Commit d9075ac6 authored by Cupertino Miranda's avatar Cupertino Miranda Committed by Andrii Nakryiko
Browse files

selftest/bpf: Adapt inline asm operand constraint for GCC support 



GCC errors when compiling tailcall_bpf2bpf_hierarchy2.c and
tailcall_bpf2bpf_hierarchy3.c with the following error:

progs/tailcall_bpf2bpf_hierarchy2.c: In function 'tailcall_bpf2bpf_hierarchy_2':
progs/tailcall_bpf2bpf_hierarchy2.c:66:9: error: input operand constraint contains '+'
   66 |         asm volatile (""::"r+"(ret));
      |         ^~~

Changed implementation to make use of __sink macro that abstracts the
desired behaviour.

The proposed change seems valid for both GCC and CLANG.

Signed-off-by: default avatarCupertino Miranda <cupertino.miranda@oracle.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240819151129.1366484-4-cupertino.miranda@oracle.com
parent 2aa93695

tools/testing/selftests/bpf/progs/tailcall_bpf2bpf_hierarchy2.c

+2 −2
Original line number Diff line number Diff line
@@ -58,12 +58,12 @@ __retval(33) 
SEC("tc")

int tailcall_bpf2bpf_hierarchy_2(struct __sk_buff *skb)

{

	volatile int ret = 0;

	int ret = 0;



	subprog_tail0(skb);

	subprog_tail1(skb);



	asm volatile (""::"r+"(ret));

	__sink(ret);

	return (count1 << 16) | count0;

}

tools/testing/selftests/bpf/progs/tailcall_bpf2bpf_hierarchy3.c

+2 −2
Original line number Diff line number Diff line
@@ -51,11 +51,11 @@ __retval(33) 
SEC("tc")

int tailcall_bpf2bpf_hierarchy_3(struct __sk_buff *skb)

{

	volatile int ret = 0;

	int ret = 0;



	bpf_tail_call_static(skb, &jmp_table0, 0);



	asm volatile (""::"r+"(ret));

	__sink(ret);

	return ret;

}