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, 468 insertions, 0 deletions

diff --git a/drivers/clk/qcom/common.c b/drivers/clk/qcom/common.c
new file mode 100644
index 000000000..08fd62ac7
--- /dev/null
+++ b/drivers/clk/qcom/common.c
@@ -0,0 +1,468 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/platform_device.h>
+#include <linux/clk-provider.h>
+#include <linux/interconnect-clk.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset-controller.h>
+#include <linux/of.h>
+
+#include "common.h"
+#include "clk-alpha-pll.h"
+#include "clk-branch.h"
+#include "clk-rcg.h"
+#include "clk-regmap.h"
+#include "reset.h"
+#include "gdsc.h"
+
+struct qcom_cc {
+	struct qcom_reset_controller reset;
+	struct clk_regmap **rclks;
+	size_t num_rclks;
+	struct dev_pm_domain_list *pd_list;
+};
+
+const
+struct freq_tbl *qcom_find_freq(const struct freq_tbl *f, unsigned long rate)
+{
+	if (!f)
+		return NULL;
+
+	if (!f->freq)
+		return f;
+
+	for (; f->freq; f++)
+		if (rate <= f->freq)
+			return f;
+
+	/* Default to our fastest rate */
+	return f - 1;
+}
+EXPORT_SYMBOL_GPL(qcom_find_freq);
+
+const struct freq_multi_tbl *qcom_find_freq_multi(const struct freq_multi_tbl *f,
+						  unsigned long rate)
+{
+	if (!f)
+		return NULL;
+
+	if (!f->freq)
+		return f;
+
+	for (; f->freq; f++)
+		if (rate <= f->freq)
+			return f;
+
+	/* Default to our fastest rate */
+	return f - 1;
+}
+EXPORT_SYMBOL_GPL(qcom_find_freq_multi);
+
+const struct freq_tbl *qcom_find_freq_floor(const struct freq_tbl *f,
+					    unsigned long rate)
+{
+	const struct freq_tbl *best = NULL;
+
+	for ( ; f->freq; f++) {
+		if (rate >= f->freq)
+			best = f;
+		else
+			break;
+	}
+
+	return best;
+}
+EXPORT_SYMBOL_GPL(qcom_find_freq_floor);
+
+int qcom_find_src_index(struct clk_hw *hw, const struct parent_map *map, u8 src)
+{
+	int i, num_parents = clk_hw_get_num_parents(hw);
+
+	for (i = 0; i < num_parents; i++)
+		if (src == map[i].src)
+			return i;
+
+	return -ENOENT;
+}
+EXPORT_SYMBOL_GPL(qcom_find_src_index);
+
+int qcom_find_cfg_index(struct clk_hw *hw, const struct parent_map *map, u8 cfg)
+{
+	int i, num_parents = clk_hw_get_num_parents(hw);
+
+	for (i = 0; i < num_parents; i++)
+		if (cfg == map[i].cfg)
+			return i;
+
+	return -ENOENT;
+}
+EXPORT_SYMBOL_GPL(qcom_find_cfg_index);
+
+struct regmap *
+qcom_cc_map(struct platform_device *pdev, const struct qcom_cc_desc *desc)
+{
+	void __iomem *base;
+	struct device *dev = &pdev->dev;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return ERR_CAST(base);
+
+	return devm_regmap_init_mmio(dev, base, desc->config);
+}
+EXPORT_SYMBOL_GPL(qcom_cc_map);
+
+void
+qcom_pll_set_fsm_mode(struct regmap *map, u32 reg, u8 bias_count, u8 lock_count)
+{
+	u32 val;
+	u32 mask;
+
+	/* De-assert reset to FSM */
+	regmap_update_bits(map, reg, PLL_VOTE_FSM_RESET, 0);
+
+	/* Program bias count and lock count */
+	val = bias_count << PLL_BIAS_COUNT_SHIFT |
+		lock_count << PLL_LOCK_COUNT_SHIFT;
+	mask = PLL_BIAS_COUNT_MASK << PLL_BIAS_COUNT_SHIFT;
+	mask |= PLL_LOCK_COUNT_MASK << PLL_LOCK_COUNT_SHIFT;
+	regmap_update_bits(map, reg, mask, val);
+
+	/* Enable PLL FSM voting */
+	regmap_update_bits(map, reg, PLL_VOTE_FSM_ENA, PLL_VOTE_FSM_ENA);
+}
+EXPORT_SYMBOL_GPL(qcom_pll_set_fsm_mode);
+
+static void qcom_cc_gdsc_unregister(void *data)
+{
+	gdsc_unregister(data);
+}
+
+/*
+ * Backwards compatibility with old DTs. Register a pass-through factor 1/1
+ * clock to translate 'path' clk into 'name' clk and register the 'path'
+ * clk as a fixed rate clock if it isn't present.
+ */
+static int _qcom_cc_register_board_clk(struct device *dev, const char *path,
+				       const char *name, unsigned long rate,
+				       bool add_factor)
+{
+	struct device_node *node = NULL;
+	struct device_node *clocks_node;
+	struct clk_fixed_factor *factor;
+	struct clk_fixed_rate *fixed;
+	struct clk_init_data init_data = { };
+	int ret;
+
+	clocks_node = of_find_node_by_path("/clocks");
+	if (clocks_node) {
+		node = of_get_child_by_name(clocks_node, path);
+		of_node_put(clocks_node);
+	}
+
+	if (!node) {
+		fixed = devm_kzalloc(dev, sizeof(*fixed), GFP_KERNEL);
+		if (!fixed)
+			return -ENOMEM;
+
+		fixed->fixed_rate = rate;
+		fixed->hw.init = &init_data;
+
+		init_data.name = path;
+		init_data.ops = &clk_fixed_rate_ops;
+
+		ret = devm_clk_hw_register(dev, &fixed->hw);
+		if (ret)
+			return ret;
+	}
+	of_node_put(node);
+
+	if (add_factor) {
+		factor = devm_kzalloc(dev, sizeof(*factor), GFP_KERNEL);
+		if (!factor)
+			return -ENOMEM;
+
+		factor->mult = factor->div = 1;
+		factor->hw.init = &init_data;
+
+		init_data.name = name;
+		init_data.parent_names = &path;
+		init_data.num_parents = 1;
+		init_data.flags = 0;
+		init_data.ops = &clk_fixed_factor_ops;
+
+		ret = devm_clk_hw_register(dev, &factor->hw);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+int qcom_cc_register_board_clk(struct device *dev, const char *path,
+			       const char *name, unsigned long rate)
+{
+	bool add_factor = true;
+
+	/*
+	 * TODO: The RPM clock driver currently does not support the xo clock.
+	 * When xo is added to the RPM clock driver, we should change this
+	 * function to skip registration of xo factor clocks.
+	 */
+
+	return _qcom_cc_register_board_clk(dev, path, name, rate, add_factor);
+}
+EXPORT_SYMBOL_GPL(qcom_cc_register_board_clk);
+
+int qcom_cc_register_sleep_clk(struct device *dev)
+{
+	return _qcom_cc_register_board_clk(dev, "sleep_clk", "sleep_clk_src",
+					   32768, true);
+}
+EXPORT_SYMBOL_GPL(qcom_cc_register_sleep_clk);
+
+/* Drop 'protected-clocks' from the list of clocks to register */
+static void qcom_cc_drop_protected(struct device *dev, struct qcom_cc *cc)
+{
+	struct device_node *np = dev->of_node;
+	u32 i;
+
+	of_property_for_each_u32(np, "protected-clocks", i) {
+		if (i >= cc->num_rclks)
+			continue;
+
+		cc->rclks[i] = NULL;
+	}
+}
+
+static struct clk_hw *qcom_cc_clk_hw_get(struct of_phandle_args *clkspec,
+					 void *data)
+{
+	struct qcom_cc *cc = data;
+	unsigned int idx = clkspec->args[0];
+
+	if (idx >= cc->num_rclks) {
+		pr_err("%s: invalid index %u\n", __func__, idx);
+		return ERR_PTR(-EINVAL);
+	}
+
+	return cc->rclks[idx] ? &cc->rclks[idx]->hw : NULL;
+}
+
+static int qcom_cc_icc_register(struct device *dev,
+				const struct qcom_cc_desc *desc)
+{
+	struct icc_clk_data *icd;
+	struct clk_hw *hws;
+	int i;
+
+	if (!IS_ENABLED(CONFIG_INTERCONNECT_CLK))
+		return 0;
+
+	if (!desc->icc_hws)
+		return 0;
+
+	icd = devm_kcalloc(dev, desc->num_icc_hws, sizeof(*icd), GFP_KERNEL);
+	if (!icd)
+		return -ENOMEM;
+
+	for (i = 0; i < desc->num_icc_hws; i++) {
+		icd[i].master_id = desc->icc_hws[i].master_id;
+		icd[i].slave_id = desc->icc_hws[i].slave_id;
+		hws = &desc->clks[desc->icc_hws[i].clk_id]->hw;
+		icd[i].clk = devm_clk_hw_get_clk(dev, hws, "icc");
+		if (IS_ERR(icd[i].clk))
+			return dev_err_probe(dev, PTR_ERR(icd[i].clk),
+					     "(%d) clock entry is null\n", i);
+		icd[i].name = clk_hw_get_name(hws);
+	}
+
+	return devm_icc_clk_register(dev, desc->icc_first_node_id,
+						     desc->num_icc_hws, icd);
+}
+
+static int qcom_cc_clk_pll_configure(const struct qcom_cc_driver_data *data,
+				     struct regmap *regmap)
+{
+	const struct clk_init_data *init;
+	struct clk_alpha_pll *pll;
+	int i;
+
+	for (i = 0; i < data->num_alpha_plls; i++) {
+		pll = data->alpha_plls[i];
+		init = pll->clkr.hw.init;
+
+		if (!pll->config || !pll->regs) {
+			pr_err("%s: missing pll config or regs\n", init->name);
+			return -EINVAL;
+		}
+
+		qcom_clk_alpha_pll_configure(pll, regmap);
+	}
+
+	return 0;
+}
+
+static void qcom_cc_clk_regs_configure(struct device *dev, const struct qcom_cc_driver_data *data,
+				       struct regmap *regmap)
+{
+	int i;
+
+	for (i = 0; i < data->num_clk_cbcrs; i++)
+		qcom_branch_set_clk_en(regmap, data->clk_cbcrs[i]);
+
+	if (data->clk_regs_configure)
+		data->clk_regs_configure(dev, regmap);
+}
+
+int qcom_cc_really_probe(struct device *dev,
+			 const struct qcom_cc_desc *desc, struct regmap *regmap)
+{
+	int i, ret;
+	struct qcom_reset_controller *reset;
+	struct qcom_cc *cc;
+	struct gdsc_desc *scd;
+	size_t num_clks = desc->num_clks;
+	struct clk_regmap **rclks = desc->clks;
+	size_t num_clk_hws = desc->num_clk_hws;
+	struct clk_hw **clk_hws = desc->clk_hws;
+
+	cc = devm_kzalloc(dev, sizeof(*cc), GFP_KERNEL);
+	if (!cc)
+		return -ENOMEM;
+
+	ret = devm_pm_domain_attach_list(dev, NULL, &cc->pd_list);
+	if (ret < 0 && ret != -EEXIST)
+		return ret;
+
+	if (desc->use_rpm) {
+		ret = devm_pm_runtime_enable(dev);
+		if (ret)
+			return ret;
+
+		ret = pm_runtime_resume_and_get(dev);
+		if (ret)
+			return ret;
+	}
+
+	if (desc->driver_data) {
+		ret = qcom_cc_clk_pll_configure(desc->driver_data, regmap);
+		if (ret)
+			goto put_rpm;
+
+		qcom_cc_clk_regs_configure(dev, desc->driver_data, regmap);
+	}
+
+	reset = &cc->reset;
+	reset->rcdev.of_node = dev->of_node;
+	reset->rcdev.ops = &qcom_reset_ops;
+	reset->rcdev.owner = dev->driver->owner;
+	reset->rcdev.nr_resets = desc->num_resets;
+	reset->regmap = regmap;
+	reset->reset_map = desc->resets;
+
+	ret = devm_reset_controller_register(dev, &reset->rcdev);
+	if (ret)
+		goto put_rpm;
+
+	if (desc->gdscs && desc->num_gdscs) {
+		scd = devm_kzalloc(dev, sizeof(*scd), GFP_KERNEL);
+		if (!scd) {
+			ret = -ENOMEM;
+			goto put_rpm;
+		}
+		scd->dev = dev;
+		scd->scs = desc->gdscs;
+		scd->num = desc->num_gdscs;
+		scd->pd_list = cc->pd_list;
+		ret = gdsc_register(scd, &reset->rcdev, regmap);
+		if (ret)
+			goto put_rpm;
+		ret = devm_add_action_or_reset(dev, qcom_cc_gdsc_unregister,
+					       scd);
+		if (ret)
+			goto put_rpm;
+	}
+
+	if (desc->driver_data &&
+	    desc->driver_data->dfs_rcgs &&
+	    desc->driver_data->num_dfs_rcgs) {
+		ret = qcom_cc_register_rcg_dfs(regmap,
+					       desc->driver_data->dfs_rcgs,
+					       desc->driver_data->num_dfs_rcgs);
+		if (ret)
+			goto put_rpm;
+	}
+
+	cc->rclks = rclks;
+	cc->num_rclks = num_clks;
+
+	qcom_cc_drop_protected(dev, cc);
+
+	for (i = 0; i < num_clk_hws; i++) {
+		ret = devm_clk_hw_register(dev, clk_hws[i]);
+		if (ret)
+			goto put_rpm;
+	}
+
+	for (i = 0; i < num_clks; i++) {
+		if (!rclks[i])
+			continue;
+
+		ret = devm_clk_register_regmap(dev, rclks[i]);
+		if (ret)
+			goto put_rpm;
+	}
+
+	ret = devm_of_clk_add_hw_provider(dev, qcom_cc_clk_hw_get, cc);
+	if (ret)
+		goto put_rpm;
+
+	ret = qcom_cc_icc_register(dev, desc);
+
+put_rpm:
+	if (desc->use_rpm)
+		pm_runtime_put_sync(dev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(qcom_cc_really_probe);
+
+int qcom_cc_probe(struct platform_device *pdev, const struct qcom_cc_desc *desc)
+{
+	struct regmap *regmap;
+
+	regmap = qcom_cc_map(pdev, desc);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	return qcom_cc_really_probe(&pdev->dev, desc, regmap);
+}
+EXPORT_SYMBOL_GPL(qcom_cc_probe);
+
+int qcom_cc_probe_by_index(struct platform_device *pdev, int index,
+			   const struct qcom_cc_desc *desc)
+{
+	struct regmap *regmap;
+	void __iomem *base;
+
+	base = devm_platform_ioremap_resource(pdev, index);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	regmap = devm_regmap_init_mmio(&pdev->dev, base, desc->config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	return qcom_cc_really_probe(&pdev->dev, desc, regmap);
+}
+EXPORT_SYMBOL_GPL(qcom_cc_probe_by_index);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("QTI Common Clock module");