From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 16C95C433E5 for ; Fri, 10 Jul 2020 23:08:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DDF0F20767 for ; Fri, 10 Jul 2020 23:08:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727850AbgGJXIg (ORCPT ); Fri, 10 Jul 2020 19:08:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:59428 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727114AbgGJXI3 (ORCPT ); Fri, 10 Jul 2020 19:08:29 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 40C8020767; Fri, 10 Jul 2020 23:08:27 +0000 (UTC) Date: Fri, 10 Jul 2020 19:08:25 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: x86@kernel.org, linux-kernel@vger.kernel.org, mhiramat@kernel.org, bristot@redhat.com, jbaron@akamai.com, torvalds@linux-foundation.org, tglx@linutronix.de, mingo@kernel.org, namit@vmware.com, hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org, jpoimboe@redhat.com, pbonzini@redhat.com, mathieu.desnoyers@efficios.com, linux@rasmusvillemoes.dk Subject: Re: [PATCH v6 13/17] static_call: Add static_call_cond() Message-ID: <20200710190825.02c75c04@oasis.local.home> In-Reply-To: <20200710134336.918547865@infradead.org> References: <20200710133831.943894387@infradead.org> <20200710134336.918547865@infradead.org> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 10 Jul 2020 15:38:44 +0200 Peter Zijlstra wrote: > +static void __static_call_transform(void *insn, enum insn_type type, void *func) > { > - const void *code = text_gen_insn(opcode, insn, func); > + int size = CALL_INSN_SIZE; > + const void *code; > > - if (WARN_ONCE(*(u8 *)insn != opcode, > - "unexpected static call insn opcode 0x%x at %pS\n", > - opcode, insn)) I would still feel better if we did some sort of sanity check before just writing to the text. Confirm this is a jmp, call, ret or nop? -- Steve > - return; > + switch (type) { > + case CALL: > + code = text_gen_insn(CALL_INSN_OPCODE, insn, func); > + break; > + > + case NOP: > + code = ideal_nops[NOP_ATOMIC5]; > + break; > + > + case JMP: > + code = text_gen_insn(JMP32_INSN_OPCODE, insn, func); > + break; > + > + case RET: > + code = text_gen_insn(RET_INSN_OPCODE, insn, func); > + size = RET_INSN_SIZE; > + break; > + } > > - if (memcmp(insn, code, CALL_INSN_SIZE) == 0) > + if (memcmp(insn, code, size) == 0) > return; > > - text_poke_bp(insn, code, CALL_INSN_SIZE, NULL); > + text_poke_bp(insn, code, size, NULL); > } >