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/driver-api/wmi.rst | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 Documentation/driver-api/wmi.rst (limited to 'Documentation/driver-api/wmi.rst') diff --git a/Documentation/driver-api/wmi.rst b/Documentation/driver-api/wmi.rst new file mode 100644 index 000000000..b847bcdcb --- /dev/null +++ b/Documentation/driver-api/wmi.rst @@ -0,0 +1,23 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +============== +WMI Driver API +============== + +The WMI driver core supports a more modern bus-based interface for interacting +with WMI devices, and an older GUID-based interface. The latter interface is +considered to be deprecated, so new WMI drivers should generally avoid it since +it has some issues with multiple WMI devices sharing the same GUID. +The modern bus-based interface instead maps each WMI device to a +:c:type:`struct wmi_device `, so it supports WMI devices sharing the +same GUID. Drivers can then register a :c:type:`struct wmi_driver ` +which will be bound to compatible WMI devices by the driver core. + +.. kernel-doc:: include/linux/wmi.h + :internal: + +.. kernel-doc:: drivers/platform/wmi/string.c + :export: + +.. kernel-doc:: drivers/platform/wmi/core.c + :export: -- cgit v1.3.1