From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751123AbVHUV2Y (ORCPT ); Sun, 21 Aug 2005 17:28:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751129AbVHUV2Y (ORCPT ); Sun, 21 Aug 2005 17:28:24 -0400 Received: from smtp3.nextra.sk ([195.168.1.142]:61711 "EHLO mailhub3.nextra.sk") by vger.kernel.org with ESMTP id S1751123AbVHUV2X (ORCPT ); Sun, 21 Aug 2005 17:28:23 -0400 Message-ID: <4308F1EF.9020609@rainbow-software.org> Date: Sun, 21 Aug 2005 23:28:15 +0200 From: Ondrej Zary User-Agent: Mozilla Thunderbird 1.0.6 (X11/20050716) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Linus Torvalds CC: Chuck Ebbert <76306.1226@compuserve.com>, linux-kernel , Ingo Molnar Subject: Re: FPU-intensive programs crashing with floating point exception on Cyrix MII References: <200508210550_MC3-1-A7CF-D29E@compuserve.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Linus Torvalds wrote: > > On Sun, 21 Aug 2005, Chuck Ebbert wrote: > >>>MATH ERROR: cwd = 0x37f, swd = 0x2800 <=========== >> >> The error I marked has no exception flags set. The rest are all (masked) >>denormal exceptions. Why your Cyrix MII would cause an FPU exception in these >>cases is beyond me. Could you try the statically-linked mprime program? I use only the statically linked mprime. > Also, please try this one, to see where it happens. I did some modification to the code so it calls show_regs() in both cases where I get problems and also added the return so it does not crash. The code looks like this: --- printk("MATH ERROR: cwd = 0x%hx, swd = 0x%hx\n", cwd, swd); switch (((~cwd) & swd & 0x3f) | (swd & 0x240)) { case 0x000: case 0x200: show_regs(regs); return; --- Here are the results. MATH ERROR: cwd = 0x37f, swd = 0x1820 Pid: 1699, comm: mprime EIP: 0073:[<08181c73>] CPU: 0 EIP is at 0x8181c73 ESP: 007b:bf927ab4 EFLAGS: 00010202 Not tainted (2.6.12-pentium) EAX: 00000001 EBX: 00000000 ECX: 0000808d EDX: b7f09480 ESI: b7455340 EDI: 080e01f0 EBP: bf927bf8 DS: 007b ES: 007b CR0: 8005003b CR2: b7ed6058 CR3: 006f0000 CR4: 00000080 MATH ERROR: cwd = 0x37f, swd = 0x1020 Pid: 1699, comm: mprime EIP: 0073:[<0818ca5f>] CPU: 0 EIP is at 0x818ca5f ESP: 007b:bf927ab0 EFLAGS: 00010207 Not tainted (2.6.12-pentium) EAX: 00000005 EBX: 00000000 ECX: 00008407 EDX: b7f08140 ESI: b789aea0 EDI: b7f08200 EBP: bf927bf8 DS: 007b ES: 007b CR0: 8005003b CR2: b75c6000 CR3: 006f0000 CR4: 00000080 MATH ERROR: cwd = 0x37f, swd = 0x2820 Pid: 1699, comm: mprime EIP: 0073:[<0818c4b1>] CPU: 0 EIP is at 0x818c4b1 ESP: 007b:bf927ab0 EFLAGS: 00010247 Not tainted (2.6.12-pentium) EAX: 00000000 EBX: 00000000 ECX: 0000880f EDX: b7f09480 ESI: b741fc20 EDI: 080e0160 EBP: bf927bf8 DS: 007b ES: 007b CR0: 8005003b CR2: b75c6000 CR3: 006f0000 CR4: 00000080 MATH ERROR: cwd = 0x37f, swd = 0x20 Pid: 1699, comm: mprime EIP: 0073:[<08181ca1>] CPU: 0 EIP is at 0x8181ca1 ESP: 007b:bf927ab4 EFLAGS: 00010202 Not tainted (2.6.12-pentium) EAX: 00000002 EBX: 00000000 ECX: 00000084 EDX: b7f09480 ESI: b74f86c0 EDI: 080e01f0 EBP: bf927bf8 DS: 007b ES: 007b CR0: 8005003b CR2: b75c6000 CR3: 006f0000 CR4: 00000080 MATH ERROR: cwd = 0x37f, swd = 0x1a20 Pid: 1699, comm: mprime EIP: 0073:[<08193c68>] CPU: 0 EIP is at 0x8193c68 ESP: 007b:bf927ab8 EFLAGS: 00010206 Not tainted (2.6.12-pentium) EAX: 00000042 EBX: 00000000 ECX: 00154306 EDX: b7e3ba40 ESI: b7a1e680 EDI: b7e3be40 EBP: bf927bf8 DS: 007b ES: 007b CR0: 8005003b CR2: b7499000 CR3: 006f0000 CR4: 00000080 MATH ERROR: cwd = 0x37f, swd = 0x20 Pid: 1699, comm: mprime EIP: 0073:[<0818de05>] CPU: 0 EIP is at 0x818de05 ESP: 007b:bf927ab4 EFLAGS: 00010247 Not tainted (2.6.12-pentium) EAX: 00000004 EBX: 00000000 ECX: 0000880f EDX: b7f06b40 ESI: b7426400 EDI: 080e1960 EBP: bf927bf8 DS: 007b ES: 007b CR0: 8005003b CR2: b7499000 CR3: 006f0000 CR4: 00000080 MATH ERROR: cwd = 0x37f, swd = 0x20 Pid: 1699, comm: mprime EIP: 0073:[<0818dfe4>] CPU: 0 EIP is at 0x818dfe4 ESP: 007b:bf927ab4 EFLAGS: 00010247 Not tainted (2.6.12-pentium) EAX: 00000200 EBX: 00000000 ECX: 0000880f EDX: b7f06b40 ESI: b742a680 EDI: 080e1c60 EBP: bf927bf8 DS: 007b ES: 007b CR0: 8005003b CR2: b7499000 CR3: 006f0000 CR4: 00000080 -- Ondrej Zary