On Wed, May 31, 2017 at 4:13 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Tue, May 30, 2017 at 02:39:51PM -0700, Kees Cook wrote: >> The coming x86 refcount protection needs to be able to add trailing >> instructions to the GEN_*_RMWcc() operations. This extracts the >> difference between the goto/non-goto cases so the helper macros >> can be defined outside the #ifdef cases. Additionally adds argument >> naming to the resulting asm for referencing from suffixed >> instructions, and adds clobbers for "cc", and "cx" to let suffixes >> use _ASM_CX, and retain any set flags. > > Another option is to simply require __GCC_ASM_FLAG_OUTPUT__ for the fast > refcount stuff. That would result in simpler and more readable code. What versions of GCC support that? -Kees -- Kees Cook Pixel Security
