Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754441AbaDFUQ2 (ORCPT ); Sun, 6 Apr 2014 16:16:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59558 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754353AbaDFUQ0 (ORCPT ); Sun, 6 Apr 2014 16:16:26 -0400 Date: Sun, 6 Apr 2014 22:16:17 +0200 From: Oleg Nesterov To: Ingo Molnar , Srikar Dronamraju Cc: Ananth N Mavinakayanahalli , Anton Arapov , David Long , Denys Vlasenko , "Frank Ch. Eigler" , Jim Keniston , Jonathan Lebon , Masami Hiramatsu , linux-kernel@vger.kernel.org Subject: [RFC PATCH 1/6] uprobes/x86: Emulate unconditional rip-relative jmp's Message-ID: <20140406201617.GA493@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140406201524.GA32694@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 0xeb and 0xe9. Anything else? TODO: move ->fixup into the union along with rip_rela_target_address. Reported-by: Jonathan Lebon Signed-off-by: Oleg Nesterov --- arch/x86/include/asm/uprobes.h | 8 +++++++- arch/x86/kernel/uprobes.c | 40 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 47 insertions(+), 1 deletions(-) diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 9f8210b..cca62c5 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -44,9 +44,15 @@ struct arch_uprobe { u16 fixups; const struct uprobe_xol_ops *ops; + union { #ifdef CONFIG_X86_64 - unsigned long rip_rela_target_address; + unsigned long rip_rela_target_address; #endif + struct { + s32 disp; + u8 ilen; + } ttt; + }; }; struct arch_uprobe_task { diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 1ea7e1a..32ab147 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -466,6 +466,42 @@ static struct uprobe_xol_ops default_xol_ops = { .post_xol = default_post_xol_op, }; +static bool ttt_emulate_op(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + regs->ip += auprobe->ttt.ilen + auprobe->ttt.disp; + return true; +} + +static struct uprobe_xol_ops ttt_xol_ops = { + .emulate = ttt_emulate_op, +}; + +static int ttt_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn) +{ + + switch (OPCODE1(insn)) { + case 0xeb: /* jmp 8 */ + case 0xe9: /* jmp 32 */ + break; + default: + return -ENOSYS; + } + + /* has the side-effect of processing the entire instruction */ + insn_get_length(insn); + if (WARN_ON_ONCE(!insn_complete(insn))) + return -ENOEXEC; + + auprobe->ttt.ilen = insn->length; + auprobe->ttt.disp = insn->moffset1.value; + /* so far we assume that it fits into ->moffset1 */ + if (WARN_ON_ONCE(insn->moffset2.nbytes)) + return -ENOEXEC; + + auprobe->ops = &ttt_xol_ops; + return 0; +} + /** * arch_uprobe_analyze_insn - instruction analysis including validity and fixups. * @mm: the probed address space. @@ -483,6 +519,10 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, if (ret) return ret; + ret = ttt_setup_xol_ops(auprobe, &insn); + if (ret == 0 || ret != ENOSYS) + return ret; + /* * Figure out which fixups arch_uprobe_post_xol() will need to perform, * and annotate arch_uprobe->fixups accordingly. To start with, ->fixups -- 1.5.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/