From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions 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) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- drivers/firmware/qcom/Kconfig | 97 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) create mode 100644 drivers/firmware/qcom/Kconfig (limited to 'drivers/firmware/qcom/Kconfig') diff --git a/drivers/firmware/qcom/Kconfig b/drivers/firmware/qcom/Kconfig new file mode 100644 index 000000000..c7f8413ab --- /dev/null +++ b/drivers/firmware/qcom/Kconfig @@ -0,0 +1,97 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# For a description of the syntax of this configuration file, +# see Documentation/kbuild/kconfig-language.rst. +# + +menu "Qualcomm firmware drivers" + +config QCOM_PAS + tristate "Qualcomm generic PAS interface driver" + help + Enable the generic Peripheral Authentication Service (PAS) provided + by the firmware. It acts as the common layer with different TZ + backends plugged in whether it's an SCM implementation or a proper + TEE bus based PAS service implementation. + +config QCOM_PAS_TEE + tristate "Qualcomm PAS TEE interface driver" + select QCOM_PAS + depends on TEE + depends on !CPU_BIG_ENDIAN + default m if ARCH_QCOM + help + Enable the generic Peripheral Authentication Service (PAS) provided + by the firmware TEE implementation as the backend. + +config QCOM_SCM + tristate "Qualcomm PAS SCM interface driver" + select QCOM_PAS + select QCOM_TZMEM + default y if ARCH_QCOM + +config QCOM_TZMEM + tristate + select GENERIC_ALLOCATOR + +choice + prompt "TrustZone interface memory allocator mode" + depends on QCOM_TZMEM + default QCOM_TZMEM_MODE_GENERIC + help + Selects the mode of the memory allocator providing memory buffers of + suitable format for sharing with the TrustZone. If in doubt, select + 'Generic'. + +config QCOM_TZMEM_MODE_GENERIC + bool "Generic" + help + Use the generic allocator mode. The memory is page-aligned, non-cachable + and physically contiguous. + +config QCOM_TZMEM_MODE_SHMBRIDGE + bool "SHM Bridge" + help + Use Qualcomm Shared Memory Bridge. The memory has the same alignment as + in the 'Generic' allocator but is also explicitly marked as an SHM Bridge + buffer. + + With this selected, all buffers passed to the TrustZone must be allocated + using the TZMem allocator or else the TrustZone will refuse to use them. + +endchoice + +config QCOM_QSEECOM + bool "Qualcomm QSEECOM interface driver" + depends on QCOM_SCM=y + select AUXILIARY_BUS + help + Various Qualcomm SoCs have a Secure Execution Environment (SEE) running + in the Trust Zone. This module provides an interface to that via the + QSEECOM mechanism, using SCM calls. + + The QSEECOM interface allows, among other things, access to applications + running in the SEE. An example of such an application is 'uefisecapp', + which is required to access UEFI variables on certain systems. If + selected, the interface will also attempt to detect and register client + devices for supported applications. + + Select Y here to enable the QSEECOM interface driver. + +config QCOM_QSEECOM_UEFISECAPP + bool "Qualcomm SEE UEFI Secure App client driver" + depends on QCOM_QSEECOM + depends on EFI + help + Various Qualcomm SoCs do not allow direct access to EFI variables. + Instead, these need to be accessed via the UEFI Secure Application + (uefisecapp), residing in the Secure Execution Environment (SEE). + + This module provides a client driver for uefisecapp, installing efivar + operations to allow the kernel accessing EFI variables, and via that also + provide user-space with access to EFI variables via efivarfs. + + Select Y here to provide access to EFI variables on the aforementioned + platforms. + +endmenu -- cgit v1.3.1