On Thu, Oct 16, 2008 at 3:07 PM, Carl-Daniel Hailfinger <[EMAIL PROTECTED]> wrote: > On 16.10.2008 23:54, ron minnich wrote: >> On Thu, Oct 16, 2008 at 2:52 PM, Carl-Daniel Hailfinger >> <[EMAIL PROTECTED]> wrote: >> >> >>> If that's it, the solution is absolutely simple. And I mean totally simple. >>> 1. Backup old content >>> 2. Write ffffffff >>> >> >> at this point it is game over. >> The code that does this is in rom. >> > > Hm. Unshare only this function, maybe with another name?
printk? > > >>> 3. Read back and save in a variable >>> 4. Restore old content. >>> Make sure no code blacked out by the decode is executed between 1 and 4 >>> and you're safe. If you're feeling paranoid, do it as inline asm. Make >>> sure that short sequence is never ever run as XIP code in ROM (I can do >>> that checking right now). >>> >>> What am I missing? >>> >>> >> >> the big thing is that the problem code is a binary vga bios over which >> we have zero control. :-( >> > > Hmmm. Is it running in vm86? If yes, we can trap I/O port writes and > reads, so this is solvable. Same should apply to x86emu. > this is getting kind of hideously complex. Let's think on it some more. ron -- coreboot mailing list: [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
