Commit a510b616 authored by Paul Cercueil's avatar Paul Cercueil Committed by Thomas Bogendoerfer
Browse files

MIPS: Add support for ZSTD-compressed kernels 



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.

Compressed kernels are now also compiled with -D__DISABLE_EXPORTS in
order to disable the EXPORT_SYMBOL() macros inside of
lib/zstd/decompress.c.

Signed-off-by: default avatarPaul Cercueil <paul@crapouillou.net>
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
parent 1c4dd334

arch/mips/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -1860,6 +1860,7 @@ 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

arch/mips/boot/compressed/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -22,7 +22,7 @@ KBUILD_CFLAGS := $(filter-out -pg, $(KBUILD_CFLAGS)) 


KBUILD_CFLAGS := $(filter-out -fstack-protector, $(KBUILD_CFLAGS))



KBUILD_CFLAGS := $(KBUILD_CFLAGS) -D__KERNEL__ \

KBUILD_CFLAGS := $(KBUILD_CFLAGS) -D__KERNEL__ -D__DISABLE_EXPORTS \

	-DBOOT_HEAP_SIZE=$(BOOT_HEAP_SIZE) -D"VMLINUX_LOAD_ADDRESS_ULL=$(VMLINUX_LOAD_ADDRESS)ull"



KBUILD_AFLAGS := $(KBUILD_AFLAGS) -D__ASSEMBLY__ \
@@ -70,6 +70,7 @@ tool_$(CONFIG_KERNEL_LZ4) = lz4 
tool_$(CONFIG_KERNEL_LZMA)    = lzma

tool_$(CONFIG_KERNEL_LZO)     = lzo

tool_$(CONFIG_KERNEL_XZ)      = xzkern

tool_$(CONFIG_KERNEL_ZSTD)    = zstd22



targets += vmlinux.bin.z

$(obj)/vmlinux.bin.z: $(obj)/vmlinux.bin FORCE

arch/mips/boot/compressed/decompress.c

+4 −0
Original line number Diff line number Diff line
@@ -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)

arch/mips/boot/compressed/string.c

+17 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
 * Very small subset of simple string routines

 */



#include <linux/compiler_attributes.h>

#include <linux/types.h>



void *memcpy(void *dest, const void *src, size_t n)
@@ -27,3 +28,19 @@ void *memset(void *s, int c, size_t n) 
		ss[i] = c;

	return s;

}



void * __weak 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;

}