ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faultsgrafted

When CONFIG_DEBUG_USER=y, and cmdline "user_debug=31" is set,
a user fault may trigger show_pte() without any lock.
If another thread in the same process concurrently calls munmap(),
the page table pages may be freed while show_pte() is still traversing
them, causing a use-after-free in show_pte().

If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table
of PMD are freed when show_pte() is running.

Acquire mmap_write_lock() around show_pte() for user faults to fix the
contention.

For user faults, additionally restrict that show_pte() is called only
when the addr is a user-space address (addr < TASK_SIZE). This is because
the lock of tsk->mm only protects the virtual memory of user address space,
furthermore, dumping the page tables of a kernel-space address for user
faults is unnecessary and may have security implications.

Keep everything unchanged for kernel faults, because the kernel is
already in the "oops" state, acquiring a lock may risk a deadlock.

Co-developed-by: Qi Xi <xiqi2@huawei.com>

Fixes: 6d021b724481 ("ARM: dump pgd, pmd and pte states on unhandled data abort faults")
Link: https://lore.kernel.org/20260716014022.2823-1-xieyuanbin1@huawei.com
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Qi Xi <xiqi2@huawei.com>
Signed-off-by: Xie Yuanbin <xieyuanbin1@huawei.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 140 insertions, 0 deletions

diff --git a/include/sound/hdmi-codec.h b/include/sound/hdmi-codec.h
new file mode 100644
index 000000000..273f4c36f
--- /dev/null
+++ b/include/sound/hdmi-codec.h
@@ -0,0 +1,140 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * hdmi-codec.h - HDMI Codec driver API
+ *
+ * Copyright (C) 2014 Texas Instruments Incorporated - https://www.ti.com
+ *
+ * Author: Jyri Sarha <jsarha@ti.com>
+ */
+
+#ifndef __HDMI_CODEC_H__
+#define __HDMI_CODEC_H__
+
+#include <linux/of_graph.h>
+#include <linux/hdmi.h>
+#include <sound/asoundef.h>
+#include <sound/soc.h>
+#include <uapi/sound/asound.h>
+
+/*
+ * Protocol between ASoC cpu-dai and HDMI-encoder
+ */
+struct hdmi_codec_daifmt {
+	enum {
+		HDMI_I2S,
+		HDMI_RIGHT_J,
+		HDMI_LEFT_J,
+		HDMI_DSP_A,
+		HDMI_DSP_B,
+		HDMI_AC97,
+		HDMI_SPDIF,
+	} fmt;
+	unsigned int bit_clk_inv:1;
+	unsigned int frame_clk_inv:1;
+	unsigned int bit_clk_provider:1;
+	unsigned int frame_clk_provider:1;
+	/* bit_fmt could be standard PCM format or
+	 * IEC958 encoded format. ALSA IEC958 plugin will pass
+	 * IEC958_SUBFRAME format to the underneath driver.
+	 */
+	snd_pcm_format_t bit_fmt;
+};
+
+/*
+ * HDMI audio parameters
+ */
+struct hdmi_codec_params {
+	struct hdmi_audio_infoframe cea;
+	struct snd_aes_iec958 iec;
+	int sample_rate;
+	int sample_width;
+	int channels;
+};
+
+typedef void (*hdmi_codec_plugged_cb)(struct device *dev,
+				      bool plugged);
+
+struct hdmi_codec_pdata;
+struct hdmi_codec_ops {
+	/*
+	 * Called when ASoC starts an audio stream setup.
+	 * Optional
+	 */
+	int (*audio_startup)(struct device *dev, void *data);
+
+	/*
+	 * Configures HDMI-encoder for audio stream.
+	 * Having either prepare or hw_params is mandatory.
+	 */
+	int (*hw_params)(struct device *dev, void *data,
+			 struct hdmi_codec_daifmt *fmt,
+			 struct hdmi_codec_params *hparms);
+
+	/*
+	 * Configures HDMI-encoder for audio stream. Can be called
+	 * multiple times for each setup.
+	 *
+	 * Having either prepare or hw_params is mandatory.
+	 */
+	int (*prepare)(struct device *dev, void *data,
+		       struct hdmi_codec_daifmt *fmt,
+		       struct hdmi_codec_params *hparms);
+
+	/*
+	 * Shuts down the audio stream.
+	 * Mandatory
+	 */
+	void (*audio_shutdown)(struct device *dev, void *data);
+
+	/*
+	 * Mute/unmute HDMI audio stream.
+	 * Optional
+	 */
+	int (*mute_stream)(struct device *dev, void *data,
+			   bool enable, int direction);
+
+	/*
+	 * Provides EDID-Like-Data from connected HDMI device.
+	 * Optional
+	 */
+	int (*get_eld)(struct device *dev, void *data,
+		       uint8_t *buf, size_t len);
+
+	/*
+	 * Getting DAI ID
+	 * Optional
+	 */
+	int (*get_dai_id)(struct snd_soc_component *comment,
+			  struct device_node *endpoint,
+			  void *data);
+
+	/*
+	 * Hook callback function to handle connector plug event.
+	 * Optional
+	 */
+	int (*hook_plugged_cb)(struct device *dev, void *data,
+			       hdmi_codec_plugged_cb fn,
+			       struct device *codec_dev);
+};
+
+/* HDMI codec initalization data */
+struct hdmi_codec_pdata {
+	const struct hdmi_codec_ops *ops;
+	u64 i2s_formats;
+	uint i2s:1;
+	uint no_i2s_playback:1;
+	uint no_i2s_capture:1;
+	uint spdif:1;
+	uint no_spdif_playback:1;
+	uint no_spdif_capture:1;
+	uint no_capture_mute:1;
+	int max_i2s_channels;
+	void *data;
+};
+
+struct snd_soc_component;
+struct snd_soc_jack;
+
+#define HDMI_CODEC_DRV_NAME "hdmi-audio-codec"
+
+#endif /* __HDMI_CODEC_H__ */