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, 65 insertions, 0 deletions

diff --git a/scripts/extract-vmlinux b/scripts/extract-vmlinux
new file mode 100755
index 000000000..266df9bc7
--- /dev/null
+++ b/scripts/extract-vmlinux
@@ -0,0 +1,65 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+# ----------------------------------------------------------------------
+# extract-vmlinux - Extract uncompressed vmlinux from a kernel image
+#
+# Inspired from extract-ikconfig
+# (c) 2009,2010 Dick Streefland <dick@streefland.net>
+#
+# (c) 2011      Corentin Chary <corentin.chary@gmail.com>
+#
+# ----------------------------------------------------------------------
+
+me=${0##*/}
+
+check_vmlinux()
+{
+	if file "$1" | grep -q 'Linux kernel.*boot executable' ||
+		readelf -h "$1" > /dev/null 2>&1
+	then
+		cat "$1"
+		echo "$me: Extracted vmlinux using '$2' from offset $3" >&2
+		exit 0
+	fi
+}
+
+try_decompress()
+{
+	# The obscure use of the "tr" filter is to work around older versions of
+	# "grep" that report the byte offset of the line instead of the pattern.
+
+	# Try to find the header ($1) and decompress from here
+	for	pos in `tr "$1\n$2" "\n$2=" < "$img" | grep -abo "^$2"`
+	do
+		pos=${pos%%:*}
+		tail -c+$pos "$img" | $3 > $tmp 2> /dev/null
+		check_vmlinux $tmp "$3" $pos
+	done
+}
+
+# Check invocation:
+img=$1
+if	[ $# -ne 1 -o ! -s "$img" ]
+then
+	echo "Usage: $me <kernel-image>" >&2
+	exit 2
+fi
+
+# Prepare temp files:
+tmp=$(mktemp /tmp/vmlinux-XXX)
+trap "rm -f $tmp" 0
+
+# That didn't work, so retry after decompression.
+try_decompress '\037\213\010' xy    gunzip
+try_decompress '\3757zXZ\000' abcde unxz
+try_decompress 'BZh'          xy    bunzip2
+try_decompress '\135\0\0\0'   xxx   unlzma
+try_decompress '\211\114\132' xy    'lzop -d'
+try_decompress '\002!L\030'   xxx   'lz4 -d'
+try_decompress '(\265/\375'   xxx   unzstd
+
+# Finally check for uncompressed images or objects:
+check_vmlinux "$img" cat 0
+
+# Bail out:
+echo "$me: Cannot find vmlinux." >&2