The current bpf_helper_defs.h helpers are llvm specific and don't work correctly with gcc. GCC appears to required kernel helper funcs to have the following attribute set: __attribute__((kernel_helper(NUM))) Generate gcc compatible headers based on the format in bpf-helpers.h. This generates GCC/Clang compatible helpers, for example: /* Helper macro for GCC/Clang compatibility */ #define NOARG #if __GNUC__ && !__clang__ #define BPF_HELPER_DEF(num, ret_star, ret_type, name, ...) \ ret_type ret_star name(__VA_ARGS__) __attribute__((kernel_helper(num))); #else #define BPF_HELPER_DEF(num, ret_star, ret_type, name, ...) \ static ret_type ret_star(*name)(__VA_ARGS__) = (void *) num; #endif BPF_HELPER_DEF(1, *, void, bpf_map_lookup_elem, void *map, const void *key) BPF_HELPER_DEF(2, NOARG, long, bpf_map_update_elem, void *map, const void *key, const void *value, __u64 flags) See: https://github.com/gcc-mirror/gcc/blob/releases/gcc-12.1.0/gcc/config/bpf/bpf-helpers.h#L24-L27 This fixes the following build error: error: indirect call in function, which are not supported by eBPF Signed-off-by: James Hilliard <james.hilliard1@xxxxxxxxx> --- Changes v2 -> v3: - use a conditional helper macro Changes v1 -> v2: - more details in commit log --- scripts/bpf_doc.py | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py index a0ec321469bd..45f51ff1318c 100755 --- a/scripts/bpf_doc.py +++ b/scripts/bpf_doc.py @@ -717,6 +717,16 @@ class PrinterHelpers(Printer): header = '''\ /* This is auto-generated file. See bpf_doc.py for details. */ +/* Helper macro for GCC/Clang compatibility */ +#define NOARG +#if __GNUC__ && !__clang__ +#define BPF_HELPER_DEF(num, ret_star, ret_type, name, ...) \\ +ret_type ret_star name(__VA_ARGS__) __attribute__((kernel_helper(num))); +#else +#define BPF_HELPER_DEF(num, ret_star, ret_type, name, ...) \\ +static ret_type ret_star(*name)(__VA_ARGS__) = (void *) num; +#endif + /* Forward declarations of BPF structs */''' print(header) @@ -746,6 +756,11 @@ class PrinterHelpers(Printer): return self.seen_helpers.add(proto['name']) + if proto['ret_star']: + ret_star = proto['ret_star'] + else: + ret_star = 'NOARG' + print('/*') print(" * %s" % proto['name']) print(" *") @@ -762,8 +777,8 @@ class PrinterHelpers(Printer): print(' *{}{}'.format(' \t' if line else '', line)) print(' */') - print('static %s %s(*%s)(' % (self.map_type(proto['ret_type']), - proto['ret_star'], proto['name']), end='') + print('BPF_HELPER_DEF(%d, %s, %s, %s, ' % (len(self.seen_helpers), + ret_star, self.map_type(proto['ret_type']), proto['name']), end='') comma = '' for i, a in enumerate(proto['args']): t = a['type'] @@ -781,7 +796,7 @@ class PrinterHelpers(Printer): comma = ', ' print(one_arg, end='') - print(') = (void *) %d;' % len(self.seen_helpers)) + print(')') print('') ############################################################################### -- 2.34.1
