| Message ID | 1453280738-18721-3-git-send-email-ard.biesheuvel@linaro.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Wed, 2016-01-20 at 10:05 +0100, Ard Biesheuvel wrote: > This enables the newly introduced text-relative kallsyms support when > building 64-bit targets. This cuts the size of the kallsyms address > table in half, and drastically reduces the size of the PIE dynamic > relocation section when building with CONFIG_RELOCATABLE=y (by about > 3 MB for ppc64_defconfig) > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > > Results for ppc64_defconfig: > > BEFORE: > ======= > $ size vmlinux > text data bss dec hex filename > 19827996 2008456 849612 22686064 15a2970 vmlinux > > $ readelf -S .tmp_kallsyms2.o > There are 9 section headers, starting at offset 0x4513f8: > > Section Headers: > [Nr] Name Type Address Offset > Size EntSize Flags Link Info Align > ... > [ 4] .rodata PROGBITS 0000000000000000 00000100 > 00000000001fcf00 0000000000000000 A 0 0 256 > [ 5] .rela.rodata RELA 0000000000000000 001fd1d8 > 0000000000254220 0000000000000018 I 7 4 8 > [ 6] .shstrtab STRTAB 0000000000000000 001fd000 > 0000000000000039 0000000000000000 0 0 1 > ... > > $ ls -l arch/powerpc/boot/zImage > -rwxrwxr-x 2 ard ard 7533160 Jan 20 08:43 arch/powerpc/boot/zImage > > AFTER: > ====== > $ size vmlinux > text data bss dec hex filename > 16979516 2009992 849612 19839120 12eb890 vmlinux > > $ readelf -S .tmp_kallsyms2.o > There are 8 section headers, starting at offset 0x199bb0: > > Section Headers: > [Nr] Name Type Address Offset > Size EntSize Flags Link Info Align > ... > [ 4] .rodata PROGBITS 0000000000000000 00000100 > 0000000000199900 0000000000000000 A 0 0 256 > [ 5] .shstrtab STRTAB 0000000000000000 00199a00 > 0000000000000034 0000000000000000 0 0 1 > ... > > $ ls -l arch/powerpc/boot/zImage > -rwxrwxr-x 2 ard ard 6985672 Jan 20 08:45 arch/powerpc/boot/zImage Nice space saving, thanks very much. I've booted this on a bunch of machines and it seems to be working fine. Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) cheers
=======
$ size vmlinux
text data bss dec hex filename
19827996 2008456 849612 22686064 15a2970 vmlinux
$ readelf -S .tmp_kallsyms2.o
There are 9 section headers, starting at offset 0x4513f8:
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
...
[ 4] .rodata PROGBITS 0000000000000000 00000100
00000000001fcf00 0000000000000000 A 0 0 256
[ 5] .rela.rodata RELA 0000000000000000 001fd1d8
0000000000254220 0000000000000018 I 7 4 8
[ 6] .shstrtab STRTAB 0000000000000000 001fd000
0000000000000039 0000000000000000 0 0 1
...
$ ls -l arch/powerpc/boot/zImage
-rwxrwxr-x 2 ard ard 7533160 Jan 20 08:43 arch/powerpc/boot/zImage
AFTER:
======
$ size vmlinux
text data bss dec hex filename
16979516 2009992 849612 19839120 12eb890 vmlinux
$ readelf -S .tmp_kallsyms2.o
There are 8 section headers, starting at offset 0x199bb0:
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
...
[ 4] .rodata PROGBITS 0000000000000000 00000100
0000000000199900 0000000000000000 A 0 0 256
[ 5] .shstrtab STRTAB 0000000000000000 00199a00
0000000000000034 0000000000000000 0 0 1
...
$ ls -l arch/powerpc/boot/zImage
-rwxrwxr-x 2 ard ard 6985672 Jan 20 08:45 arch/powerpc/boot/zImage
---
arch/powerpc/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 94f6c5089e0c..d1c26749632b 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -158,6 +158,7 @@ config PPC
select ARCH_HAS_DMA_SET_COHERENT_MASK
select ARCH_HAS_DEVMEM_IS_ALLOWED
select HAVE_ARCH_SECCOMP_FILTER
+ select KALLSYMS_TEXT_RELATIVE if PPC64
config GENERIC_CSUM
def_bool CPU_LITTLE_ENDIAN
This enables the newly introduced text-relative kallsyms support when building 64-bit targets. This cuts the size of the kallsyms address table in half, and drastically reduces the size of the PIE dynamic relocation section when building with CONFIG_RELOCATABLE=y (by about 3 MB for ppc64_defconfig) Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- Results for ppc64_defconfig: BEFORE: