aarch64: update NEWS about branch protection

After some discussions it seems the original news was not clear
and that it is valid to manually pass the branch protection flags
iff GCC target libs are built with them too. The main difference
between manually passing the flags and using the configure
option is that the latter also makes branch protection the
default in GCC which may not be desirable in some cases.

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

diff --git a/NEWS b/NEWS
index 7454a4bfa077884a9d1fba8782b3989b081c6928..e48d7438e27e4c14e097c373468ef6ccee2a2df7 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -70,7 +70,9 @@ Major new features:
 
 * 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
+  --enable-standard-branch-protection (or if -mbranch-protection=standard
+  flag is passed when building both GCC target libraries and glibc,
+  in either case a custom GCC is needed).  This includes branch target
   identification (BTI) and pointer authentication for return addresses
   (PAC-RET).  They require armv8.5-a and armv8.3-a architecture
   extensions respectively for the protection to be effective,