the limit. In 32-bit processes X + * has a value of 4, in 64-bit processes X has a value of 8. */ -#define UMIP_GDT_IDT_BASE_SIZE 4 +#define UMIP_GDT_IDT_BASE_SIZE_64BIT 8 +#define UMIP_GDT_IDT_BASE_SIZE_32BIT 4 #define UMIP_GDT_IDT_LIMIT_SIZE 2 #define UMIP_INST_SGDT 0 /* 0F 01 /0 */ @@ -189,6 +188,7 @@ static int identify_insn(struct insn *insn) * @umip_inst: A constant indicating the instruction to emulate * @data: Buffer into which the dummy result is stored * @data_size: Size of the emulated result + * @x86_64: true if process is 64-bit, false otherwise * * Emulate an instruction protected by UMIP and provide a dummy result. The * result of the emulation is saved in @data. The size of the results depends @@ -202,11 +202,8 @@ static int identify_insn(struct insn *insn) * 0 on success, -EINVAL on error while emulating. */ static int emulate_umip_insn(struct insn *insn, int umip_inst, - unsigned char *data, int *data_size) + unsigned char *data, int *data_size, bool x86_64) { - unsigned long dummy_base_addr, dummy_value; - unsigned short dummy_limit = 0; - if (!data || !data_size || !insn) return -EINVAL; /* @@ -219,6 +216,9 @@ static int emulate_umip_insn(struct insn *insn, int umip_inst, * is always returned irrespective of the operand size. */ if (umip_inst == UMIP_INST_SGDT || umip_inst == UMIP_INST_SIDT) { + u64 dummy_base_addr; + u16 dummy_limit = 0; + /* SGDT and SIDT do not use registers operands. */ if (X86_MODRM_MOD(insn->modrm.value) == 3) return -EINVAL; @@ -228,13 +228,24 @@ static int emulate_umip_insn(struct insn *insn, int umip_inst, else dummy_base_addr = UMIP_DUMMY_IDT_BASE; - *data_size = UMIP_GDT_IDT_LIMIT_SIZE + UMIP_GDT_IDT_BASE_SIZE; + /* + * 64-bit processes use the entire dummy base address. + * 32-bit processes use the lower 32 bits of the base address. + * dummy_base_addr is always 64 bits, but we memcpy the correct + * number of bytes from it to the destination. + */ + if (x86_64) + *data_size = UMIP_GDT_IDT_BASE_SIZE_64BIT; + else + *data_size = UMIP_GDT_IDT_BASE_SIZE_32BIT; + + memcpy(data + 2, &dummy_base_addr, *data_size); - memcpy(data + 2, &dummy_base_addr, UMIP_GDT_IDT_BASE_SIZE); + *data_size += UMIP_GDT_IDT_LIMIT_SIZE; memcpy(data, &dummy_limit, UMIP_GDT_IDT_LIMIT_SIZE); } else if (umip_inst == UMIP_INST_SMSW) { - dummy_value = CR0_STATE; + unsigned long dummy_value = CR0_STATE; /* * Even though the CR0 register has 4 bytes, the number @@ -291,10 +302,9 @@ static void force_sig_info_umip_fault(void __user *addr, struct pt_regs *regs) * @regs: Registers as saved when entering the #GP handler * * The instructions sgdt, sidt, str, smsw, sldt cause a general protection - * fault if executed with CPL > 0 (i.e., from user space). If the offending - * user-space process is not in long mode, this function fixes the exception - * up and provides dummy results for sgdt, sidt and smsw; str and sldt are not - * fixed up. Also long mode user-space processes are not fixed up. + * fault if executed with CPL > 0 (i.e., from user space). This function fixes + * the exception up and provides dummy results for sgdt, sidt and smsw; str + * and sldt are not fixed up. * * If operands are memory addresses, results are copied to user-space memory as * indicated by the instruction pointed by eIP using the registers indicated in @@ -373,13 +383,14 @@ bool fixup_umip_exception(struct pt_regs *regs) umip_pr_warning(regs, "%s instruction cannot be used by applications.\n", umip_insns[umip_inst]); - /* Do not emulate SLDT, STR or user long mode processes. */ - if (umip_inst == UMIP_INST_STR || umip_inst == UMIP_INST_SLDT || user_64bit_mode(regs)) + /* Do not emulate SLDT or STR. */ + if (umip_inst == UMIP_INST_STR || umip_inst == UMIP_INST_SLDT) return false; umip_pr_warning(regs, "For now, expensive software emulation returns the result.\n"); - if (emulate_umip_insn(&insn, umip_inst, dummy_data, &dummy_data_size)) + if (emulate_umip_insn(&insn, umip_inst, dummy_data, &dummy_data_size, + user_64bit_mode(regs))) return false; /* -- 2.17.1