openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user
pointers, v1 and v2, and swaps the words they point to in hand-written
assembly.

    l.lwz   r29,0(r4)
    l.lwz   r27,0(r5)
    l.sw    0(r4),r27
    l.sw    0(r5),r29

The pointers are not checked with access_ok(). The four memory
accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall
reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It
overwrites kernel data such as the sys_call_table, gaining code
execution in kernel context.

Check both pointers before entering the critical section. Add fixups
for the four memory accesses so faults on valid but unmapped user
addresses return -EFAULT.

[shorne@gmail.com: fix comment style]
Fixes: 9d02a4283e9c ("OpenRISC: Boot code")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Ahmet Memis <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/Documentation/gpu/intel-display/index.rst b/Documentation/gpu/intel-display/index.rst
new file mode 100644
index 000000000..01c3d1e57
--- /dev/null
+++ b/Documentation/gpu/intel-display/index.rst
@@ -0,0 +1,44 @@
+.. SPDX-License-Identifier: MIT
+.. Copyright © 2026 Intel Corporation
+
+.. _drm/intel-display:
+
+====================
+Intel Display Driver
+====================
+
+The Intel display driver provides the display, or :ref:`drm-kms`, support for
+both the :ref:`drm/xe <drm/xe>` and :ref:`drm/i915 <drm/i915>` Intel GPU
+drivers.
+
+The source code currently resides under ``drivers/gpu/drm/i915/display`` due to
+historical reasons, and it's compiled separately into both drm/xe and drm/i915
+kernel modules.
+
+The drm/xe and drm/i915 drivers are the "core" or "parent" drivers for display,
+as they initialize and own the drm device, and pass that on to the display
+driver. The display driver isn't an independent driver in that sense.
+
+.. toctree::
+   :maxdepth: 1
+   :caption: Detailed display topics
+
+   async-flip
+   atomic
+   audio
+   casf
+   cdclk
+   cmtg
+   dmc
+   dpio
+   dpll
+   drrs
+   dsb
+   fbc
+   fifo-underrun
+   frontbuffer
+   hotplug
+   plane
+   psr
+   snps-phy
+   vbt