From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall 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 Signed-off-by: Stafford Horne --- Documentation/gpu/meson.rst | 55 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 Documentation/gpu/meson.rst (limited to 'Documentation/gpu/meson.rst') diff --git a/Documentation/gpu/meson.rst b/Documentation/gpu/meson.rst new file mode 100644 index 000000000..b9e2f9aa3 --- /dev/null +++ b/Documentation/gpu/meson.rst @@ -0,0 +1,55 @@ +============================================= +drm/meson AmLogic Meson Video Processing Unit +============================================= + +.. kernel-doc:: drivers/gpu/drm/meson/meson_drv.c + :doc: Video Processing Unit + +Video Processing Unit +===================== + +The Amlogic Meson Display controller is composed of several components +that are going to be documented below: + +.. code:: + + DMC|---------------VPU (Video Processing Unit)----------------|------HHI------| + | vd1 _______ _____________ _________________ | | + D |-------| |----| | | | | HDMI PLL | + D | vd2 | VIU | | Video Post | | Video Encoders |<---|-----VCLK | + R |-------| |----| Processing | | | | | + | osd2 | | | |---| Enci ----------|----|-----VDAC------| + R |-------| CSC |----| Scalers | | Encp ----------|----|----HDMI-TX----| + A | osd1 | | | Blenders | | Encl ----------|----|---------------| + M |-------|______|----|____________| |________________| | | + ___|__________________________________________________________|_______________| + +Video Input Unit +================ + +.. kernel-doc:: drivers/gpu/drm/meson/meson_viu.c + :doc: Video Input Unit + +Video Post Processing +===================== + +.. kernel-doc:: drivers/gpu/drm/meson/meson_vpp.c + :doc: Video Post Processing + +Video Encoder +============= + +.. kernel-doc:: drivers/gpu/drm/meson/meson_venc.c + :doc: Video Encoder + +Video Clocks +============ + +.. kernel-doc:: drivers/gpu/drm/meson/meson_vclk.c + :doc: Video Clocks + +HDMI Video Output +================= + +.. kernel-doc:: drivers/gpu/drm/meson/meson_dw_hdmi.c + :doc: HDMI Output -- cgit v1.3.1