x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 516 insertions, 0 deletions

diff --git a/drivers/ssb/driver_gpio.c b/drivers/ssb/driver_gpio.c
new file mode 100644
index 000000000..879224799
--- /dev/null
+++ b/drivers/ssb/driver_gpio.c
@@ -0,0 +1,516 @@
+/*
+ * Sonics Silicon Backplane
+ * GPIO driver
+ *
+ * Copyright 2011, Broadcom Corporation
+ * Copyright 2012, Hauke Mehrtens <hauke@hauke-m.de>
+ *
+ * Licensed under the GNU/GPL. See COPYING for details.
+ */
+
+#include "ssb_private.h"
+
+#include <linux/gpio/driver.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/irqdomain.h>
+#include <linux/export.h>
+#include <linux/property.h>
+#include <linux/ssb/ssb.h>
+
+const struct software_node ssb_gpio_swnode = {
+	.name = "ssb-gpio",
+};
+EXPORT_SYMBOL_GPL(ssb_gpio_swnode);
+
+
+/**************************************************
+ * Shared
+ **************************************************/
+
+#if IS_ENABLED(CONFIG_SSB_EMBEDDED)
+static int ssb_gpio_to_irq(struct gpio_chip *chip, unsigned int gpio)
+{
+	struct ssb_bus *bus = gpiochip_get_data(chip);
+
+	if (bus->bustype == SSB_BUSTYPE_SSB)
+		return irq_find_mapping(bus->irq_domain, gpio);
+	else
+		return -EINVAL;
+}
+#endif
+
+/**************************************************
+ * ChipCommon
+ **************************************************/
+
+static int ssb_gpio_chipco_get_value(struct gpio_chip *chip, unsigned int gpio)
+{
+	struct ssb_bus *bus = gpiochip_get_data(chip);
+
+	return !!ssb_chipco_gpio_in(&bus->chipco, 1 << gpio);
+}
+
+static int ssb_gpio_chipco_set_value(struct gpio_chip *chip, unsigned int gpio,
+				     int value)
+{
+	struct ssb_bus *bus = gpiochip_get_data(chip);
+
+	ssb_chipco_gpio_out(&bus->chipco, 1 << gpio, value ? 1 << gpio : 0);
+
+	return 0;
+}
+
+static int ssb_gpio_chipco_direction_input(struct gpio_chip *chip,
+					   unsigned int gpio)
+{
+	struct ssb_bus *bus = gpiochip_get_data(chip);
+
+	ssb_chipco_gpio_outen(&bus->chipco, 1 << gpio, 0);
+	return 0;
+}
+
+static int ssb_gpio_chipco_direction_output(struct gpio_chip *chip,
+					    unsigned int gpio, int value)
+{
+	struct ssb_bus *bus = gpiochip_get_data(chip);
+
+	ssb_chipco_gpio_outen(&bus->chipco, 1 << gpio, 1 << gpio);
+	ssb_chipco_gpio_out(&bus->chipco, 1 << gpio, value ? 1 << gpio : 0);
+	return 0;
+}
+
+static int ssb_gpio_chipco_request(struct gpio_chip *chip, unsigned int gpio)
+{
+	struct ssb_bus *bus = gpiochip_get_data(chip);
+
+	ssb_chipco_gpio_control(&bus->chipco, 1 << gpio, 0);
+	/* clear pulldown */
+	ssb_chipco_gpio_pulldown(&bus->chipco, 1 << gpio, 0);
+	/* Set pullup */
+	ssb_chipco_gpio_pullup(&bus->chipco, 1 << gpio, 1 << gpio);
+
+	return 0;
+}
+
+static void ssb_gpio_chipco_free(struct gpio_chip *chip, unsigned int gpio)
+{
+	struct ssb_bus *bus = gpiochip_get_data(chip);
+
+	/* clear pullup */
+	ssb_chipco_gpio_pullup(&bus->chipco, 1 << gpio, 0);
+}
+
+#if IS_ENABLED(CONFIG_SSB_EMBEDDED)
+static void ssb_gpio_irq_chipco_mask(struct irq_data *d)
+{
+	struct ssb_bus *bus = irq_data_get_irq_chip_data(d);
+	int gpio = irqd_to_hwirq(d);
+
+	ssb_chipco_gpio_intmask(&bus->chipco, BIT(gpio), 0);
+}
+
+static void ssb_gpio_irq_chipco_unmask(struct irq_data *d)
+{
+	struct ssb_bus *bus = irq_data_get_irq_chip_data(d);
+	int gpio = irqd_to_hwirq(d);
+	u32 val = ssb_chipco_gpio_in(&bus->chipco, BIT(gpio));
+
+	ssb_chipco_gpio_polarity(&bus->chipco, BIT(gpio), val);
+	ssb_chipco_gpio_intmask(&bus->chipco, BIT(gpio), BIT(gpio));
+}
+
+static struct irq_chip ssb_gpio_irq_chipco_chip = {
+	.name		= "SSB-GPIO-CC",
+	.irq_mask	= ssb_gpio_irq_chipco_mask,
+	.irq_unmask	= ssb_gpio_irq_chipco_unmask,
+};
+
+static irqreturn_t ssb_gpio_irq_chipco_handler(int irq, void *dev_id)
+{
+	struct ssb_bus *bus = dev_id;
+	struct ssb_chipcommon *chipco = &bus->chipco;
+	u32 val = chipco_read32(chipco, SSB_CHIPCO_GPIOIN);
+	u32 mask = chipco_read32(chipco, SSB_CHIPCO_GPIOIRQ);
+	u32 pol = chipco_read32(chipco, SSB_CHIPCO_GPIOPOL);
+	unsigned long irqs = (val ^ pol) & mask;
+	int gpio;
+
+	if (!irqs)
+		return IRQ_NONE;
+
+	for_each_set_bit(gpio, &irqs, bus->gpio.ngpio)
+		generic_handle_domain_irq_safe(bus->irq_domain, gpio);
+
+	ssb_chipco_gpio_polarity(chipco, irqs, val & irqs);
+
+	return IRQ_HANDLED;
+}
+
+static int ssb_gpio_irq_chipco_domain_init(struct ssb_bus *bus)
+{
+	struct ssb_chipcommon *chipco = &bus->chipco;
+	struct gpio_chip *chip = &bus->gpio;
+	int gpio, hwirq, err;
+
+	if (bus->bustype != SSB_BUSTYPE_SSB)
+		return 0;
+
+	bus->irq_domain = irq_domain_create_linear(NULL, chip->ngpio, &irq_domain_simple_ops,
+						   chipco);
+	if (!bus->irq_domain) {
+		err = -ENODEV;
+		goto err_irq_domain;
+	}
+	for (gpio = 0; gpio < chip->ngpio; gpio++) {
+		int irq = irq_create_mapping(bus->irq_domain, gpio);
+
+		irq_set_chip_data(irq, bus);
+		irq_set_chip_and_handler(irq, &ssb_gpio_irq_chipco_chip,
+					 handle_simple_irq);
+	}
+
+	hwirq = ssb_mips_irq(bus->chipco.dev) + 2;
+	err = request_irq(hwirq, ssb_gpio_irq_chipco_handler, IRQF_SHARED,
+			  "gpio", bus);
+	if (err)
+		goto err_req_irq;
+
+	ssb_chipco_gpio_intmask(&bus->chipco, ~0, 0);
+	chipco_set32(chipco, SSB_CHIPCO_IRQMASK, SSB_CHIPCO_IRQ_GPIO);
+
+	return 0;
+
+err_req_irq:
+	for (gpio = 0; gpio < chip->ngpio; gpio++) {
+		int irq = irq_find_mapping(bus->irq_domain, gpio);
+
+		irq_dispose_mapping(irq);
+	}
+	irq_domain_remove(bus->irq_domain);
+err_irq_domain:
+	return err;
+}
+
+static void ssb_gpio_irq_chipco_domain_exit(struct ssb_bus *bus)
+{
+	struct ssb_chipcommon *chipco = &bus->chipco;
+	struct gpio_chip *chip = &bus->gpio;
+	int gpio;
+
+	if (bus->bustype != SSB_BUSTYPE_SSB)
+		return;
+
+	chipco_mask32(chipco, SSB_CHIPCO_IRQMASK, ~SSB_CHIPCO_IRQ_GPIO);
+	free_irq(ssb_mips_irq(bus->chipco.dev) + 2, chipco);
+	for (gpio = 0; gpio < chip->ngpio; gpio++) {
+		int irq = irq_find_mapping(bus->irq_domain, gpio);
+
+		irq_dispose_mapping(irq);
+	}
+	irq_domain_remove(bus->irq_domain);
+}
+#else
+static int ssb_gpio_irq_chipco_domain_init(struct ssb_bus *bus)
+{
+	return 0;
+}
+
+static void ssb_gpio_irq_chipco_domain_exit(struct ssb_bus *bus)
+{
+}
+#endif
+
+static int ssb_gpio_chipco_init(struct ssb_bus *bus)
+{
+	struct gpio_chip *chip = &bus->gpio;
+	int err;
+
+	chip->label		= "ssb_chipco_gpio";
+	chip->owner		= THIS_MODULE;
+	chip->request		= ssb_gpio_chipco_request;
+	chip->free		= ssb_gpio_chipco_free;
+	chip->get		= ssb_gpio_chipco_get_value;
+	chip->set		= ssb_gpio_chipco_set_value;
+	chip->direction_input	= ssb_gpio_chipco_direction_input;
+	chip->direction_output	= ssb_gpio_chipco_direction_output;
+#if IS_ENABLED(CONFIG_SSB_EMBEDDED)
+	chip->to_irq		= ssb_gpio_to_irq;
+#endif
+	chip->ngpio		= 16;
+	if (bus->bustype == SSB_BUSTYPE_SSB)
+		chip->fwnode	= software_node_fwnode(&ssb_gpio_swnode);
+	/* There is just one SoC in one device and its GPIO addresses should be
+	 * deterministic to address them more easily. The other buses could get
+	 * a random base number.
+	 */
+	if (bus->bustype == SSB_BUSTYPE_SSB)
+		chip->base		= 0;
+	else
+		chip->base		= -1;
+
+	err = ssb_gpio_irq_chipco_domain_init(bus);
+	if (err)
+		return err;
+
+	err = gpiochip_add_data(chip, bus);
+	if (err) {
+		ssb_gpio_irq_chipco_domain_exit(bus);
+		return err;
+	}
+
+	return 0;
+}
+
+/**************************************************
+ * EXTIF
+ **************************************************/
+
+#ifdef CONFIG_SSB_DRIVER_EXTIF
+
+static int ssb_gpio_extif_get_value(struct gpio_chip *chip, unsigned int gpio)
+{
+	struct ssb_bus *bus = gpiochip_get_data(chip);
+
+	return !!ssb_extif_gpio_in(&bus->extif, 1 << gpio);
+}
+
+static int ssb_gpio_extif_set_value(struct gpio_chip *chip, unsigned int gpio,
+				    int value)
+{
+	struct ssb_bus *bus = gpiochip_get_data(chip);
+
+	ssb_extif_gpio_out(&bus->extif, 1 << gpio, value ? 1 << gpio : 0);
+
+	return 0;
+}
+
+static int ssb_gpio_extif_direction_input(struct gpio_chip *chip,
+					  unsigned int gpio)
+{
+	struct ssb_bus *bus = gpiochip_get_data(chip);
+
+	ssb_extif_gpio_outen(&bus->extif, 1 << gpio, 0);
+	return 0;
+}
+
+static int ssb_gpio_extif_direction_output(struct gpio_chip *chip,
+					   unsigned int gpio, int value)
+{
+	struct ssb_bus *bus = gpiochip_get_data(chip);
+
+	ssb_extif_gpio_outen(&bus->extif, 1 << gpio, 1 << gpio);
+	ssb_extif_gpio_out(&bus->extif, 1 << gpio, value ? 1 << gpio : 0);
+	return 0;
+}
+
+#if IS_ENABLED(CONFIG_SSB_EMBEDDED)
+static void ssb_gpio_irq_extif_mask(struct irq_data *d)
+{
+	struct ssb_bus *bus = irq_data_get_irq_chip_data(d);
+	int gpio = irqd_to_hwirq(d);
+
+	ssb_extif_gpio_intmask(&bus->extif, BIT(gpio), 0);
+}
+
+static void ssb_gpio_irq_extif_unmask(struct irq_data *d)
+{
+	struct ssb_bus *bus = irq_data_get_irq_chip_data(d);
+	int gpio = irqd_to_hwirq(d);
+	u32 val = ssb_extif_gpio_in(&bus->extif, BIT(gpio));
+
+	ssb_extif_gpio_polarity(&bus->extif, BIT(gpio), val);
+	ssb_extif_gpio_intmask(&bus->extif, BIT(gpio), BIT(gpio));
+}
+
+static struct irq_chip ssb_gpio_irq_extif_chip = {
+	.name		= "SSB-GPIO-EXTIF",
+	.irq_mask	= ssb_gpio_irq_extif_mask,
+	.irq_unmask	= ssb_gpio_irq_extif_unmask,
+};
+
+static irqreturn_t ssb_gpio_irq_extif_handler(int irq, void *dev_id)
+{
+	struct ssb_bus *bus = dev_id;
+	struct ssb_extif *extif = &bus->extif;
+	u32 val = ssb_read32(extif->dev, SSB_EXTIF_GPIO_IN);
+	u32 mask = ssb_read32(extif->dev, SSB_EXTIF_GPIO_INTMASK);
+	u32 pol = ssb_read32(extif->dev, SSB_EXTIF_GPIO_INTPOL);
+	unsigned long irqs = (val ^ pol) & mask;
+	int gpio;
+
+	if (!irqs)
+		return IRQ_NONE;
+
+	for_each_set_bit(gpio, &irqs, bus->gpio.ngpio)
+		generic_handle_domain_irq_safe(bus->irq_domain, gpio);
+
+	ssb_extif_gpio_polarity(extif, irqs, val & irqs);
+
+	return IRQ_HANDLED;
+}
+
+static int ssb_gpio_irq_extif_domain_init(struct ssb_bus *bus)
+{
+	struct ssb_extif *extif = &bus->extif;
+	struct gpio_chip *chip = &bus->gpio;
+	int gpio, hwirq, err;
+
+	if (bus->bustype != SSB_BUSTYPE_SSB)
+		return 0;
+
+	bus->irq_domain = irq_domain_create_linear(NULL, chip->ngpio, &irq_domain_simple_ops,
+						   extif);
+	if (!bus->irq_domain) {
+		err = -ENODEV;
+		goto err_irq_domain;
+	}
+	for (gpio = 0; gpio < chip->ngpio; gpio++) {
+		int irq = irq_create_mapping(bus->irq_domain, gpio);
+
+		irq_set_chip_data(irq, bus);
+		irq_set_chip_and_handler(irq, &ssb_gpio_irq_extif_chip,
+					 handle_simple_irq);
+	}
+
+	hwirq = ssb_mips_irq(bus->extif.dev) + 2;
+	err = request_irq(hwirq, ssb_gpio_irq_extif_handler, IRQF_SHARED,
+			  "gpio", bus);
+	if (err)
+		goto err_req_irq;
+
+	ssb_extif_gpio_intmask(&bus->extif, ~0, 0);
+
+	return 0;
+
+err_req_irq:
+	for (gpio = 0; gpio < chip->ngpio; gpio++) {
+		int irq = irq_find_mapping(bus->irq_domain, gpio);
+
+		irq_dispose_mapping(irq);
+	}
+	irq_domain_remove(bus->irq_domain);
+err_irq_domain:
+	return err;
+}
+
+static void ssb_gpio_irq_extif_domain_exit(struct ssb_bus *bus)
+{
+	struct ssb_extif *extif = &bus->extif;
+	struct gpio_chip *chip = &bus->gpio;
+	int gpio;
+
+	if (bus->bustype != SSB_BUSTYPE_SSB)
+		return;
+
+	free_irq(ssb_mips_irq(bus->extif.dev) + 2, extif);
+	for (gpio = 0; gpio < chip->ngpio; gpio++) {
+		int irq = irq_find_mapping(bus->irq_domain, gpio);
+
+		irq_dispose_mapping(irq);
+	}
+	irq_domain_remove(bus->irq_domain);
+}
+#else
+static int ssb_gpio_irq_extif_domain_init(struct ssb_bus *bus)
+{
+	return 0;
+}
+
+static void ssb_gpio_irq_extif_domain_exit(struct ssb_bus *bus)
+{
+}
+#endif
+
+static int ssb_gpio_extif_init(struct ssb_bus *bus)
+{
+	struct gpio_chip *chip = &bus->gpio;
+	int err;
+
+	chip->label		= "ssb_extif_gpio";
+	chip->owner		= THIS_MODULE;
+	chip->get		= ssb_gpio_extif_get_value;
+	chip->set		= ssb_gpio_extif_set_value;
+	chip->direction_input	= ssb_gpio_extif_direction_input;
+	chip->direction_output	= ssb_gpio_extif_direction_output;
+#if IS_ENABLED(CONFIG_SSB_EMBEDDED)
+	chip->to_irq		= ssb_gpio_to_irq;
+#endif
+	chip->ngpio		= 5;
+	/* There is just one SoC in one device and its GPIO addresses should be
+	 * deterministic to address them more easily. The other buses could get
+	 * a random base number.
+	 */
+	if (bus->bustype == SSB_BUSTYPE_SSB) {
+		chip->base	= 0;
+		chip->fwnode	= software_node_fwnode(&ssb_gpio_swnode);
+	} else {
+		chip->base	= -1;
+	}
+
+	err = ssb_gpio_irq_extif_domain_init(bus);
+	if (err)
+		return err;
+
+	err = gpiochip_add_data(chip, bus);
+	if (err) {
+		ssb_gpio_irq_extif_domain_exit(bus);
+		return err;
+	}
+
+	return 0;
+}
+
+#else
+static int ssb_gpio_extif_init(struct ssb_bus *bus)
+{
+	return -ENOTSUPP;
+}
+#endif
+
+/**************************************************
+ * Init
+ **************************************************/
+
+int ssb_gpio_init(struct ssb_bus *bus)
+{
+	int err = 0;
+
+	/*
+	 * Register software node only for the host SoC bus. There is only
+	 * one SoC instance in the system, so there are no concerns with
+	 * registration conflicts.
+	 */
+	if (bus->bustype == SSB_BUSTYPE_SSB) {
+		err = software_node_register(&ssb_gpio_swnode);
+		if (err)
+			return err;
+	}
+
+	if (ssb_chipco_available(&bus->chipco))
+		err = ssb_gpio_chipco_init(bus);
+	else if (ssb_extif_available(&bus->extif))
+		err = ssb_gpio_extif_init(bus);
+	else
+		err = -ENODEV;
+
+	if (err) {
+		if (bus->bustype == SSB_BUSTYPE_SSB)
+			software_node_unregister(&ssb_gpio_swnode);
+		return err;
+	}
+
+	return 0;
+}
+
+int ssb_gpio_unregister(struct ssb_bus *bus)
+{
+	if (ssb_chipco_available(&bus->chipco) ||
+	    ssb_extif_available(&bus->extif)) {
+		gpiochip_remove(&bus->gpio);
+		if (bus->bustype == SSB_BUSTYPE_SSB)
+			software_node_unregister(&ssb_gpio_swnode);
+		return 0;
+	}
+	return -1;
+}