On 7/8/2014 5:38 PM, H. Peter Anvin wrote: > On 07/08/2014 03:34 PM, Stuart Hayes wrote: >> >> I haven't received any responses... is there a problem with the patch? Also >> CCing a couple people. >> > > I was on vacation last week and am still catching up. > > It would also help if you describe the real-world scenario that made you > trip over this. > > -hpa >
Well... I got this issue because a co-worker tripped over it. He had NX disabled in BIOS for some reason, and found that linux wouldn't boot--it hung right after grub2. I guess it took a while to figure out that it was the fact that NX was disabled that caused linux not to come up--and that could happen to other people. I don't know of any real-world scenarios in which someone would actually prefer to run a recent linux kernel with NX disabled, though. It looks like some of the other boot paths into the kernel automatically clear the XD_DISABLE bit in the MISC_ENABLE MSR in the CPU (in verify_cpu), but that doesn't happen when grub2 jumps to startup_64 in arch/x86/boot/compressed/head_64.S. I guess instead of this patch, I could try to make a patch that turns NX back on (somewhere in startup_64), but since the kernel already supports NX being disabled, so I thought maybe just fixing that would be better. I didn't like seeing the kernel just die without giving any indication of what the problem is. Stuart -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
