Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750855AbWHBMnr (ORCPT ); Wed, 2 Aug 2006 08:43:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750852AbWHBMnr (ORCPT ); Wed, 2 Aug 2006 08:43:47 -0400 Received: from liaag2af.mx.compuserve.com ([149.174.40.157]:1699 "EHLO liaag2af.mx.compuserve.com") by vger.kernel.org with ESMTP id S1750783AbWHBMnq (ORCPT ); Wed, 2 Aug 2006 08:43:46 -0400 Date: Wed, 2 Aug 2006 08:37:59 -0400 From: Chuck Ebbert <76306.1226@compuserve.com> Subject: [patch] x86: rename is_at_popf(), add iret to tests and fix insn length To: linux-kernel Cc: Andi Kleen , Linus Torvalds Message-ID: <200608020840_MC3-1-C6D8-A1A6@compuserve.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2765 Lines: 89 is_at_popf() needs to test for the iret instruction as well as popf. So add that test and rename it to is_setting_trap_flag(). Also change max insn length from 16 to 15 to match reality. LAHF / SAHF can't affect TF, so the comment in x86_64 is removed. Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> --- Tested on x86_64. --- 2.6.18-rc3-64.orig/arch/i386/kernel/ptrace.c +++ 2.6.18-rc3-64/arch/i386/kernel/ptrace.c @@ -185,17 +185,17 @@ static unsigned long convert_eip_to_line return addr; } -static inline int is_at_popf(struct task_struct *child, struct pt_regs *regs) +static inline int is_setting_trap_flag(struct task_struct *child, struct pt_regs *regs) { int i, copied; - unsigned char opcode[16]; + unsigned char opcode[15]; unsigned long addr = convert_eip_to_linear(child, regs); copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0); for (i = 0; i < copied; i++) { switch (opcode[i]) { - /* popf */ - case 0x9d: + /* popf and iret */ + case 0x9d: case 0xcf: return 1; /* opcode and address size prefixes */ case 0x66: case 0x67: @@ -247,7 +247,7 @@ static void set_singlestep(struct task_s * don't mark it as being "us" that set it, so that we * won't clear it by hand later. */ - if (is_at_popf(child, regs)) + if (is_setting_trap_flag(child, regs)) return; child->ptrace |= PT_DTRACE; --- 2.6.18-rc3-64.orig/arch/x86_64/kernel/ptrace.c +++ 2.6.18-rc3-64/arch/x86_64/kernel/ptrace.c @@ -116,17 +116,17 @@ unsigned long convert_rip_to_linear(stru return addr; } -static int is_at_popf(struct task_struct *child, struct pt_regs *regs) +static int is_setting_trap_flag(struct task_struct *child, struct pt_regs *regs) { int i, copied; - unsigned char opcode[16]; + unsigned char opcode[15]; unsigned long addr = convert_rip_to_linear(child, regs); copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0); for (i = 0; i < copied; i++) { switch (opcode[i]) { - /* popf */ - case 0x9d: + /* popf and iret */ + case 0x9d: case 0xcf: return 1; /* CHECKME: 64 65 */ @@ -189,10 +189,8 @@ static void set_singlestep(struct task_s * ..but if TF is changed by the instruction we will trace, * don't mark it as being "us" that set it, so that we * won't clear it by hand later. - * - * AK: this is not enough, LAHF and IRET can change TF in user space too. */ - if (is_at_popf(child, regs)) + if (is_setting_trap_flag(child, regs)) return; child->ptrace |= PT_DTRACE; -- Chuck - 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/