#! /bin/bash -efu

# Generator of RPM "Provides:" tags for Intel microcode files.

#

# SPDX-License-Identifier: CC0-1.0

IFS=$'\n'

UPDATED="intel-beta"

CODENAMES="codenames"

if [ "$#" -ge 1 ]; then

	CODENAMES="$1"

	shift

fi

# Match only FF-MM-SS ucode files under intel-ucode/intel-ucode-with-caveats

# directories.

for f in $(grep -E '/intel-ucode.*/[0-9a-f][0-9a-f]-[0-9a-f][0-9a-f]-[0-9a-f][0-9a-f]$'); do

	ucode=$(basename "$f")

	ucode_caveat="$(basename "$(dirname "$(dirname "$f")")")"

	ucode_fname="$ucode_caveat/$ucode"

	file_sz="$(stat -c "%s" "$f")"

	skip=0

	ext_hdr=0

	ext_sig_cnt=0

	ext_sig_pos=0

	next_skip=0

	# Microcode header format description:

	# https://gitlab.com/iucode-tool/iucode-tool/blob/master/intel_microcode.c

	while :; do

		[ "$skip" -lt "$file_sz" ] || break

		# Do we parse ext_sig table or another microcode header?

		if [ 0 != "$next_skip" ]; then

			# Check whether we should abort ext_sig table parsing

			[ \( "${skip}" -lt "${next_skip}" \) -a \

			  \( "${ext_sig_pos}" -lt "${ext_sig_cnt}" \) ] || {

				skip="${next_skip}"

				next_skip=0

				continue

			}

			# ext_sig, 12 bytes in size

			IFS=' ' read cpuid pf_mask <<- EOF

			$(hexdump -s "$skip" -n 8 \

				-e '"" 1/4 "%08x " 1/4 "%u" "\n"' "$f")

			EOF

			skip="$((skip + 12))"

			ext_sig_pos="$((ext_sig_pos + 1))"

		else

			# Microcode header, 48 bytes, last 3 fields reserved

			IFS=' ' read hdrver rev \

			       date_y date_d date_m \

			       cpuid cksum ldrver \

			       pf_mask datasz totalsz <<- EOF

			$(hexdump -s "$skip" -n 36 \

				-e '"" 1/4 "%u " 1/4 "%#x " \

			               1/2 "%04x " 1/1 "%02x " 1/1 "%02x " \

				       1/4 "%08x " 1/4 "%x " 1/4 "%#x " \

				       1/4 "%u " 1/4 "%u " 1/4 "%u" "\n"' "$f")

			EOF

			[ 0 != "$datasz" ] || datasz=2000

			[ 0 != "$totalsz" ] || totalsz=2048

			# TODO: add some sanity/safety checks here.  As of now,

			#       there's a (pretty fragile) assumption that all

			#       the matched files are valid Intel microcode

			#       files in the expected format.

			# ext_sig table is after the microcode payload,

			# check for its presence

			if [ 48 -lt "$((totalsz - datasz))" ]; then

				next_skip="$((skip + totalsz))"

				skip="$((skip + datasz + 48))"

				ext_sig_pos=0

				# ext_sig table header, 20 bytes in size,

				# last 3 fields are reserved.

				IFS=' ' read ext_sig_cnt  <<- EOF

				$(hexdump -s "$skip" -n 4 \

					-e '"" 1/4 "%u" "\n"' "$f")

				EOF

				skip="$((skip + 20))"

			else

				skip="$((skip + totalsz))"

				next_skip=0

			fi

		fi

		#[ -n "$rev" ] || continue

		# Basic "Provides:" tag. Everything else is bells and whistles.

		# It's possible that microcode files for different platform_id's

		# and the same CPUID have the same version, that's why "sort -u"

		# in the end.

		printf "firmware(intel-ucode/%s) = %s\n" "$ucode" "$rev"

		# Generate extended "Provides:" tags with additional

		# information, which allow more precise matching.

		printf "iucode_date(fname:%s;cpuid:%s;pf_mask:0x%x) = %s.%s.%s\n" \

			"$ucode_fname" "$cpuid" "$pf_mask" "$date_y" "$date_m" "$date_d"

		printf "iucode_rev(fname:%s;cpuid:%s;pf_mask:0x%x) = %s\n" \

			"$ucode_fname" "$cpuid" "$pf_mask" "$rev"

		# Generate tags for each possible platform_id

		_pf=1

		_pf_mask="$pf_mask"

		while [ 0 -lt "$_pf_mask" ]; do

			[ 1 -ne "$((_pf_mask % 2))" ] || \

				# We try to provide a more specific firmware()

				# dependency here.  It has incorrect file name,

				# but allows constructing a required RPM

				# capability name by (directly) using

				# the contents of /proc/cpuinfo and

				# /sys/devices/system/cpu/cpu*/microcode/processor_flags

				# (except for a Deschutes CPU with sig 0x1632)

				printf "iucode_rev(fname:%s;platform_id:0x%x) = %s\n" \

					"$ucode_fname" "$_pf" "$rev"

			_pf_mask=$((_pf_mask / 2))

			_pf=$((_pf * 2))

		done

		# Generate tags with codename information, in case

		# it is available

		cpuid_up="$(echo "$cpuid" | tr 'a-z' 'A-Z')"

		if [ -e "$CODENAMES" ]; then

			grep '	'"$cpuid_up"'	' "$CODENAMES" \

			| while IFS=$'\t' read segm int_fname codename stepping candidate_pf rest; do

				codename=$(echo "$codename" | tr ' (),' '_[];')

				candidate_pf=$(printf "%u" "0x${candidate_pf}")

				[ \( 0 -ne "$pf_mask" \) -a \

				  \( "$candidate_pf" -ne "$((candidate_pf & pf_mask))" \) ] || { \

					printf "iucode_rev(fname:%s;cpuid:%s;pf_mask:0x%x;segment:\"%s\";codename:\"%s\";stepping:\"%s\";pf_model:0x%x) = %s\n" \

						"$ucode_fname" "$cpuid" "$pf_mask" \

						"$segm" "$codename" "$stepping" "$candidate_pf" \

						"$rev";

					printf "iucode_date(fname:%s;cpuid:%s;pf_mask:0x%x;segment:\"%s\";codename:\"%s\";stepping:\"%s\";pf_model:0x%x) = %s.%s.%s\n" \

						"$ucode_fname" "$cpuid" "$pf_mask" \

						"$segm" "$codename" "$stepping" "$candidate_pf" \

						"$date_y" "$date_m" "$date_d";

				  }

			done

		fi

		# Kludge squared: generate additional "Provides:" tags

		# for the files in the overrides tarball (that a placed

		# in a separate caveat with a specific name)

		[ "x${ucode_caveat}" != "x${UPDATED}" ] || {

			printf "firmware_updated(intel-ucode/%s) = %s\n" \

				"$ucode" "$rev";

		}

	done

done | sort -u