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, 264 insertions, 0 deletions

diff --git a/drivers/ata/pata_imx.c b/drivers/ata/pata_imx.c
new file mode 100644
index 000000000..ad559058c
--- /dev/null
+++ b/drivers/ata/pata_imx.c
@@ -0,0 +1,264 @@
+/*
+ * Freescale iMX PATA driver
+ *
+ * Copyright (C) 2011 Arnaud Patard <arnaud.patard@rtp-net.org>
+ *
+ * Based on pata_platform - Copyright (C) 2006 - 2007  Paul Mundt
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * TODO:
+ * - dmaengine support
+ */
+
+#include <linux/ata.h>
+#include <linux/clk.h>
+#include <linux/libata.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define DRV_NAME "pata_imx"
+
+#define PATA_IMX_ATA_TIME_OFF		0x00
+#define PATA_IMX_ATA_TIME_ON		0x01
+#define PATA_IMX_ATA_TIME_1		0x02
+#define PATA_IMX_ATA_TIME_2W		0x03
+#define PATA_IMX_ATA_TIME_2R		0x04
+#define PATA_IMX_ATA_TIME_AX		0x05
+#define PATA_IMX_ATA_TIME_PIO_RDX	0x06
+#define PATA_IMX_ATA_TIME_4		0x07
+#define PATA_IMX_ATA_TIME_9		0x08
+
+#define PATA_IMX_ATA_CONTROL		0x24
+#define PATA_IMX_ATA_CTRL_FIFO_RST_B	(1<<7)
+#define PATA_IMX_ATA_CTRL_ATA_RST_B	(1<<6)
+#define PATA_IMX_ATA_CTRL_IORDY_EN	(1<<0)
+#define PATA_IMX_ATA_INT_EN		0x2C
+#define PATA_IMX_ATA_INTR_ATA_INTRQ2	(1<<3)
+#define PATA_IMX_DRIVE_DATA		0xA0
+#define PATA_IMX_DRIVE_CONTROL		0xD8
+
+static u32 pio_t4[] = { 30,  20,  15,  10,  10 };
+static u32 pio_t9[] = { 20,  15,  10,  10,  10 };
+static u32 pio_tA[] = { 35,  35,  35,  35,  35 };
+
+struct pata_imx_priv {
+	struct clk *clk;
+	/* timings/interrupt/control regs */
+	void __iomem *host_regs;
+	u32 ata_ctl;
+};
+
+static void pata_imx_set_timing(struct ata_device *adev,
+				struct pata_imx_priv *priv)
+{
+	struct ata_timing timing;
+	unsigned long clkrate;
+	u32 T, mode;
+
+	clkrate = clk_get_rate(priv->clk);
+
+	if (adev->pio_mode < XFER_PIO_0 || adev->pio_mode > XFER_PIO_4 ||
+	    !clkrate)
+		return;
+
+	T = 1000000000 / clkrate;
+	ata_timing_compute(adev, adev->pio_mode, &timing, T * 1000, 0);
+
+	mode = adev->pio_mode - XFER_PIO_0;
+
+	writeb(3, priv->host_regs + PATA_IMX_ATA_TIME_OFF);
+	writeb(3, priv->host_regs + PATA_IMX_ATA_TIME_ON);
+	writeb(timing.setup, priv->host_regs + PATA_IMX_ATA_TIME_1);
+	writeb(timing.act8b, priv->host_regs + PATA_IMX_ATA_TIME_2W);
+	writeb(timing.act8b, priv->host_regs + PATA_IMX_ATA_TIME_2R);
+	writeb(1, priv->host_regs + PATA_IMX_ATA_TIME_PIO_RDX);
+
+	writeb(pio_t4[mode] / T + 1, priv->host_regs + PATA_IMX_ATA_TIME_4);
+	writeb(pio_t9[mode] / T + 1, priv->host_regs + PATA_IMX_ATA_TIME_9);
+	writeb(pio_tA[mode] / T + 1, priv->host_regs + PATA_IMX_ATA_TIME_AX);
+}
+
+static void pata_imx_set_piomode(struct ata_port *ap, struct ata_device *adev)
+{
+	struct pata_imx_priv *priv = ap->host->private_data;
+	u32 val;
+
+	pata_imx_set_timing(adev, priv);
+
+	val = __raw_readl(priv->host_regs + PATA_IMX_ATA_CONTROL);
+	if (ata_pio_need_iordy(adev))
+		val |= PATA_IMX_ATA_CTRL_IORDY_EN;
+	else
+		val &= ~PATA_IMX_ATA_CTRL_IORDY_EN;
+	__raw_writel(val, priv->host_regs + PATA_IMX_ATA_CONTROL);
+}
+
+static const struct scsi_host_template pata_imx_sht = {
+	ATA_PIO_SHT(DRV_NAME),
+};
+
+static struct ata_port_operations pata_imx_port_ops = {
+	.inherits		= &ata_sff_port_ops,
+	.sff_data_xfer		= ata_sff_data_xfer32,
+	.cable_detect		= ata_cable_unknown,
+	.set_piomode		= pata_imx_set_piomode,
+};
+
+static void pata_imx_setup_port(struct ata_ioports *ioaddr)
+{
+	/* Fixup the port shift for platforms that need it */
+	ioaddr->data_addr	= ioaddr->cmd_addr + (ATA_REG_DATA    << 2);
+	ioaddr->error_addr	= ioaddr->cmd_addr + (ATA_REG_ERR     << 2);
+	ioaddr->feature_addr	= ioaddr->cmd_addr + (ATA_REG_FEATURE << 2);
+	ioaddr->nsect_addr	= ioaddr->cmd_addr + (ATA_REG_NSECT   << 2);
+	ioaddr->lbal_addr	= ioaddr->cmd_addr + (ATA_REG_LBAL    << 2);
+	ioaddr->lbam_addr	= ioaddr->cmd_addr + (ATA_REG_LBAM    << 2);
+	ioaddr->lbah_addr	= ioaddr->cmd_addr + (ATA_REG_LBAH    << 2);
+	ioaddr->device_addr	= ioaddr->cmd_addr + (ATA_REG_DEVICE  << 2);
+	ioaddr->status_addr	= ioaddr->cmd_addr + (ATA_REG_STATUS  << 2);
+	ioaddr->command_addr	= ioaddr->cmd_addr + (ATA_REG_CMD     << 2);
+}
+
+static int pata_imx_probe(struct platform_device *pdev)
+{
+	struct ata_host *host;
+	struct ata_port *ap;
+	struct pata_imx_priv *priv;
+	int irq = 0;
+	struct resource *io_res;
+	int ret;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	priv = devm_kzalloc(&pdev->dev,
+				sizeof(struct pata_imx_priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->clk = devm_clk_get_enabled(&pdev->dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		dev_err(&pdev->dev, "Failed to get and enable clock\n");
+		return PTR_ERR(priv->clk);
+	}
+
+	host = ata_host_alloc(&pdev->dev, 1);
+	if (!host)
+		return -ENOMEM;
+
+	host->private_data = priv;
+	ap = host->ports[0];
+
+	ap->ops = &pata_imx_port_ops;
+	ap->pio_mask = ATA_PIO4;
+	ap->flags |= ATA_FLAG_SLAVE_POSS;
+
+	priv->host_regs = devm_platform_get_and_ioremap_resource(pdev, 0, &io_res);
+	if (IS_ERR(priv->host_regs))
+		return PTR_ERR(priv->host_regs);
+
+	ap->ioaddr.cmd_addr = priv->host_regs + PATA_IMX_DRIVE_DATA;
+	ap->ioaddr.ctl_addr = priv->host_regs + PATA_IMX_DRIVE_CONTROL;
+
+	ap->ioaddr.altstatus_addr = ap->ioaddr.ctl_addr;
+
+	pata_imx_setup_port(&ap->ioaddr);
+
+	ata_port_desc(ap, "cmd 0x%llx ctl 0x%llx",
+		(unsigned long long)io_res->start + PATA_IMX_DRIVE_DATA,
+		(unsigned long long)io_res->start + PATA_IMX_DRIVE_CONTROL);
+
+	/* deassert resets */
+	__raw_writel(PATA_IMX_ATA_CTRL_FIFO_RST_B |
+			PATA_IMX_ATA_CTRL_ATA_RST_B,
+			priv->host_regs + PATA_IMX_ATA_CONTROL);
+	/* enable interrupts */
+	__raw_writel(PATA_IMX_ATA_INTR_ATA_INTRQ2,
+			priv->host_regs + PATA_IMX_ATA_INT_EN);
+
+	/* activate */
+	ret = ata_host_activate(host, irq, ata_sff_interrupt, 0,
+				&pata_imx_sht);
+
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void pata_imx_remove(struct platform_device *pdev)
+{
+	struct ata_host *host = platform_get_drvdata(pdev);
+	struct pata_imx_priv *priv = host->private_data;
+
+	ata_host_detach(host);
+
+	__raw_writel(0, priv->host_regs + PATA_IMX_ATA_INT_EN);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int pata_imx_suspend(struct device *dev)
+{
+	struct ata_host *host = dev_get_drvdata(dev);
+	struct pata_imx_priv *priv = host->private_data;
+
+	ata_host_suspend(host, PMSG_SUSPEND);
+
+	__raw_writel(0, priv->host_regs + PATA_IMX_ATA_INT_EN);
+	priv->ata_ctl = __raw_readl(priv->host_regs + PATA_IMX_ATA_CONTROL);
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static int pata_imx_resume(struct device *dev)
+{
+	struct ata_host *host = dev_get_drvdata(dev);
+	struct pata_imx_priv *priv = host->private_data;
+
+	int ret = clk_prepare_enable(priv->clk);
+	if (ret)
+		return ret;
+
+	__raw_writel(priv->ata_ctl, priv->host_regs + PATA_IMX_ATA_CONTROL);
+
+	__raw_writel(PATA_IMX_ATA_INTR_ATA_INTRQ2,
+			priv->host_regs + PATA_IMX_ATA_INT_EN);
+
+	ata_host_resume(host);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(pata_imx_pm_ops, pata_imx_suspend, pata_imx_resume);
+
+static const struct of_device_id imx_pata_dt_ids[] = {
+	{
+		.compatible = "fsl,imx27-pata",
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(of, imx_pata_dt_ids);
+
+static struct platform_driver pata_imx_driver = {
+	.probe		= pata_imx_probe,
+	.remove		= pata_imx_remove,
+	.driver = {
+		.name		= DRV_NAME,
+		.of_match_table	= imx_pata_dt_ids,
+		.pm		= &pata_imx_pm_ops,
+	},
+};
+
+module_platform_driver(pata_imx_driver);
+
+MODULE_AUTHOR("Arnaud Patard <arnaud.patard@rtp-net.org>");
+MODULE_DESCRIPTION("low-level driver for iMX PATA");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);