From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933265AbcCIQfq (ORCPT ); Wed, 9 Mar 2016 11:35:46 -0500 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:58705 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753712AbcCIQfk (ORCPT ); Wed, 9 Mar 2016 11:35:40 -0500 From: Will Deacon To: linux-kernel@vger.kernel.org Cc: Will Deacon , Tony Luck , Heiko Carstens , Andrew Morton Subject: [PATCH] Kconfig: disable LATENCYTOP for IA64 Date: Wed, 9 Mar 2016 16:35:44 +0000 Message-Id: <1457541344-16961-1-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit da48d094ce5d ("Kconfig: remove HAVE_LATENCYTOP_SUPPORT") allows CONFIG_LATENCYTOP to be selected on all architectures, since save_stack_trace_tsk is now provided unconditionally by core code. Unfortunately, this results in a build error for ia64 when the option is enabled: arch/ia64/kernel/entry.S: Assembler messages: arch/ia64/kernel/entry.S:621: Error: Operand 2 of `adds' should be a 14-bit integer (-8192-8191) arch/ia64/kernel/entry.S:728: Error: Operand 2 of `adds' should be a 14-bit integer (-8192-8191) arch/ia64/kernel/entry.S:859: Error: Operand 2 of `adds' should be a 14-bit integer (-8192-8191) make[1]: *** [arch/ia64/kernel/entry.o] Error 1 This is because task_struct is now over 8k thanks to the latency_record array, which means that the 14-bit immediate offset expect by the adds instruction to grab hold of the thread info flags is now out-of-range on ia64. Fixing the ia64 entry code without making it less efficient is beyond me, but rather than revert da48d094ce5d entirely, we can simply make LATENCYTOP depend on !IA64 until somebody brave steps up to tackle the entry code over there. Cc: Tony Luck Cc: Heiko Carstens Cc: Andrew Morton Reported-by: Al Viro Signed-off-by: Will Deacon --- I previously reported this on linux-arch, but the conversation didn't go anywhere: http://marc.info/?l=linux-arch&m=145390684108109 lib/Kconfig.debug | 1 + 1 file changed, 1 insertion(+) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 8bfd1aca7a3d..c8d12808b9aa 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1615,6 +1615,7 @@ config LATENCYTOP depends on DEBUG_KERNEL depends on STACKTRACE_SUPPORT depends on PROC_FS + depends on !IA64 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC select KALLSYMS select KALLSYMS_ALL -- 2.1.4