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: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This commit is contained in:
Paul Cercueil 2020-09-01 16:26:51 +02:00 committed by Thomas Bogendoerfer
parent 1c4dd334df
commit a510b61613
4 changed files with 24 additions and 1 deletions

View File

@ -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

View File

@ -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

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@ -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)

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@ -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;
}