From 2bc6b218717b9d08f466f88209251d54bc09b207 Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 22 Sep 2026 19:14:30 +0100 Subject: arm64/boot: Disable trapping of PMZR_EL0 writes to EL2 __init_el2_fgt2() writes one mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2. PMZR_EL0 is write-only, so its trap bit, nPMZR_EL0, exists only in HDFGWTR2_EL2 and is therefore never set: a PMZR_EL0 write from the host traps to EL2, where the nVHE hypervisor has no handler and BUG()s. The kernel never writes PMZR_EL0, but kernel.perf_user_access=1 has the PMU driver set PMUSERENR_EL0.UEN for a task with a user-read event, so a write from EL0 reaches the trap and takes the host down without a panic message. Accumulate the HDFGWTR2_EL2 bits separately, as __init_el2_fgt() already does for HDFGWTR_EL2, and set nPMZR_EL0 with the other FEAT_PMUv3p9 bits. Fixes: 858c7bfcb35e1 ("arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9") Cc: stable@vger.kernel.org Signed-off-by: Fuad Tabba Reviewed-by: Anshuman Khandual Reviewed-by: Oliver Upton Signed-off-by: Will Deacon --- Documentation/userspace-api/ebpf/index.rst | 17 +++++++++++++++++ Documentation/userspace-api/ebpf/syscall.rst | 24 ++++++++++++++++++++++++ 2 files changed, 41 insertions(+) create mode 100644 Documentation/userspace-api/ebpf/index.rst create mode 100644 Documentation/userspace-api/ebpf/syscall.rst (limited to 'Documentation/userspace-api/ebpf') diff --git a/Documentation/userspace-api/ebpf/index.rst b/Documentation/userspace-api/ebpf/index.rst new file mode 100644 index 000000000..473dfba78 --- /dev/null +++ b/Documentation/userspace-api/ebpf/index.rst @@ -0,0 +1,17 @@ +.. SPDX-License-Identifier: GPL-2.0 + +eBPF Userspace API +================== + +eBPF is a kernel mechanism to provide a sandboxed runtime environment in the +Linux kernel for runtime extension and instrumentation without changing kernel +source code or loading kernel modules. eBPF programs can be attached to various +kernel subsystems, including networking, tracing and Linux security modules +(LSM). + +For internal kernel documentation on eBPF, see Documentation/bpf/index.rst. + +.. toctree:: + :maxdepth: 1 + + syscall diff --git a/Documentation/userspace-api/ebpf/syscall.rst b/Documentation/userspace-api/ebpf/syscall.rst new file mode 100644 index 000000000..ea9918084 --- /dev/null +++ b/Documentation/userspace-api/ebpf/syscall.rst @@ -0,0 +1,24 @@ +.. SPDX-License-Identifier: GPL-2.0 + +eBPF Syscall +------------ + +:Authors: - Alexei Starovoitov + - Joe Stringer + - Michael Kerrisk + +The primary info for the bpf syscall is available in the `man-pages`_ +for `bpf(2)`_. + +bpf() subcommand reference +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. kernel-doc:: include/uapi/linux/bpf.h + :doc: eBPF Syscall Preamble + +.. kernel-doc:: include/uapi/linux/bpf.h + :doc: eBPF Syscall Commands + +.. Links: +.. _man-pages: https://www.kernel.org/doc/man-pages/ +.. _bpf(2): https://man7.org/linux/man-pages/man2/bpf.2.html -- cgit v1.3.1