[ptxdist] [PATCH v3] image-root-cpio: Add custom compressor and compressor options.

[Christian Melki <christian.melki@t2data.com>]

* Add possibility for custom compression.
* Options are now issued with the compressor util.
* Fill in some more help regarding the methods.
* xz needs crc32 instead of crc64 for the kernel cpio.
* Set zstd compression level to the same as for the kernel (19).
* Use multithreading for zstd (deterministic, afaiu).

Actively decided against -T0 for xz, as compression
is not deterministic when number of threads varies.

Signed-off-by: Christian Melki <christian.melki@t2data.com>
---
 platforms/image-root-cpio.in | 45 +++++++++++++++++++++++++-----------
 rules/image-root-cpio.make   |  2 +-
 2 files changed, 32 insertions(+), 15 deletions(-)

diff --git a/platforms/image-root-cpio.in b/platforms/image-root-cpio.in
index d3090dc29..0338175a0 100644
--- a/platforms/image-root-cpio.in
+++ b/platforms/image-root-cpio.in
@@ -15,6 +15,8 @@ menuconfig IMAGE_ROOT_CPIO
 	  When including a cpio archive inside the kernel blob,
 	  the kernel build system can manage compressing the cpio
 	  archive itself.
+	  Beware, not all compressors are inherently deterministic
+	  when using them in a multithreaded fashion.
 
 if IMAGE_ROOT_CPIO
 
@@ -32,42 +34,57 @@ config IMAGE_ROOT_CPIO_COMPRESSION_MODE_GZ
 	bool
 	prompt "gz"
 	help
-	  Compress root.cpio with gz
+	  Compress root.cpio with gz.
+	  Uses default compression level.
 
 config IMAGE_ROOT_CPIO_COMPRESSION_MODE_ZSTD
 	bool
 	prompt "zstd"
 	help
-	  Compress root.cpio with zstd
+	  Compress root.cpio with zstd.
+	  Uses multithreaded, compression level 19.
 
 config IMAGE_ROOT_CPIO_COMPRESSION_MODE_XZ
 	bool
 	prompt "xz"
 	help
-	  Compress root.cpio with xz
+	  Compress root.cpio with xz.
+	  Uses default compression level and
+	  crc32 checksum for kernel cpio compatibility.
 
 config IMAGE_ROOT_CPIO_COMPRESSION_MODE_LZOP
 	bool
 	prompt "lzop"
 	help
-	  Compress root.cpio with lzop
+	  Compress root.cpio with lzop.
+	  Uses default compression level.
 
 endchoice
 
+config IMAGE_ROOT_CPIO_CUSTOM_COMPRESSION
+	bool
+	prompt "customize compression command"
+	help
+	  This allows specifying additional arguments to the compressor
+	  command. Note that the command itself should not be changed.
+	  Otherwise ptxdist cannot ensure that the tool is available.
+
 config IMAGE_ROOT_CPIO_COMPRESSION_SUFFIX
 	string
-	default ""		if IMAGE_ROOT_CPIO_COMPRESSION_MODE_NONE
-	default ".gz"		if IMAGE_ROOT_CPIO_COMPRESSION_MODE_GZ
-	default ".zst"		if IMAGE_ROOT_CPIO_COMPRESSION_MODE_ZSTD
-	default ".xz"		if IMAGE_ROOT_CPIO_COMPRESSION_MODE_XZ
-	default ".lzo"		if IMAGE_ROOT_CPIO_COMPRESSION_MODE_LZOP
+	prompt "compression suffix"	if IMAGE_ROOT_CPIO_CUSTOM_COMPRESSION
+	default ""			if IMAGE_ROOT_CPIO_COMPRESSION_MODE_NONE
+	default ".gz"			if IMAGE_ROOT_CPIO_COMPRESSION_MODE_GZ
+	default ".zst"			if IMAGE_ROOT_CPIO_COMPRESSION_MODE_ZSTD
+	default ".xz"			if IMAGE_ROOT_CPIO_COMPRESSION_MODE_XZ
+	default ".lzo"			if IMAGE_ROOT_CPIO_COMPRESSION_MODE_LZOP
 
 config IMAGE_ROOT_CPIO_COMPRESSION_UTIL
 	string
-	default ""		if IMAGE_ROOT_CPIO_COMPRESSION_MODE_NONE
-	default "gzip"		if IMAGE_ROOT_CPIO_COMPRESSION_MODE_GZ
-	default "zstd"		if IMAGE_ROOT_CPIO_COMPRESSION_MODE_ZSTD
-	default "xz"		if IMAGE_ROOT_CPIO_COMPRESSION_MODE_XZ
-	default "lzop"		if IMAGE_ROOT_CPIO_COMPRESSION_MODE_LZOP
+	prompt "compression tool"	if IMAGE_ROOT_CPIO_CUSTOM_COMPRESSION
+	default ""			if IMAGE_ROOT_CPIO_COMPRESSION_MODE_NONE
+	default "gzip"			if IMAGE_ROOT_CPIO_COMPRESSION_MODE_GZ
+	default "zstd -T0 -19"		if IMAGE_ROOT_CPIO_COMPRESSION_MODE_ZSTD
+	default "xz --check=crc32"	if IMAGE_ROOT_CPIO_COMPRESSION_MODE_XZ
+	default "lzop"			if IMAGE_ROOT_CPIO_COMPRESSION_MODE_LZOP
 
 endif
diff --git a/rules/image-root-cpio.make b/rules/image-root-cpio.make
index fdb0ccfff..447a649c8 100644
--- a/rules/image-root-cpio.make
+++ b/rules/image-root-cpio.make
@@ -26,7 +26,7 @@ IMAGE_ROOT_CPIO_CONFIG	:= cpio.config
 
 IMAGE_ROOT_CPIO_ENV := \
 	FORMAT="newc" \
-	COMPRESS=$(call remove_quotes, $(PTXCONF_IMAGE_ROOT_CPIO_COMPRESSION_UTIL))
+	COMPRESS=$(PTXCONF_IMAGE_ROOT_CPIO_COMPRESSION_UTIL)
 
 ifdef PTXCONF_IMAGE_ROOT_CPIO
 $(IMAGE_ROOT_CPIO_IMAGE):
-- 
2.32.0


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