libbpf: add support for bpf_call
- recognize relocation emitted by llvm
- since all regular function will be kept in .text section and llvm
takes care of pc-relative offsets in bpf_call instruction
simply copy all of .text to relevant program section while adjusting
bpf_call instructions in program section to point to newly copied
body of instructions from .text
- do so for all programs in the elf file
- set all programs types to the one passed to bpf_prog_load()
Note for elf files with multiple programs that use different
functions in .text section we need to do 'linker' style logic.
This work is still TBD
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index cf446c2..db1b092 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -197,8 +197,14 @@ enum bpf_attach_type {
*/
#define BPF_F_STRICT_ALIGNMENT (1U << 0)
+/* when bpf_ldimm64->src_reg == BPF_PSEUDO_MAP_FD, bpf_ldimm64->imm == fd */
#define BPF_PSEUDO_MAP_FD 1
+/* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
+ * offset to another bpf function
+ */
+#define BPF_PSEUDO_CALL 1
+
/* flags for BPF_MAP_UPDATE_ELEM command */
#define BPF_ANY 0 /* create new element or update existing */
#define BPF_NOEXIST 1 /* create new element if it didn't exist */