Date: Mon, 11 Nov 1996 19:58:33 -0800 From: David Greenman <dg@root.com> To: Soren Schmidt <sos@freefall.freebsd.org> Cc: CVS-committers@freefall.freebsd.org, cvs-all@freefall.freebsd.org, cvs-sys@freefall.freebsd.org Subject: Re: cvs commit: src/sys/i386/isa syscons.c Message-ID: <199611120358.TAA04500@root.com> In-Reply-To: Your message of "Mon, 11 Nov 1996 14:21:16 PST." <199611112221.OAA15183@freefall.freebsd.org>
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> 4. (Most important.) Don't corrupt memory beyond the screen buffers if
> the cursor happens to be off the 80x25 screen when syscons starts.
Should this patch be brought into 2.1.6?
Index: syscons.c
===================================================================
RCS file: /home/ncvs/src/sys/i386/isa/syscons.c,v
retrieving revision 1.117.4.12
diff -c -r1.117.4.12 syscons.c
*** syscons.c 1996/06/27 21:39:55 1.117.4.12
--- syscons.c 1996/11/12 03:55:19
***************
*** 1984,1989 ****
--- 1984,1996 ----
outb(crtc_addr, 15);
hw_cursor |= inb(crtc_addr + 1);
+ /*
+ * Validate cursor location. It may be off the screen. Then we must
+ * not use it for the initial buffer offset.
+ */
+ if (hw_cursor >= ROW * COL)
+ hw_cursor = (ROW - 1) * COL;
+
/* move hardware cursor out of the way */
outb(crtc_addr, 14);
outb(crtc_addr + 1, 0xff);
-DG
David Greenman
Core-team/Principal Architect, The FreeBSD Project
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