[Mesa-stable] [PATCH] configure.ac: Add support to enable read-only text segment on x86.

[Ian Romanick]

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

On 09/03/2015 09:36 PM, Matt Turner wrote:
> From: Jeremy Huddleston <jeremyhu at freedesktop.org>
> 
> Cc: "10.6 11.0" <mesa-stable at lists.freedesktop.org>
> Bugzilla: https://bugs.gentoo.org/240956
> ---
> After talking with Ian today, we determined that this disables an
> optimization.
> 
> And FWIW, NVIDIA's fork of glapi (libglvnd) contains this kind of
> writable-text optimization for x86-64.
> 
>  configure.ac | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/configure.ac b/configure.ac
> index 90ba4fe..259f770 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -1289,6 +1289,16 @@ AC_SUBST(GLX_TLS, ${GLX_USE_TLS})
>  AS_IF([test "x$GLX_USE_TLS" = xyes -a "x$ax_pthread_ok" = xyes],
>        [DEFINES="${DEFINES} -DGLX_USE_TLS"])
>  
> +dnl Read-only text section on x86 hardened platforms
> +AC_ARG_ENABLE([glx-read-only-text],
> +    [AS_HELP_STRING([--enable-glx-read-only-text],
> +        [Disable writable .text section on x86 (decreases performance) @<:@default=disabled@:>@])],
> +    [enable_glx_read_only_text="$enableval"],
> +    [enable_glx_read_only_text=no])
> +if test "x$enable_glx_read_only_text" = xyes; then
> +    DEFINES="$DEFINES -DGLX_X86_READONLY_TEXT"
> +fi
> +
>  dnl
>  dnl More DRI setup
>  dnl
>