samples/bpf: fix build with new clang
authorAlexei Starovoitov <ast@kernel.org>
Thu, 4 Apr 2019 21:37:14 +0000 (14:37 -0700)
committerDaniel Borkmann <daniel@iogearbox.net>
Fri, 5 Apr 2019 14:28:36 +0000 (16:28 +0200)
commit636e78b1cdb40b77a79b143dbd9d94847b360efa
tree8b8c0d6b2b6bc641875640544e3c2c787215e856
parente67b2c715415b121339049b630f0b4e1ede888dc
samples/bpf: fix build with new clang

clang started to error on invalid asm clobber usage in x86 headers
and many bpf program samples failed to build with the message:

  CLANG-bpf  /data/users/ast/bpf-next/samples/bpf/xdp_redirect_kern.o
In file included from /data/users/ast/bpf-next/samples/bpf/xdp_redirect_kern.c:14:
In file included from ../include/linux/in.h:23:
In file included from ../include/uapi/linux/in.h:24:
In file included from ../include/linux/socket.h:8:
In file included from ../include/linux/uio.h:14:
In file included from ../include/crypto/hash.h:16:
In file included from ../include/linux/crypto.h:26:
In file included from ../include/linux/uaccess.h:5:
In file included from ../include/linux/sched.h:15:
In file included from ../include/linux/sem.h:5:
In file included from ../include/uapi/linux/sem.h:5:
In file included from ../include/linux/ipc.h:9:
In file included from ../include/linux/refcount.h:72:
../arch/x86/include/asm/refcount.h:72:36: error: asm-specifier for input or output variable conflicts with asm clobber list
                                         r->refs.counter, e, "er", i, "cx");
                                                                      ^
../arch/x86/include/asm/refcount.h:86:27: error: asm-specifier for input or output variable conflicts with asm clobber list
                                         r->refs.counter, e, "cx");
                                                             ^
2 errors generated.

Override volatile() to workaround the problem.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
samples/bpf/asm_goto_workaround.h