[PATCH] Add NEWS entry about the change in handling of PT_GNU_STACK on MIPS

[Dragan Mladjenovic]

From: "Dragan Mladjenovic" <dmladjenovic@wavecomp.com>

The change was introduced in:

commit 33bc9efd91de1b14354291fc8ebd5bce96379f12
Author: Dragan Mladjenovic <dmladjenovic@wavecomp.com>
Date:   Fri Aug 23 16:38:04 2019 +0000

    mips: Force RWX stack for hard-float builds that can run on pre-4.8 kernels

and probably requires a small explanation.
---
 NEWS | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/NEWS b/NEWS
index 44065d9..1e5dcf3 100644
--- a/NEWS
+++ b/NEWS
@@ -112,6 +112,18 @@ Deprecated and removed features, and other changes affecting compatibility:
   captured in a dlerror message.  In general, this is unsafe because
   resetting the stack in an arbitrary function call is not possible.
 
+* For the MIPS hard-float ABIs, the glibc will no longer honor RW PT_GNU_STACK
+  and will run on executable stack unless explicitly configured at build time
+  to require minimum kernel version 4.8 or newer. On Linux kernels prior to
+  4.8 executing floating-point branches on non-executable stack can
+  lead to application crashes for some MIPS configurations. While currently
+  the PT_GNU_STACK is not widely used on MIPS, the future releases of GCC are
+  expected to enable RW PT_GNU_STACK by default thus likely to trigger the
+  crash on older kernels.
+
+  The glibc can be built with --enable-kernel=4.8.0 in order to honor
+  RW PT_GNU_STACK while dropping support for older kernels.
+
 Changes to build and runtime requirements:
 
 * It is no longer necessary to have recent Linux kernel headers to build
-- 
1.9.1