Date: Wed, 22 Apr 1998 15:42:11 -0700 (PDT) From: gilham@csl.sri.com To: freebsd-gnats-submit@FreeBSD.ORG Subject: kern/6389: Need to be able to access trap-to-signal mapping to for Linux emulation to allow Allegro Common Lisp (and maybe other apps) to run. Message-ID: <199804222242.PAA22024@hub.freebsd.org>
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>Number: 6389 >Category: kern >Synopsis: Need to be able to access trap-to-signal mapping to for Linux emulation to allow Allegro Common Lisp (and maybe other apps) to run. >Confidential: no >Severity: serious >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: change-request >Submitter-Id: current-users >Arrival-Date: Wed Apr 22 15:50:02 PDT 1998 >Last-Modified: >Originator: Fred Gilham >Organization: SRI International >Release: FreeBSD 2.2?, FreeBSD 3.0 >Environment: N/A >Description: The mapping between traps and signals is slightly different in FreeBSD and Linux. Ordinarily this doesn't cause problems but some applications depend on being able to handle certain traps. In particular, Allegro Common Lisp, a commercial version of Common Lisp that was released to the Linux community for free non-commercial use, depends on being able to intercept T_PROTFLT traps to expand its heap if necessary. In Linux these traps are mapped to segmentation violations. In FreeBSD they are bus errors. As a result, ACL will come up under the FreeBSD Linux emulator and execute small programs but will die with a bus error if you try to do anything significant. I've worked with Mike Smith to resolve this problem. He suggested adding a mapping function to the sigentvec structure that emulators could use to remap traps to the signals they wish. I've implemented a test version of this change and it allows ACL to work and run significant applications. >How-To-Repeat: Run Allegro Common Lisp (available from www.franz.com) under the Linux emulator. Try to compile a lisp program. You will get a bus error. >Fix: My test fixes are available from ftp.csl.sri.com:/pub/gilham/trap-fixes.tar.gz. They are directly applicable to FreeBSD 3.0-980414-SNAP but they are relatively trivial to apply to other releases. >Audit-Trail: >Unformatted: To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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