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>
Signed-off-by: David S. Miller <davem@davemloft.net>
}
EXPORT_SYMBOL_GPL(bpf_prog_free);
+/* Weak definitions of helper functions in case we don't have bpf syscall. */
+const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
+const struct bpf_func_proto bpf_map_update_elem_proto __weak;
+const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
+
/* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
* skb_copy_bits(), so provide a weak definition of it for NET-less config.
*/