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2004-x86-Add-support-for-ZSTD-compressed-kernel.patch
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2004-x86-Add-support-for-ZSTD-compressed-kernel.patch
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From 31714e3795c54f31f7edbfb1bf1808ab12439347 Mon Sep 17 00:00:00 2001
From: Nick Terrell <[email protected]>
Date: Thu, 30 Jul 2020 12:08:39 -0700
Subject: [PATCH 2004/2007] x86: Add support for ZSTD compressed kernel
- Add support for zstd compressed kernel
- Define __DISABLE_EXPORTS in Makefile
- Remove __DISABLE_EXPORTS definition from kaslr.c
- Bump the heap size for zstd.
- Update the documentation.
Integrates the ZSTD decompression code to the x86 pre-boot code.
Zstandard requires slightly more memory during the kernel decompression
on x86 (192 KB vs 64 KB), and the memory usage is independent of the
window size.
__DISABLE_EXPORTS is now defined in the Makefile, which covers both
the existing use in kaslr.c, and the use needed by the zstd decompressor
in misc.c.
This patch has been boot tested with both a zstd and gzip compressed
kernel on i386 and x86_64 using buildroot and QEMU.
Additionally, this has been tested in production on x86_64 devices.
We saw a 2 second boot time reduction by switching kernel compression
from xz to zstd.
Signed-off-by: Nick Terrell <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Tested-by: Sedat Dilek <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
(cherry picked from commit fb46d057db824693994b048d3a8c869892afaa3f)
[fixed merge conflict in arch/x86/boot/compressed/Makefile]
Signed-off-by: Arnaldo Garcia Rincon <[email protected]>
---
Documentation/x86/boot.rst | 6 +++---
arch/x86/Kconfig | 1 +
arch/x86/boot/compressed/Makefile | 6 +++++-
arch/x86/boot/compressed/kaslr.c | 7 -------
arch/x86/boot/compressed/misc.c | 4 ++++
arch/x86/include/asm/boot.h | 11 +++++++++--
6 files changed, 22 insertions(+), 13 deletions(-)
diff --git a/Documentation/x86/boot.rst b/Documentation/x86/boot.rst
index 08a2f100c0e6..4e6b8ee2978e 100644
--- a/Documentation/x86/boot.rst
+++ b/Documentation/x86/boot.rst
@@ -767,9 +767,9 @@ Protocol: 2.08+
uncompressed data should be determined using the standard magic
numbers. The currently supported compression formats are gzip
(magic numbers 1F 8B or 1F 9E), bzip2 (magic number 42 5A), LZMA
- (magic number 5D 00), XZ (magic number FD 37), and LZ4 (magic number
- 02 21). The uncompressed payload is currently always ELF (magic
- number 7F 45 4C 46).
+ (magic number 5D 00), XZ (magic number FD 37), LZ4 (magic number
+ 02 21) and ZSTD (magic number 28 B5). The uncompressed payload is
+ currently always ELF (magic number 7F 45 4C 46).
============ ==============
Field name: payload_length
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 36a28b9e46cb..9e7067cdebbf 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -179,6 +179,7 @@ config X86
select HAVE_KERNEL_LZMA
select HAVE_KERNEL_LZO
select HAVE_KERNEL_XZ
+ select HAVE_KERNEL_ZSTD
select HAVE_KPROBES
select HAVE_KPROBES_ON_FTRACE
select HAVE_FUNCTION_ERROR_INJECTION
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 292b5bc6e3a3..dfe6782d76db 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -24,7 +24,7 @@ OBJECT_FILES_NON_STANDARD := y
KCOV_INSTRUMENT := n
targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
- vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4
+ vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4 vmlinux.bin.zst
KBUILD_CFLAGS := -m$(BITS) -O2
KBUILD_CFLAGS += -fno-strict-aliasing $(call cc-option, -fPIE, -fPIC)
@@ -40,6 +40,7 @@ KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
KBUILD_CFLAGS += -Wno-pointer-sign
# Disable relocation relaxation in case the link is not PIE.
KBUILD_CFLAGS += $(call as-option,-Wa$(comma)-mrelax-relocations=no)
+KBUILD_CFLAGS += -D__DISABLE_EXPORTS
KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__
GCOV_PROFILE := n
@@ -146,6 +147,8 @@ $(obj)/vmlinux.bin.lzo: $(vmlinux.bin.all-y) FORCE
$(call if_changed,lzo)
$(obj)/vmlinux.bin.lz4: $(vmlinux.bin.all-y) FORCE
$(call if_changed,lz4)
+$(obj)/vmlinux.bin.zst: $(vmlinux.bin.all-y) FORCE
+ $(call if_changed,zstd22)
suffix-$(CONFIG_KERNEL_GZIP) := gz
suffix-$(CONFIG_KERNEL_BZIP2) := bz2
@@ -153,6 +156,7 @@ suffix-$(CONFIG_KERNEL_LZMA) := lzma
suffix-$(CONFIG_KERNEL_XZ) := xz
suffix-$(CONFIG_KERNEL_LZO) := lzo
suffix-$(CONFIG_KERNEL_LZ4) := lz4
+suffix-$(CONFIG_KERNEL_ZSTD) := zst
quiet_cmd_mkpiggy = MKPIGGY $@
cmd_mkpiggy = $(obj)/mkpiggy $< > $@
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 2e53c056ba20..ae7e1698587f 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -19,13 +19,6 @@
*/
#define BOOT_CTYPE_H
-/*
- * _ctype[] in lib/ctype.c is needed by isspace() of linux/ctype.h.
- * While both lib/ctype.c and lib/cmdline.c will bring EXPORT_SYMBOL
- * which is meaningless and will cause compiling error in some cases.
- */
-#define __DISABLE_EXPORTS
-
#include "misc.h"
#include "error.h"
#include "../string.h"
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 9652d5c2afda..39e592d0e0b4 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -77,6 +77,10 @@ static int lines, cols;
#ifdef CONFIG_KERNEL_LZ4
#include "../../../../lib/decompress_unlz4.c"
#endif
+
+#ifdef CONFIG_KERNEL_ZSTD
+#include "../../../../lib/decompress_unzstd.c"
+#endif
/*
* NOTE: When adding a new decompressor, please update the analysis in
* ../header.S.
diff --git a/arch/x86/include/asm/boot.h b/arch/x86/include/asm/boot.h
index 680c320363db..9191280d9ea3 100644
--- a/arch/x86/include/asm/boot.h
+++ b/arch/x86/include/asm/boot.h
@@ -24,9 +24,16 @@
# error "Invalid value for CONFIG_PHYSICAL_ALIGN"
#endif
-#ifdef CONFIG_KERNEL_BZIP2
+#if defined(CONFIG_KERNEL_BZIP2)
# define BOOT_HEAP_SIZE 0x400000
-#else /* !CONFIG_KERNEL_BZIP2 */
+#elif defined(CONFIG_KERNEL_ZSTD)
+/*
+ * Zstd needs to allocate the ZSTD_DCtx in order to decompress the kernel.
+ * The ZSTD_DCtx is ~160KB, so set the heap size to 192KB because it is a
+ * round number and to allow some slack.
+ */
+# define BOOT_HEAP_SIZE 0x30000
+#else
# define BOOT_HEAP_SIZE 0x10000
#endif
--
2.30.2