From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933328AbdKAVIX (ORCPT ); Wed, 1 Nov 2017 17:08:23 -0400 Received: from terminus.zytor.com ([65.50.211.136]:47253 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755288AbdKAVIU (ORCPT ); Wed, 1 Nov 2017 17:08:20 -0400 Date: Wed, 1 Nov 2017 14:01:16 -0700 From: tip-bot for Ricardo Neri Message-ID: Cc: akpm@linux-foundation.org, keescook@chromium.org, linux-kernel@vger.kernel.org, thgarnie@google.com, adrian.hunter@intel.com, ravi.v.shankar@intel.com, dave.hansen@linux.intel.com, bp@suse.de, adam.buchbinder@gmail.com, pbonzini@redhat.com, brgerst@gmail.com, hpa@zytor.com, corbet@lwn.net, peterz@infradead.org, mingo@kernel.org, colin.king@canonical.com, paul.gortmaker@windriver.com, mst@redhat.com, acme@redhat.com, ricardo.neri-calderon@linux.intel.com, ray.huang@amd.com, tglx@linutronix.de, shuah@kernel.org, dvyukov@google.com, cmetcalf@mellanox.com, mhiramat@kernel.org, slaoub@gmail.com, jslaby@suse.cz, luto@kernel.org, vbabka@suse.cz, qiaowei.ren@intel.com, lstoakes@gmail.com Reply-To: peterz@infradead.org, corbet@lwn.net, hpa@zytor.com, brgerst@gmail.com, acme@redhat.com, ricardo.neri-calderon@linux.intel.com, mst@redhat.com, colin.king@canonical.com, mingo@kernel.org, paul.gortmaker@windriver.com, thgarnie@google.com, linux-kernel@vger.kernel.org, keescook@chromium.org, akpm@linux-foundation.org, pbonzini@redhat.com, dave.hansen@linux.intel.com, adam.buchbinder@gmail.com, bp@suse.de, adrian.hunter@intel.com, ravi.v.shankar@intel.com, slaoub@gmail.com, jslaby@suse.cz, luto@kernel.org, mhiramat@kernel.org, lstoakes@gmail.com, qiaowei.ren@intel.com, vbabka@suse.cz, tglx@linutronix.de, ray.huang@amd.com, dvyukov@google.com, cmetcalf@mellanox.com, shuah@kernel.org In-Reply-To: <1509135945-13762-17-git-send-email-ricardo.neri-calderon@linux.intel.com> References: <1509135945-13762-17-git-send-email-ricardo.neri-calderon@linux.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mpx] x86/insn-eval: Add function to get default params of code segment Git-Commit-ID: 4efea85fb56fa1691b79af1eea4c1425660cf4e3 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 4efea85fb56fa1691b79af1eea4c1425660cf4e3 Gitweb: https://git.kernel.org/tip/4efea85fb56fa1691b79af1eea4c1425660cf4e3 Author: Ricardo Neri AuthorDate: Fri, 27 Oct 2017 13:25:43 -0700 Committer: Thomas Gleixner CommitDate: Wed, 1 Nov 2017 21:50:12 +0100 x86/insn-eval: Add function to get default params of code segment Obtain the default values of the address and operand sizes as specified in the D and L bits of the the segment descriptor selected by the register CS. The function can be used for both protected and long modes. For virtual-8086 mode, the default address and operand sizes are always 2 bytes. The returned parameters are encoded in a signed 8-bit data type. Auxiliar macros are provided to encode and decode such values. Improvements-by: Borislav Petkov Signed-off-by: Ricardo Neri Signed-off-by: Thomas Gleixner Reviewed-by: Borislav Petkov Cc: "Michael S. Tsirkin" Cc: Peter Zijlstra Cc: Dave Hansen Cc: ricardo.neri@intel.com Cc: Adrian Hunter Cc: Paul Gortmaker Cc: Huang Rui Cc: Qiaowei Ren Cc: Shuah Khan Cc: Kees Cook Cc: Jonathan Corbet Cc: Jiri Slaby Cc: Dmitry Vyukov Cc: "Ravi V. Shankar" Cc: Chris Metcalf Cc: Brian Gerst Cc: Arnaldo Carvalho de Melo Cc: Andy Lutomirski Cc: Colin Ian King Cc: Chen Yucong Cc: Adam Buchbinder Cc: Vlastimil Babka Cc: Lorenzo Stoakes Cc: Masami Hiramatsu Cc: Paolo Bonzini Cc: Andrew Morton Cc: Thomas Garnier Link: https://lkml.kernel.org/r/1509135945-13762-17-git-send-email-ricardo.neri-calderon@linux.intel.com --- arch/x86/include/asm/insn-eval.h | 5 ++++ arch/x86/lib/insn-eval.c | 64 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 69 insertions(+) diff --git a/arch/x86/include/asm/insn-eval.h b/arch/x86/include/asm/insn-eval.h index 25d6e44..e1d3b4c 100644 --- a/arch/x86/include/asm/insn-eval.h +++ b/arch/x86/include/asm/insn-eval.h @@ -11,8 +11,13 @@ #include #include +#define INSN_CODE_SEG_ADDR_SZ(params) ((params >> 4) & 0xf) +#define INSN_CODE_SEG_OPND_SZ(params) (params & 0xf) +#define INSN_CODE_SEG_PARAMS(oper_sz, addr_sz) (oper_sz | (addr_sz << 4)) + void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs); int insn_get_modrm_rm_off(struct insn *insn, struct pt_regs *regs); unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx); +char insn_get_code_seg_params(struct pt_regs *regs); #endif /* _ASM_X86_INSN_EVAL_H */ diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index 89d5c89..01e36bd 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -640,6 +640,70 @@ static unsigned long get_seg_limit(struct pt_regs *regs, int seg_reg_idx) } /** + * insn_get_code_seg_params() - Obtain code segment parameters + * @regs: Structure with register values as seen when entering kernel mode + * + * Obtain address and operand sizes of the code segment. It is obtained from the + * selector contained in the CS register in regs. In protected mode, the default + * address is determined by inspecting the L and D bits of the segment + * descriptor. In virtual-8086 mode, the default is always two bytes for both + * address and operand sizes. + * + * Returns: + * + * A signed 8-bit value containing the default parameters on success. + * + * -EINVAL on error. + */ +char insn_get_code_seg_params(struct pt_regs *regs) +{ + struct desc_struct *desc; + short sel; + + if (v8086_mode(regs)) + /* Address and operand size are both 16-bit. */ + return INSN_CODE_SEG_PARAMS(2, 2); + + sel = get_segment_selector(regs, INAT_SEG_REG_CS); + if (sel < 0) + return sel; + + desc = get_desc(sel); + if (!desc) + return -EINVAL; + + /* + * The most significant byte of the Type field of the segment descriptor + * determines whether a segment contains data or code. If this is a data + * segment, return error. + */ + if (!(desc->type & BIT(3))) + return -EINVAL; + + switch ((desc->l << 1) | desc->d) { + case 0: /* + * Legacy mode. CS.L=0, CS.D=0. Address and operand size are + * both 16-bit. + */ + return INSN_CODE_SEG_PARAMS(2, 2); + case 1: /* + * Legacy mode. CS.L=0, CS.D=1. Address and operand size are + * both 32-bit. + */ + return INSN_CODE_SEG_PARAMS(4, 4); + case 2: /* + * IA-32e 64-bit mode. CS.L=1, CS.D=0. Address size is 64-bit; + * operand size is 32-bit. + */ + return INSN_CODE_SEG_PARAMS(4, 8); + case 3: /* Invalid setting. CS.L=1, CS.D=1 */ + /* fall through */ + default: + return -EINVAL; + } +} + +/** * insn_get_modrm_rm_off() - Obtain register in r/m part of the ModRM byte * @insn: Instruction containing the ModRM byte * @regs: Register values as seen when entering kernel mode