bpf: Pass bpf_verifier_env to JIT

Pass bpf_verifier_env to bpf_int_jit_compile(). The follow-up patch will
use env->insn_aux_data in the JIT stage to detect indirect jump targets.

Since bpf_prog_select_runtime() can be called by cbpf and lib/test_bpf.c
code without verifier, introduce helper __bpf_prog_select_runtime()
to accept the env parameter.

Remove the call to bpf_prog_select_runtime() in bpf_prog_load(), and
switch to call __bpf_prog_select_runtime() in the verifier, with env
variable passed. The original bpf_prog_select_runtime() is preserved for
cbpf and lib/test_bpf.c, where env is NULL.

Now all constants blinding calls are moved into the verifier, except
the cbpf and lib/test_bpf.c cases. The instructions arrays are adjusted
by bpf_patch_insn_data() function for normal cases, so there is no need
to call adjust_insn_arrays() in bpf_jit_blind_constants(). Remove it.

Reviewed-by: Anton Protopopov <a.s.protopopov@gmail.com> # v8
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> # v12
Acked-by: Hengqi Chen <hengqi.chen@gmail.com> # v14
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Link: https://lore.kernel.org/r/20260416064341.151802-3-xukuohai@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

4 files changed, 56 insertions, 58 deletions

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index fc9fb3c07866..79361aa11757 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1491,23 +1491,6 @@ void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
 	bpf_prog_clone_free(fp_other);
 }
 
-static void adjust_insn_arrays(struct bpf_prog *prog, u32 off, u32 len)
-{
-#ifdef CONFIG_BPF_SYSCALL
-	struct bpf_map *map;
-	int i;
-
-	if (len <= 1)
-		return;
-
-	for (i = 0; i < prog->aux->used_map_cnt; i++) {
-		map = prog->aux->used_maps[i];
-		if (map->map_type == BPF_MAP_TYPE_INSN_ARRAY)
-			bpf_insn_array_adjust(map, off, len);
-	}
-#endif
-}
-
 /*
  * Now this function is used only to blind the main prog and must be invoked only when
  * bpf_prog_need_blind() returns true.
@@ -1580,13 +1563,6 @@ struct bpf_prog *bpf_jit_blind_constants(struct bpf_verifier_env *env, struct bp
 
 		if (env)
 			env->prog = clone;
-		else
-			/*
-			 * Instructions arrays must be updated using absolute xlated offsets.
-			 * The arrays have already been adjusted by bpf_patch_insn_data() when
-			 * env is not NULL.
-			 */
-			adjust_insn_arrays(clone, i, rewritten);
 
 		/* Walk new program and skip insns we just inserted. */
 		insn = clone->insnsi + i + insn_delta;
@@ -2555,47 +2531,55 @@ static bool bpf_prog_select_interpreter(struct bpf_prog *fp)
 	return select_interpreter;
 }
 
-static struct bpf_prog *bpf_prog_jit_compile(struct bpf_prog *prog)
+static struct bpf_prog *bpf_prog_jit_compile(struct bpf_verifier_env *env, struct bpf_prog *prog)
 {
 #ifdef CONFIG_BPF_JIT
 	struct bpf_prog *orig_prog;
+	struct bpf_insn_aux_data *orig_insn_aux;
 
 	if (!bpf_prog_need_blind(prog))
-		return bpf_int_jit_compile(prog);
+		return bpf_int_jit_compile(env, prog);
+
+	if (env) {
+		/*
+		 * If env is not NULL, we are called from the end of bpf_check(), at this
+		 * point, only insn_aux_data is used after failure, so it should be restored
+		 * on failure.
+		 */
+		orig_insn_aux = bpf_dup_insn_aux_data(env);
+		if (!orig_insn_aux)
+			return prog;
+	}
 
 	orig_prog = prog;
-	prog = bpf_jit_blind_constants(NULL, prog);
+	prog = bpf_jit_blind_constants(env, prog);
 	/*
 	 * If blinding was requested and we failed during blinding, we must fall
 	 * back to the interpreter.
 	 */
 	if (IS_ERR(prog))
-		return orig_prog;
+		goto out_restore;
 
-	prog = bpf_int_jit_compile(prog);
+	prog = bpf_int_jit_compile(env, prog);
 	if (prog->jited) {
 		bpf_jit_prog_release_other(prog, orig_prog);
+		if (env)
+			vfree(orig_insn_aux);
 		return prog;
 	}
 
 	bpf_jit_prog_release_other(orig_prog, prog);
+
+out_restore:
 	prog = orig_prog;
+	if (env)
+		bpf_restore_insn_aux_data(env, orig_insn_aux);
 #endif
 	return prog;
 }
 
-/**
- *	bpf_prog_select_runtime - select exec runtime for BPF program
- *	@fp: bpf_prog populated with BPF program
- *	@err: pointer to error variable
- *
- * Try to JIT eBPF program, if JIT is not available, use interpreter.
- * The BPF program will be executed via bpf_prog_run() function.
- *
- * Return: the &fp argument along with &err set to 0 for success or
- * a negative errno code on failure
- */
-struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
+struct bpf_prog *__bpf_prog_select_runtime(struct bpf_verifier_env *env, struct bpf_prog *fp,
+					   int *err)
 {
 	/* In case of BPF to BPF calls, verifier did all the prep
 	 * work with regards to JITing, etc.
@@ -2623,7 +2607,7 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
 		if (*err)
 			return fp;
 
-		fp = bpf_prog_jit_compile(fp);
+		fp = bpf_prog_jit_compile(env, fp);
 		bpf_prog_jit_attempt_done(fp);
 		if (!fp->jited && jit_needed) {
 			*err = -ENOTSUPP;
@@ -2649,6 +2633,22 @@ finalize:
 
 	return fp;
 }
+
+/**
+ *	bpf_prog_select_runtime - select exec runtime for BPF program
+ *	@fp: bpf_prog populated with BPF program
+ *	@err: pointer to error variable
+ *
+ * Try to JIT eBPF program, if JIT is not available, use interpreter.
+ * The BPF program will be executed via bpf_prog_run() function.
+ *
+ * Return: the &fp argument along with &err set to 0 for success or
+ * a negative errno code on failure
+ */
+struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
+{
+	return __bpf_prog_select_runtime(NULL, fp, err);
+}
 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
 
 static unsigned int __bpf_prog_ret1(const void *ctx,
@@ -3136,7 +3136,7 @@ const struct bpf_func_proto bpf_tail_call_proto = {
  * It is encouraged to implement bpf_int_jit_compile() instead, so that
  * eBPF and implicitly also cBPF can get JITed!
  */
-struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
+struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_verifier_env *env, struct bpf_prog *prog)
 {
 	return prog;
 }
diff --git a/kernel/bpf/fixups.c b/kernel/bpf/fixups.c
index 721b830b5ef2..6c86980cc9e8 100644
--- a/kernel/bpf/fixups.c
+++ b/kernel/bpf/fixups.c
@@ -993,7 +993,7 @@ static void bpf_restore_subprog_starts(struct bpf_verifier_env *env, u32 *orig_s
 	env->subprog_info[env->subprog_cnt].start = env->prog->len;
 }
 
-static struct bpf_insn_aux_data *bpf_dup_insn_aux_data(struct bpf_verifier_env *env)
+struct bpf_insn_aux_data *bpf_dup_insn_aux_data(struct bpf_verifier_env *env)
 {
 	size_t size;
 	void *new_aux;
@@ -1005,8 +1005,8 @@ static struct bpf_insn_aux_data *bpf_dup_insn_aux_data(struct bpf_verifier_env *
 	return new_aux;
 }
 
-static void bpf_restore_insn_aux_data(struct bpf_verifier_env *env,
-				      struct bpf_insn_aux_data *orig_insn_aux)
+void bpf_restore_insn_aux_data(struct bpf_verifier_env *env,
+			       struct bpf_insn_aux_data *orig_insn_aux)
 {
 	/* the expanded elements are zero-filled, so no special handling is required */
 	vfree(env->insn_aux_data);
@@ -1150,7 +1150,7 @@ static int jit_subprogs(struct bpf_verifier_env *env)
 		func[i]->aux->token = prog->aux->token;
 		if (!i)
 			func[i]->aux->exception_boundary = env->seen_exception;
-		func[i] = bpf_int_jit_compile(func[i]);
+		func[i] = bpf_int_jit_compile(env, func[i]);
 		if (!func[i]->jited) {
 			err = -ENOTSUPP;
 			goto out_free;
@@ -1194,7 +1194,7 @@ static int jit_subprogs(struct bpf_verifier_env *env)
 	}
 	for (i = 0; i < env->subprog_cnt; i++) {
 		old_bpf_func = func[i]->bpf_func;
-		tmp = bpf_int_jit_compile(func[i]);
+		tmp = bpf_int_jit_compile(env, func[i]);
 		if (tmp != func[i] || func[i]->bpf_func != old_bpf_func) {
 			verbose(env, "JIT doesn't support bpf-to-bpf calls\n");
 			err = -ENOTSUPP;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index b73b25c63073..a3c0214ca934 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3083,10 +3083,6 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
 	if (err < 0)
 		goto free_used_maps;
 
-	prog = bpf_prog_select_runtime(prog, &err);
-	if (err < 0)
-		goto free_used_maps;
-
 	err = bpf_prog_mark_insn_arrays_ready(prog);
 	if (err < 0)
 		goto free_used_maps;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 9e4980128151..e804e0da3500 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -20155,6 +20155,14 @@ skip_full_check:
 
 	adjust_btf_func(env);
 
+	/* extension progs temporarily inherit the attach_type of their targets
+	   for verification purposes, so set it back to zero before returning
+	 */
+	if (env->prog->type == BPF_PROG_TYPE_EXT)
+		env->prog->expected_attach_type = 0;
+
+	env->prog = __bpf_prog_select_runtime(env, env->prog, &ret);
+
 err_release_maps:
 	if (ret)
 		release_insn_arrays(env);
@@ -20166,12 +20174,6 @@ err_release_maps:
 	if (!env->prog->aux->used_btfs)
 		release_btfs(env);
 
-	/* extension progs temporarily inherit the attach_type of their targets
-	   for verification purposes, so set it back to zero before returning
-	 */
-	if (env->prog->type == BPF_PROG_TYPE_EXT)
-		env->prog->expected_attach_type = 0;
-
 	*prog = env->prog;
 
 	module_put(env->attach_btf_mod);