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>

1 files changed, 62 insertions, 0 deletions

diff --git a/include/drm/intel/step.h b/include/drm/intel/step.h
new file mode 100644
index 000000000..4de752010
--- /dev/null
+++ b/include/drm/intel/step.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: MIT */
+/* Copyright © 2026 Intel Corporation */
+
+#ifndef __STEP_H__
+#define __STEP_H__
+
+#define STEP_ENUM_VAL(name)  STEP_##name,
+
+#define STEP_NAME_LIST(func)		\
+	func(A0)			\
+	func(A1)			\
+	func(A2)			\
+	func(A3)			\
+	func(B0)			\
+	func(B1)			\
+	func(B2)			\
+	func(B3)			\
+	func(C0)			\
+	func(C1)			\
+	func(C2)			\
+	func(C3)			\
+	func(D0)			\
+	func(D1)			\
+	func(D2)			\
+	func(D3)			\
+	func(E0)			\
+	func(E1)			\
+	func(E2)			\
+	func(E3)			\
+	func(F0)			\
+	func(F1)			\
+	func(F2)			\
+	func(F3)			\
+	func(G0)			\
+	func(G1)			\
+	func(G2)			\
+	func(G3)			\
+	func(H0)			\
+	func(H1)			\
+	func(H2)			\
+	func(H3)			\
+	func(I0)			\
+	func(I1)			\
+	func(I2)			\
+	func(I3)			\
+	func(J0)			\
+	func(J1)			\
+	func(J2)			\
+	func(J3)
+
+/*
+ * Symbolic steppings that do not match the hardware. These are valid both as gt
+ * and display steppings as symbolic names.
+ */
+enum intel_step {
+	STEP_NONE = 0,
+	STEP_NAME_LIST(STEP_ENUM_VAL)
+	STEP_FUTURE,
+	STEP_FOREVER,
+};
+
+#endif /* __STEP_H__ */