From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Fri, 12 Oct 2001 01:11:23 +0000 Subject: Re: [Linux-ia64] Probable seamless bug: can't pop es Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org >>>>> On Thu, 11 Oct 2001 17:19:32 -0700, "Robboy, David G" said: David.R> The following simple program runs on a P4 linux system, but David.R> gets a SIGSEGV on an Itanium. Most likely a seamless bug David.R> rather than a hardware bug. Even though we don't use David.R> segment registers in Linux, it is legal to push and pop David.R> them, isn't it? Actually, even segmentation is supported (via modify_ldt()), so the program should work. GDB says it dies on the "popl" instruction. The address that triggering the fault is 0x4c. I don't see where this is coming from. My suspicion is that the segv happens when the CPU attempts to load the segment descriptor from the GDT, but if that's the case, the address should be somewhere in the 0xc0000000 range. Another possibility is that the GDTD is not set up properly, but I don't see anything obvious that's wrong there. Perhaps someone more familiar with x86 could take a look? --david