Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752877AbZKCNjp (ORCPT ); Tue, 3 Nov 2009 08:39:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751170AbZKCNjo (ORCPT ); Tue, 3 Nov 2009 08:39:44 -0500 Received: from mail-gx0-f226.google.com ([209.85.217.226]:37973 "EHLO mail-gx0-f226.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750861AbZKCNjo (ORCPT ); Tue, 3 Nov 2009 08:39:44 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; b=A4ZVsrNvYFMpNdCm0mr8OM8nSBtVUj8CSv0VNUpXPHrpCCkIsOaoxPRHBsnyrD+ln8 QYY1pnKO30uRCvmZ9Mv50NtuO6YWyz4tsZs/ONrGcO/9NKtHRh7CZaZOant+JkbaBzku LzokQYP0BlIKdagAvkdYa7zWuR2HdrhLfXmvs= MIME-Version: 1.0 In-Reply-To: <20091103132935.GA12841@linux-sh.org> References: <9b2b86520911020852q49c55695rb05d87090fa9ad33@mail.gmail.com> <1257242782-10496-5-git-send-email-alan-jenkins@tuffmail.co.uk> <8bd0f97a0911030219y685a1dafy2a8e066d7132ac45@mail.gmail.com> <4AF01F18.8040807@tuffmail.co.uk> <8bd0f97a0911030430s3ecb2467hc52ebac658c39ccd@mail.gmail.com> <20091103132935.GA12841@linux-sh.org> From: Mike Frysinger Date: Tue, 3 Nov 2009 08:39:29 -0500 Message-ID: <8bd0f97a0911030539s582598d6k2f78693bbfa559b0@mail.gmail.com> Subject: Re: [PATCH 04/10] module: make MODULE_SYMBOL_PREFIX into a CONFIG option To: Paul Mundt Cc: Alan Jenkins , greg@kroah.com, linux-kbuild@vger.kernel.org, carmelo73@gmail.com, linux-kernel@vger.kernel.org, rusty@rustcorp.com.au Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3220 Lines: 69 On Tue, Nov 3, 2009 at 08:29, Paul Mundt wrote: > On Tue, Nov 03, 2009 at 07:30:20AM -0500, Mike Frysinger wrote: >> On Tue, Nov 3, 2009 at 07:16, Alan Jenkins wrote: >> > Mike Frysinger wrote: >> >> On Tue, Nov 3, 2009 at 05:06, Alan Jenkins wrote: >> >>> The next commit will require the use of MODULE_SYMBOL_PREFIX in >> >>> .tmp_exports-asm.S. ??Currently it is mixed in with C structure >> >>> definitions in "asm/module.h". ??Move the definition of this arch option >> >>> into Kconfig, so it can be easily accessed by any code. >> >>> >> >>> This also lets modpost.c use the same definition. ??Previously modpost >> >>> relied on a hardcoded list of architectures in mk_elfconfig.c. >> >> >> >> this should also let us push VMLINUX_SYMBOL() out of >> >> arch/*/kernel/vmlinux.lds.S and into asm-generic/vmlinux.lds.h ... >> > >> > I don't think that's possible. >> > >> > ?? #define VMLINUX_SYMBOL(_sym_) _##_sym_ >> > >> > I don't know any "unstringify" operation. ??So I can't convert a string value >> > of CONFIG_SYMBOL_PREFIX to the unquoted underscore we neeed for this macro. >> > ??The same applies for the SYM() macro I use. >> >> let the build system do the unstringify operation. >> qstrip = $(strip $(subst ",,$(1))) >> CPPFLAGS_vmlinux.lds += -DVMLINUX_SYMBOL_PREFIX=$(call >> qstrip,CONFIG_SYMBOL_PREFIX) >> >> > If we positively want to keep the generality, I guess I should put >> > MODULE_SYMBOL_PREFIX in a header file of it's own. ??The disadvantage is that >> > it makes it inaccessible to host programs again, like modpost (which >> > currently hardcodes the list of affected architectures in mk_elfconfig.c). >> >> having it in the arch Kconfig removes any and all possible >> limitations, and it keeps the cruft out of the common init/Kconfig and >> in the arch-specific Kconfig, and avoids a dead symbol >> (HAVE_SYMBOL_PREFIX) > > Having it in the Kconfig also makes it a nuisance for platforms that can > use -elf and -linux toolchains for the same tree for different platforms. > It would be nice to have this supported in such a way that we can just > set a flag from the Makefile and have a compiler test that determines > whether it is necessary or not. what arch is this an issue for ? the only symbol prefixed arches are Blackfin and H8300, and they dont provide toolchains that omit the prefix. if anything, the common build code could easily do: ifeq ($(CONFIG_SYMBOL_PREFIX),) CFLAGS += $(call cc-option,-fno-leading-underscore) endif trying to enable symbol prefix support dynamically based on the toolchain is a bad idea and pretty fragile. the arch-specific assembly code would have to be all rewritten to wrap all C-visible symbols with a macro like VMLINUX_SYMBOL(). i say let anyone who actually has such a system and wants to do such a crazy ass thing put together a working arch first before we worry about it. the current code doesnt preclude dynamic hooking anyways (manually adding -DCONFIG_xxx to CPPFLAGS). -mike -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/