https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113225
Bug ID: 113225
Summary: bpf: attributekernel_helper function declarations
create a BTF_FUNC_EXTERN.
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: cupertino.miranda at oracle dot com
Target Milestone: ---
When using attribute kernel_helper such as the one in the example:
extern int foo (int arg) __attribute__((kernel_helper (666)));
int bar ()
{
return foo (20);
}
The following BTF entries are created:
[1] int 'int'(1U#B) size=4U#B offset=0UB#b bits=32UB#b SIGNED
[2] func_proto <anonymous> type=1
param '' type=1
[3] func_proto <anonymous> type=1
[4] func 'foo'(5U#B) type=2 linkage=0 (extern)
[5] func 'bar'(9U#B) type=3 linkage=1 (global)
BTF information is generated for the extern function declaration, imposing some
problem to tools such as bpftool that relies on BTF information to validate
completeness of the BTF information.
Since kernel helpers are not true functions the BTF information created,
although accurate with how the function is declared, it is not accurate with
its semantics.
Plan resolution is to skip btf output to any attributed kernel_helper function
declaration, since the BTF information in this case is not really required.
