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, 171 insertions, 0 deletions

diff --git a/drivers/phy/broadcom/phy-brcm-usb-init.h b/drivers/phy/broadcom/phy-brcm-usb-init.h
new file mode 100644
index 000000000..4c7be78d0
--- /dev/null
+++ b/drivers/phy/broadcom/phy-brcm-usb-init.h
@@ -0,0 +1,171 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2014-2017 Broadcom
+ */
+
+#ifndef _USB_BRCM_COMMON_INIT_H
+#define _USB_BRCM_COMMON_INIT_H
+
+#include <linux/regmap.h>
+
+#define USB_CTLR_MODE_HOST 0
+#define USB_CTLR_MODE_DEVICE 1
+#define USB_CTLR_MODE_DRD 2
+#define USB_CTLR_MODE_TYPEC_PD 3
+
+enum brcmusb_reg_sel {
+	BRCM_REGS_CTRL = 0,
+	BRCM_REGS_XHCI_EC,
+	BRCM_REGS_XHCI_GBL,
+	BRCM_REGS_USB_PHY,
+	BRCM_REGS_USB_MDIO,
+	BRCM_REGS_BDC_EC,
+	BRCM_REGS_MAX
+};
+
+#define USB_CTRL_REG(base, reg)	((void __iomem *)base + USB_CTRL_##reg)
+#define USB_XHCI_EC_REG(base, reg) ((void __iomem *)base + USB_XHCI_EC_##reg)
+#define USB_CTRL_MASK(reg, field) \
+	USB_CTRL_##reg##_##field##_MASK
+#define USB_CTRL_SET(base, reg, field)	\
+	brcm_usb_ctrl_set(USB_CTRL_REG(base, reg),	\
+			  USB_CTRL_##reg##_##field##_MASK)
+#define USB_CTRL_UNSET(base, reg, field)	\
+	brcm_usb_ctrl_unset(USB_CTRL_REG(base, reg),		\
+			    USB_CTRL_##reg##_##field##_MASK)
+
+#define USB_XHCI_GBL_REG(base, reg) ((void __iomem *)base + USB_XHCI_GBL_##reg)
+#define USB_XHCI_GBL_SET(base, reg, field) \
+	brcm_usb_ctrl_set(USB_XHCI_GBL_REG(base, reg), \
+			  USB_XHCI_GBL_##reg##_##field##_MASK)
+#define USB_XHCI_GBL_UNSET(base, reg, field) \
+	brcm_usb_ctrl_unset(USB_XHCI_GBL_REG(base, reg), \
+			    USB_XHCI_GBL_##reg##_##field##_MASK)
+
+struct  brcm_usb_init_params;
+
+struct brcm_usb_init_ops {
+	void (*init_ipp)(struct brcm_usb_init_params *params);
+	void (*init_common)(struct brcm_usb_init_params *params);
+	void (*init_eohci)(struct brcm_usb_init_params *params);
+	void (*init_xhci)(struct brcm_usb_init_params *params);
+	void (*uninit_common)(struct brcm_usb_init_params *params);
+	void (*uninit_eohci)(struct brcm_usb_init_params *params);
+	void (*uninit_xhci)(struct brcm_usb_init_params *params);
+	int  (*get_dual_select)(struct brcm_usb_init_params *params);
+	void (*set_dual_select)(struct brcm_usb_init_params *params);
+};
+
+struct  brcm_usb_init_params {
+	void __iomem *regs[BRCM_REGS_MAX];
+	int ioc;
+	int ipp;
+	int supported_port_modes;
+	int port_mode;
+	u32 family_id;
+	u32 product_id;
+	int selected_family;
+	const char *family_name;
+	const u32 *usb_reg_bits_map;
+	const struct brcm_usb_init_ops *ops;
+	struct regmap *syscon_piarbctl;
+	bool wake_enabled;
+};
+
+void brcm_usb_dvr_init_74110(struct brcm_usb_init_params *params);
+void brcm_usb_dvr_init_4908(struct brcm_usb_init_params *params);
+void brcm_usb_dvr_init_7445(struct brcm_usb_init_params *params);
+void brcm_usb_dvr_init_7216(struct brcm_usb_init_params *params);
+void brcm_usb_dvr_init_7211b0(struct brcm_usb_init_params *params);
+
+static inline u32 brcm_usb_readl(void __iomem *addr)
+{
+	/*
+	 * MIPS endianness is configured by boot strap, which also reverses all
+	 * bus endianness (i.e., big-endian CPU + big endian bus ==> native
+	 * endian I/O).
+	 *
+	 * Other architectures (e.g., ARM) either do not support big endian, or
+	 * else leave I/O in little endian mode.
+	 */
+	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
+		return __raw_readl(addr);
+	else
+		return readl_relaxed(addr);
+}
+
+static inline void brcm_usb_writel(u32 val, void __iomem *addr)
+{
+	/* See brcmnand_readl() comments */
+	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
+		__raw_writel(val, addr);
+	else
+		writel_relaxed(val, addr);
+}
+
+static inline void brcm_usb_ctrl_unset(void __iomem *reg, u32 mask)
+{
+	brcm_usb_writel(brcm_usb_readl(reg) & ~(mask), reg);
+};
+
+static inline void brcm_usb_ctrl_set(void __iomem *reg, u32 mask)
+{
+	brcm_usb_writel(brcm_usb_readl(reg) | (mask), reg);
+};
+
+static inline void brcm_usb_init_ipp(struct brcm_usb_init_params *ini)
+{
+	if (ini->ops->init_ipp)
+		ini->ops->init_ipp(ini);
+}
+
+static inline void brcm_usb_init_common(struct brcm_usb_init_params *ini)
+{
+	if (ini->ops->init_common)
+		ini->ops->init_common(ini);
+}
+
+static inline void brcm_usb_init_eohci(struct brcm_usb_init_params *ini)
+{
+	if (ini->ops->init_eohci)
+		ini->ops->init_eohci(ini);
+}
+
+static inline void brcm_usb_init_xhci(struct brcm_usb_init_params *ini)
+{
+	if (ini->ops->init_xhci)
+		ini->ops->init_xhci(ini);
+}
+
+static inline void brcm_usb_uninit_common(struct brcm_usb_init_params *ini)
+{
+	if (ini->ops->uninit_common)
+		ini->ops->uninit_common(ini);
+}
+
+static inline void brcm_usb_uninit_eohci(struct brcm_usb_init_params *ini)
+{
+	if (ini->ops->uninit_eohci)
+		ini->ops->uninit_eohci(ini);
+}
+
+static inline void brcm_usb_uninit_xhci(struct brcm_usb_init_params *ini)
+{
+	if (ini->ops->uninit_xhci)
+		ini->ops->uninit_xhci(ini);
+}
+
+static inline int brcm_usb_get_dual_select(struct brcm_usb_init_params *ini)
+{
+	if (ini->ops->get_dual_select)
+		return ini->ops->get_dual_select(ini);
+	return 0;
+}
+
+static inline void brcm_usb_set_dual_select(struct brcm_usb_init_params *ini)
+{
+	if (ini->ops->set_dual_select)
+		ini->ops->set_dual_select(ini);
+}
+
+#endif /* _USB_BRCM_COMMON_INIT_H */