Documentation/bpf/llvm_reloc.rst

40        6:       0f 10 00 00 00 00 00 00 r0 += r1
44       10:       0f 10 00 00 00 00 00 00 r0 += r1
48       14:       0f 10 00 00 00 00 00 00 r0 += r1
115   10    R_BPF_64_32        call insn        32       r_offset + 4  (S + A) / 8 - 1
168          2:       85 10 00 00 ff ff ff ff call -1
173          6:       85 10 00 00 02 00 00 00 call 2
178         10:       61 11 00 00 00 00 00 00 r1 = *(u32 *)(r1 + 0)
179         11:       0f 10 00 00 00 00 00 00 r0 += r1
186          1:       2f 10 00 00 00 00 00 00 r0 *= r1
191          4:       0f 10 00 00 00 00 00 00 r0 += r1
204   struct t { void *g; } gbl = { global };
206 Compiled with ``clang --target=bpf -O2 -g -c test.c``, we will see a
272 * Field-based - patch instruction with field related information, e.g.
276 * Type-based - patch instruction with type related information, e.g.
280 * Enum-based - patch instruction with enum related information, e.g.
299 	BPF_CORE_ENUMVAL_EXISTS    = 10, /* enum value existence in target kernel */
381            struct { int c[10]; };
450   void alpha(struct foo *s, volatile unsigned long *g) {
451     *g = s->a;
460            10:  CO-RE <byte_off> [2] struct foo::a (0:0)
465 E.g. field-based relocations:
469   void bravo(struct foo *s, volatile unsigned long *g) {
470     *g = __builtin_preserve_field_info(s->b, 0 /* field byte offset */);
471     *g = __builtin_preserve_field_info(s->b, 1 /* field byte size */);
472     *g = __builtin_preserve_field_info(s->b, 2 /* field existence */);
473     *g = __builtin_preserve_field_info(s->b, 3 /* field signedness */);
474     *g = __builtin_preserve_field_info(s->c, 4 /* bitfield left shift */);
475     *g = __builtin_preserve_field_info(s->c, 5 /* bitfield right shift */);
488     10:     r1 = 0x1
504   void charlie(struct foo *s, volatile unsigned long *g) {
505     *g = __builtin_preserve_type_info(*s, 0 /* type existence */);
506     *g = __builtin_preserve_type_info(*s, 1 /* type size */);
507     *g = __builtin_preserve_type_info(*s, 2 /* type matches */);
508     *g = __builtin_btf_type_id(*s, 0 /* type id in this object file */);
509     *g = __builtin_btf_type_id(*s, 1 /* type id in target kernel */);
534   void delta(struct foo *s, volatile unsigned long *g) {
535     *g = __builtin_preserve_enum_value(*(enum bar *)U, 0 /* enum literal existence */);
536     *g = __builtin_preserve_enum_value(*(enum bar *)V, 1 /* enum literal value */);