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, 65 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-driver-ivpu b/Documentation/ABI/testing/sysfs-driver-ivpu
new file mode 100644
index 000000000..91685774e
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-ivpu
@@ -0,0 +1,65 @@
+What:		/sys/bus/pci/drivers/intel_vpu/.../npu_busy_time_us
+Date:		May 2024
+KernelVersion:	6.11
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Time in microseconds that the device spent executing jobs. The time is
+		counted when and only when there are jobs submitted to firmware. This time
+		can be used to measure the utilization of NPU, either by calculating the
+		difference between two timepoints or monitoring utilization percentage by
+		reading periodically. Recommended read period is 1 second to avoid impact
+		on job submission performance. Read-only.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../npu_memory_utilization
+Date:		Jan 2025
+KernelVersion:	6.15
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Current NPU memory utilization in bytes. Reports the total size of all
+		resident buffer objects allocated for NPU use. Read-only.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../freq/hw_min_freq
+Date:		April 2026
+KernelVersion:	7.2
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Minimum frequency in MHz supported by the NPU hardware. This is a
+		hardware capability and cannot be changed. Read-only.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../freq/hw_efficient_freq
+Date:		April 2026
+KernelVersion:	7.2
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Most efficient operating frequency in MHz for the NPU. This represents
+		the frequency at which the NPU operates most efficiently in terms of power
+		and performance. Read-only.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../freq/hw_max_freq
+Date:		April 2026
+KernelVersion:	7.2
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Maximum frequency in MHz supported by the NPU hardware. This is a
+		hardware capability and cannot be changed. Read-only.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../freq/current_freq
+Date:		April 2026
+KernelVersion:	7.2
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Current operating frequency in MHz of the NPU. The value is valid only
+		when the device is active; returns 0 when idle. The actual frequency may
+		be lower than the requested range due to power or thermal constraints.
+		Read-only.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../freq/set_min_freq
+Date:		April 2026
+KernelVersion:	7.2
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Configured minimum operating frequency in MHz (50XX devices and newer).
+		Values written are clamped to hardware limits (hw_min_freq to hw_max_freq).
+		If set_min_freq exceeds set_max_freq, the driver clamps set_min_freq to
+		set_max_freq when selecting the operating frequency. Read-write.
+
+What:		/sys/bus/pci/drivers/intel_vpu/.../freq/set_max_freq
+Date:		April 2026
+KernelVersion:	7.2
+Contact:	dri-devel@lists.freedesktop.org
+Description:	Configured maximum operating frequency in MHz (50XX devices and newer).
+		Values written are clamped to hardware limits (hw_min_freq to hw_max_freq).
+		Read-write.