From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932065Ab0JDRvy (ORCPT ); Mon, 4 Oct 2010 13:51:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38113 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756293Ab0JDRvx (ORCPT ); Mon, 4 Oct 2010 13:51:53 -0400 Date: Mon, 4 Oct 2010 13:50:39 -0400 From: Jason Baron To: David Daney 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. Message-ID: <20101004175039.GC2900@redhat.com> References: <1285697432-29244-1-git-send-email-ddaney@caviumnetworks.com> <4CAA122B.40502@caviumnetworks.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4CAA122B.40502@caviumnetworks.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 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. thanks, -Jason