Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933635AbdCHAkk (ORCPT ); Tue, 7 Mar 2017 19:40:40 -0500 Received: from mga02.intel.com ([134.134.136.20]:48913 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933355AbdCHAf5 (ORCPT ); Tue, 7 Mar 2017 19:35:57 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,261,1486454400"; d="scan'208";a="1105982600" From: Ricardo Neri To: Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , Andy Lutomirski , Borislav Petkov Cc: Peter Zijlstra , Andrew Morton , Brian Gerst , Chris Metcalf , Dave Hansen , Paolo Bonzini , Liang Z Li , Masami Hiramatsu , Huang Rui , Jiri Slaby , Jonathan Corbet , "Michael S. Tsirkin" , Paul Gortmaker , Vlastimil Babka , Chen Yucong , Alexandre Julliard , Stas Sergeev , Fenghua Yu , "Ravi V. Shankar" , Shuah Khan , linux-kernel@vger.kernel.org, x86@kernel.org, linux-msdos@vger.kernel.org, wine-devel@winehq.org, Ricardo Neri , Adam Buchbinder , Colin Ian King , Lorenzo Stoakes , Qiaowei Ren , Arnaldo Carvalho de Melo , Adrian Hunter , Kees Cook , Thomas Garnier , Dmitry Vyukov Subject: [v6 PATCH 12/21] x86/insn: Support both signed 32-bit and 64-bit effective addresses Date: Tue, 7 Mar 2017 16:32:45 -0800 Message-Id: <20170308003254.27833-13-ricardo.neri-calderon@linux.intel.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170308003254.27833-1-ricardo.neri-calderon@linux.intel.com> References: <20170308003254.27833-1-ricardo.neri-calderon@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4652 Lines: 130 The 32-bit and 64-bit address encodings are identical. This means that we can use the same function in both cases. In order to reuse the function for 32-bit address encodings, we must sign-extend our 32-bit signed operands to 64-bit signed variables (only for 64-bit builds). To decide on whether sign extension is needed, we rely on the address size as given by the instruction structure. Lastly, before computing the linear address, we must truncate our signed 64-bit signed effective address if the address size is 32-bit. Cc: Dave Hansen Cc: Adam Buchbinder Cc: Colin Ian King Cc: Lorenzo Stoakes Cc: Qiaowei Ren Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Adrian Hunter Cc: Kees Cook Cc: Thomas Garnier Cc: Peter Zijlstra Cc: Borislav Petkov Cc: Dmitry Vyukov Cc: Ravi V. Shankar Cc: x86@kernel.org Signed-off-by: Ricardo Neri --- arch/x86/lib/insn-eval.c | 44 ++++++++++++++++++++++++++++++++------------ 1 file changed, 32 insertions(+), 12 deletions(-) diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index edb360f..a9a1704 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -559,6 +559,15 @@ int insn_get_reg_offset_sib_index(struct insn *insn, struct pt_regs *regs) return get_reg_offset(insn, regs, REG_TYPE_INDEX); } +static inline long __to_signed_long(unsigned long val, int long_bytes) +{ +#ifdef CONFIG_X86_64 + return long_bytes == 4 ? (long)((int)((val) & 0xffffffff)) : (long)val; +#else + return (long)val; +#endif +} + /* * return the address being referenced be instruction * for rm=3 returning the content of the rm reg @@ -567,19 +576,21 @@ int insn_get_reg_offset_sib_index(struct insn *insn, struct pt_regs *regs) void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs) { unsigned long linear_addr, seg_base_addr; - long eff_addr, base, indx; - int addr_offset, base_offset, indx_offset; + long eff_addr, base, indx, tmp; + int addr_offset, base_offset, indx_offset, addr_bytes; insn_byte_t sib; insn_get_modrm(insn); insn_get_sib(insn); sib = insn->sib.value; + addr_bytes = insn->addr_bytes; if (X86_MODRM_MOD(insn->modrm.value) == 3) { addr_offset = get_reg_offset(insn, regs, REG_TYPE_RM); if (addr_offset < 0) goto out_err; - eff_addr = regs_get_register(regs, addr_offset); + tmp = regs_get_register(regs, addr_offset); + eff_addr = __to_signed_long(tmp, addr_bytes); seg_base_addr = insn_get_seg_base(regs, insn, addr_offset, false); } else { @@ -591,20 +602,24 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs) * in the address computation. */ base_offset = get_reg_offset(insn, regs, REG_TYPE_BASE); - if (unlikely(base_offset == -EDOM)) + if (unlikely(base_offset == -EDOM)) { base = 0; - else if (unlikely(base_offset < 0)) + } else if (unlikely(base_offset < 0)) { goto out_err; - else - base = regs_get_register(regs, base_offset); + } else { + tmp = regs_get_register(regs, base_offset); + base = __to_signed_long(tmp, addr_bytes); + } indx_offset = get_reg_offset(insn, regs, REG_TYPE_INDEX); - if (unlikely(indx_offset == -EDOM)) + if (unlikely(indx_offset == -EDOM)) { indx = 0; - else if (unlikely(indx_offset < 0)) + } else if (unlikely(indx_offset < 0)) { goto out_err; - else - indx = regs_get_register(regs, indx_offset); + } else { + tmp = regs_get_register(regs, indx_offset); + indx = __to_signed_long(tmp, addr_bytes); + } eff_addr = base + indx * (1 << X86_SIB_SCALE(sib)); seg_base_addr = insn_get_seg_base(regs, insn, @@ -625,13 +640,18 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs) } else if (addr_offset < 0) { goto out_err; } else { - eff_addr = regs_get_register(regs, addr_offset); + tmp = regs_get_register(regs, addr_offset); + eff_addr = __to_signed_long(tmp, addr_bytes); } seg_base_addr = insn_get_seg_base(regs, insn, addr_offset, false); } eff_addr += insn->displacement.value; } + /* truncate to 4 bytes for 32-bit effective addresses */ + if (addr_bytes == 4) + eff_addr &= 0xffffffff; + linear_addr = (unsigned long)eff_addr + seg_base_addr; return (void __user *)linear_addr; -- 2.9.3