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, 33 insertions, 0 deletions

diff --git a/include/kunit/visibility.h b/include/kunit/visibility.h
new file mode 100644
index 000000000..7c34c8ffc
--- /dev/null
+++ b/include/kunit/visibility.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * KUnit API to allow symbols to be conditionally visible during KUnit
+ * testing
+ *
+ * Copyright (C) 2022, Google LLC.
+ * Author: Rae Moar <rmoar@google.com>
+ */
+
+#ifndef _KUNIT_VISIBILITY_H
+#define _KUNIT_VISIBILITY_H
+
+#if IS_ENABLED(CONFIG_KUNIT)
+    /**
+     * VISIBLE_IF_KUNIT - A macro that sets symbols to be static if
+     * CONFIG_KUNIT is not enabled. Otherwise if CONFIG_KUNIT is enabled
+     * there is no change to the symbol definition.
+     */
+    #define VISIBLE_IF_KUNIT
+    /**
+     * EXPORT_SYMBOL_IF_KUNIT(symbol) - Exports symbol into
+     * EXPORTED_FOR_KUNIT_TESTING namespace only if CONFIG_KUNIT is
+     * enabled. Must use MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING")
+     * in test file in order to use symbols.
+     * @symbol: the symbol identifier to export
+     */
+    #define EXPORT_SYMBOL_IF_KUNIT(symbol) EXPORT_SYMBOL_NS(symbol, "EXPORTED_FOR_KUNIT_TESTING")
+#else
+    #define VISIBLE_IF_KUNIT static
+    #define EXPORT_SYMBOL_IF_KUNIT(symbol)
+#endif
+
+#endif /* _KUNIT_VISIBILITY_H */