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, 362 insertions, 0 deletions

diff --git a/drivers/mfd/sec-common.c b/drivers/mfd/sec-common.c
new file mode 100644
index 000000000..fe92bc4a3
--- /dev/null
+++ b/drivers/mfd/sec-common.c
@@ -0,0 +1,362 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2012 Samsung Electronics Co., Ltd
+ *                http://www.samsung.com
+ * Copyright 2025 Linaro Ltd.
+ *
+ * Samsung SxM core driver
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/samsung/core.h>
+#include <linux/mfd/samsung/irq.h>
+#include <linux/mfd/samsung/s2mps11.h>
+#include <linux/mfd/samsung/s2mps13.h>
+#include <linux/mfd/samsung/s2mu005.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include "sec-core.h"
+
+static const struct resource s5m8767_rtc_resources[] = {
+	DEFINE_RES_IRQ_NAMED(S5M8767_IRQ_RTCA1, "alarm"),
+};
+
+static const struct mfd_cell s5m8767_devs[] = {
+	MFD_CELL_NAME("s5m8767-pmic"),
+	MFD_CELL_RES("s5m-rtc", s5m8767_rtc_resources),
+	MFD_CELL_OF("s5m8767-clk", NULL, NULL, 0, 0, "samsung,s5m8767-clk"),
+};
+
+static const struct mfd_cell s2dos05_devs[] = {
+	MFD_CELL_NAME("s2dos05-regulator"),
+};
+
+static const struct resource s2mpg10_rtc_resources[] = {
+	DEFINE_RES_IRQ_NAMED(S2MPG10_IRQ_RTCA0, "alarm"),
+};
+
+static const struct mfd_cell s2mpg10_devs[] = {
+	MFD_CELL_NAME("s2mpg10-meter"),
+	MFD_CELL_NAME("s2mpg10-regulator"),
+	MFD_CELL_RES("s2mpg10-rtc", s2mpg10_rtc_resources),
+	MFD_CELL_OF("s2mpg10-clk", NULL, NULL, 0, 0, "samsung,s2mpg10-clk"),
+	MFD_CELL_OF("s2mpg10-gpio", NULL, NULL, 0, 0, "samsung,s2mpg10-gpio"),
+};
+
+static const struct mfd_cell s2mpg11_devs[] = {
+	MFD_CELL_NAME("s2mpg11-meter"),
+	MFD_CELL_NAME("s2mpg11-regulator"),
+	MFD_CELL_OF("s2mpg11-gpio", NULL, NULL, 0, 0, "samsung,s2mpg11-gpio"),
+};
+
+static const struct resource s2mps11_rtc_resources[] = {
+	DEFINE_RES_IRQ_NAMED(S2MPS11_IRQ_RTCA0, "alarm"),
+};
+
+static const struct mfd_cell s2mps11_devs[] = {
+	MFD_CELL_NAME("s2mps11-regulator"),
+	MFD_CELL_RES("s2mps14-rtc", s2mps11_rtc_resources),
+	MFD_CELL_OF("s2mps11-clk", NULL, NULL, 0, 0, "samsung,s2mps11-clk"),
+};
+
+static const struct resource s2mps14_rtc_resources[] = {
+	DEFINE_RES_IRQ_NAMED(S2MPS14_IRQ_RTCA0, "alarm"),
+};
+
+static const struct mfd_cell s2mps13_devs[] = {
+	MFD_CELL_NAME("s2mps13-regulator"),
+	MFD_CELL_RES("s2mps13-rtc", s2mps14_rtc_resources),
+	MFD_CELL_OF("s2mps13-clk", NULL, NULL, 0, 0, "samsung,s2mps13-clk"),
+};
+
+static const struct mfd_cell s2mps14_devs[] = {
+	MFD_CELL_NAME("s2mps14-regulator"),
+	MFD_CELL_RES("s2mps14-rtc", s2mps14_rtc_resources),
+	MFD_CELL_OF("s2mps14-clk", NULL, NULL, 0, 0, "samsung,s2mps14-clk"),
+};
+
+static const struct mfd_cell s2mps15_devs[] = {
+	MFD_CELL_NAME("s2mps15-regulator"),
+	MFD_CELL_RES("s2mps15-rtc", s2mps14_rtc_resources),
+	MFD_CELL_OF("s2mps13-clk", NULL, NULL, 0, 0, "samsung,s2mps13-clk"),
+};
+
+static const struct mfd_cell s2mpa01_devs[] = {
+	MFD_CELL_NAME("s2mpa01-pmic"),
+	MFD_CELL_RES("s2mps14-rtc", s2mps14_rtc_resources),
+};
+
+static const struct mfd_cell s2mpu02_devs[] = {
+	MFD_CELL_NAME("s2mpu02-regulator"),
+};
+
+static const struct resource s2mpu05_rtc_resources[] = {
+	DEFINE_RES_IRQ_NAMED(S2MPU05_IRQ_RTCA0, "alarm"),
+};
+
+static const struct mfd_cell s2mpu05_devs[] = {
+	MFD_CELL_NAME("s2mpu05-regulator"),
+	MFD_CELL_RES("s2mps15-rtc", s2mpu05_rtc_resources),
+};
+
+static const struct resource s2mu005_muic_resources[] = {
+	DEFINE_RES_IRQ_NAMED(S2MU005_IRQ_MUIC_ATTACH, "attach"),
+	DEFINE_RES_IRQ_NAMED(S2MU005_IRQ_MUIC_DETACH, "detach"),
+};
+
+static const struct mfd_cell s2mu005_devs[] = {
+	MFD_CELL_NAME("s2mu005-charger"),
+	MFD_CELL_OF("s2mu005-flash", NULL, NULL, 0, 0, "samsung,s2mu005-flash"),
+	MFD_CELL_OF("s2mu005-muic", s2mu005_muic_resources, NULL, 0, 0, "samsung,s2mu005-muic"),
+	MFD_CELL_OF("s2mu005-rgb", NULL, NULL, 0, 0, "samsung,s2mu005-rgb"),
+};
+
+static void sec_pmic_dump_rev(struct sec_pmic_dev *sec_pmic)
+{
+	unsigned int reg, mask, val;
+
+	switch (sec_pmic->device_type) {
+	case S2MPG10:
+	case S2MPG11:
+		/* For s2mpg1x, the revision is in a different regmap */
+		return;
+	case S2MU005:
+		reg = S2MU005_REG_ID;
+		mask = S2MU005_ID_MASK;
+		break;
+	default:
+		/* For other device types, REG_ID is always the first register. */
+		reg = S2MPS11_REG_ID;
+		mask = ~0;
+	}
+
+	if (!regmap_read(sec_pmic->regmap_pmic, reg, &val))
+		dev_dbg(sec_pmic->dev, "Revision: 0x%x\n", field_get(mask, val));
+}
+
+static void sec_pmic_configure(struct sec_pmic_dev *sec_pmic)
+{
+	int err;
+
+	if (sec_pmic->device_type != S2MPS13X)
+		return;
+
+	if (sec_pmic->pdata->disable_wrstbi) {
+		/*
+		 * If WRSTBI pin is pulled down this feature must be disabled
+		 * because each Suspend to RAM will trigger buck voltage reset
+		 * to default values.
+		 */
+		err = regmap_update_bits(sec_pmic->regmap_pmic,
+					 S2MPS13_REG_WRSTBI,
+					 S2MPS13_REG_WRSTBI_MASK, 0x0);
+		if (err)
+			dev_warn(sec_pmic->dev,
+				 "Cannot initialize WRSTBI config: %d\n",
+				 err);
+	}
+}
+
+/*
+ * Only the common platform data elements for s5m8767 are parsed here from the
+ * device tree. Other sub-modules of s5m8767 such as pmic, rtc , charger and
+ * others have to parse their own platform data elements from device tree.
+ *
+ * The s5m8767 platform data structure is instantiated here and the drivers for
+ * the sub-modules need not instantiate another instance while parsing their
+ * platform data.
+ */
+static struct sec_platform_data *
+sec_pmic_parse_dt_pdata(struct device *dev)
+{
+	struct sec_platform_data *pd;
+
+	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
+	if (!pd)
+		return ERR_PTR(-ENOMEM);
+
+	pd->manual_poweroff = of_property_read_bool(dev->of_node,
+						    "samsung,s2mps11-acokb-ground");
+	pd->disable_wrstbi = of_property_read_bool(dev->of_node,
+						   "samsung,s2mps11-wrstbi-ground");
+	return pd;
+}
+
+int sec_pmic_probe(struct device *dev, int device_type, unsigned int irq,
+		   struct regmap *regmap, struct i2c_client *client)
+{
+	struct regmap_irq_chip_data *irq_data;
+	struct sec_platform_data *pdata;
+	const struct mfd_cell *sec_devs;
+	struct sec_pmic_dev *sec_pmic;
+	int ret, num_sec_devs;
+
+	sec_pmic = devm_kzalloc(dev, sizeof(*sec_pmic), GFP_KERNEL);
+	if (!sec_pmic)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, sec_pmic);
+	sec_pmic->dev = dev;
+	sec_pmic->device_type = device_type;
+	sec_pmic->i2c = client;
+	sec_pmic->irq = irq;
+	sec_pmic->regmap_pmic = regmap;
+
+	pdata = sec_pmic_parse_dt_pdata(sec_pmic->dev);
+	if (IS_ERR(pdata)) {
+		ret = PTR_ERR(pdata);
+		return ret;
+	}
+
+	sec_pmic->pdata = pdata;
+
+	irq_data = sec_irq_init(sec_pmic);
+	if (IS_ERR(irq_data))
+		return PTR_ERR(irq_data);
+
+	dev->coherent_dma_mask = 0;
+	dev->dma_mask = &dev->coherent_dma_mask;
+
+	pm_runtime_set_active(sec_pmic->dev);
+
+	switch (sec_pmic->device_type) {
+	case S5M8767X:
+		sec_devs = s5m8767_devs;
+		num_sec_devs = ARRAY_SIZE(s5m8767_devs);
+		break;
+	case S2DOS05:
+		sec_devs = s2dos05_devs;
+		num_sec_devs = ARRAY_SIZE(s2dos05_devs);
+		break;
+	case S2MPA01:
+		sec_devs = s2mpa01_devs;
+		num_sec_devs = ARRAY_SIZE(s2mpa01_devs);
+		break;
+	case S2MPG10:
+		sec_devs = s2mpg10_devs;
+		num_sec_devs = ARRAY_SIZE(s2mpg10_devs);
+		break;
+	case S2MPG11:
+		sec_devs = s2mpg11_devs;
+		num_sec_devs = ARRAY_SIZE(s2mpg11_devs);
+		break;
+	case S2MPS11X:
+		sec_devs = s2mps11_devs;
+		num_sec_devs = ARRAY_SIZE(s2mps11_devs);
+		break;
+	case S2MPS13X:
+		sec_devs = s2mps13_devs;
+		num_sec_devs = ARRAY_SIZE(s2mps13_devs);
+		break;
+	case S2MPS14X:
+		sec_devs = s2mps14_devs;
+		num_sec_devs = ARRAY_SIZE(s2mps14_devs);
+		break;
+	case S2MPS15X:
+		sec_devs = s2mps15_devs;
+		num_sec_devs = ARRAY_SIZE(s2mps15_devs);
+		break;
+	case S2MPU02:
+		sec_devs = s2mpu02_devs;
+		num_sec_devs = ARRAY_SIZE(s2mpu02_devs);
+		break;
+	case S2MPU05:
+		sec_devs = s2mpu05_devs;
+		num_sec_devs = ARRAY_SIZE(s2mpu05_devs);
+		break;
+	case S2MU005:
+		sec_devs = s2mu005_devs;
+		num_sec_devs = ARRAY_SIZE(s2mu005_devs);
+		break;
+	default:
+		return dev_err_probe(sec_pmic->dev, -EINVAL,
+				     "Unsupported device type %d\n",
+				     sec_pmic->device_type);
+	}
+	ret = devm_mfd_add_devices(sec_pmic->dev, -1, sec_devs, num_sec_devs,
+				   NULL, 0, regmap_irq_get_domain(irq_data));
+	if (ret)
+		return ret;
+
+	sec_pmic_configure(sec_pmic);
+	sec_pmic_dump_rev(sec_pmic);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sec_pmic_probe);
+
+void sec_pmic_shutdown(struct device *dev)
+{
+	struct sec_pmic_dev *sec_pmic = dev_get_drvdata(dev);
+	unsigned int reg, mask;
+
+	if (!sec_pmic->pdata->manual_poweroff)
+		return;
+
+	switch (sec_pmic->device_type) {
+	case S2MPS11X:
+		reg = S2MPS11_REG_CTRL1;
+		mask = S2MPS11_CTRL1_PWRHOLD_MASK;
+		break;
+	default:
+		/*
+		 * Currently only one board with S2MPS11 needs this, so just
+		 * ignore the rest.
+		 */
+		dev_warn(sec_pmic->dev,
+			 "Unsupported device %d for manual power off\n",
+			 sec_pmic->device_type);
+		return;
+	}
+
+	regmap_update_bits(sec_pmic->regmap_pmic, reg, mask, 0);
+}
+EXPORT_SYMBOL_GPL(sec_pmic_shutdown);
+
+static int sec_pmic_suspend(struct device *dev)
+{
+	struct sec_pmic_dev *sec_pmic = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(sec_pmic->irq);
+	/*
+	 * PMIC IRQ must be disabled during suspend for RTC alarm
+	 * to work properly.
+	 * When device is woken up from suspend, an
+	 * interrupt occurs before resuming I2C bus controller.
+	 * The interrupt is handled by regmap_irq_thread which tries
+	 * to read RTC registers. This read fails (I2C is still
+	 * suspended) and RTC Alarm interrupt is disabled.
+	 */
+	disable_irq(sec_pmic->irq);
+
+	return 0;
+}
+
+static int sec_pmic_resume(struct device *dev)
+{
+	struct sec_pmic_dev *sec_pmic = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(sec_pmic->irq);
+	enable_irq(sec_pmic->irq);
+
+	return 0;
+}
+
+DEFINE_SIMPLE_DEV_PM_OPS(sec_pmic_pm_ops, sec_pmic_suspend, sec_pmic_resume);
+EXPORT_SYMBOL_GPL(sec_pmic_pm_ops);
+
+MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
+MODULE_AUTHOR("Krzysztof Kozlowski <krzk@kernel.org>");
+MODULE_AUTHOR("Sangbeom Kim <sbkim73@samsung.com>");
+MODULE_AUTHOR("André Draszik <andre.draszik@linaro.org>");
+MODULE_DESCRIPTION("Core driver for the Samsung S5M");
+MODULE_LICENSE("GPL");