Commit 3055ddd6 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
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libbpf: misc internal libbpf clean ups around log fixup 



Normalize internal constants, field names, and comments related to log
fixup. Also add explicit `ext_idx` alias for relocation where relocation
is pointing to extern description for additional information.

No functional changes, just a clean up before subsequent additions.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230418002148.3255690-2-andrii@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 49859de9

tools/lib/bpf/libbpf.c

+14 −12
Original line number Diff line number Diff line
@@ -333,6 +333,7 @@ struct reloc_desc { 
		struct {

			int map_idx;

			int sym_off;

			int ext_idx;

		};

	};

};
@@ -4042,7 +4043,7 @@ static int bpf_program__record_reloc(struct bpf_program *prog, 
		else

			reloc_desc->type = RELO_EXTERN_LD64;

		reloc_desc->insn_idx = insn_idx;

		reloc_desc->sym_off = i; /* sym_off stores extern index */

		reloc_desc->ext_idx = i;

		return 0;

	}
@@ -5811,8 +5812,8 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) 
}



/* base map load ldimm64 special constant, used also for log fixup logic */

#define MAP_LDIMM64_POISON_BASE 2001000000

#define MAP_LDIMM64_POISON_PFX "200100"

#define POISON_LDIMM64_MAP_BASE 2001000000

#define POISON_LDIMM64_MAP_PFX "200100"



static void poison_map_ldimm64(struct bpf_program *prog, int relo_idx,

			       int insn_idx, struct bpf_insn *insn,
@@ -5834,7 +5835,7 @@ static void poison_map_ldimm64(struct bpf_program *prog, int relo_idx, 
		 * invalid func unknown#2001000123

		 * where lower 123 is map index into obj->maps[] array

		 */

		insn->imm = MAP_LDIMM64_POISON_BASE + map_idx;

		insn->imm = POISON_LDIMM64_MAP_BASE + map_idx;



		insn++;

	}
@@ -5885,7 +5886,7 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) 
			}

			break;

		case RELO_EXTERN_LD64:

			ext = &obj->externs[relo->sym_off];

			ext = &obj->externs[relo->ext_idx];

			if (ext->type == EXT_KCFG) {

				if (obj->gen_loader) {

					insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE;
@@ -5907,7 +5908,7 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) 
			}

			break;

		case RELO_EXTERN_CALL:

			ext = &obj->externs[relo->sym_off];

			ext = &obj->externs[relo->ext_idx];

			insn[0].src_reg = BPF_PSEUDO_KFUNC_CALL;

			if (ext->is_set) {

				insn[0].imm = ext->ksym.kernel_btf_id;
@@ -7022,13 +7023,13 @@ static void fixup_log_missing_map_load(struct bpf_program *prog, 
				       char *buf, size_t buf_sz, size_t log_sz,

				       char *line1, char *line2, char *line3)

{

	/* Expected log for failed and not properly guarded CO-RE relocation:

	/* Expected log for failed and not properly guarded map reference:

	 * line1 -> 123: (85) call unknown#2001000345

	 * line2 -> invalid func unknown#2001000345

	 * line3 -> <anything else or end of buffer>

	 *

	 * "123" is the index of the instruction that was poisoned.

	 * "345" in "2001000345" are map index in obj->maps to fetch map name.

	 * "345" in "2001000345" is a map index in obj->maps to fetch map name.

	 */

	struct bpf_object *obj = prog->obj;

	const struct bpf_map *map;
@@ -7038,7 +7039,7 @@ static void fixup_log_missing_map_load(struct bpf_program *prog, 
	if (sscanf(line1, "%d: (%*d) call unknown#%d\n", &insn_idx, &map_idx) != 2)

		return;



	map_idx -= MAP_LDIMM64_POISON_BASE;

	map_idx -= POISON_LDIMM64_MAP_BASE;

	if (map_idx < 0 || map_idx >= obj->nr_maps)

		return;

	map = &obj->maps[map_idx];
@@ -7070,20 +7071,21 @@ static void fixup_verifier_log(struct bpf_program *prog, char *buf, size_t buf_s 
		if (!cur_line)

			return;



		/* failed CO-RE relocation case */

		if (str_has_pfx(cur_line, "invalid func unknown#195896080\n")) {

			prev_line = find_prev_line(buf, cur_line);

			if (!prev_line)

				continue;



			/* failed CO-RE relocation case */

			fixup_log_failed_core_relo(prog, buf, buf_sz, log_sz,

						   prev_line, cur_line, next_line);

			return;

		} else if (str_has_pfx(cur_line, "invalid func unknown#"MAP_LDIMM64_POISON_PFX)) {

		} else if (str_has_pfx(cur_line, "invalid func unknown#"POISON_LDIMM64_MAP_PFX)) {

			prev_line = find_prev_line(buf, cur_line);

			if (!prev_line)

				continue;



			/* reference to uncreated BPF map */

			fixup_log_missing_map_load(prog, buf, buf_sz, log_sz,

						   prev_line, cur_line, next_line);

			return;
@@ -7098,7 +7100,7 @@ static int bpf_program_record_relos(struct bpf_program *prog) 


	for (i = 0; i < prog->nr_reloc; i++) {

		struct reloc_desc *relo = &prog->reloc_desc[i];

		struct extern_desc *ext = &obj->externs[relo->sym_off];

		struct extern_desc *ext = &obj->externs[relo->ext_idx];

		int kind;



		switch (relo->type) {