From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932356Ab0JDTGL (ORCPT ); Mon, 4 Oct 2010 15:06:11 -0400 Received: from mail3.caviumnetworks.com ([12.108.191.235]:19874 "EHLO mail3.caviumnetworks.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932243Ab0JDTGK (ORCPT ); Mon, 4 Oct 2010 15:06:10 -0400 Message-ID: <4CAA25A1.4000302@caviumnetworks.com> Date: Mon, 04 Oct 2010 12:06:09 -0700 From: David Daney User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.11) Gecko/20100720 Fedora/3.0.6-1.fc12 Thunderbird/3.0.6 MIME-Version: 1.0 To: Jason Baron CC: Rabin Vincent , linux-mips@linux-mips.org, ralf@linux-mips.org, linux-kernel@vger.kernel.org, rostedt@goodmis.org, David Miller Subject: Re: [PATCH] jump label: Add MIPS support. References: <1285697432-29244-1-git-send-email-ddaney@caviumnetworks.com> <4CAA122B.40502@caviumnetworks.com> <20101004175039.GC2900@redhat.com> In-Reply-To: <20101004175039.GC2900@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 04 Oct 2010 19:06:15.0425 (UTC) FILETIME=[37CA0710:01CB63F7] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/04/2010 10:50 AM, Jason Baron wrote: > On Mon, Oct 04, 2010 at 10:43:07AM -0700, David Daney wrote: >> On 10/03/2010 11:15 AM, Rabin Vincent wrote: >>> On Tue, Sep 28, 2010 at 11:40 PM, David Daney wrote: >>>> +void arch_jump_label_text_poke_early(jump_label_t addr) >>>> +{ >>>> + union mips_instruction *insn_p = >>>> + (union mips_instruction *)(unsigned long)addr; >>>> + >>>> + insn_p->word = 0; /* nop */ >>>> + flush_icache_range((unsigned long)insn_p, >>>> + (unsigned long)insn_p + sizeof(*insn_p)); >>>> +} >>> >>> Can't this function be a no-op on MIPS? This seems to be >>> used on x86 to patch in the optimal nop instruction, but >>> on MIPS the optimal/only nop instruction should already >>> be in place at build time. Same thing for the SPARC >>> implementation. >>> >> >> Yes, I think you are correct. >> >> On MIPS the NOP is already optimal. I will respin the MIPS patch to >> make arch_jump_label_text_poke_early() be empty. >> >> davem wasn't CCed on the original message, so I added him. I would >> defer to him on the SPARC version. >> >> > > that's right, arch_jump_label_text_poke_early() can probably be a no-op > for most arches. > > We can also look at adding an empty definition into the generic > header. So that arches don't have to provide an empty definition. > I just sent the patch that does that. It should be showing up in an In-Box near you soon. David Daney