Hi! > x86, setup: "glove box" BIOS calls -- infrastructure > > Impact: new interfaces (not yet used) > > For all the platforms out there, there is an infinite number of buggy > BIOSes. This adds infrastructure to treat BIOS interrupts more like > toxic waste and "glove box" them -- we switch out the register set, > perform the BIOS interrupt, and then restore the previous state. > > LKML-Reference: <49DE7F79.4030106@xxxxxxxxx> > Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx> > Cc: Pavel Machek <pavel@xxxxxx> Sounds quite sane. Disadvantage is that we will no longer detect those buggy BIOSen. > +/* > + * "Glove box" for BIOS calls. Avoids the constant problems with BIOSes > + * touching memory they shouldn't be. > + */ Touching memory? AFAICT it only prevents touching registers. > + .code16 > + .text > + .globl intcall > + .type intcall, @function > +intcall: > + /* Self-modify the INT instruction. Ugly, but works. */ > + cmpb %al, 3f > + je 1f > + movb %al, 3f > + jmp 1f /* Synchronize pipeline */ > +1: There are various CPU bugs with self-modifying code, but I guess we are not using it heavily enough. Also we are single-threaded so that should be ok. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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