From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 18 May 2001 09:39:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 18 May 2001 09:39:33 -0400 Received: from tomts7.bellnexxia.net ([209.226.175.40]:58019 "EHLO tomts7-srv.bellnexxia.net") by vger.kernel.org with ESMTP id ; Fri, 18 May 2001 09:39:24 -0400 To: linux-kernel@vger.kernel.org Subject: APIC, AMD-K6/2 -mcpu=586... From: Bill Pringlemeir Date: 18 May 2001 09:38:01 -0400 Message-ID: User-Agent: Gnus/5.0803 (Gnus v5.8.3) Emacs/20.4 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello, I have the 2.4.4 distribution from kernel.org. "http://www.kernel.org/pub/linux/kernel/v2.4/" I have a Mandrake system and selected the AMD processors and APIC option. The egcs-2.91.66 compiler with -mcpu=586. It appears that the structure alignment of the floating point registers was not correct under this configuration. This code was being compiled and a linker error produced. if (offsetof(struct task_struct, thread.i387.fxsave) & 15) { /* printk("WJP: value is %x.\n", offsetof(struct task_struct, thread.i387.fxsave) & 15); */ /* while(1); */ extern void __buggy_fxsr_alignment(void); __buggy_fxsr_alignment(); } The alignment was to 8 bytes instead of 16. I added some padding to the thread structure to produce an alignment of 16 and the code compiled and seemed to work fine; I used it for a few days. [in processor.h] /* floating point info */ /* unsigned char wjpDummy[8]; */ union i387_union i387; I did not see any mention of this in the archives [but the volume of mailings is large... which I may be contributing to]. I recompiled without the padding and APIC support and everything seems to be fine, but _VERY_ slow. Is this change ok locally? Has it been addressed in a patch? regards, Bill Pringlemeir.