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, 98 insertions, 0 deletions

diff --git a/scripts/syscallhdr.sh b/scripts/syscallhdr.sh
new file mode 100755
index 000000000..22e34cd46
--- /dev/null
+++ b/scripts/syscallhdr.sh
@@ -0,0 +1,98 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Generate a syscall number header.
+#
+# Each line of the syscall table should have the following format:
+#
+# NR ABI NAME [NATIVE] [COMPAT]
+#
+# NR       syscall number
+# ABI      ABI name
+# NAME     syscall name
+# NATIVE   native entry point (optional)
+# COMPAT   compat entry point (optional)
+
+set -e
+
+usage() {
+	echo >&2 "usage: $0 [--abis ABIS] [--emit-nr] [--offset OFFSET] [--prefix PREFIX] INFILE OUTFILE" >&2
+	echo >&2
+	echo >&2 "  INFILE    input syscall table"
+	echo >&2 "  OUTFILE   output header file"
+	echo >&2
+	echo >&2 "options:"
+	echo >&2 "  --abis ABIS        ABI(s) to handle (By default, all lines are handled)"
+	echo >&2 "  --emit-nr          Emit the macro of the number of syscalls (__NR_syscalls)"
+	echo >&2 "  --offset OFFSET    The offset of syscall numbers"
+	echo >&2 "  --prefix PREFIX    The prefix to the macro like __NR_<PREFIX><NAME>"
+	exit 1
+}
+
+# default unless specified by options
+abis=
+emit_nr=
+offset=
+prefix=
+
+while [ $# -gt 0 ]
+do
+	case $1 in
+	--abis)
+		abis=$(echo "($2)" | tr ',' '|')
+		shift 2;;
+	--emit-nr)
+		emit_nr=1
+		shift 1;;
+	--offset)
+		offset=$2
+		shift 2;;
+	--prefix)
+		prefix=$2
+		shift 2;;
+	-*)
+		echo "$1: unknown option" >&2
+		usage;;
+	*)
+		break;;
+	esac
+done
+
+if [ $# -ne 2 ]; then
+	usage
+fi
+
+infile="$1"
+outfile="$2"
+
+guard=_UAPI_ASM_$(basename "$outfile" |
+	sed -e 'y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/' \
+	-e 's/[^A-Z0-9_]/_/g' -e 's/__/_/g')
+
+grep -E "^[0-9A-Fa-fXx]+[[:space:]]+$abis" "$infile" | {
+	echo "#ifndef $guard"
+	echo "#define $guard"
+	echo
+
+	max=0
+	while read nr abi name native compat ; do
+
+		max=$nr
+
+		if [ -n "$offset" ]; then
+			nr="($offset + $nr)"
+		fi
+
+		echo "#define __NR_$prefix$name $nr"
+	done
+
+	if [ -n "$emit_nr" ]; then
+		echo
+		echo "#ifdef __KERNEL__"
+		echo "#define __NR_${prefix}syscalls $(($max + 1))"
+		echo "#endif"
+	fi
+
+	echo
+	echo "#endif /* $guard */"
+} > "$outfile"