x86/entry/64: Clear registers for exceptions/interrupts, to reduce speculation attack...
authorDan Williams <dan.j.williams@intel.com>
Tue, 6 Feb 2018 01:18:11 +0000 (17:18 -0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 22 Feb 2018 14:42:21 +0000 (15:42 +0100)
commitd10d0bb86d974c41ccbbf1f22044e700597a84d0
treedb4794c96b9abdb1ef58c68defb3e6c64c19c47c
parente578fedba81e72e195fe71f893828d4597714db5
x86/entry/64: Clear registers for exceptions/interrupts, to reduce speculation attack surface

commit 3ac6d8c787b835b997eb23e43e09aa0895ef7d58 upstream.

Clear the 'extra' registers on entering the 64-bit kernel for exceptions
and interrupts. The common registers are not cleared since they are
likely clobbered well before they can be exploited in a speculative
execution attack.

Originally-From: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/151787989146.7847.15749181712358213254.stgit@dwillia2-desk3.amr.corp.intel.com
[ Made small improvements to the changelog and the code comments. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/entry/calling.h
arch/x86/entry/entry_64.S