[U-Boot] Beaglebone Black U-boot won't buid - THUMB instruction issue

[Måns Rullgård]

John Babrick <johnbabrick at gmail.com> writes:

> Hello - I am trying to work through the book "Mastering Embedded Linux
> Programming" by Chris Simmonds, and trying to work through building u-boot
> after having built the cross toolchain. I am running into an error when I
> try to build u-boot, any ideas?
>
> johann at mars:~/uboot-work/u-boot$ make
> CROSS_COMPILE=arm-cortex_a8-linux-gnueabihf- am335x_evm_defconfig
> #
> # configuration written to .config
> #
> johann at mars:~/uboot-work/u-boot$ make
> CROSS_COMPILE=arm-cortex_a8-linux-gnueabihf-
> scripts/kconfig/conf  --silentoldconfig Kconfig
>   CHK     include/config.h
>   UPD     include/config.h
>   CFG     u-boot.cfg
>   GEN     include/autoconf.mk
>   GEN     include/autoconf.mk.dep
>   CFG     spl/u-boot.cfg
>   GEN     spl/include/autoconf.mk
>   CHK     include/config/uboot.release
>   CHK     include/generated/version_autogenerated.h
>   CHK     include/generated/timestamp_autogenerated.h
>   UPD     include/generated/timestamp_autogenerated.h
> *  CC      lib/asm-offsets.s*
> *cc1: warning: target CPU does not support THUMB instructions*
> *  CHK     include/generated/generic-asm-offsets.h*
> *  CC      arch/arm/lib/asm-offsets.s*
> *cc1: warning: target CPU does not support THUMB instructions*
>   CHK     include/generated/asm-offsets.h
>   HOSTCC  scripts/dtc/dtc.o
>   HOSTCC  scripts/dtc/flattree.o
>   HOSTCC  scripts/dtc/fstree.o
>   HOSTCC  scripts/dtc/data.o
>   HOSTCC  scripts/dtc/livetree.o
>   HOSTCC  scripts/dtc/treesource.o
>   HOSTCC  scripts/dtc/srcpos.o
>   HOSTCC  scripts/dtc/checks.o
>   HOSTCC  scripts/dtc/util.o
>   SHIPPED scripts/dtc/dtc-lexer.lex.c
>   SHIPPED scripts/dtc/dtc-parser.tab.h
>   HOSTCC  scripts/dtc/dtc-lexer.lex.o
>   SHIPPED scripts/dtc/dtc-parser.tab.c
>   HOSTCC  scripts/dtc/dtc-parser.tab.o
>   HOSTLD  scripts/dtc/dtc
>   HOSTCC  tools/mkenvimage.o
>   HOSTCC  tools/lib/crc32.o
>   HOSTLD  tools/mkenvimage
>   HOSTCC  tools/common/bootm.o
>   HOSTCC  tools/lib/fdtdec.o
>   HOSTCC  tools/fit_image.o
>   HOSTCC  tools/image-host.o
>   HOSTCC  tools/dumpimage.o
>   HOSTLD  tools/dumpimage
>   HOSTCC  tools/mkimage.o
>   HOSTLD  tools/mkimage
>   CC      arch/arm/cpu/armv7/cache_v7.o
> *cc1: warning: target CPU does not support THUMB instructions*
> *{standard input}: Assembler messages:*
> *{standard input}:42: Error: selected processor does not support `dsb sy'
> in ARM mode*
> *{standard input}:46: Error: selected processor does not support `isb sy'
> in ARM mode*
> *{standard input}:240: Error: selected processor does not support `dsb sy'
> in ARM mode*
> *{standard input}:244: Error: selected processor does not support `isb sy'
> in ARM mode*
> *{standard input}:368: Error: selected processor does not support `dsb sy'
> in ARM mode*
> *{standard input}:460: Error: selected processor does not support `dsb sy'
> in ARM mode*
> *{standard input}:464: Error: selected processor does not support `isb sy'
> in ARM mode*
> *{standard input}:594: Error: selected processor does not support `dsb sy'
> in ARM mode*
> *scripts/Makefile.build:278: recipe for target
> 'arch/arm/cpu/armv7/cache_v7.o' failed*
> make[1]: *** [arch/arm/cpu/armv7/cache_v7.o] Error 1
> Makefile:1363: recipe for target 'arch/arm/cpu/armv7' failed

I get a deluge of such errors with gcc-8.  Use gcc-7 or earlier until
someone fixes it (or fix it yourself and send a patch).

-- 
Måns Rullgård