Building the NVIDIA Kernel

Hello ,
My toolchain is succucessed install int the path /opt/nvidia/toolchain-build-aarch64/install/bin/, but when i build the tegra kernel ,i got the err info:
"/home/jc/share/nvidia/system/kernel/arch/arm64/kernel/vdso32/vgettimeofday.c:1:0: error: unknown value ‘armv7-a’ for -march
I don’t known what had happend, so could you help me to solve this problem? Thanks!

my platform is NVIDIA Jetson TX1

Can anyone help me with another problem?

I used crosstool-ng to build the toolchain Suite? but i got err infomation:

"[ALL ] checking for iconv declaration… install-shextern size_t iconv (iconv_t cd, char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);
[ALL ] *** BFD does not support target aarch64-cortex_a9-linux-gnueabi.
[ALL ] *** Look in bfd/config.bfd for supported targets.
[ERROR] make[2]: *** [configure-binutils] Error 1
[ALL ] make[2]: Leaving directory `/root/crosstool/crosstool-ng/work/aarch64-cortex_a9-linux-gnueabi/build/build-binutils-host-i686-build_pc-linux-gnu’
[ERROR] >>