Commit 2fa5b0f2 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Daniel Borkmann
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libbpf: Use weak hidden modifier for USDT BPF-side API functions 



Use __weak __hidden for bpf_usdt_xxx() APIs instead of much more
confusing `static inline __noinline`. This was previously impossible due
to libbpf erroring out on CO-RE relocations pointing to eliminated weak
subprogs. Now that previous patch fixed this issue, switch back to
__weak __hidden as it's a more direct way of specifying the desired
behavior.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220408181425.2287230-3-andrii@kernel.org
parent e89d57d9

tools/lib/bpf/usdt.bpf.h

+3 −3
Original line number Diff line number Diff line
@@ -103,7 +103,7 @@ int __bpf_usdt_spec_id(struct pt_regs *ctx) 
}



/* Return number of USDT arguments defined for currently traced USDT. */

static inline __noinline

__weak __hidden

int bpf_usdt_arg_cnt(struct pt_regs *ctx)

{

	struct __bpf_usdt_spec *spec;
@@ -124,7 +124,7 @@ int bpf_usdt_arg_cnt(struct pt_regs *ctx) 
 * Returns 0 on success; negative error, otherwise.

 * On error *res is guaranteed to be set to zero.

 */

static inline __noinline

__weak __hidden

int bpf_usdt_arg(struct pt_regs *ctx, __u64 arg_num, long *res)

{

	struct __bpf_usdt_spec *spec;
@@ -204,7 +204,7 @@ int bpf_usdt_arg(struct pt_regs *ctx, __u64 arg_num, long *res) 
 * utilizing BPF cookies internally, so user can't use BPF cookie directly

 * for USDT programs and has to use bpf_usdt_cookie() API instead.

 */

static inline __noinline

__weak __hidden

long bpf_usdt_cookie(struct pt_regs *ctx)

{

	struct __bpf_usdt_spec *spec;