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authorFuad Tabba <fuad.tabba@linux.dev>2026-09-22 19:14:30 +0100
committerWill Deacon <will@kernel.org>2026-09-23 12:34:30 +0000
commit2bc6b218717b9d08f466f88209251d54bc09b207 (patch)
treecb91c941eccb15f94cbec4e96aa3a9c8736b5d66 /drivers/mcb/Kconfig
downloadlinux-stable-2bc6b218717b9d08f466f88209251d54bc09b207.tar.gz
linux-stable-2bc6b218717b9d08f466f88209251d54bc09b207.zip
arm64/boot: Disable trapping of PMZR_EL0 writes to EL2grafted
__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 <fuad.tabba@linux.dev> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Oliver Upton <oupton@kernel.org> Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'drivers/mcb/Kconfig')
-rw-r--r--drivers/mcb/Kconfig41
1 files changed, 41 insertions, 0 deletions
diff --git a/drivers/mcb/Kconfig b/drivers/mcb/Kconfig
new file mode 100644
index 000000000..0a883486f
--- /dev/null
+++ b/drivers/mcb/Kconfig
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# MEN Chameleon Bus (MCB) support
+#
+
+menuconfig MCB
+ tristate "MCB support"
+ default n
+ depends on HAS_IOMEM
+ help
+
+ The MCB (MEN Chameleon Bus) is a Bus specific to MEN Mikroelektronik
+ FPGA based devices. It is used to identify MCB based IP-Cores within
+ an FPGA and provide the necessary framework for instantiating drivers
+ for these devices.
+
+ If build as a module, the module is called mcb.ko
+
+if MCB
+config MCB_PCI
+ tristate "PCI based MCB carrier"
+ default n
+ depends on PCI
+ help
+
+ This is a MCB carrier on a PCI device. Both PCI attached on-board
+ FPGAs as well as CompactPCI attached MCB FPGAs are supported with
+ this driver.
+
+ If build as a module, the module is called mcb-pci.ko
+
+config MCB_LPC
+ tristate "LPC (non PCI) based MCB carrier"
+ default n
+ help
+
+ This is a MCB carrier on a LPC or non PCI device.
+
+ If build as a module, the module is called mcb-lpc.ko
+
+endif # MCB