From: Nick Terrell <terre...@fb.com> Add support for extracting ZSTD-compressed kernel images, as well as ZSTD-compressed ramdisk images in the kernel boot process.
When neither `fill' nor `flush' are used, the decompression function requires a constant amount of memory (192 KB is sufficient). When either is used the decompression function requires memory proportional to the window size used during compression, which is limited to 8 MB. The maximum memory usage is just over 8 MB. Fix up lib/zstd and lib/xxhash.c for the preboot environment. They avoid declaring themselves as modules. A memcpy() call needs to be a __builtin_memcpy() for performance. The gcc-7.1 bug in ZSTD_wildcopy() was fixed in gcc-7.2, so it can be gated, since it hurts performance. Signed-off-by: Nick Terrell <terre...@fb.com> --- include/linux/decompress/unzstd.h | 26 +++ init/Kconfig | 14 +- lib/Kconfig | 4 + lib/Makefile | 1 + lib/decompress.c | 5 + lib/decompress_unzstd.c | 341 ++++++++++++++++++++++++++++++ lib/xxhash.c | 21 +- lib/zstd/decompress.c | 2 + lib/zstd/fse_decompress.c | 9 +- lib/zstd/zstd_internal.h | 10 +- scripts/Makefile.lib | 15 ++ usr/Kconfig | 22 ++ 12 files changed, 451 insertions(+), 19 deletions(-) create mode 100644 include/linux/decompress/unzstd.h create mode 100644 lib/decompress_unzstd.c diff --git a/include/linux/decompress/unzstd.h b/include/linux/decompress/unzstd.h new file mode 100644 index 000000000000..6f3022cd0955 --- /dev/null +++ b/include/linux/decompress/unzstd.h @@ -0,0 +1,26 @@ +/* + * Copyright (C) 2017 Facebook + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License v2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +#ifndef LINUX_DECOMPRESS_UNZSTD_H +#define LINUX_DECOMPRESS_UNZSTD_H + +int unzstd(unsigned char *inbuf, long len, + long (*fill)(void*, unsigned long), + long (*flush)(void*, unsigned long), + unsigned char *output, + long *pos, + void (*error_fn)(char *x)); +#endif diff --git a/init/Kconfig b/init/Kconfig index a4112e95724a..ffa5ae4abc88 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -134,13 +134,16 @@ config HAVE_KERNEL_LZO config HAVE_KERNEL_LZ4 bool +config HAVE_KERNEL_ZSTD + bool + config HAVE_KERNEL_UNCOMPRESSED bool choice prompt "Kernel compression mode" default KERNEL_GZIP - depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 || HAVE_KERNEL_UNCOMPRESSED + depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 || HAVE_KERNEL_ZSTD || HAVE_KERNEL_UNCOMPRESSED help The linux kernel is a kind of self-extracting executable. Several compression algorithms are available, which differ @@ -219,6 +222,15 @@ config KERNEL_LZ4 is about 8% bigger than LZO. But the decompression speed is faster than LZO. +config KERNEL_ZSTD + bool "ZSTD" + depends on HAVE_KERNEL_ZSTD + help + ZSTD is a compression algorithm targeting intermediate compression + with fast decompression speed. It will compress better than GZIP and + decompress around the same speed as LZO, but slower than LZ4. You + will need at least 192 KB RAM or more for booting. + config KERNEL_UNCOMPRESSED bool "None" depends on HAVE_KERNEL_UNCOMPRESSED diff --git a/lib/Kconfig b/lib/Kconfig index a9965f4af4dd..e7ab43fd5461 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -304,6 +304,10 @@ config DECOMPRESS_LZ4 select LZ4_DECOMPRESS tristate +config DECOMPRESS_ZSTD + select ZSTD_DECOMPRESS + tristate + # # Generic allocator support is selected if needed # diff --git a/lib/Makefile b/lib/Makefile index db06d1237898..58b48993f48a 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -139,6 +139,7 @@ lib-$(CONFIG_DECOMPRESS_LZMA) += decompress_unlzma.o lib-$(CONFIG_DECOMPRESS_XZ) += decompress_unxz.o lib-$(CONFIG_DECOMPRESS_LZO) += decompress_unlzo.o lib-$(CONFIG_DECOMPRESS_LZ4) += decompress_unlz4.o +lib-$(CONFIG_DECOMPRESS_ZSTD) += decompress_unzstd.o obj-$(CONFIG_TEXTSEARCH) += textsearch.o obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o diff --git a/lib/decompress.c b/lib/decompress.c index 857ab1af1ef3..ab3fc90ffc64 100644 --- a/lib/decompress.c +++ b/lib/decompress.c @@ -13,6 +13,7 @@ #include <linux/decompress/inflate.h> #include <linux/decompress/unlzo.h> #include <linux/decompress/unlz4.h> +#include <linux/decompress/unzstd.h> #include <linux/types.h> #include <linux/string.h> @@ -37,6 +38,9 @@ #ifndef CONFIG_DECOMPRESS_LZ4 # define unlz4 NULL #endif +#ifndef CONFIG_DECOMPRESS_ZSTD +# define unzstd NULL +#endif struct compress_format { unsigned char magic[2]; @@ -52,6 +56,7 @@ static const struct compress_format compressed_formats[] __initconst = { { {0xfd, 0x37}, "xz", unxz }, { {0x89, 0x4c}, "lzo", unlzo }, { {0x02, 0x21}, "lz4", unlz4 }, + { {0x28, 0xb5}, "zstd", unzstd }, { {0, 0}, NULL, NULL } }; diff --git a/lib/decompress_unzstd.c b/lib/decompress_unzstd.c new file mode 100644 index 000000000000..84315dc9bf24 --- /dev/null +++ b/lib/decompress_unzstd.c @@ -0,0 +1,341 @@ +/* + * Copyright (C) 2017 Facebook + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License v2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +/* + * Important notes about in-place decompression + * + * At least on x86, the kernel is decompressed in place: the compressed data + * is placed to the end of the output buffer, and the decompressor overwrites + * most of the compressed data. There must be enough safety margin to + * guarantee that the write position is always behind the read position. + * + * The safety margin for ZSTD with a 128 KB block size is calculated below. + * Note that the margin with ZSTD is bigger than with GZIP or XZ! + * + * The worst case for in-place decompression is that the beginning of + * the file is compressed extremely well, and the rest of the file is + * uncompressible. Thus, we must look for worst-case expansion when the + * compressor is encoding uncompressible data. + * + * The structure of the .zst file in case of a compresed kernel is as follows. + * Maximum sizes (as bytes) of the fields are in parenthesis. + * + * Frame Header: (18) + * Blocks: (N) + * Checksum: (4) + * + * The frame header and checksum overhead is at most 22 bytes. + * + * ZSTD stores the data in blocks. Each block has a header whose size is + * a 3 bytes. After the block header, there is up to 128 KB of payload. + * The maximum uncompressed size of the payload is 128 KB. The minimum + * uncompressed size of the payload is never less than the payload size + * (excluding the block header). + * + * The assumption, that the uncompressed size of the payload is never + * smaller than the payload itself, is valid only when talking about + * the payload as a whole. It is possible that the payload has parts where + * the decompressor consumes more input than it produces output. Calculating + * the worst case for this would be tricky. Instead of trying to do that, + * let's simply make sure that the decompressor never overwrites any bytes + * of the payload which it is currently reading. + * + * Now we have enough information to calculate the safety margin. We need + * - 22 bytes for the .zst file format headers; + * - 3 bytes per every 128 KiB of uncompressed size (one block header per + * block); and + * - 128 KiB (biggest possible zstd block size) to make sure that the + * decompressor never overwrites anything from the block it is currently + * reading. + * + * We get the following formula: + * + * safety_margin = 22 + uncompressed_size * 3 / 131072 + 131072 + * <= 22 + (uncompressed_size >> 15) + 131072 + */ + +#ifdef STATIC + /* Preboot environments #include "path/to/decompress_unzstd.c". + * All of the source files we depend on must be #included. + * zstd's only source dependeny is xxhash, which has no source + * dependencies. + * + * zstd and xxhash both avoid declaring themselves as modules + * when PREBOOT is defined. + */ +# define PREBOOT +# include "xxhash.c" +# include "zstd/entropy_common.c" +# include "zstd/fse_decompress.c" +# include "zstd/huf_decompress.c" +# include "zstd/zstd_common.c" +# include "zstd/decompress.c" +#endif + +#include <linux/decompress/mm.h> +#include <linux/kernel.h> +#include <linux/zstd.h> + +/* 8 MB maximum window size */ +#define ZSTD_WINDOWSIZE_MAX (1 << 23) +/* Size of the input and output buffers in multi-call mdoe */ +#define ZSTD_IOBUF_SIZE 4096 + +static int INIT handle_zstd_error(size_t ret, void (*error)(char *x)) +{ + const int err = ZSTD_getErrorCode(ret); + + if (!ZSTD_isError(ret)) + return 0; + + switch (err) { + case ZSTD_error_memory_allocation: + error("ZSTD decompressor ran out of memory"); + break; + case ZSTD_error_prefix_unknown: + error("Input is not in the ZSTD format (wrong magic bytes)"); + break; + case ZSTD_error_dstSize_tooSmall: + case ZSTD_error_corruption_detected: + case ZSTD_error_checksum_wrong: + error("ZSTD-compressed data is corrupt"); + break; + default: + error("ZSTD-compressed data is probably corrupt"); + break; + } + return -1; +} + +/* Handle the case where we have the entire input and output in one segment. + * We can allocate less memory (no circular buffer for the sliding window), + * and avoid some memcpy() calls. + */ +static int INIT decompress_single(const u8 *in_buf, long in_len, u8 *out_buf, + long out_len, long *in_pos, + void (*error)(char *x)) +{ + const size_t wksp_size = ZSTD_DCtxWorkspaceBound(); + void *wksp = large_malloc(wksp_size); + ZSTD_DCtx *dctx = ZSTD_initDCtx(wksp, wksp_size); + int err; + size_t ret; + + if (dctx == NULL) { + error("Out of memory while allocating ZSTD_DCtx"); + err = -1; + goto out; + } + /* Find out how large the frame actually is, there may be junk at + * the end of the frame that ZSTD_decompressDCtx() can't handle. + */ + ret = ZSTD_findFrameCompressedSize(in_buf, in_len); + err = handle_zstd_error(ret, error); + if (err) + goto out; + in_len = (long)ret; + + ret = ZSTD_decompressDCtx(dctx, out_buf, out_len, in_buf, in_len); + err = handle_zstd_error(ret, error); + if (err) + goto out; + + if (in_pos != NULL) + *in_pos = in_len; + + err = 0; +out: + if (wksp != NULL) + large_free(wksp); + return err; +} + +static int INIT __unzstd(unsigned char *in_buf, long in_len, + long (*fill)(void*, unsigned long), + long (*flush)(void*, unsigned long), + unsigned char *out_buf, long out_len, + long *in_pos, + void (*error)(char *x)) +{ + ZSTD_inBuffer in; + ZSTD_outBuffer out; + ZSTD_frameParams params; + void *in_allocated = NULL; + void *out_allocated = NULL; + void *wksp = NULL; + size_t wksp_size; + ZSTD_DStream *dstream; + int err; + size_t ret; + + if (out_len == 0) + out_len = LONG_MAX; /* no limit */ + + if (fill == NULL && flush == NULL) + /* We can decompress faster and with less memory when we have a + * single chunk. + */ + return decompress_single(in_buf, in_len, out_buf, out_len, + in_pos, error); + + /* If in_buf is not provided, we must be using fill(), so allocate + * a large enough buffer. If it is provided, it must be at least + * ZSTD_IOBUF_SIZE large. + */ + if (in_buf == NULL) { + in_allocated = malloc(ZSTD_IOBUF_SIZE); + if (in_allocated == NULL) { + error("Out of memory while allocating input buffer"); + err = -1; + goto out; + } + in_buf = in_allocated; + in_len = 0; + } + /* Read the first chunk, since we need to decode the frame header */ + if (fill != NULL) + in_len = fill(in_buf, ZSTD_IOBUF_SIZE); + if (in_len < 0) { + error("ZSTD-compressed data is truncated"); + err = -1; + goto out; + } + /* Set the first non-empty input buffer */ + in.src = in_buf; + in.pos = 0; + in.size = in_len; + /* Allocate the output buffer if we are using flush(). */ + if (flush != NULL) { + out_allocated = malloc(ZSTD_IOBUF_SIZE); + if (out_allocated == NULL) { + error("Out of memory while allocating output buffer"); + err = -1; + goto out; + } + out_buf = out_allocated; + out_len = ZSTD_IOBUF_SIZE; + } + /* Set the output buffer */ + out.dst = out_buf; + out.pos = 0; + out.size = out_len; + + /* We need to know the window size to allocate the ZSTD_DStream. + * Since we are streaming, we need to allocate a buffer for the sliding + * window. The window size varies from 1 KB to ZSTD_WINDOWSIZE_MAX + * (8 MB), so it is important to use the actual value so as not to + * waste memory when it is smaller. + */ + ret = ZSTD_getFrameParams(¶ms, in.src, in.size); + err = handle_zstd_error(ret, error); + if (err) + goto out; + if (ret != 0) { + error("ZSTD-compressed data has an incomplete frame header"); + err = -1; + goto out; + } + if (params.windowSize > ZSTD_WINDOWSIZE_MAX) { + error("ZSTD-compressed data has too large a window size"); + err = -1; + goto out; + } + + /* Allocate the ZSTD_DStream now that we know how much memory is + * required. + */ + wksp_size = ZSTD_DStreamWorkspaceBound(params.windowSize); + wksp = large_malloc(wksp_size); + dstream = ZSTD_initDStream(params.windowSize, wksp, wksp_size); + if (dstream == NULL) { + error("Out of memory while allocating ZSTD_DStream"); + err = -1; + goto out; + } + /* Decompression loop: + * Read more data if necessary (error if no more data can be read). + * Call the decompression function, which returns 0 when finished. + * Flush any data produced if using flush(). + */ + if (in_pos != NULL) + *in_pos = 0; + do { + /* If we need to reload data, either we have fill() and can + * try to get more data, or we don't and the input is truncated. + */ + if (in.pos == in.size) { + if (in_pos != NULL) + *in_pos += in.pos; + in_len = fill ? fill(in_buf, ZSTD_IOBUF_SIZE) : -1; + if (in_len < 0) { + error("ZSTD-compressed data is truncated"); + err = -1; + goto out; + } + in.pos = 0; + in.size = in_len; + } + /* Returns zero when the frame is complete */ + ret = ZSTD_decompressStream(dstream, &out, &in); + err = handle_zstd_error(ret, error); + if (err) + goto out; + /* Flush all of the data produced if using flush() */ + if (flush != NULL && out.pos > 0) { + if (out.pos != flush(out.dst, out.pos)) { + error("Failed to flush()"); + err = -1; + goto out; + } + out.pos = 0; + } + } while (ret != 0); + + if (in_pos != NULL) + *in_pos += in.pos; + + err = 0; +out: + if (in_allocated != NULL) + free(in_allocated); + if (out_allocated != NULL) + free(out_allocated); + if (wksp != NULL) + large_free(wksp); + return err; +} + +#ifndef PREBOOT +STATIC int INIT unzstd(unsigned char *buf, long len, + long (*fill)(void*, unsigned long), + long (*flush)(void*, unsigned long), + unsigned char *out_buf, + long *pos, + void (*error)(char *x)) +{ + return __unzstd(buf, len, fill, flush, out_buf, 0, pos, error); +} +#else +STATIC int INIT __decompress(unsigned char *buf, long len, + long (*fill)(void*, unsigned long), + long (*flush)(void*, unsigned long), + unsigned char *out_buf, long out_len, + long *pos, + void (*error)(char *x)) +{ + return __unzstd(buf, len, fill, flush, out_buf, out_len, pos, error); +} +#endif diff --git a/lib/xxhash.c b/lib/xxhash.c index aa61e2a3802f..7f1d3cb01729 100644 --- a/lib/xxhash.c +++ b/lib/xxhash.c @@ -80,13 +80,11 @@ void xxh32_copy_state(struct xxh32_state *dst, const struct xxh32_state *src) { memcpy(dst, src, sizeof(*dst)); } -EXPORT_SYMBOL(xxh32_copy_state); void xxh64_copy_state(struct xxh64_state *dst, const struct xxh64_state *src) { memcpy(dst, src, sizeof(*dst)); } -EXPORT_SYMBOL(xxh64_copy_state); /*-*************************** * Simple Hash Functions @@ -151,7 +149,6 @@ uint32_t xxh32(const void *input, const size_t len, const uint32_t seed) return h32; } -EXPORT_SYMBOL(xxh32); static uint64_t xxh64_round(uint64_t acc, const uint64_t input) { @@ -234,7 +231,6 @@ uint64_t xxh64(const void *input, const size_t len, const uint64_t seed) return h64; } -EXPORT_SYMBOL(xxh64); /*-************************************************** * Advanced Hash Functions @@ -251,7 +247,6 @@ void xxh32_reset(struct xxh32_state *statePtr, const uint32_t seed) state.v4 = seed - PRIME32_1; memcpy(statePtr, &state, sizeof(state)); } -EXPORT_SYMBOL(xxh32_reset); void xxh64_reset(struct xxh64_state *statePtr, const uint64_t seed) { @@ -265,7 +260,6 @@ void xxh64_reset(struct xxh64_state *statePtr, const uint64_t seed) state.v4 = seed - PRIME64_1; memcpy(statePtr, &state, sizeof(state)); } -EXPORT_SYMBOL(xxh64_reset); int xxh32_update(struct xxh32_state *state, const void *input, const size_t len) { @@ -334,7 +328,6 @@ int xxh32_update(struct xxh32_state *state, const void *input, const size_t len) return 0; } -EXPORT_SYMBOL(xxh32_update); uint32_t xxh32_digest(const struct xxh32_state *state) { @@ -372,7 +365,6 @@ uint32_t xxh32_digest(const struct xxh32_state *state) return h32; } -EXPORT_SYMBOL(xxh32_digest); int xxh64_update(struct xxh64_state *state, const void *input, const size_t len) { @@ -439,7 +431,6 @@ int xxh64_update(struct xxh64_state *state, const void *input, const size_t len) return 0; } -EXPORT_SYMBOL(xxh64_update); uint64_t xxh64_digest(const struct xxh64_state *state) { @@ -494,7 +485,19 @@ uint64_t xxh64_digest(const struct xxh64_state *state) return h64; } + +#ifndef PREBOOT +EXPORT_SYMBOL(xxh32_copy_state); +EXPORT_SYMBOL(xxh64_copy_state); +EXPORT_SYMBOL(xxh32); +EXPORT_SYMBOL(xxh64); +EXPORT_SYMBOL(xxh32_reset); +EXPORT_SYMBOL(xxh64_reset); +EXPORT_SYMBOL(xxh32_update); +EXPORT_SYMBOL(xxh32_digest); +EXPORT_SYMBOL(xxh64_update); EXPORT_SYMBOL(xxh64_digest); MODULE_LICENSE("Dual BSD/GPL"); MODULE_DESCRIPTION("xxHash"); +#endif diff --git a/lib/zstd/decompress.c b/lib/zstd/decompress.c index b17846725ca0..b7b6599be69e 100644 --- a/lib/zstd/decompress.c +++ b/lib/zstd/decompress.c @@ -2487,6 +2487,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output, ZSTD_inB } } +#ifndef PREBOOT EXPORT_SYMBOL(ZSTD_DCtxWorkspaceBound); EXPORT_SYMBOL(ZSTD_initDCtx); EXPORT_SYMBOL(ZSTD_decompressDCtx); @@ -2526,3 +2527,4 @@ EXPORT_SYMBOL(ZSTD_insertBlock); MODULE_LICENSE("Dual BSD/GPL"); MODULE_DESCRIPTION("Zstd Decompressor"); +#endif diff --git a/lib/zstd/fse_decompress.c b/lib/zstd/fse_decompress.c index a84300e5a013..0b353530fb3f 100644 --- a/lib/zstd/fse_decompress.c +++ b/lib/zstd/fse_decompress.c @@ -47,6 +47,7 @@ ****************************************************************/ #include "bitstream.h" #include "fse.h" +#include "zstd_internal.h" #include <linux/compiler.h> #include <linux/kernel.h> #include <linux/string.h> /* memcpy, memset */ @@ -60,14 +61,6 @@ enum { FSE_static_assert = 1 / (int)(!!(c)) }; \ } /* use only *after* variable declarations */ -/* check and forward error code */ -#define CHECK_F(f) \ - { \ - size_t const e = f; \ - if (FSE_isError(e)) \ - return e; \ - } - /* ************************************************************** * Templates ****************************************************************/ diff --git a/lib/zstd/zstd_internal.h b/lib/zstd/zstd_internal.h index 1a79fab9e13a..40026c0da892 100644 --- a/lib/zstd/zstd_internal.h +++ b/lib/zstd/zstd_internal.h @@ -127,7 +127,13 @@ static const U32 OF_defaultNormLog = OF_DEFAULTNORMLOG; * Shared functions to include for inlining *********************************************/ ZSTD_STATIC void ZSTD_copy8(void *dst, const void *src) { - memcpy(dst, src, 8); + /* zstd relies heavily on gcc being able to analyze and inline this + * memcpy() call, since it is called in a tight loop. Preboot mode + * is compiled in freestanding mode, which stops gcc from analyzing + * memcpy(). Use __builtin_memcpy() to tell gcc to analyze this as a + * regular memcpy(). + */ + __builtin_memcpy(dst, src, 8); } /*! ZSTD_wildcopy() : * custom version of memcpy(), can copy up to 7 bytes too many (8 bytes if length==0) */ @@ -137,6 +143,7 @@ ZSTD_STATIC void ZSTD_wildcopy(void *dst, const void *src, ptrdiff_t length) const BYTE* ip = (const BYTE*)src; BYTE* op = (BYTE*)dst; BYTE* const oend = op + length; +#if GCC_VERSION >= 70000 && GCC_VERSION < 70200 /* Work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81388. * Avoid the bad case where the loop only runs once by handling the * special case separately. This doesn't trigger the bug because it @@ -144,6 +151,7 @@ ZSTD_STATIC void ZSTD_wildcopy(void *dst, const void *src, ptrdiff_t length) */ if (length <= 8) return ZSTD_copy8(dst, src); +#endif do { ZSTD_copy8(op, ip); op += 8; diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 8fe4468f9bda..e79bb1444b29 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -389,6 +389,21 @@ cmd_xzmisc = (cat $(filter-out FORCE,$^) | \ xz --check=crc32 --lzma2=dict=1MiB) > $@ || \ (rm -f $@ ; false) +# ZSTD +# --------------------------------------------------------------------------- +# Appends the uncompressed size of the data using size_append. The .zst +# format has the size information available at the beginning of the file too, +# but it's in a more complex format and it's good to avoid changing the part +# of the boot code that reads the uncompressed size. +# Note that the bytes added by size_append will make the zstd tool think that +# the file is corrupt. This is expected. + +quiet_cmd_zstd = ZSTD $@ +cmd_zstd = (cat $(filter-out FORCE,$^) | \ + zstd -19 && \ + $(call size_append, $(filter-out FORCE,$^))) > $@ || \ + (rm -f $@ ; false) + # ASM offsets # --------------------------------------------------------------------------- diff --git a/usr/Kconfig b/usr/Kconfig index 43658b8a975e..5ff529b75ee1 100644 --- a/usr/Kconfig +++ b/usr/Kconfig @@ -106,6 +106,15 @@ config RD_LZ4 Support loading of a LZ4 encoded initial ramdisk or cpio buffer If unsure, say N. +config RD_ZSTD + bool "Support initial ramdisk/ramfs compressed using ZSTD" + default y + depends on BLK_DEV_INITRD + select DECOMPRESS_ZSTD + help + Support loading of a ZSTD encoded initial ramdisk or cpio buffer. + If unsure, say N. + choice prompt "Built-in initramfs compression mode" depends on INITRAMFS_SOURCE!="" @@ -214,6 +223,17 @@ config INITRAMFS_COMPRESSION_LZ4 If you choose this, keep in mind that most distros don't provide lz4 by default which could cause a build failure. +config INITRAMFS_COMPRESSION_ZSTD + bool "ZSTD" + depends on RD_ZSTD + help + ZSTD is a compression algorithm targeting intermediate compression + with fast decompression speed. It will compress better than GZIP and + decompress around the same speed as LZO, but slower than LZ4. + + If you choose this, keep in mind that you may need to install the zstd + tool to be able to compress the initram. + endchoice config INITRAMFS_COMPRESSION @@ -226,10 +246,12 @@ config INITRAMFS_COMPRESSION default ".xz" if INITRAMFS_COMPRESSION_XZ default ".lzo" if INITRAMFS_COMPRESSION_LZO default ".lz4" if INITRAMFS_COMPRESSION_LZ4 + default ".zst" if INITRAMFS_COMPRESSION_ZSTD default ".gz" if RD_GZIP default ".lz4" if RD_LZ4 default ".lzo" if RD_LZO default ".xz" if RD_XZ default ".lzma" if RD_LZMA default ".bz2" if RD_BZIP2 + default ".zst" if RD_ZSTD default "" -- 2.19.1
