Date: Mon, 27 Nov 2000 10:33:05 -0800 (PST) From: John Baldwin <jhb@FreeBSD.org> To: Jake Burkholder <jburkhol@home.com> Cc: smp@FreeBSD.org Subject: RE: BSD/OS interrupt code Message-ID: <XFMail.001127103305.jhb@FreeBSD.org> In-Reply-To: <20001126220749.BFB35BA7A@io.yi.org>
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On 26-Nov-00 Jake Burkholder wrote: > Hi, > > If anyone with access to the BSD/OS code is interested, I've written > a little program that runs their interrupt stub code generator in > userland. You can then abort(); and disassemble the stub from > the core dump to look at the code all in one piece. Makes it much > easier to follow. > > In case you haven't looked, their interrupt handlers are generated > by bcopy-ing various blocks of assembler code into an array at > runtime, and then poking in arguments and relocating branches. Hmm. The best way to do this probably is to have stubs with psuedo-relocation information. I.e., have 1 stub interrupt handler template for each type (fast, threaded, fast apic, threaded apic, etc.), then have a "relocation" table on the side that specifies offsets in the code that should receive one of a number of things: vector number, vector address, etc. Alternatively, we could store all of that info in a struct (gee, we already do with intrhand :)) and just have the code always dereference a pointer to that struct and have the relocation entries simply point to places that that pointer should be written. Granted, on sparc this could get much uglier (based on my understanding of relocation address on sparc since an address can be formed across several instructions. Yuck.) > Jake -- John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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