Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754393Ab3JXJKo (ORCPT ); Thu, 24 Oct 2013 05:10:44 -0400 Received: from mail-vc0-f179.google.com ([209.85.220.179]:47385 "EHLO mail-vc0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751610Ab3JXJKn (ORCPT ); Thu, 24 Oct 2013 05:10:43 -0400 MIME-Version: 1.0 In-Reply-To: <20131024084559.GD16735@n2100.arm.linux.org.uk> References: <1382498320-26594-1-git-send-email-tom.leiming@gmail.com> <87eh7bfoq9.fsf@rustcorp.com.au> <20131024084559.GD16735@n2100.arm.linux.org.uk> Date: Thu, 24 Oct 2013 17:10:42 +0800 Message-ID: Subject: Re: [RFC PATCH] kernel/kallsyms.c: only show legal kernel symbol From: Ming Lei To: Russell King - ARM Linux Cc: Rusty Russell , Andrew Morton , Linux Kernel Mailing List , Chen Gang , linux-arm-kernel Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1889 Lines: 53 On Thu, Oct 24, 2013 at 4:45 PM, Russell King - ARM Linux wrote: > On Thu, Oct 24, 2013 at 11:51:18AM +1030, Rusty Russell wrote: >> Ming Lei writes: >> > Address of non-module kernel symbol should always be located >> > from CONFIG_PAGE_OFFSET on, so only show these legal kernel >> > symbols in /proc/kallsyms. >> > >> > On ARM, some symbols(see below) may drop in relocatable code, so >> > perf can't parse kernel symbols any more from /proc/kallsyms, this >> > patch fixes the problem. >> > >> > 00000000 t __vectors_start >> > 00000020 A cpu_v7_suspend_size >> > 00001000 t __stubs_start >> > 00001004 t vector_rst >> > 00001020 t vector_irq >> > 000010a0 t vector_dabt >> > 00001120 t vector_pabt >> > 000011a0 t vector_und >> > 00001220 t vector_addrexcptn >> > 00001224 t vector_fiq >> > 00001224 T vector_fiq_offset >> > >> > The issue can be fixed in scripts/kallsyms.c too, but looks this >> > approach is easier. >> >> This fix looks hacky; if these symbols are not available, don't just >> remove them from /proc/kallsyms, but don't put them in the kernel at >> all. > > How do you "don't put them in the kernel at all" when they're used by > the kernel internally as offsets? > > If you mean, just get rid of them, shall I just add these as magic > numbers instead based on the values in this email? Is that really a > sane solution? > > No, we have to keep these symbols IMHO. If so, looks we have to hide them to userspace, so the patch should be OK because the approach is correct and no obvious side-effect. Thanks, -- Ming Lei -- 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/