Messages in this thread | | | Date | Fri, 19 Nov 2021 09:15:43 -0800 | From | Kees Cook <> | Subject | Re: [PATCH 3/3] x86: Add straight-line-speculation mitigation |
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On Fri, Nov 19, 2021 at 05:50:26PM +0100, Peter Zijlstra wrote: > This little patch makes use of an upcomming GCC feature to mitigate > straight-line-speculation for x86: > > https://gcc.gnu.org/g:53a643f8568067d7700a9f2facc8ba39974973d3 > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102952 > https://bugs.llvm.org/show_bug.cgi?id=52323 > > It's built tested on x86_64-allyesconfig using GCC-12 and GCC-11. > It's also been boot tested on x86_64-defconfig+kvm_guest.config using > GCC-12. > > Maintenace overhead of this should be fairly low due to objtool > validation. > > Size overhead of all these additional int3 instructions comes to: > > text data bss dec hex filename > 22267751 6933356 2011368 31212475 1dc43bb defconfig-build/vmlinux > 22804126 6933356 1470696 31208178 1dc32f2 defconfig-build/vmlinux.sls > > Or roughly 2.4% additional text.
Thanks for adding the size details. (I remain surprised it's so much.)
> [...] > 125 files changed, 441 insertions(+), 386 deletions(-)
I wonder if this patch should be split into a few pieces:
- objtool validation - asm macro definitions - mechanical ret/RET replacement - Kconfig & Makefile
Personally I'd find that much easier to review, but either way:
Reviewed-by: Kees Cook <keescook@chromium.org>
Thanks!
-- Kees Cook
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