From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756614Ab1I3QD4 (ORCPT ); Fri, 30 Sep 2011 12:03:56 -0400 Received: from claw.goop.org ([74.207.240.146]:45501 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752176Ab1I3QDz (ORCPT ); Fri, 30 Sep 2011 12:03:55 -0400 Message-ID: <4E85E867.8080809@goop.org> Date: Fri, 30 Sep 2011 09:03:51 -0700 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:6.0.2) Gecko/20110906 Thunderbird/6.0.2 MIME-Version: 1.0 To: Jan Glauber CC: Steven Rostedt , "David S. Miller" , David Daney , Michael Ellerman , Jason Baron , the arch/x86 maintainers , Xen Devel , Linux Kernel Mailing List , Jeremy Fitzhardinge Subject: Re: [PATCH RFC 7/8] s390/jump-label: add arch_jump_label_transform_early() References: <1317394099.11297.54.camel@localhost.localdomain> In-Reply-To: <1317394099.11297.54.camel@localhost.localdomain> X-Enigmail-Version: 1.3.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/30/2011 07:48 AM, Jan Glauber wrote: > On Thu, 2011-09-29 at 16:26 -0700, Jeremy Fitzhardinge wrote: >> From: Jeremy Fitzhardinge >> >> This allows jump-label entries to be modified early, in a pre-SMP >> environment. >> >> Signed-off-by: Jeremy Fitzhardinge >> Cc: Jan Glauber > Hi Jeremy, > > Your patch looks fine, if you can fix the minor compiler warnings > below. Excluding stop_machine() on pre-SMP also looks safer too me. Do you think there would be an actual problem, or are you just being cautious? It seems to me - in general - stop_machine could just be defined to be a no-op (ie, just directly calls the callback) until enough SMP is initialized for it to make sense, rather than having to make every user work around it (if there's a chance they might call it early). > CC arch/s390/kernel/jump_label.o > arch/s390/kernel/jump_label.c: In function ‘__jump_label_transform’: > arch/s390/kernel/jump_label.c:41:2: error: ‘rc’ undeclared (first use in this function) > arch/s390/kernel/jump_label.c:41:2: note: each undeclared identifier is reported only once for each function it appears in > arch/s390/kernel/jump_label.c:41:2: warning: passing argument 1 of ‘probe_kernel_write’ makes pointer from integer without a cast [enabled by default] > include/linux/uaccess.h:108:21: note: expected ‘void *’ but argument is of type ‘jump_label_t’ > arch/s390/kernel/jump_label.c:28:19: warning: unused variable ‘args’ [-Wunused-variable] > make[2]: *** [arch/s390/kernel/jump_label.o] Error 1 > > Like so? >>From 9572689d1e5e6f54a1936a1dca09a6920d1bce27 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Thu, 29 Sep 2011 10:58:46 -0700 Subject: [PATCH] s390/jump-label: add arch_jump_label_transform_early() This allows jump-label entries to be modified early, in a pre-SMP environment. Signed-off-by: Jeremy Fitzhardinge Cc: Jan Glauber diff --git a/arch/s390/kernel/jump_label.c b/arch/s390/kernel/jump_label.c index 44cc06b..4fbe63b 100644 --- a/arch/s390/kernel/jump_label.c +++ b/arch/s390/kernel/jump_label.c @@ -18,26 +18,15 @@ struct insn { } __packed; struct insn_args { - unsigned long *target; - struct insn *insn; - ssize_t size; + struct jump_entry *entry; + enum jump_label_type type; }; -static int __arch_jump_label_transform(void *data) +static void __jump_label_transform(struct jump_entry *entry, + enum jump_label_type type) { - struct insn_args *args = data; - int rc; - - rc = probe_kernel_write(args->target, args->insn, args->size); - WARN_ON_ONCE(rc < 0); - return 0; -} - -void arch_jump_label_transform(struct jump_entry *entry, - enum jump_label_type type) -{ - struct insn_args args; struct insn insn; + int rc; if (type == JUMP_LABEL_ENABLE) { /* brcl 15,offset */ @@ -49,11 +38,33 @@ void arch_jump_label_transform(struct jump_entry *entry, insn.offset = 0; } - args.target = (void *) entry->code; - args.insn = &insn; - args.size = JUMP_LABEL_NOP_SIZE; + rc = probe_kernel_write((void *)entry->code, &insn, JUMP_LABEL_NOP_SIZE); + WARN_ON_ONCE(rc < 0); +} - stop_machine(__arch_jump_label_transform, &args, NULL); +static int __sm_arch_jump_label_transform(void *data) +{ + struct insn_args *args = data; + + __jump_label_transform(args->entry, args->type); + return 0; +} + +void arch_jump_label_transform(struct jump_entry *entry, + enum jump_label_type type) +{ + struct insn_args args; + + args.entry = entry; + args.type = type; + + stop_machine(__sm_arch_jump_label_transform, &args, NULL); +} + +void __init arch_jump_label_transform_early(struct jump_entry *entry, + enum jump_label_type type) +{ + __jump_label_transform(entry, type); } #endif J