Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2EC98C636D6 for ; Thu, 9 Feb 2023 15:37:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231379AbjBIPhm (ORCPT ); Thu, 9 Feb 2023 10:37:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230331AbjBIPhk (ORCPT ); Thu, 9 Feb 2023 10:37:40 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD6E863136 for ; Thu, 9 Feb 2023 07:37:13 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 16287B82193 for ; Thu, 9 Feb 2023 15:36:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A59FC433D2; Thu, 9 Feb 2023 15:36:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1675957000; bh=gHYGLHg1aB0ik45JC+4zloo1eDdi2WUI1kKJrxICvNI=; h=From:To:Cc:Subject:Date:From; b=U4AkSmo7WhLntlQo82gyxHgscJ70CK/zQRakf0C8DdZHYsAWBIIPjcQpBcU/pBt4n 0W9FmAVjgqkRgkzDP6EngmkXLngTBCVZz7e4ysvdebw+b2njayu6BjiacCBW1cn8MT JfoJ65IwMJ3/1uSV7BhCgtoUGAVSKjwaaHwXnE8ndDQJ9TV03iTOD8inzQrOAB2jHs xb4Gw9LBR84PxzKxutQFnJEkPS1oWCpVPzlCgA0ZgXHBhNMw1f2SlRiN9SFJzmEkvw aNwyZiPkHgdIG1b5jlSxexrCs9+2PodSEYdTBxEQyPShDcsbHJIs1uP6OkPsO9OqxV jyM0QLnVFnU2g== From: "Masami Hiramatsu (Google)" To: x86@kernel.org Cc: Nadav Amit , Borislav Petkov , Peter Zijlstra , Steven Rostedt , Masami Hiramatsu , linux-kernel@vger.kernel.org Subject: [PATCH -tip] kprobes/x86: Remove unneeded casting from immediate value Date: Fri, 10 Feb 2023 00:36:36 +0900 Message-Id: <167595699689.1303232.13460109151246012198.stgit@mhiramat.roam.corp.google.com> X-Mailer: git-send-email 2.39.1.519.gcb327c4b5f-goog User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Masami Hiramatsu (Google) Remove unneeded casting from immediate value assignments for relative jump offset. Since the immediate values in the 'insn' data structure are assigned from immediate bytes as a signed value to insn.immediate.value by insn_field_set(). Thus, if we need to access that value as a signed value (in this kprobe's case), we don't need to cast it. This is a kind of clean up (should not change behavior) follows Nadav's bugfix. Link: https://lore.kernel.org/all/20230208071708.4048-1-namit@vmware.com/ Signed-off-by: Masami Hiramatsu (Google) --- arch/x86/kernel/kprobes/core.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 695873c0f50b..2440e736d0e4 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -607,19 +607,19 @@ static int prepare_emulation(struct kprobe *p, struct insn *insn) case 0xe8: /* near call relative */ p->ainsn.emulate_op = kprobe_emulate_call; if (insn->immediate.nbytes == 2) - p->ainsn.rel32 = *(s16 *)&insn->immediate.value; + p->ainsn.rel32 = insn->immediate.value; else - p->ainsn.rel32 = *(s32 *)&insn->immediate.value; + p->ainsn.rel32 = insn->immediate.value; break; case 0xeb: /* short jump relative */ case 0xe9: /* near jump relative */ p->ainsn.emulate_op = kprobe_emulate_jmp; if (insn->immediate.nbytes == 1) - p->ainsn.rel32 = *(s8 *)&insn->immediate.value; + p->ainsn.rel32 = insn->immediate.value; else if (insn->immediate.nbytes == 2) - p->ainsn.rel32 = *(s16 *)&insn->immediate.value; + p->ainsn.rel32 = insn->immediate.value; else - p->ainsn.rel32 = *(s32 *)&insn->immediate.value; + p->ainsn.rel32 = insn->immediate.value; break; case 0x70 ... 0x7f: /* 1 byte conditional jump */ @@ -634,9 +634,9 @@ static int prepare_emulation(struct kprobe *p, struct insn *insn) p->ainsn.emulate_op = kprobe_emulate_jcc; p->ainsn.jcc.type = opcode & 0xf; if (insn->immediate.nbytes == 2) - p->ainsn.rel32 = *(s16 *)&insn->immediate.value; + p->ainsn.rel32 = insn->immediate.value; else - p->ainsn.rel32 = *(s32 *)&insn->immediate.value; + p->ainsn.rel32 = insn->immediate.value; } else if (opcode == 0x01 && X86_MODRM_REG(insn->modrm.bytes[0]) == 0 && X86_MODRM_MOD(insn->modrm.bytes[0]) == 3) { @@ -651,7 +651,7 @@ static int prepare_emulation(struct kprobe *p, struct insn *insn) p->ainsn.emulate_op = kprobe_emulate_loop; p->ainsn.loop.type = opcode & 0x3; p->ainsn.loop.asize = insn->addr_bytes * 8; - p->ainsn.rel32 = *(s8 *)&insn->immediate.value; + p->ainsn.rel32 = insn->immediate.value; break; case 0xff: /*