[PATCH 0/4] function/data-sections

From: Denys Vlasenko
Date: Wed Jul 28 2010 - 19:48:34 EST


Hi Michal,

Please take this patch series onto linux-kbuild.

Most of work needed for working -ffunction-sections -fdata-sections build
is already in the mainline, but a few bits are still missing.
In order to have a working kernel with this make invocation:
make KCFLAGS="-ffunction-sections -fdata-sections"
we need these patches:

modpost: support objects with more than 64k sections
This patch is in -mm, it still did not reach mainline,
thus resending. Sam suggested some readability improvements.
module linker script: coalesce function and data sections
kernel linker stripts: accomodate function and data sections
boot linker stripts: accomodate function and data sections

Please see individual patches for more detailed changelogs.

A rough idea what sort of size savings are achievable
with section garbage collection:
Kernel:
text data bss dec hex filename
8299299 857324 785348 9941971 97b3d3 2.6.35-rc4/vmlinux
7566908 832388 717844 9117140 8b1dd4 2.6.35-rc4-fsgs/vmlinux
-9.2% -2.9% -9.0% -8.6%
The largest module in the build:
451009 54640 2224 507873 7bfe1 2.6.35-rc4/fs/xfs/xfs.ko
450521 54292 2202 507015 7bc87 2.6.35-rc4-fsgs/fs/xfs/xfs.ko
(negligible size change since section garbage collection
for modules is not done. TODO: figure out how to do it)

Signed-off-by: Denys Vlasenko <vda.linux@xxxxxxxxxxxxxx>
Acked-by: Sam Ravnborg <sam@xxxxxxxxxxxx>


Denys Vlasenko (4):
modpost: support objects with more than 64k sections
module linker script: coalesce sections
kernel linker stripts: accomodate function and data sections
boot linker stripts: accomodate function and data sections

arch/alpha/boot/bootloader.lds | 6 +-
arch/arm/boot/bootp/bootp.lds | 1 +
arch/cris/boot/compressed/decompress_v10.lds | 3 +
arch/cris/boot/compressed/decompress_v32.lds | 3 +
arch/cris/boot/rescue/rescue_v10.lds | 2 +
arch/cris/boot/rescue/rescue_v32.lds | 3 +
arch/frv/kernel/vmlinux.lds.S | 1 -
arch/h8300/boot/compressed/vmlinux.lds | 2 +
arch/h8300/boot/compressed/vmlinux.scr | 1 +
arch/ia64/hp/sim/boot/bootloader.lds | 6 +-
arch/ia64/scripts/check-segrel.lds | 4 +-
arch/m32r/boot/compressed/vmlinux.lds.S | 6 +-
arch/m32r/boot/compressed/vmlinux.scr | 1 +
arch/m68knommu/kernel/vmlinux.lds.S | 1 +
arch/mips/lasat/image/romscript.normal | 1 +
arch/mn10300/boot/compressed/vmlinux.lds | 1 +
arch/parisc/kernel/vmlinux.lds.S | 1 +
arch/powerpc/boot/zImage.coff.lds.S | 2 +
arch/powerpc/boot/zImage.lds.S | 2 +
arch/powerpc/boot/zImage.ps3.lds.S | 2 +
arch/sh/boot/compressed/vmlinux.scr | 1 +
arch/sh/kernel/vsyscall/vsyscall.lds.S | 2 +-
arch/x86/boot/setup.ld | 3 +-
arch/x86/kernel/acpi/realmode/wakeup.lds.S | 1 +
arch/x86/kernel/vmlinux.lds.S | 1 +
arch/xtensa/boot/boot-elf/boot.lds.S | 5 +-
arch/xtensa/boot/boot-redboot/boot.ld | 5 +-
include/asm-generic/vmlinux.lds.h | 18 ++++-
scripts/mod/file2alias.c | 6 +-
scripts/mod/modpost.c | 102 +++++++++++++++++++-------
scripts/mod/modpost.h | 43 +++++++++++
scripts/module-common.lds | 23 ++++++
32 files changed, 213 insertions(+), 46 deletions(-)

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