Messages in this thread | | | Date | Mon, 24 Aug 2020 23:02:00 +0200 | From | Paul Cercueil <> | Subject | Re: [PATCH 2/2] MIPS: Add support for ZSTD-compressed kernels |
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Hi Nick,
Le lun. 24 août 2020 à 19:51, Nick Terrell <terrelln@fb.com> a écrit : > > >> On Aug 21, 2020, at 9:29 AM, Paul Cercueil <paul@crapouillou.net> >> wrote: >> >> Add support for self-extracting kernels with a ZSTD compression. >> >> Tested on a kernel for the GCW-Zero, it allows to reduce the size >> of the >> kernel file from 4.1 MiB with gzip to 3.5 MiB with ZSTD, and boots >> just >> as fast. >> >> Signed-off-by: Paul Cercueil <paul@crapouillou.net> >> --- >> arch/mips/Kconfig | 1 + >> arch/mips/boot/compressed/Makefile | 1 + >> arch/mips/boot/compressed/decompress.c | 4 ++++ >> arch/mips/boot/compressed/string.c | 16 ++++++++++++++++ >> 4 files changed, 22 insertions(+) >> >> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig >> index c95fa3a2484c..b9d7c4249dc9 100644 >> --- a/arch/mips/Kconfig >> +++ b/arch/mips/Kconfig >> @@ -1890,6 +1890,7 @@ config SYS_SUPPORTS_ZBOOT >> select HAVE_KERNEL_LZMA >> select HAVE_KERNEL_LZO >> select HAVE_KERNEL_XZ >> + select HAVE_KERNEL_ZSTD >> >> config SYS_SUPPORTS_ZBOOT_UART16550 >> bool >> diff --git a/arch/mips/boot/compressed/Makefile >> b/arch/mips/boot/compressed/Makefile >> index 6e56caef69f0..86ddc6fc16f4 100644 >> --- a/arch/mips/boot/compressed/Makefile >> +++ b/arch/mips/boot/compressed/Makefile >> @@ -70,6 +70,7 @@ tool_$(CONFIG_KERNEL_LZ4) = lz4 >> tool_$(CONFIG_KERNEL_LZMA) = lzma >> tool_$(CONFIG_KERNEL_LZO) = lzo >> tool_$(CONFIG_KERNEL_XZ) = xzkern >> +tool_$(CONFIG_KERNEL_ZSTD) = zstd > > You can use zstd22 here. It will give you slightly better compression > without any additional memory usage. Also, you should add > -D__DISABLE_EXPORTS to the KBUILD_CFLAGS like x86 does [1].
Indeed, it's 0.01% smaller :)
What is __DISABLE_EXPORTS for?
-Paul
> > [1] > https://github.com/torvalds/linux/blob/master/arch/x86/boot/compressed/Makefile > > -Nick > >> targets += vmlinux.bin.z >> $(obj)/vmlinux.bin.z: $(obj)/vmlinux.bin FORCE >> diff --git a/arch/mips/boot/compressed/decompress.c >> b/arch/mips/boot/compressed/decompress.c >> index 88f5d637b1c4..c61c641674e6 100644 >> --- a/arch/mips/boot/compressed/decompress.c >> +++ b/arch/mips/boot/compressed/decompress.c >> @@ -72,6 +72,10 @@ void error(char *x) >> #include "../../../../lib/decompress_unxz.c" >> #endif >> >> +#ifdef CONFIG_KERNEL_ZSTD >> +#include "../../../../lib/decompress_unzstd.c" >> +#endif >> + >> const unsigned long __stack_chk_guard = 0x000a0dff; >> >> void __stack_chk_fail(void) >> diff --git a/arch/mips/boot/compressed/string.c >> b/arch/mips/boot/compressed/string.c >> index 43beecc3587c..ab95722ec0c9 100644 >> --- a/arch/mips/boot/compressed/string.c >> +++ b/arch/mips/boot/compressed/string.c >> @@ -27,3 +27,19 @@ void *memset(void *s, int c, size_t n) >> ss[i] = c; >> return s; >> } >> + >> +void *memmove(void *dest, const void *src, size_t n) >> +{ >> + unsigned int i; >> + const char *s = src; >> + char *d = dest; >> + >> + if ((uintptr_t)dest < (uintptr_t)src) { >> + for (i = 0; i < n; i++) >> + d[i] = s[i]; >> + } else { >> + for (i = n; i > 0; i--) >> + d[i - 1] = s[i - 1]; >> + } >> + return dest; >> +} >> -- >> 2.28.0 >>
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