Makefile, copy-firmware: support xz/zstd compressed firmware

The kernel has supported compressed firmware for quite some time. So
let's add a couple of targets to produce that. In practical terms this
means it we'll use ~5x times less space on disk.

Reportedly the amd ucode, needs to be uncompressed _within_ the
initrd in order to work. Using compressed ucode in late load just works.
Ideally this will be addressed by the initrd generators, but considering
the files are tiny in size let's skip the compression.

v2
 - commit message, skip compression for files annotated as Raw

v3
 - rebase

[Drop extra verbose statement in zstd case, Josh Boyer
<jwboyer@kernel.org>]

Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>

Makefile

@@ -11,3 +11,11 @@ check:
 install:
 	install -d $(DESTDIR)$(FIRMWAREDIR)
 	./copy-firmware.sh $(DESTDIR)$(FIRMWAREDIR)
+
+install-xz:
+	install -d $(DESTDIR)$(FIRMWAREDIR)
+	./copy-firmware.sh --xz $(DESTDIR)$(FIRMWAREDIR)
+
+install-zst:
+	install -d $(DESTDIR)$(FIRMWAREDIR)
+	./copy-firmware.sh --zstd $(DESTDIR)$(FIRMWAREDIR)

WHENCE

@@ -3890,14 +3890,19 @@ License: Redistributable. See LICENSE.amd-sev for details
 Driver: microcode_amd - AMD CPU Microcode Update Driver for Linux
 
 File: amd-ucode/microcode_amd.bin
+Raw: amd-ucode/microcode_amd.bin
 Version: 2013-07-10
 File: amd-ucode/microcode_amd_fam15h.bin
+Raw: amd-ucode/microcode_amd_fam15h.bin
 Version: 2018-05-24
 File: amd-ucode/microcode_amd_fam16h.bin
+Raw: amd-ucode/microcode_amd_fam16h.bin
 Version: 2014-10-28
 File: amd-ucode/microcode_amd_fam17h.bin
+Raw: amd-ucode/microcode_amd_fam17h.bin
 Version: 2023-04-13
 File: amd-ucode/microcode_amd_fam19h.bin
+Raw: amd-ucode/microcode_amd_fam19h.bin
 Version: 2023-01-31
 File: amd-ucode/README
 

copy-firmware.sh

@@ -6,6 +6,9 @@
 
 verbose=:
 prune=no
+# shellcheck disable=SC2209
+compress=cat
+compext=
 
 while test $# -gt 0; do
     case $1 in
@@ -20,6 +23,27 @@ while test $# -gt 0; do
             shift
             ;;
 
+        --xz)
+            if test "$compext" == ".zst"; then
+                echo "ERROR: cannot mix XZ and ZSTD compression"
+                exit 1
+            fi
+            compress="xz --compress --quiet --stdout --check=crc32"
+            compext=".xz"
+            shift
+            ;;
+
+        --zstd)
+            if test "$compext" == ".xz"; then
+                echo "ERROR: cannot mix XZ and ZSTD compression"
+                exit 1
+            fi
+            # shellcheck disable=SC2209
+            compress="zstd --compress --quiet --stdout"
+            compext=".zst"
+            shift
+            ;;
+
         *)
             if test "x$destdir" != "x"; then
                 echo "ERROR: unknown command-line options: $*"
@@ -35,18 +59,23 @@ done
 # shellcheck disable=SC2162 # file/folder name can include escaped symbols
 grep '^File:' WHENCE | sed -e 's/^File: *//g;s/"//g' | while read f; do
     test -f "$f" || continue
-    $verbose "copying file $f"
     install -d "$destdir/$(dirname "$f")"
-    cp -d "$f" "$destdir/$f"
+    $verbose "copying/compressing file $f$compext"
+    if test "$compress" != "cat" && grep -q "^Raw: $f\$" WHENCE; then
+        $verbose "compression will be skipped for file $f"
+        cat "$f" > "$destdir/$f"
+    else
+        $compress "$f" > "$destdir/$f$compext"
+    fi
 done
 
 # shellcheck disable=SC2162 # file/folder name can include escaped symbols
 grep -E '^Link:' WHENCE | sed -e 's/^Link: *//g;s/-> //g' | while read f d; do
-    if test -L "$f"; then
-        test -f "$destdir/$f" && continue
-        $verbose "copying link $f"
+    if test -L "$f$compext"; then
+        test -f "$destdir/$f$compext" && continue
+        $verbose "copying link $f$compext"
         install -d "$destdir/$(dirname "$f")"
-        cp -d "$f" "$destdir/$f"
+        cp -d "$f$compext" "$destdir/$f$compext"
 
         if test "x$d" != "x"; then
             target="$(readlink "$f")"
@@ -58,16 +87,16 @@ grep -E '^Link:' WHENCE | sed -e 's/^Link: *//g;s/-> //g' | while read f d; do
                     $verbose "WARNING: unneeded symlink detected: $f"
                 else
                     $verbose "WARNING: pruning unneeded symlink $f"
-                    rm -f "$f"
+                    rm -f "$f$compext"
                 fi
             fi
         else
             $verbose "WARNING: missing target for symlink $f"
         fi
     else
-        $verbose "creating link $f -> $d"
         install -d "$destdir/$(dirname "$f")"
-        ln -sf "$d" "$destdir/$f"
+        $verbose "creating link $f$compext -> $d$compext"
+        ln -s "$d$compext" "$destdir/$f$compext"
     fi
 done