lkml.org 
[lkml]   [2017]   [May]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH v5 2/3] x86/asm: Add suffix macro for GEN_*_RMWcc()
    On Wed, May 31, 2017 at 4:13 AM, Peter Zijlstra <peterz@infradead.org> 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

    \
     
     \ /
      Last update: 2017-05-31 15:18    [W:2.480 / U:0.024 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site