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, 25 insertions, 0 deletions

diff --git a/scripts/module-common.c b/scripts/module-common.c
new file mode 100644
index 000000000..12fbc6d3a
--- /dev/null
+++ b/scripts/module-common.c
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/module.h>
+/*
+ * Include build-salt.h after module.h in order to
+ * inherit the definitions.
+ */
+#define INCLUDE_VERMAGIC
+#include <linux/build-salt.h>
+#include <linux/elfnote-lto.h>
+#include <linux/vermagic.h>
+
+#ifdef CONFIG_UNWINDER_ORC
+#include <asm/orc_header.h>
+ORC_HEADER;
+#endif
+
+BUILD_SALT;
+BUILD_LTO_INFO;
+
+MODULE_INFO(vermagic, VERMAGIC_STRING);
+
+#ifdef CONFIG_MITIGATION_RETPOLINE
+MODULE_INFO(retpoline, "Y");
+#endif