On 7/27/10 12:06 AM, Xiangfu Liu wrote:
what about split this patch to two: one is all *.lds files, the other one is for the argument,
Sounds good.
I have one question here. if we decete the board cpu by CONFIG_CPU_LITTLE_ENDIAN. why we need check the toolchina again.
The answer is described right above:
+# We explicitly add the endianness specifier if needed, this allows +# to compile kernels with a toolchain for the other endianness. We +# carefully avoid to add it redundantly because gcc 3.3/3.4 complains +# when fed the toolchain default! +# +# Certain gcc versions upto gcc 4.1.1 (probably 4.2-subversion as of +# 2006-10-10 don't properly change the predefined symbols if -EB / -EL +# are used, so we kludge that here. A bug has been filed at +# http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29413.
This part is copied from Linux/MIPS kernel, and has been working with the wide range of GCC versions for years.
the original U-Boot is detect -EL/-EB by toolchain name. maybe the CONFIG_CPU_LITTLE_ENDIAN option is better.
True. CONFIG_CPU_LITTLE_ENDIAN (and CONFIG_CPU_BIG_ENDIAN) configs are also derived from Linux/MIPS kernel, and IMO they're right steps toward cross-endian build support. U-Boot, however, tends to think it less important, so don't hold your breath about this approach to be accepted. Cross-endian build is common practice for MIPS people, but might be uncommon for other architectures.
Note that CONFIG_CPU_LITTLE_ENDIAN works not only for cross-endian builds, but also toolchain default endian builds with non-ELDK tools. If CONFIG_CPU_LITTLE_ENDIAN is not accepted, we have to think an alternative way.