From patchwork Wed Nov 4 14:54:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 11880829 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=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 3B461C2D0A3 for ; Wed, 4 Nov 2020 14:54:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EAFD9221E2 for ; Wed, 4 Nov 2020 14:54:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730208AbgKDOyw (ORCPT ); Wed, 4 Nov 2020 09:54:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:48582 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726900AbgKDOyw (ORCPT ); Wed, 4 Nov 2020 09:54:52 -0500 Received: from suppilovahvero.lan (83-245-197-237.elisa-laajakaista.fi [83.245.197.237]) (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 3F665207BB; Wed, 4 Nov 2020 14:54:45 +0000 (UTC) From: Jarkko Sakkinen To: x86@kernel.org, linux-sgx@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jarkko Sakkinen , Jethro Beekman , Darren Kenny , Sean Christopherson , akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com, asapek@google.com, bp@alien8.de, cedric.xing@intel.com, chenalexchen@google.com, conradparker@google.com, cyhanish@google.com, dave.hansen@intel.com, haitao.huang@intel.com, kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com, ludloff@google.com, luto@kernel.org, nhorman@redhat.com, npmccallum@redhat.com, puiterwijk@redhat.com, rientjes@google.com, tglx@linutronix.de, yaozhangx@google.com, mikko.ylinen@intel.com Subject: [PATCH v40 02/24] x86/sgx: Add wrappers for ENCLS functions Date: Wed, 4 Nov 2020 16:54:08 +0200 Message-Id: <20201104145430.300542-3-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20201104145430.300542-1-jarkko.sakkinen@linux.intel.com> References: <20201104145430.300542-1-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org ENCLS is the userspace instruction which wraps virtually all unprivileged SGX functionality for managing enclaves. It is essentially the ioctl() of instructions with each function implementing different SGX-related functionality. Add macros to wrap the ENCLS functionality. There are two main groups, one for functions which do not return error codes and a “ret_” set for those that do. ENCLS functions are documented in Intel SDM section 36.6. Acked-by: Jethro Beekman Tested-by: Darren Kenny Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson Signed-off-by: Jarkko Sakkinen --- arch/x86/kernel/cpu/sgx/encls.h | 231 ++++++++++++++++++++++++++++++++ 1 file changed, 231 insertions(+) create mode 100644 arch/x86/kernel/cpu/sgx/encls.h diff --git a/arch/x86/kernel/cpu/sgx/encls.h b/arch/x86/kernel/cpu/sgx/encls.h new file mode 100644 index 000000000000..443188fe7e70 --- /dev/null +++ b/arch/x86/kernel/cpu/sgx/encls.h @@ -0,0 +1,231 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _X86_ENCLS_H +#define _X86_ENCLS_H + +#include +#include +#include +#include +#include +#include +#include +#include "sgx.h" + +enum sgx_encls_function { + ECREATE = 0x00, + EADD = 0x01, + EINIT = 0x02, + EREMOVE = 0x03, + EDGBRD = 0x04, + EDGBWR = 0x05, + EEXTEND = 0x06, + ELDU = 0x08, + EBLOCK = 0x09, + EPA = 0x0A, + EWB = 0x0B, + ETRACK = 0x0C, +}; + +/** + * ENCLS_FAULT_FLAG - flag signifying an ENCLS return code is a trapnr + * + * ENCLS has its own (positive value) error codes and also generates + * ENCLS specific #GP and #PF faults. And the ENCLS values get munged + * with system error codes as everything percolates back up the stack. + * Unfortunately (for us), we need to precisely identify each unique + * error code, e.g. the action taken if EWB fails varies based on the + * type of fault and on the exact SGX error code, i.e. we can't simply + * convert all faults to -EFAULT. + * + * To make all three error types coexist, we set bit 30 to identify an + * ENCLS fault. Bit 31 (technically bits N:31) is used to differentiate + * between positive (faults and SGX error codes) and negative (system + * error codes) values. + */ +#define ENCLS_FAULT_FLAG 0x40000000 + +/* Retrieve the encoded trapnr from the specified return code. */ +#define ENCLS_TRAPNR(r) ((r) & ~ENCLS_FAULT_FLAG) + +/* Issue a WARN() about an ENCLS function. */ +#define ENCLS_WARN(r, name) { \ + do { \ + int _r = (r); \ + WARN_ONCE(_r, "%s returned %d (0x%x)\n", (name), _r, _r); \ + } while (0); \ +} + +/** + * encls_failed() - Check if an ENCLS function failed + * @ret: the return value of an ENCLS function call + * + * Check if an ENCLS function failed. This happens when the function causes a + * fault that is not caused by an EPCM conflict or when the function returns a + * non-zero value. + */ +static inline bool encls_failed(int ret) +{ + if (ret & ENCLS_FAULT_FLAG) + return ENCLS_TRAPNR(ret) != X86_TRAP_PF; + + return !!ret; +} + +/** + * __encls_ret_N - encode an ENCLS function that returns an error code in EAX + * @rax: function number + * @inputs: asm inputs for the function + * + * Emit assembly for an ENCLS function that returns an error code, e.g. EREMOVE. + * And because SGX isn't complex enough as it is, function that return an error + * code also modify flags. + * + * Return: + * 0 on success, + * SGX error code on failure + */ +#define __encls_ret_N(rax, inputs...) \ + ({ \ + int ret; \ + asm volatile( \ + "1: .byte 0x0f, 0x01, 0xcf;\n\t" \ + "2:\n" \ + ".section .fixup,\"ax\"\n" \ + "3: orl $"__stringify(ENCLS_FAULT_FLAG)",%%eax\n" \ + " jmp 2b\n" \ + ".previous\n" \ + _ASM_EXTABLE_FAULT(1b, 3b) \ + : "=a"(ret) \ + : "a"(rax), inputs \ + : "memory", "cc"); \ + ret; \ + }) + +#define __encls_ret_1(rax, rcx) \ + ({ \ + __encls_ret_N(rax, "c"(rcx)); \ + }) + +#define __encls_ret_2(rax, rbx, rcx) \ + ({ \ + __encls_ret_N(rax, "b"(rbx), "c"(rcx)); \ + }) + +#define __encls_ret_3(rax, rbx, rcx, rdx) \ + ({ \ + __encls_ret_N(rax, "b"(rbx), "c"(rcx), "d"(rdx)); \ + }) + +/** + * __encls_N - encode an ENCLS function that doesn't return an error code + * @rax: function number + * @rbx_out: optional output variable + * @inputs: asm inputs for the function + * + * Emit assembly for an ENCLS function that does not return an error code, e.g. + * ECREATE. Leaves without error codes either succeed or fault. @rbx_out is an + * optional parameter for use by EDGBRD, which returns the requested value in + * RBX. + * + * Return: + * 0 on success, + * trapnr with ENCLS_FAULT_FLAG set on fault + */ +#define __encls_N(rax, rbx_out, inputs...) \ + ({ \ + int ret; \ + asm volatile( \ + "1: .byte 0x0f, 0x01, 0xcf;\n\t" \ + " xor %%eax,%%eax;\n" \ + "2:\n" \ + ".section .fixup,\"ax\"\n" \ + "3: orl $"__stringify(ENCLS_FAULT_FLAG)",%%eax\n" \ + " jmp 2b\n" \ + ".previous\n" \ + _ASM_EXTABLE_FAULT(1b, 3b) \ + : "=a"(ret), "=b"(rbx_out) \ + : "a"(rax), inputs \ + : "memory"); \ + ret; \ + }) + +#define __encls_2(rax, rbx, rcx) \ + ({ \ + unsigned long ign_rbx_out; \ + __encls_N(rax, ign_rbx_out, "b"(rbx), "c"(rcx)); \ + }) + +#define __encls_1_1(rax, data, rcx) \ + ({ \ + unsigned long rbx_out; \ + int ret = __encls_N(rax, rbx_out, "c"(rcx)); \ + if (!ret) \ + data = rbx_out; \ + ret; \ + }) + +static inline int __ecreate(struct sgx_pageinfo *pginfo, void *secs) +{ + return __encls_2(ECREATE, pginfo, secs); +} + +static inline int __eextend(void *secs, void *addr) +{ + return __encls_2(EEXTEND, secs, addr); +} + +static inline int __eadd(struct sgx_pageinfo *pginfo, void *addr) +{ + return __encls_2(EADD, pginfo, addr); +} + +static inline int __einit(void *sigstruct, void *token, void *secs) +{ + return __encls_ret_3(EINIT, sigstruct, secs, token); +} + +static inline int __eremove(void *addr) +{ + return __encls_ret_1(EREMOVE, addr); +} + +static inline int __edbgwr(void *addr, unsigned long *data) +{ + return __encls_2(EDGBWR, *data, addr); +} + +static inline int __edbgrd(void *addr, unsigned long *data) +{ + return __encls_1_1(EDGBRD, *data, addr); +} + +static inline int __etrack(void *addr) +{ + return __encls_ret_1(ETRACK, addr); +} + +static inline int __eldu(struct sgx_pageinfo *pginfo, void *addr, + void *va) +{ + return __encls_ret_3(ELDU, pginfo, addr, va); +} + +static inline int __eblock(void *addr) +{ + return __encls_ret_1(EBLOCK, addr); +} + +static inline int __epa(void *addr) +{ + unsigned long rbx = SGX_PAGE_TYPE_VA; + + return __encls_2(EPA, rbx, addr); +} + +static inline int __ewb(struct sgx_pageinfo *pginfo, void *addr, + void *va) +{ + return __encls_ret_3(EWB, pginfo, addr, va); +} + +#endif /* _X86_ENCLS_H */