V2 [PATCH] x86/CET: Document glibc.tune.x86_ibt and glibc.tune.x86_shstk

[Carlos O'Donell]

On 07/18/2018 01:27 PM, H.J. Lu wrote
> From ae2b7b566530aa6a83f6afe589245418d1946952 Mon Sep 17 00:00:00 2001
> From: "H.J. Lu" <hjl.tools@gmail.com>
> Date: Tue, 17 Jul 2018 19:51:23 -0700
> Subject: [PATCH] x86/CET: Document glibc.tune.x86_ibt and glibc.tune.x86_shstk
> 
> 	* manual/tunables.texi: Document glibc.tune.x86_ibt and
> 	glibc.tune.x86_shstk.
> ---

OK for 2.28.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

>  manual/tunables.texi | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/manual/tunables.texi b/manual/tunables.texi
> index be33c9fc79..bb4819bdf1 100644
> --- a/manual/tunables.texi
> +++ b/manual/tunables.texi
> @@ -356,3 +356,31 @@ to set threshold in bytes for non temporal store.
>  
>  This tunable is specific to i386 and x86-64.
>  @end deftp
> +
> +@deftp Tunable glibc.tune.x86_ibt
> +The @code{glibc.tune.x86_ibt} tunable allows the user to control how
> +indirect branch tracking (IBT) should be enabled.  Accepted values are
> +@code{on}, @code{off}, and @code{permissive}.  @code{on} always turns
> +on IBT regardless of whether IBT is enabled in the executable and its
> +dependent shared libraries.  @code{off} always turns off IBT regardless
> +of whether IBT is enabled in the executable and its dependent shared
> +libraries.  @code{permissive} is the same as the default which disables
> +IBT on non-CET executables and shared libraries.
> +

OK. Though I'm always squeamish about starting sentences with @code{foo}.

> +This tunable is specific to i386 and x86-64.
> +@end deftp
> +
> +@deftp Tunable glibc.tune.x86_shstk
> +The @code{glibc.tune.x86_shstk} tunable allows the user to control how
> +the shadow stack (SHSTK) should be enabled.  Accepted values are
> +@code{on}, @code{off}, and @code{permissive}.  @code{on} always turns on
> +SHSTK regardless of whether SHSTK is enabled in the executable and its
> +dependent shared libraries.  @code{off} always turns off SHSTK regardless
> +of whether SHSTK is enabled in the executable and its dependent shared
> +libraries.  @code{permissive} changes how dlopen works on non-CET shared
> +libraries.  By default, when SHSTK is enabled, dlopening a non-CET shared
> +library returns an error.  With @code{permissive}, it turns off SHSTK
> +instead.

OK.

> +
> +This tunable is specific to i386 and x86-64.
> +@end deftp
> -- 2.17.1


-- 
Cheers,
Carlos.