Date: Thu, 30 Jun 2011 23:44:29 GMT From: Marcel Moolenaar <marcel@FreeBSD.org> To: freebsd-gnats-submit@FreeBSD.org Subject: ia64/158547: [ia64] Epilog counter (ar.ec) needs to be saved and restored for exceptions Message-ID: <201106302344.p5UNiTXv055671@red.freebsd.org> Resent-Message-ID: <201106302350.p5UNo4Z4084213@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
>Number: 158547 >Category: ia64 >Synopsis: [ia64] Epilog counter (ar.ec) needs to be saved and restored for exceptions >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-ia64 >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Thu Jun 30 23:50:04 UTC 2011 >Closed-Date: >Last-Modified: >Originator: Marcel Moolenaar >Release: -CURRENT >Organization: >Environment: FreeBSD eris.freebsd.org 9.0-CURRENT FreeBSD 9.0-CURRENT #1 r223702M: Thu Jun 30 23:04:04 UTC 2011 marcel@eris.freebsd.org:/usr/obj/tank/usr/src/sys/ERIS ia64 >Description: The epilog counter (ar.ec) is implicitly saved and restored across function calls. The counter is saved in the previous frame register. Consequently, synchronous context switches do not need to save/restore this register. For asynchronous context switches this is obviously not the case. Currently we do not save ar.ec in "exception_save" and we do not restore ar.ec in "exception_restore". SInce the GCC version in the source tree does not generate modulo-scheduled loops with the default options, ar.ec is typically not used. But as soon as GCC generates these loops are a different compiler is used, programs will misbehave and generally fail unless we save and restore ar.ec. >How-To-Repeat: >Fix: >Release-Note: >Audit-Trail: >Unformatted:
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201106302344.p5UNiTXv055671>