Date: Thu, 16 Jul 1998 16:31:58 +0200 From: Johan Karlsson <k@numeri.campus.luth.se> To: freebsd-hackers@FreeBSD.ORG Subject: Special memory board on ISA bus Message-ID: <199807161431.QAA27635@numeri.campus.luth.se>
next in thread | raw e-mail | index | archive | help
Hi I have a special memory board on the ISA bus that responds to addresses from BOARD_BASE up to BOARD_BASE+BOARD_MASK. Now I need to make sure that the memory manager in FreeBSD does not use this part of the memory address space. Is there an "easy" way to do this or do I have to rewrite init386 in /usr/src/sys/i386/i386/machdep.c to ensure that it will not use the board. I also need to make sure that the cache is not used when I read/write to my board. To do this one can use the MTRR:s (Memory Type Range Registers). These registers only exists in a P6 cpu. (see http://www.intel.com/design/pro/manuals/ "Intel Architecture Software Developer's Manual, Volume 3: System Programming Guide" Chapter 9) I have noticed that FBSD detects the existens of MTRR:s but it does not seem to use it anywhere. Is there any support in FBSD to set these registers? Any suggestions on how I should handle uncachable memory in FreeBSD? BTW I've been using FBSD-stable for 2 years but I have never needed to change anything in the kernel before. Please keep that in mind when replying. Any help appreciated. /K - -- Johan Karlsson mailto:k@numeri.campus.luth.se SWEDEN To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199807161431.QAA27635>