On 01/15/2018, 01:35 PM, Greg Kroah-Hartman wrote: > 4.9-stable review patch. If anyone has any objections, please let me know.
May I ask if somebody has started the 4.4 port yet? > ------------------ > > From: David Woodhouse <d...@amazon.co.uk> > > commit 76b043848fd22dbf7f8bf3a1452f8c70d557b860 upstream. > > Enable the use of -mindirect-branch=thunk-extern in newer GCC, and provide > the corresponding thunks. Provide assembler macros for invoking the thunks > in the same way that GCC does, from native and inline assembler. > > This adds X86_FEATURE_RETPOLINE and sets it by default on all CPUs. In > some circumstances, IBRS microcode features may be used instead, and the > retpoline can be disabled. > > On AMD CPUs if lfence is serialising, the retpoline can be dramatically > simplified to a simple "lfence; jmp *\reg". A future patch, after it has > been verified that lfence really is serialising in all circumstances, can > enable this by setting the X86_FEATURE_RETPOLINE_AMD feature bit in addition > to X86_FEATURE_RETPOLINE. > > Do not align the retpoline in the altinstr section, because there is no > guarantee that it stays aligned when it's copied over the oldinstr during > alternative patching. > > [ Andi Kleen: Rename the macros, add CONFIG_RETPOLINE option, export thunks] > [ tglx: Put actual function CALL/JMP in front of the macros, convert to > symbolic labels ] > [ dwmw2: Convert back to numeric labels, merge objtool fixes ] > > Signed-off-by: David Woodhouse <d...@amazon.co.uk> > Signed-off-by: Thomas Gleixner <t...@linutronix.de> > Acked-by: Arjan van de Ven <ar...@linux.intel.com> > Acked-by: Ingo Molnar <mi...@kernel.org> > Cc: gno...@lxorguk.ukuu.org.uk > Cc: Rik van Riel <r...@redhat.com> > Cc: Andi Kleen <a...@linux.intel.com> > Cc: Josh Poimboeuf <jpoim...@redhat.com> > Cc: thomas.lenda...@amd.com > Cc: Peter Zijlstra <pet...@infradead.org> > Cc: Linus Torvalds <torva...@linux-foundation.org> > Cc: Jiri Kosina <ji...@kernel.org> > Cc: Andy Lutomirski <l...@amacapital.net> > Cc: Dave Hansen <dave.han...@intel.com> > Cc: Kees Cook <keesc...@google.com> > Cc: Tim Chen <tim.c.c...@linux.intel.com> > Cc: Greg Kroah-Hartman <gre...@linux-foundation.org> > Cc: Paul Turner <p...@google.com> > Link: > https://lkml.kernel.org/r/1515707194-20531-4-git-send-email-d...@amazon.co.uk > Signed-off-by: David Woodhouse <d...@amazon.co.uk> > Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> thanks, -- js suse labs
