Messages in this thread | | | Date | Fri, 24 Nov 2017 20:10:05 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH 14/43] x86/asm/64: Return to userspace from the trampoline stack |
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On Fri, Nov 24, 2017 at 06:23:42PM +0100, Ingo Molnar wrote: > From: Andy Lutomirski <luto@kernel.org> > > By itself, this is useless. It gives us the ability to run some final > code before exit that cannnot run on the kernel stack. This could > include a CR3 switch a la KAISER or some kernel stack erasing, for > example. (Or even weird things like *changing* which kernel stack > gets used as an ASLR-strengthening mechanism.) > > The SYSRET32 path is not covered yet. It could be in the future or > we could just ignore it and force the slow path if needed. > > Signed-off-by: Andy Lutomirski <luto@kernel.org> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Cc: Borislav Petkov <bpetkov@suse.de> > Cc: Brian Gerst <brgerst@gmail.com> > Cc: Dave Hansen <dave.hansen@intel.com> > Cc: Josh Poimboeuf <jpoimboe@redhat.com> > Cc: Linus Torvalds <torvalds@linux-foundation.org> > Cc: Peter Zijlstra <peterz@infradead.org> > Link: https://lkml.kernel.org/r/d350017000eed20922c3b2711a2d9229dc809256.1511497875.git.luto@kernel.org > Signed-off-by: Ingo Molnar <mingo@kernel.org> > --- > arch/x86/entry/entry_64.S | 55 +++++++++++++++++++++++++++++++++++++++++++---- > 1 file changed, 51 insertions(+), 4 deletions(-)
Nice commenting, future generations will appreciate it!
:-)
Reviewed-by: Borislav Petkov <bp@suse.de>
-- Regards/Gruss, Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
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