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, 299 insertions, 0 deletions

diff --git a/drivers/pci/controller/pcie-rockchip.c b/drivers/pci/controller/pcie-rockchip.c
new file mode 100644
index 000000000..8d78ab1b3
--- /dev/null
+++ b/drivers/pci/controller/pcie-rockchip.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Rockchip AXI PCIe host controller driver
+ *
+ * Copyright (c) 2016 Rockchip, Inc.
+ *
+ * Author: Shawn Lin <shawn.lin@rock-chips.com>
+ *         Wenrui Li <wenrui.li@rock-chips.com>
+ *
+ * Bits taken from Synopsys DesignWare Host controller driver and
+ * ARM PCI Host generic driver.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/iopoll.h>
+#include <linux/of.h>
+#include <linux/of_pci.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+#include "../pci.h"
+#include "pcie-rockchip.h"
+
+int rockchip_pcie_parse_dt(struct rockchip_pcie *rockchip)
+{
+	struct device *dev = rockchip->dev;
+	struct platform_device *pdev = to_platform_device(dev);
+	struct device_node *node = dev->of_node;
+	struct resource *regs;
+	int err, i;
+
+	if (rockchip->is_rc) {
+		regs = platform_get_resource_byname(pdev,
+						    IORESOURCE_MEM,
+						    "axi-base");
+		rockchip->reg_base = devm_pci_remap_cfg_resource(dev, regs);
+		if (IS_ERR(rockchip->reg_base))
+			return PTR_ERR(rockchip->reg_base);
+	} else {
+		rockchip->mem_res =
+			platform_get_resource_byname(pdev, IORESOURCE_MEM,
+						     "mem-base");
+		if (!rockchip->mem_res)
+			return -EINVAL;
+	}
+
+	rockchip->apb_base =
+		devm_platform_ioremap_resource_byname(pdev, "apb-base");
+	if (IS_ERR(rockchip->apb_base))
+		return PTR_ERR(rockchip->apb_base);
+
+	err = rockchip_pcie_get_phys(rockchip);
+	if (err)
+		return err;
+
+	rockchip->lanes = 1;
+	err = of_property_read_u32(node, "num-lanes", &rockchip->lanes);
+	if (!err && (rockchip->lanes == 0 ||
+		     rockchip->lanes == 3 ||
+		     rockchip->lanes > 4)) {
+		dev_warn(dev, "invalid num-lanes, default to use one lane\n");
+		rockchip->lanes = 1;
+	}
+
+	rockchip->link_gen = of_pci_get_max_link_speed(node);
+	if (rockchip->link_gen < 0 || rockchip->link_gen > 2)
+		rockchip->link_gen = 2;
+
+	for (i = 0; i < ROCKCHIP_NUM_PM_RSTS; i++)
+		rockchip->pm_rsts[i].id = rockchip_pci_pm_rsts[i];
+
+	err = devm_reset_control_bulk_get_exclusive(dev,
+						    ROCKCHIP_NUM_PM_RSTS,
+						    rockchip->pm_rsts);
+	if (err)
+		return dev_err_probe(dev, err, "Cannot get the PM reset\n");
+
+	for (i = 0; i < ROCKCHIP_NUM_CORE_RSTS; i++)
+		rockchip->core_rsts[i].id = rockchip_pci_core_rsts[i];
+
+	err = devm_reset_control_bulk_get_exclusive(dev,
+						    ROCKCHIP_NUM_CORE_RSTS,
+						    rockchip->core_rsts);
+	if (err)
+		return dev_err_probe(dev, err, "Cannot get the Core resets\n");
+
+	if (rockchip->is_rc)
+		rockchip->perst_gpio = devm_gpiod_get_optional(dev, "ep",
+							       GPIOD_OUT_LOW);
+	else
+		rockchip->perst_gpio = devm_gpiod_get_optional(dev, "reset",
+							       GPIOD_IN);
+	if (IS_ERR(rockchip->perst_gpio))
+		return dev_err_probe(dev, PTR_ERR(rockchip->perst_gpio),
+				     "failed to get PERST# GPIO\n");
+
+	rockchip->num_clks = devm_clk_bulk_get_all(dev, &rockchip->clks);
+	if (rockchip->num_clks < 0)
+		return dev_err_probe(dev, rockchip->num_clks,
+				     "failed to get clocks\n");
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(rockchip_pcie_parse_dt);
+
+#define rockchip_pcie_read_addr(addr) rockchip_pcie_read(rockchip, addr)
+/* 100 ms max wait time for PHY PLLs to lock */
+#define RK_PHY_PLL_LOCK_TIMEOUT_US 100000
+/* Sleep should be less than 20ms */
+#define RK_PHY_PLL_LOCK_SLEEP_US 1000
+
+int rockchip_pcie_init_port(struct rockchip_pcie *rockchip)
+{
+	struct device *dev = rockchip->dev;
+	int err, i;
+	u32 regs;
+
+	err = reset_control_bulk_assert(ROCKCHIP_NUM_PM_RSTS,
+					rockchip->pm_rsts);
+	if (err)
+		return dev_err_probe(dev, err, "Couldn't assert PM resets\n");
+
+	for (i = 0; i < MAX_LANE_NUM; i++) {
+		err = phy_init(rockchip->phys[i]);
+		if (err) {
+			dev_err(dev, "init phy%d err %d\n", i, err);
+			goto err_exit_phy;
+		}
+	}
+
+	err = reset_control_bulk_assert(ROCKCHIP_NUM_CORE_RSTS,
+					rockchip->core_rsts);
+	if (err) {
+		dev_err_probe(dev, err, "Couldn't assert Core resets\n");
+		goto err_exit_phy;
+	}
+
+	udelay(10);
+
+	err = reset_control_bulk_deassert(ROCKCHIP_NUM_PM_RSTS,
+					  rockchip->pm_rsts);
+	if (err) {
+		dev_err(dev, "Couldn't deassert PM resets %d\n", err);
+		goto err_exit_phy;
+	}
+
+	if (rockchip->link_gen == 2)
+		rockchip_pcie_write(rockchip, PCIE_CLIENT_GEN_SEL_2,
+				    PCIE_CLIENT_CONFIG);
+	else
+		rockchip_pcie_write(rockchip, PCIE_CLIENT_GEN_SEL_1,
+				    PCIE_CLIENT_CONFIG);
+
+	regs = PCIE_CLIENT_ARI_ENABLE |
+	       PCIE_CLIENT_CONF_LANE_NUM(rockchip->lanes);
+
+	if (rockchip->is_rc)
+		regs |= PCIE_CLIENT_LINK_TRAIN_ENABLE |
+			PCIE_CLIENT_CONF_ENABLE | PCIE_CLIENT_MODE_RC;
+	else
+		regs |= PCIE_CLIENT_CONF_DISABLE | PCIE_CLIENT_MODE_EP;
+
+	rockchip_pcie_write(rockchip, regs, PCIE_CLIENT_CONFIG);
+
+	for (i = 0; i < MAX_LANE_NUM; i++) {
+		err = phy_power_on(rockchip->phys[i]);
+		if (err) {
+			dev_err(dev, "power on phy%d err %d\n", i, err);
+			goto err_power_off_phy;
+		}
+	}
+
+	err = readx_poll_timeout(rockchip_pcie_read_addr,
+				 PCIE_CLIENT_SIDE_BAND_STATUS,
+				 regs, !(regs & PCIE_CLIENT_PHY_ST),
+				 RK_PHY_PLL_LOCK_SLEEP_US,
+				 RK_PHY_PLL_LOCK_TIMEOUT_US);
+	if (err) {
+		dev_err(dev, "PHY PLLs could not lock, %d\n", err);
+		goto err_power_off_phy;
+	}
+
+	err = reset_control_bulk_deassert(ROCKCHIP_NUM_CORE_RSTS,
+					  rockchip->core_rsts);
+	if (err) {
+		dev_err(dev, "Couldn't deassert Core reset %d\n", err);
+		goto err_power_off_phy;
+	}
+
+	return 0;
+err_power_off_phy:
+	while (i--)
+		phy_power_off(rockchip->phys[i]);
+	i = MAX_LANE_NUM;
+err_exit_phy:
+	while (i--)
+		phy_exit(rockchip->phys[i]);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rockchip_pcie_init_port);
+
+int rockchip_pcie_get_phys(struct rockchip_pcie *rockchip)
+{
+	struct device *dev = rockchip->dev;
+	struct phy *phy;
+	char *name;
+	u32 i;
+
+	phy = devm_phy_get(dev, "pcie-phy");
+	if (!IS_ERR(phy)) {
+		rockchip->legacy_phy = true;
+		rockchip->phys[0] = phy;
+		dev_warn(dev, "legacy phy model is deprecated!\n");
+		return 0;
+	}
+
+	if (PTR_ERR(phy) == -EPROBE_DEFER)
+		return PTR_ERR(phy);
+
+	dev_dbg(dev, "missing legacy phy; search for per-lane PHY\n");
+
+	for (i = 0; i < MAX_LANE_NUM; i++) {
+		name = kasprintf(GFP_KERNEL, "pcie-phy-%u", i);
+		if (!name)
+			return -ENOMEM;
+
+		phy = devm_of_phy_get(dev, dev->of_node, name);
+		kfree(name);
+
+		if (IS_ERR(phy)) {
+			if (PTR_ERR(phy) != -EPROBE_DEFER)
+				dev_err(dev, "missing phy for lane %d: %pe\n",
+					i, phy);
+			return PTR_ERR(phy);
+		}
+
+		rockchip->phys[i] = phy;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(rockchip_pcie_get_phys);
+
+void rockchip_pcie_deinit_phys(struct rockchip_pcie *rockchip)
+{
+	int i;
+
+	for (i = 0; i < MAX_LANE_NUM; i++) {
+		/* inactive lanes are already powered off */
+		if (rockchip->lanes_map & BIT(i))
+			phy_power_off(rockchip->phys[i]);
+		phy_exit(rockchip->phys[i]);
+	}
+}
+EXPORT_SYMBOL_GPL(rockchip_pcie_deinit_phys);
+
+int rockchip_pcie_enable_clocks(struct rockchip_pcie *rockchip)
+{
+	struct device *dev = rockchip->dev;
+	int err;
+
+	err = clk_bulk_prepare_enable(rockchip->num_clks, rockchip->clks);
+	if (err)
+		return dev_err_probe(dev, err, "failed to enable clocks\n");
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(rockchip_pcie_enable_clocks);
+
+void rockchip_pcie_disable_clocks(struct rockchip_pcie *rockchip)
+{
+
+	clk_bulk_disable_unprepare(rockchip->num_clks, rockchip->clks);
+}
+EXPORT_SYMBOL_GPL(rockchip_pcie_disable_clocks);
+
+void rockchip_pcie_cfg_configuration_accesses(
+		struct rockchip_pcie *rockchip, u32 type)
+{
+	u32 ob_desc_0;
+
+	/* Configuration Accesses for region 0 */
+	rockchip_pcie_write(rockchip, 0x0, PCIE_RC_BAR_CONF);
+
+	rockchip_pcie_write(rockchip,
+			    (RC_REGION_0_ADDR_TRANS_L + RC_REGION_0_PASS_BITS),
+			    PCIE_CORE_OB_REGION_ADDR0);
+	rockchip_pcie_write(rockchip, RC_REGION_0_ADDR_TRANS_H,
+			    PCIE_CORE_OB_REGION_ADDR1);
+	ob_desc_0 = rockchip_pcie_read(rockchip, PCIE_CORE_OB_REGION_DESC0);
+	ob_desc_0 &= ~(RC_REGION_0_TYPE_MASK);
+	ob_desc_0 |= (type | (0x1 << 23));
+	rockchip_pcie_write(rockchip, ob_desc_0, PCIE_CORE_OB_REGION_DESC0);
+	rockchip_pcie_write(rockchip, 0x0, PCIE_CORE_OB_REGION_DESC1);
+}
+EXPORT_SYMBOL_GPL(rockchip_pcie_cfg_configuration_accesses);