[PATCH v6 14/14] aarch64: add NEWS entry about branch protection support

[Adhemerval Zanella]

On 01/07/2020 11:41, Szabolcs Nagy wrote:
> This is a new security feature that relies on architecture
> extensions and needs glibc to be built with a gcc configured
> with branch protection.
> ---
>  NEWS | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/NEWS b/NEWS
> index a660fc59a8..7d0ca3f520 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -31,6 +31,18 @@ Major new features:
>    pthread_attr_getsigmask_np have been added.  They allow applications
>    to specify the signal mask of a thread created with pthread_create.
>  
> +* AArch64 now supports standard branch protection security hardening
> +  in glibc when it is built with a GCC that is configured with
> +  --enable-standard-branch-protection. This includes branch target

Should we state that user can also set the required flags on compiler
specification as well (CC='gcc -mbranch-protection=pac-ret+bti -O2)?

> +  identification (BTI) and pointer authentication for return addresses
> +  (PAC-RET). They require armv8.5-a and armv8.3-a architecture

Two space after period.

> +  extensions respectively for the protection to be effective,
> +  otherwise the used instructions are nops. User code can use PAC-RET
> +  without libc support, but BTI requires a libc that is built with BTI
> +  support, otherwise runtime objects linked into user code will not be
> +  BTI compatible. It is recommended to use GCC 10 or newer when
> +  building glibc with branch protection.

Should we extend why gcc 10 is required here? This statement without much
explanation might raise some questioning. 

> +
>  Deprecated and removed features, and other changes affecting compatibility:
>  
>  * The deprecated <sys/sysctl.h> header and the sysctl function have been
>