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, 447 insertions, 0 deletions

diff --git a/drivers/video/backlight/tdo24m.c b/drivers/video/backlight/tdo24m.c
new file mode 100644
index 000000000..c04ee3d04
--- /dev/null
+++ b/drivers/video/backlight/tdo24m.c
@@ -0,0 +1,447 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * tdo24m - SPI-based drivers for Toppoly TDO24M series LCD panels
+ *
+ * Copyright (C) 2008 Marvell International Ltd.
+ *	Eric Miao <eric.miao@marvell.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/tdo24m.h>
+#include <linux/lcd.h>
+#include <linux/slab.h>
+
+#define POWER_IS_ON(pwr)	((pwr) <= LCD_POWER_REDUCED)
+
+#define TDO24M_SPI_BUFF_SIZE	(4)
+#define MODE_QVGA	0
+#define MODE_VGA	1
+
+struct tdo24m {
+	struct spi_device	*spi_dev;
+	struct lcd_device	*lcd_dev;
+
+	struct spi_message	msg;
+	struct spi_transfer	xfer;
+	uint8_t			*buf;
+
+	int (*adj_mode)(struct tdo24m *lcd, int mode);
+	int color_invert;
+
+	int			power;
+	int			mode;
+};
+
+/* use bit 30, 31 as the indicator of command parameter number */
+#define CMD0(x)		((0 << 30) | (x))
+#define CMD1(x, x1)	((1 << 30) | ((x) << 9) | 0x100 | (x1))
+#define CMD2(x, x1, x2)	((2 << 30) | ((x) << 18) | 0x20000 |\
+			((x1) << 9) | 0x100 | (x2))
+#define CMD_NULL	(-1)
+
+static const uint32_t lcd_panel_reset[] = {
+	CMD0(0x1), /* reset */
+	CMD0(0x0), /* nop */
+	CMD0(0x0), /* nop */
+	CMD0(0x0), /* nop */
+	CMD_NULL,
+};
+
+static const uint32_t lcd_panel_on[] = {
+	CMD0(0x29),		/* Display ON */
+	CMD2(0xB8, 0xFF, 0xF9),	/* Output Control */
+	CMD0(0x11),		/* Sleep out */
+	CMD1(0xB0, 0x16),	/* Wake */
+	CMD_NULL,
+};
+
+static const uint32_t lcd_panel_off[] = {
+	CMD0(0x28),		/* Display OFF */
+	CMD2(0xB8, 0x80, 0x02),	/* Output Control */
+	CMD0(0x10),		/* Sleep in */
+	CMD1(0xB0, 0x00),	/* Deep stand by in */
+	CMD_NULL,
+};
+
+static const uint32_t lcd_vga_pass_through_tdo24m[] = {
+	CMD1(0xB0, 0x16),
+	CMD1(0xBC, 0x80),
+	CMD1(0xE1, 0x00),
+	CMD1(0x36, 0x50),
+	CMD1(0x3B, 0x00),
+	CMD_NULL,
+};
+
+static const uint32_t lcd_qvga_pass_through_tdo24m[] = {
+	CMD1(0xB0, 0x16),
+	CMD1(0xBC, 0x81),
+	CMD1(0xE1, 0x00),
+	CMD1(0x36, 0x50),
+	CMD1(0x3B, 0x22),
+	CMD_NULL,
+};
+
+static const uint32_t lcd_vga_transfer_tdo24m[] = {
+	CMD1(0xcf, 0x02),	/* Blanking period control (1) */
+	CMD2(0xd0, 0x08, 0x04),	/* Blanking period control (2) */
+	CMD1(0xd1, 0x01),	/* CKV timing control on/off */
+	CMD2(0xd2, 0x14, 0x00),	/* CKV 1,2 timing control */
+	CMD2(0xd3, 0x1a, 0x0f),	/* OEV timing control */
+	CMD2(0xd4, 0x1f, 0xaf),	/* ASW timing control (1) */
+	CMD1(0xd5, 0x14),	/* ASW timing control (2) */
+	CMD0(0x21),		/* Invert for normally black display */
+	CMD0(0x29),		/* Display on */
+	CMD_NULL,
+};
+
+static const uint32_t lcd_qvga_transfer[] = {
+	CMD1(0xd6, 0x02),	/* Blanking period control (1) */
+	CMD2(0xd7, 0x08, 0x04),	/* Blanking period control (2) */
+	CMD1(0xd8, 0x01),	/* CKV timing control on/off */
+	CMD2(0xd9, 0x00, 0x08),	/* CKV 1,2 timing control */
+	CMD2(0xde, 0x05, 0x0a),	/* OEV timing control */
+	CMD2(0xdf, 0x0a, 0x19),	/* ASW timing control (1) */
+	CMD1(0xe0, 0x0a),	/* ASW timing control (2) */
+	CMD0(0x21),		/* Invert for normally black display */
+	CMD0(0x29),		/* Display on */
+	CMD_NULL,
+};
+
+static const uint32_t lcd_vga_pass_through_tdo35s[] = {
+	CMD1(0xB0, 0x16),
+	CMD1(0xBC, 0x80),
+	CMD1(0xE1, 0x00),
+	CMD1(0x3B, 0x00),
+	CMD_NULL,
+};
+
+static const uint32_t lcd_qvga_pass_through_tdo35s[] = {
+	CMD1(0xB0, 0x16),
+	CMD1(0xBC, 0x81),
+	CMD1(0xE1, 0x00),
+	CMD1(0x3B, 0x22),
+	CMD_NULL,
+};
+
+static const uint32_t lcd_vga_transfer_tdo35s[] = {
+	CMD1(0xcf, 0x02),	/* Blanking period control (1) */
+	CMD2(0xd0, 0x08, 0x04),	/* Blanking period control (2) */
+	CMD1(0xd1, 0x01),	/* CKV timing control on/off */
+	CMD2(0xd2, 0x00, 0x1e),	/* CKV 1,2 timing control */
+	CMD2(0xd3, 0x14, 0x28),	/* OEV timing control */
+	CMD2(0xd4, 0x28, 0x64),	/* ASW timing control (1) */
+	CMD1(0xd5, 0x28),	/* ASW timing control (2) */
+	CMD0(0x21),		/* Invert for normally black display */
+	CMD0(0x29),		/* Display on */
+	CMD_NULL,
+};
+
+static const uint32_t lcd_panel_config[] = {
+	CMD2(0xb8, 0xff, 0xf9),	/* Output control */
+	CMD0(0x11),		/* sleep out */
+	CMD1(0xba, 0x01),	/* Display mode (1) */
+	CMD1(0xbb, 0x00),	/* Display mode (2) */
+	CMD1(0x3a, 0x60),	/* Display mode 18-bit RGB */
+	CMD1(0xbf, 0x10),	/* Drive system change control */
+	CMD1(0xb1, 0x56),	/* Booster operation setup */
+	CMD1(0xb2, 0x33),	/* Booster mode setup */
+	CMD1(0xb3, 0x11),	/* Booster frequency setup */
+	CMD1(0xb4, 0x02),	/* Op amp/system clock */
+	CMD1(0xb5, 0x35),	/* VCS voltage */
+	CMD1(0xb6, 0x40),	/* VCOM voltage */
+	CMD1(0xb7, 0x03),	/* External display signal */
+	CMD1(0xbd, 0x00),	/* ASW slew rate */
+	CMD1(0xbe, 0x00),	/* Dummy data for QuadData operation */
+	CMD1(0xc0, 0x11),	/* Sleep out FR count (A) */
+	CMD1(0xc1, 0x11),	/* Sleep out FR count (B) */
+	CMD1(0xc2, 0x11),	/* Sleep out FR count (C) */
+	CMD2(0xc3, 0x20, 0x40),	/* Sleep out FR count (D) */
+	CMD2(0xc4, 0x60, 0xc0),	/* Sleep out FR count (E) */
+	CMD2(0xc5, 0x10, 0x20),	/* Sleep out FR count (F) */
+	CMD1(0xc6, 0xc0),	/* Sleep out FR count (G) */
+	CMD2(0xc7, 0x33, 0x43),	/* Gamma 1 fine tuning (1) */
+	CMD1(0xc8, 0x44),	/* Gamma 1 fine tuning (2) */
+	CMD1(0xc9, 0x33),	/* Gamma 1 inclination adjustment */
+	CMD1(0xca, 0x00),	/* Gamma 1 blue offset adjustment */
+	CMD2(0xec, 0x01, 0xf0),	/* Horizontal clock cycles */
+	CMD_NULL,
+};
+
+static int tdo24m_writes(struct tdo24m *lcd, const uint32_t *array)
+{
+	struct spi_transfer *x = &lcd->xfer;
+	const uint32_t *p = array;
+	uint32_t data;
+	int nparams, err = 0;
+
+	for (; *p != CMD_NULL; p++) {
+		if (!lcd->color_invert && *p == CMD0(0x21))
+			continue;
+
+		nparams = (*p >> 30) & 0x3;
+
+		data = *p << (7 - nparams);
+		switch (nparams) {
+		case 0:
+			lcd->buf[0] = (data >> 8) & 0xff;
+			lcd->buf[1] = data & 0xff;
+			break;
+		case 1:
+			lcd->buf[0] = (data >> 16) & 0xff;
+			lcd->buf[1] = (data >> 8) & 0xff;
+			lcd->buf[2] = data & 0xff;
+			break;
+		case 2:
+			lcd->buf[0] = (data >> 24) & 0xff;
+			lcd->buf[1] = (data >> 16) & 0xff;
+			lcd->buf[2] = (data >> 8) & 0xff;
+			lcd->buf[3] = data & 0xff;
+			break;
+		default:
+			continue;
+		}
+		x->len = nparams + 2;
+		err = spi_sync(lcd->spi_dev, &lcd->msg);
+		if (err)
+			break;
+	}
+
+	return err;
+}
+
+static int tdo24m_adj_mode(struct tdo24m *lcd, int mode)
+{
+	switch (mode) {
+	case MODE_VGA:
+		tdo24m_writes(lcd, lcd_vga_pass_through_tdo24m);
+		tdo24m_writes(lcd, lcd_panel_config);
+		tdo24m_writes(lcd, lcd_vga_transfer_tdo24m);
+		break;
+	case MODE_QVGA:
+		tdo24m_writes(lcd, lcd_qvga_pass_through_tdo24m);
+		tdo24m_writes(lcd, lcd_panel_config);
+		tdo24m_writes(lcd, lcd_qvga_transfer);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	lcd->mode = mode;
+	return 0;
+}
+
+static int tdo35s_adj_mode(struct tdo24m *lcd, int mode)
+{
+	switch (mode) {
+	case MODE_VGA:
+		tdo24m_writes(lcd, lcd_vga_pass_through_tdo35s);
+		tdo24m_writes(lcd, lcd_panel_config);
+		tdo24m_writes(lcd, lcd_vga_transfer_tdo35s);
+		break;
+	case MODE_QVGA:
+		tdo24m_writes(lcd, lcd_qvga_pass_through_tdo35s);
+		tdo24m_writes(lcd, lcd_panel_config);
+		tdo24m_writes(lcd, lcd_qvga_transfer);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	lcd->mode = mode;
+	return 0;
+}
+
+static int tdo24m_power_on(struct tdo24m *lcd)
+{
+	int err;
+
+	err = tdo24m_writes(lcd, lcd_panel_on);
+	if (err)
+		goto out;
+
+	err = tdo24m_writes(lcd, lcd_panel_reset);
+	if (err)
+		goto out;
+
+	err = lcd->adj_mode(lcd, lcd->mode);
+out:
+	return err;
+}
+
+static int tdo24m_power_off(struct tdo24m *lcd)
+{
+	return tdo24m_writes(lcd, lcd_panel_off);
+}
+
+static int tdo24m_power(struct tdo24m *lcd, int power)
+{
+	int ret = 0;
+
+	if (POWER_IS_ON(power) && !POWER_IS_ON(lcd->power))
+		ret = tdo24m_power_on(lcd);
+	else if (!POWER_IS_ON(power) && POWER_IS_ON(lcd->power))
+		ret = tdo24m_power_off(lcd);
+
+	if (!ret)
+		lcd->power = power;
+
+	return ret;
+}
+
+
+static int tdo24m_set_power(struct lcd_device *ld, int power)
+{
+	struct tdo24m *lcd = lcd_get_data(ld);
+
+	return tdo24m_power(lcd, power);
+}
+
+static int tdo24m_get_power(struct lcd_device *ld)
+{
+	struct tdo24m *lcd = lcd_get_data(ld);
+
+	return lcd->power;
+}
+
+static int tdo24m_set_mode(struct lcd_device *ld, u32 xres, u32 yres)
+{
+	struct tdo24m *lcd = lcd_get_data(ld);
+	int mode = MODE_QVGA;
+
+	if (xres == 640 || xres == 480)
+		mode = MODE_VGA;
+
+	if (lcd->mode == mode)
+		return 0;
+
+	return lcd->adj_mode(lcd, mode);
+}
+
+static const struct lcd_ops tdo24m_ops = {
+	.get_power	= tdo24m_get_power,
+	.set_power	= tdo24m_set_power,
+	.set_mode	= tdo24m_set_mode,
+};
+
+static int tdo24m_probe(struct spi_device *spi)
+{
+	struct tdo24m *lcd;
+	struct spi_message *m;
+	struct spi_transfer *x;
+	struct tdo24m_platform_data *pdata;
+	enum tdo24m_model model;
+	int err;
+
+	pdata = dev_get_platdata(&spi->dev);
+	if (pdata)
+		model = pdata->model;
+	else
+		model = TDO24M;
+
+	spi->bits_per_word = 8;
+	spi->mode = SPI_MODE_3;
+	err = spi_setup(spi);
+	if (err)
+		return err;
+
+	lcd = devm_kzalloc(&spi->dev, sizeof(struct tdo24m), GFP_KERNEL);
+	if (!lcd)
+		return -ENOMEM;
+
+	lcd->spi_dev = spi;
+	lcd->power = LCD_POWER_OFF;
+	lcd->mode = MODE_VGA;	/* default to VGA */
+
+	lcd->buf = devm_kzalloc(&spi->dev, TDO24M_SPI_BUFF_SIZE, GFP_KERNEL);
+	if (lcd->buf == NULL)
+		return -ENOMEM;
+
+	m = &lcd->msg;
+	x = &lcd->xfer;
+
+	spi_message_init(m);
+
+	x->cs_change = 0;
+	x->tx_buf = &lcd->buf[0];
+	spi_message_add_tail(x, m);
+
+	switch (model) {
+	case TDO24M:
+		lcd->color_invert = 1;
+		lcd->adj_mode = tdo24m_adj_mode;
+		break;
+	case TDO35S:
+		lcd->adj_mode = tdo35s_adj_mode;
+		lcd->color_invert = 0;
+		break;
+	default:
+		dev_err(&spi->dev, "Unsupported model");
+		return -EINVAL;
+	}
+
+	lcd->lcd_dev = devm_lcd_device_register(&spi->dev, "tdo24m", &spi->dev,
+						lcd, &tdo24m_ops);
+	if (IS_ERR(lcd->lcd_dev))
+		return PTR_ERR(lcd->lcd_dev);
+
+	spi_set_drvdata(spi, lcd);
+	err = tdo24m_power(lcd, LCD_POWER_ON);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static void tdo24m_remove(struct spi_device *spi)
+{
+	struct tdo24m *lcd = spi_get_drvdata(spi);
+
+	tdo24m_power(lcd, LCD_POWER_OFF);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tdo24m_suspend(struct device *dev)
+{
+	struct tdo24m *lcd = dev_get_drvdata(dev);
+
+	return tdo24m_power(lcd, LCD_POWER_OFF);
+}
+
+static int tdo24m_resume(struct device *dev)
+{
+	struct tdo24m *lcd = dev_get_drvdata(dev);
+
+	return tdo24m_power(lcd, LCD_POWER_ON);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(tdo24m_pm_ops, tdo24m_suspend, tdo24m_resume);
+
+/* Power down all displays on reboot, poweroff or halt */
+static void tdo24m_shutdown(struct spi_device *spi)
+{
+	struct tdo24m *lcd = spi_get_drvdata(spi);
+
+	tdo24m_power(lcd, LCD_POWER_OFF);
+}
+
+static struct spi_driver tdo24m_driver = {
+	.driver = {
+		.name		= "tdo24m",
+		.pm		= &tdo24m_pm_ops,
+	},
+	.probe		= tdo24m_probe,
+	.remove		= tdo24m_remove,
+	.shutdown	= tdo24m_shutdown,
+};
+
+module_spi_driver(tdo24m_driver);
+
+MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
+MODULE_DESCRIPTION("Driver for Toppoly TDO24M LCD Panel");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:tdo24m");