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

3 files changed, 89 insertions, 0 deletions

diff --git a/include/soc/imx/cpu.h b/include/soc/imx/cpu.h
new file mode 100644
index 000000000..0bf610aca
--- /dev/null
+++ b/include/soc/imx/cpu.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef __IMX_CPU_H__
+#define __IMX_CPU_H__
+
+#define MXC_CPU_MX1		1
+#define MXC_CPU_MX21		21
+#define MXC_CPU_MX25		25
+#define MXC_CPU_MX27		27
+#define MXC_CPU_MX31		31
+#define MXC_CPU_MX35		35
+#define MXC_CPU_MX50		50
+#define MXC_CPU_MX51		51
+#define MXC_CPU_MX53		53
+#define MXC_CPU_IMX6SL		0x60
+#define MXC_CPU_IMX6DL		0x61
+#define MXC_CPU_IMX6SX		0x62
+#define MXC_CPU_IMX6Q		0x63
+#define MXC_CPU_IMX6UL		0x64
+#define MXC_CPU_IMX6ULL		0x65
+/* virtual cpu id for i.mx6ulz */
+#define MXC_CPU_IMX6ULZ		0x6b
+#define MXC_CPU_IMX6SLL		0x67
+#define MXC_CPU_IMX7D		0x72
+#define MXC_CPU_IMX7ULP		0xff
+
+#define MXC_CPU_VFx10		0x010
+#define MXC_CPU_VF500		0x500
+#define MXC_CPU_VF510		(MXC_CPU_VF500 | MXC_CPU_VFx10)
+#define MXC_CPU_VF600		0x600
+#define MXC_CPU_VF610		(MXC_CPU_VF600 | MXC_CPU_VFx10)
+
+#ifndef __ASSEMBLY__
+extern unsigned int __mxc_cpu_type;
+#endif
+
+#endif
diff --git a/include/soc/imx/cpuidle.h b/include/soc/imx/cpuidle.h
new file mode 100644
index 000000000..7d9202801
--- /dev/null
+++ b/include/soc/imx/cpuidle.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2016 Pengutronix, <kernel@pengutronix.de>
+ */
+
+#ifndef __SOC_IMX_CPUIDLE_H__
+#define __SOC_IMX_CPUIDLE_H__
+
+#if defined(CONFIG_CPU_IDLE) && defined(CONFIG_SOC_IMX6Q)
+void imx6q_cpuidle_fec_irqs_used(void);
+void imx6q_cpuidle_fec_irqs_unused(void);
+#else
+static inline void imx6q_cpuidle_fec_irqs_used(void) { }
+static inline void imx6q_cpuidle_fec_irqs_unused(void) { }
+#endif
+
+#endif /* __SOC_IMX_CPUIDLE_H__ */
diff --git a/include/soc/imx/revision.h b/include/soc/imx/revision.h
new file mode 100644
index 000000000..b122d2fc8
--- /dev/null
+++ b/include/soc/imx/revision.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2015 Linaro Ltd.
+ */
+
+#ifndef __SOC_IMX_REVISION_H__
+#define __SOC_IMX_REVISION_H__
+
+#define IMX_CHIP_REVISION_1_0		0x10
+#define IMX_CHIP_REVISION_1_1		0x11
+#define IMX_CHIP_REVISION_1_2		0x12
+#define IMX_CHIP_REVISION_1_3		0x13
+#define IMX_CHIP_REVISION_1_4		0x14
+#define IMX_CHIP_REVISION_1_5		0x15
+#define IMX_CHIP_REVISION_2_0		0x20
+#define IMX_CHIP_REVISION_2_1		0x21
+#define IMX_CHIP_REVISION_2_2		0x22
+#define IMX_CHIP_REVISION_2_3		0x23
+#define IMX_CHIP_REVISION_3_0		0x30
+#define IMX_CHIP_REVISION_3_1		0x31
+#define IMX_CHIP_REVISION_3_2		0x32
+#define IMX_CHIP_REVISION_3_3		0x33
+#define IMX_CHIP_REVISION_UNKNOWN	0xff
+
+int mx25_revision(void);
+int mx27_revision(void);
+int mx31_revision(void);
+int mx35_revision(void);
+int mx51_revision(void);
+int mx53_revision(void);
+
+unsigned int imx_get_soc_revision(void);
+void imx_print_silicon_rev(const char *cpu, int srev);
+
+#endif /* __SOC_IMX_REVISION_H__ */