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, 447 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/dsp/fsl,dsp.yaml b/Documentation/devicetree/bindings/dsp/fsl,dsp.yaml
new file mode 100644
index 000000000..e610b7636
--- /dev/null
+++ b/Documentation/devicetree/bindings/dsp/fsl,dsp.yaml
@@ -0,0 +1,249 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dsp/fsl,dsp.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NXP i.MX8 DSP core
+
+maintainers:
+  - Daniel Baluta <daniel.baluta@nxp.com>
+  - Shengjiu Wang <shengjiu.wang@nxp.com>
+
+description: |
+  Some boards from i.MX8 family contain a DSP core used for
+  advanced pre- and post- audio processing.
+
+properties:
+  compatible:
+    enum:
+      - fsl,imx8qxp-dsp
+      - fsl,imx8qm-dsp
+      - fsl,imx8mp-dsp
+      - fsl,imx8ulp-dsp
+      - fsl,imx8qxp-hifi4
+      - fsl,imx8qm-hifi4
+      - fsl,imx8mp-hifi4
+      - fsl,imx8ulp-hifi4
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: ipg clock
+      - description: ocram clock
+      - description: core clock
+      - description: debug interface clock
+      - description: message unit clock
+    minItems: 3
+
+  clock-names:
+    items:
+      - const: ipg
+      - const: ocram
+      - const: core
+      - const: debug
+      - const: mu
+    minItems: 3
+
+  power-domains:
+    description:
+      List of phandle and PM domain specifier as documented in
+      Documentation/devicetree/bindings/power/power_domain.txt
+    minItems: 1
+    maxItems: 4
+
+  mboxes:
+    description:
+      List of <&phandle type channel> - 2 channels for TXDB, 2 channels for RXDB
+      or - 1 channel for TX, 1 channel for RX, 1 channel for RXDB
+      (see mailbox/fsl,mu.txt)
+    minItems: 3
+    maxItems: 4
+
+  mbox-names:
+    minItems: 3
+    maxItems: 4
+
+  memory-region:
+    description:
+      phandle to a node describing reserved memory (System RAM memory)
+      used by DSP (see bindings/reserved-memory/reserved-memory.txt)
+    minItems: 1
+    maxItems: 4
+
+  firmware-name:
+    description: |
+      Default name of the firmware to load to the remote processor.
+
+  fsl,dsp-ctrl:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle to syscon block which provide access for processor enablement
+
+  resets:
+    minItems: 1
+
+  reset-names:
+    minItems: 1
+    items:
+      - const: runstall
+      - const: softreset
+
+  access-controllers:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - power-domains
+  - mboxes
+  - mbox-names
+  - memory-region
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - fsl,imx8qxp-dsp
+              - fsl,imx8qxp-hifi4
+    then:
+      properties:
+        power-domains:
+          minItems: 2
+          maxItems: 2
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - fsl,imx8qm-dsp
+              - fsl,imx8qm-hifi4
+    then:
+      properties:
+        power-domains:
+          minItems: 4
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - fsl,imx8mp-dsp
+              - fsl,imx8mp-hifi4
+              - fsl,imx8ulp-dsp
+              - fsl,imx8ulp-hifi4
+    then:
+      properties:
+        power-domains:
+          maxItems: 1
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - fsl,imx8qxp-hifi4
+              - fsl,imx8qm-hifi4
+              - fsl,imx8mp-hifi4
+              - fsl,imx8ulp-hifi4
+    then:
+      properties:
+        memory-region:
+          minItems: 4
+        mboxes:
+          maxItems: 3
+        mbox-names:
+          items:
+            - const: tx
+            - const: rx
+            - const: rxdb
+    else:
+      properties:
+        memory-region:
+          maxItems: 1
+        mboxes:
+          minItems: 4
+        mbox-names:
+          items:
+            - const: txdb0
+            - const: txdb1
+            - const: rxdb0
+            - const: rxdb1
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - fsl,imx8mp-dsp
+              - fsl,imx8mp-hifi4
+    then:
+      required:
+        - resets
+        - reset-names
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/firmware/imx/rsrc.h>
+    #include <dt-bindings/clock/imx8-clock.h>
+    dsp@596e8000 {
+        compatible = "fsl,imx8qxp-dsp";
+        reg = <0x596e8000 0x88000>;
+        clocks = <&adma_lpcg IMX_ADMA_LPCG_DSP_IPG_CLK>,
+                 <&adma_lpcg IMX_ADMA_LPCG_OCRAM_IPG_CLK>,
+                 <&adma_lpcg IMX_ADMA_LPCG_DSP_CORE_CLK>;
+        clock-names = "ipg", "ocram", "core";
+        power-domains = <&pd IMX_SC_R_MU_13B>,
+                        <&pd IMX_SC_R_MU_2A>;
+        mbox-names = "txdb0", "txdb1", "rxdb0", "rxdb1";
+        mboxes = <&lsio_mu13 2 0>, <&lsio_mu13 2 1>, <&lsio_mu13 3 0>, <&lsio_mu13 3 1>;
+        memory-region = <&dsp_reserved>;
+    };
+  - |
+    #include <dt-bindings/clock/imx8mp-clock.h>
+    #include <dt-bindings/reset/imx8mp-reset-audiomix.h>
+    dsp_reserved: dsp@92400000 {
+      reg = <0x92400000 0x1000000>;
+      no-map;
+    };
+    dsp_vdev0vring0: vdev0vring0@942f0000 {
+      reg = <0x942f0000 0x8000>;
+      no-map;
+    };
+    dsp_vdev0vring1: vdev0vring1@942f8000 {
+      reg = <0x942f8000 0x8000>;
+      no-map;
+    };
+    dsp_vdev0buffer: vdev0buffer@94300000 {
+      compatible = "shared-dma-pool";
+      reg = <0x94300000 0x100000>;
+      no-map;
+    };
+
+    dsp: dsp@3b6e8000 {
+      compatible = "fsl,imx8mp-hifi4";
+      reg = <0x3b6e8000 0x88000>;
+      clocks = <&audio_blk_ctrl IMX8MP_CLK_AUDIOMIX_DSP_ROOT>,
+               <&audio_blk_ctrl IMX8MP_CLK_AUDIOMIX_OCRAMA_IPG>,
+               <&audio_blk_ctrl IMX8MP_CLK_AUDIOMIX_DSP_ROOT>,
+               <&audio_blk_ctrl IMX8MP_CLK_AUDIOMIX_DSPDBG_ROOT>;
+      clock-names = "ipg", "ocram", "core", "debug";
+      firmware-name = "imx/dsp/hifi4.bin";
+      power-domains = <&audiomix_pd>;
+      mbox-names = "tx", "rx", "rxdb";
+      mboxes = <&mu2 0 0>,
+               <&mu2 1 0>,
+               <&mu2 3 0>;
+      memory-region = <&dsp_vdev0buffer>, <&dsp_vdev0vring0>,
+                      <&dsp_vdev0vring1>, <&dsp_reserved>;
+      resets = <&audio_blk_ctrl IMX8MP_AUDIOMIX_DSP_RUNSTALL>;
+      reset-names = "runstall";
+    };
diff --git a/Documentation/devicetree/bindings/dsp/mediatek,mt8186-dsp.yaml b/Documentation/devicetree/bindings/dsp/mediatek,mt8186-dsp.yaml
new file mode 100644
index 000000000..508b8c2f1
--- /dev/null
+++ b/Documentation/devicetree/bindings/dsp/mediatek,mt8186-dsp.yaml
@@ -0,0 +1,93 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dsp/mediatek,mt8186-dsp.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek mt8186 DSP core
+
+maintainers:
+  - AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
+
+description: |
+  MediaTek mt8186 SoC contains a DSP core used for
+  advanced pre- and post- audio processing.
+
+properties:
+  compatible:
+    enum:
+      - mediatek,mt8186-dsp
+      - mediatek,mt8188-dsp
+
+  reg:
+    items:
+      - description: Address and size of the DSP config registers
+      - description: Address and size of the DSP SRAM
+      - description: Address and size of the DSP secure registers
+      - description: Address and size of the DSP bus registers
+
+  reg-names:
+    items:
+      - const: cfg
+      - const: sram
+      - const: sec
+      - const: bus
+
+  clocks:
+    items:
+      - description: mux for audio dsp clock
+      - description: mux for audio dsp local bus
+
+  clock-names:
+    items:
+      - const: audiodsp
+      - const: adsp_bus
+
+  power-domains:
+    maxItems: 1
+
+  mboxes:
+    items:
+      - description: mailbox for receiving audio DSP requests.
+      - description: mailbox for transmitting requests to audio DSP.
+
+  mbox-names:
+    items:
+      - const: rx
+      - const: tx
+
+  memory-region:
+    items:
+      - description: dma buffer between host and DSP.
+      - description: DSP system memory.
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - clocks
+  - clock-names
+  - power-domains
+  - mbox-names
+  - mboxes
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/mt8186-clk.h>
+    dsp@10680000 {
+        compatible = "mediatek,mt8186-dsp";
+        reg = <0x10680000 0x2000>,
+              <0x10800000 0x100000>,
+              <0x1068b000 0x100>,
+              <0x1068f000 0x1000>;
+        reg-names = "cfg", "sram", "sec", "bus";
+        clocks = <&topckgen CLK_TOP_AUDIODSP>,
+                 <&topckgen CLK_TOP_ADSP_BUS>;
+        clock-names = "audiodsp",
+                      "adsp_bus";
+        power-domains = <&spm 6>;
+        mbox-names = "rx", "tx";
+        mboxes = <&adsp_mailbox0>, <&adsp_mailbox1>;
+    };
diff --git a/Documentation/devicetree/bindings/dsp/mediatek,mt8195-dsp.yaml b/Documentation/devicetree/bindings/dsp/mediatek,mt8195-dsp.yaml
new file mode 100644
index 000000000..994afb1c3
--- /dev/null
+++ b/Documentation/devicetree/bindings/dsp/mediatek,mt8195-dsp.yaml
@@ -0,0 +1,105 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dsp/mediatek,mt8195-dsp.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Mediatek mt8195 DSP core
+
+maintainers:
+  - YC Hung <yc.hung@mediatek.com>
+
+description: |
+  Some boards from mt8195 contain a DSP core used for
+  advanced pre- and post- audio processing.
+
+properties:
+  compatible:
+    const: mediatek,mt8195-dsp
+
+  reg:
+    items:
+      - description: Address and size of the DSP Cfg registers
+      - description: Address and size of the DSP SRAM
+
+  reg-names:
+    items:
+      - const: cfg
+      - const: sram
+
+  clocks:
+    items:
+      - description: mux for audio dsp clock
+      - description: 26M clock
+      - description: mux for audio dsp local bus
+      - description: default audio dsp local bus clock source
+      - description: clock gate for audio dsp clock
+      - description: mux for audio dsp access external bus
+
+  clock-names:
+    items:
+      - const: adsp_sel
+      - const: clk26m_ck
+      - const: audio_local_bus
+      - const: mainpll_d7_d2
+      - const: scp_adsp_audiodsp
+      - const: audio_h
+
+  power-domains:
+    maxItems: 1
+
+  mboxes:
+    items:
+      - description: mailbox for receiving audio DSP requests.
+      - description: mailbox for transmitting requests to audio DSP.
+
+  mbox-names:
+    items:
+      - const: rx
+      - const: tx
+
+  memory-region:
+    items:
+      - description: dma buffer between host and DSP.
+      - description: DSP system memory.
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - clocks
+  - clock-names
+  - memory-region
+  - power-domains
+  - mbox-names
+  - mboxes
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    dsp@10803000 {
+        compatible = "mediatek,mt8195-dsp";
+        reg = <0x10803000 0x1000>,
+              <0x10840000 0x40000>;
+        reg-names = "cfg", "sram";
+        clocks = <&topckgen 10>, //CLK_TOP_ADSP
+                 <&clk26m>,
+                 <&topckgen 107>, //CLK_TOP_AUDIO_LOCAL_BUS
+                 <&topckgen 136>, //CLK_TOP_MAINPLL_D7_D2
+                 <&scp_adsp 0>, //CLK_SCP_ADSP_AUDIODSP
+                 <&topckgen 34>; //CLK_TOP_AUDIO_H
+        clock-names = "adsp_sel",
+                      "clk26m_ck",
+                      "audio_local_bus",
+                      "mainpll_d7_d2",
+                      "scp_adsp_audiodsp",
+                      "audio_h";
+        memory-region = <&adsp_dma_mem_reserved>,
+                        <&adsp_mem_reserved>;
+        power-domains = <&spm 6>; //MT8195_POWER_DOMAIN_ADSP
+        mbox-names = "rx", "tx";
+        mboxes = <&adsp_mailbox0>, <&adsp_mailbox1>;
+    };