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POWERPC: enable --gc-sections and -ffunction-sections -fdata-sections

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The switch from archive libraries to partial linking has introduced a
number of problems, that are non-trivial to solve.  For example, it is
no longer possible to include individual object files in the linker
script as we did before for example in the case of boards with
embedded environment to fill up the gap caused by the need to align
the environment on flash erase block boundaries.

The best (but unfortunately not easiest) approach to address this
problem is to enable -ffunction-sections (and -fdata-sections) so
we can again (and even in much finer granularity) place certain code
where we want it.  When doing this step, it seems only consequent to
also add --gc-sections which has the added benefit of reducing the
memory footprint of the U-Boot image (both in flash and in RAM).

Unfortunately, this requires changes to a lot of linker scripts.

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Stefan Roese <sr@denx.de>
Cc: Kim Phillips <kim.phillips@freescale.com>
Cc: Andy Fleming <afleming@gmail.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Stefan Roese <sr@denx.de>
This commit is contained in:
Wolfgang Denk 2010-11-21 20:46:02 +01:00
parent f1c574d400
commit c08e5cf7c7
2 changed files with 2 additions and 6 deletions
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4
arch/powerpc/config.mk
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@ -25,9 +25,9 @@ CROSS_COMPILE ?= ppc_8xx-
STANDALONE_LOAD_ADDR = 0x40000
PLATFORM_RELFLAGS += -mrelocatable
PLATFORM_RELFLAGS += -mrelocatable -ffunction-sections -fdata-sections
PLATFORM_CPPFLAGS += -DCONFIG_PPC -D__powerpc__
PLATFORM_LDFLAGS += -n
PLATFORM_LDFLAGS += -n --gc-sections
ifdef CONFIG_SYS_LDSCRIPT
# need to strip off double quotes

4
arch/powerpc/cpu/mpc85xx/config.mk
View File

@ -25,10 +25,6 @@ PLATFORM_RELFLAGS += -fPIC -meabi
PLATFORM_CPPFLAGS += -ffixed-r2 -Wa,-me500 -msoft-float -mno-string
# Enable gc-sections to enable generation of smaller images.
PLATFORM_LDFLAGS += --gc-sections
PLATFORM_RELFLAGS += -ffunction-sections -fdata-sections
# -mspe=yes is needed to have -mno-spe accepted by a buggy GCC;
# see "[PATCH,rs6000] make -mno-spe work as expected" on
# http://gcc.gnu.org/ml/gcc-patches/2008-04/msg00311.html