Re: [PATCH net-next] ebpf: bpf_map_*: fix linker error on avr32 and openrisc arch

[Alexei Starovoitov <ast@plumgrid.com>]

On 3/5/15 2:27 PM, Daniel Borkmann wrote:
> Fengguang reported, that on openrisc and avr32 architectures, we
> get the following linker errors on *_defconfig builds that have
> no bpf syscall support:
>
>    net/built-in.o:(.rodata+0x1cd0): undefined reference to `bpf_map_lookup_elem_proto'
>    net/built-in.o:(.rodata+0x1cd4): undefined reference to `bpf_map_update_elem_proto'
>    net/built-in.o:(.rodata+0x1cd8): undefined reference to `bpf_map_delete_elem_proto'
>
> Fix it up by providing built-in weak definitions of the symbols,
> so they can be overridden when the syscall is enabled. I think
> the issue might be that gcc is not able to optimize all that away.
> This patch fixes the linker errors for me, tested with Fengguang's
> make.cross [1] script.
>
>    [1] https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross
>
> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
> Fixes: d4052c4aea0c ("ebpf: remove CONFIG_BPF_SYSCALL ifdefs in socket filter code")
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Acked-by: Alexei Starovoitov <ast@plumgrid.com>

thanks :)