x86/intel/quark: Switch off CR4.PGE so TLB flush uses CR3 instead
authorBryan O'Donoghue <pure.logic@nexus-software.ie>
Tue, 23 Sep 2014 23:26:24 +0000 (00:26 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 30 Oct 2014 16:35:10 +0000 (09:35 -0700)
commit75b6cf03dd5cae671b84f60e018a6c08e5f6d4b7
tree621dbe3d6c8938076cab201507480b04910fede5
parent7889ddde2798154828d49da8d7c8863b7573e62d
x86/intel/quark: Switch off CR4.PGE so TLB flush uses CR3 instead

commit ee1b5b165c0a2f04d2107e634e51f05d0eb107de upstream.

Quark x1000 advertises PGE via the standard CPUID method
PGE bits exist in Quark X1000's PTEs. In order to flush
an individual PTE it is necessary to reload CR3 irrespective
of the PTE.PGE bit.

See Quark Core_DevMan_001.pdf section 6.4.11

This bug was fixed in Galileo kernels, unfixed vanilla kernels are expected to
crash and burn on this platform.

Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/1411514784-14885-1-git-send-email-pure.logic@nexus-software.ie
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/kernel/cpu/intel.c