linux/arch
Nicholas Piggin b67067f117 kbuild: allow archs to select link dead code/data elimination
Introduce LD_DEAD_CODE_DATA_ELIMINATION option for architectures to
select to build with -ffunction-sections, -fdata-sections, and link
with --gc-sections. It requires some work (documented) to ensure all
unreferenced entrypoints are live, and requires toolchain and build
verification, so it is made a per-arch option for now.

On a random powerpc64le build, this yelds a significant size saving,
it boots and runs fine, but there is a lot I haven't tested as yet, so
these savings may be reduced if there are bugs in the link.

    text      data        bss        dec   filename
11169741   1180744    1923176	14273661   vmlinux
10445269   1004127    1919707	13369103   vmlinux.dce

~700K text, ~170K data, 6% removed from kernel image size.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-09-09 10:47:00 +02:00
..
alpha alpha: move exports to actual definitions 2016-08-07 23:47:18 -04:00
arc dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
arm arm: move exports to definitions 2016-08-07 23:47:21 -04:00
arm64 * ARM bugfix and MSI injection support 2016-08-06 09:18:21 -04:00
avr32 dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
blackfin dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
c6x dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
cris dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
frv RTC for 4.8 2016-08-05 09:48:22 -04:00
h8300 RTC for 4.8 2016-08-05 09:48:22 -04:00
hexagon dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
ia64 ia64: move exports to definitions 2016-08-07 23:55:50 -04:00
m32r mm: do not pass mm_struct into handle_mm_fault 2016-07-26 16:19:19 -07:00
m68k m68k: move exports to definitions 2016-08-07 23:47:19 -04:00
metag Metag architecture changes for v4.8 2016-08-05 08:58:00 -04:00
microblaze dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
mips Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2016-08-06 09:13:11 -04:00
mn10300 RTC for 4.8 2016-08-05 09:48:22 -04:00
nios2 dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
openrisc dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
parisc RTC for 4.8 2016-08-05 09:48:22 -04:00
powerpc ppc: move exports to definitions 2016-08-07 23:50:09 -04:00
s390 s390: move exports to definitions 2016-08-07 23:47:20 -04:00
score treewide: replace obsolete _refok by __ref 2016-08-02 17:31:41 -04:00
sh These changes improve device tree support (including builtin DTB), add 2016-08-06 09:00:05 -04:00
sparc sparc32: debride memcpy.S a bit 2016-08-07 23:55:49 -04:00
tile tile: support static_key usage in non-module __exit sections 2016-08-04 08:50:07 -04:00
um Merge branch 'for-linus-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml 2016-08-04 19:37:59 -04:00
unicore32 dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
x86 x86: move exports to actual definitions 2016-08-07 23:47:15 -04:00
xtensa dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
.gitignore
Kconfig kbuild: allow archs to select link dead code/data elimination 2016-09-09 10:47:00 +02:00