Commit 523a4cf4 authored by Dmitrii Banshchikov's avatar Dmitrii Banshchikov Committed by Alexei Starovoitov
Browse files

bpf: Use MAX_BPF_FUNC_REG_ARGS macro 



Instead of using integer literal here and there use macro name for
better context.

Signed-off-by: default avatarDmitrii Banshchikov <me@ubique.spb.ru>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210225202629.585485-1-me@ubique.spb.ru
parent a7d24d95

include/linux/bpf.h

+5 −0
Original line number Diff line number Diff line
@@ -506,6 +506,11 @@ enum bpf_cgroup_storage_type { 
 */

#define MAX_BPF_FUNC_ARGS 12



/* The maximum number of arguments passed through registers

 * a single function may have.

 */

#define MAX_BPF_FUNC_REG_ARGS 5



struct btf_func_model {

	u8 ret_size;

	u8 nr_args;

kernel/bpf/btf.c

+14 −11
Original line number Diff line number Diff line
@@ -4594,8 +4594,10 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, 
	}

	arg = off / 8;

	args = (const struct btf_param *)(t + 1);

	/* if (t == NULL) Fall back to default BPF prog with 5 u64 arguments */

	nr_args = t ? btf_type_vlen(t) : 5;

	/* if (t == NULL) Fall back to default BPF prog with

	 * MAX_BPF_FUNC_REG_ARGS u64 arguments.

	 */

	nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;

	if (prog->aux->attach_btf_trace) {

		/* skip first 'void *__data' argument in btf_trace_##name typedef */

		args++;
@@ -4651,7 +4653,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, 
		}

	} else {

		if (!t)

			/* Default prog with 5 args */

			/* Default prog with MAX_BPF_FUNC_REG_ARGS args */

			return true;

		t = btf_type_by_id(btf, args[arg].type);

	}
@@ -5102,12 +5104,12 @@ int btf_distill_func_proto(struct bpf_verifier_log *log, 


	if (!func) {

		/* BTF function prototype doesn't match the verifier types.

		 * Fall back to 5 u64 args.

		 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.

		 */

		for (i = 0; i < 5; i++)

		for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++)

			m->arg_size[i] = 8;

		m->ret_size = 8;

		m->nr_args = 5;

		m->nr_args = MAX_BPF_FUNC_REG_ARGS;

		return 0;

	}

	args = (const struct btf_param *)(func + 1);
@@ -5330,8 +5332,9 @@ int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog, 
	}

	args = (const struct btf_param *)(t + 1);

	nargs = btf_type_vlen(t);

	if (nargs > 5) {

		bpf_log(log, "Function %s has %d > 5 args\n", tname, nargs);

	if (nargs > MAX_BPF_FUNC_REG_ARGS) {

		bpf_log(log, "Function %s has %d > %d args\n", tname, nargs,

			MAX_BPF_FUNC_REG_ARGS);

		goto out;

	}
@@ -5460,9 +5463,9 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog, 
	}

	args = (const struct btf_param *)(t + 1);

	nargs = btf_type_vlen(t);

	if (nargs > 5) {

		bpf_log(log, "Global function %s() with %d > 5 args. Buggy compiler.\n",

			tname, nargs);

	if (nargs > MAX_BPF_FUNC_REG_ARGS) {

		bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",

			tname, nargs, MAX_BPF_FUNC_REG_ARGS);

		return -EINVAL;

	}

	/* check that function returns int */

kernel/bpf/verifier.c

+1 −1
Original line number Diff line number Diff line
@@ -5544,7 +5544,7 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn 


	meta.func_id = func_id;

	/* check args */

	for (i = 0; i < 5; i++) {

	for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {

		err = check_func_arg(env, i, &meta, fn);

		if (err)

			return err;