bpf: Move trampoline JIT image allocation to a function (98e8627e) · Commits · 戴 / test

include/linux/bpf.h

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -475,6 +475,7 @@ struct bpf_trampoline *bpf_trampoline_lookup(u64 key);
	int bpf_trampoline_link_prog(struct bpf_prog *prog);		int bpf_trampoline_link_prog(struct bpf_prog *prog);
	int bpf_trampoline_unlink_prog(struct bpf_prog *prog);		int bpf_trampoline_unlink_prog(struct bpf_prog *prog);
	void bpf_trampoline_put(struct bpf_trampoline *tr);		void bpf_trampoline_put(struct bpf_trampoline *tr);
			void *bpf_jit_alloc_exec_page(void);
	#else		#else
	static inline struct bpf_trampoline *bpf_trampoline_lookup(u64 key)		static inline struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
	{		{

kernel/bpf/trampoline.c

+17 −7

Original line number	Original line	Diff line number	Diff line
	@@ -13,6 +13,22 @@ static struct hlist_head trampoline_table[TRAMPOLINE_TABLE_SIZE];
	/* serializes access to trampoline_table */		/* serializes access to trampoline_table */
	static DEFINE_MUTEX(trampoline_mutex);		static DEFINE_MUTEX(trampoline_mutex);

			void *bpf_jit_alloc_exec_page(void)
			{
			void *image;

			image = bpf_jit_alloc_exec(PAGE_SIZE);
			if (!image)
			return NULL;

			set_vm_flush_reset_perms(image);
			/* Keep image as writeable. The alternative is to keep flipping ro/rw
			* everytime new program is attached or detached.
			*/
			set_memory_x((long)image, 1);
			return image;
			}

	struct bpf_trampoline *bpf_trampoline_lookup(u64 key)		struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
	{		{
	struct bpf_trampoline *tr;		struct bpf_trampoline *tr;
	@@ -33,7 +49,7 @@ struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
	goto out;		goto out;

	/* is_root was checked earlier. No need for bpf_jit_charge_modmem() */		/* is_root was checked earlier. No need for bpf_jit_charge_modmem() */
	image = bpf_jit_alloc_exec(PAGE_SIZE);		image = bpf_jit_alloc_exec_page();
	if (!image) {		if (!image) {
	kfree(tr);		kfree(tr);
	tr = NULL;		tr = NULL;
	@@ -47,12 +63,6 @@ struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
	mutex_init(&tr->mutex);		mutex_init(&tr->mutex);
	for (i = 0; i < BPF_TRAMP_MAX; i++)		for (i = 0; i < BPF_TRAMP_MAX; i++)
	INIT_HLIST_HEAD(&tr->progs_hlist[i]);		INIT_HLIST_HEAD(&tr->progs_hlist[i]);

	set_vm_flush_reset_perms(image);
	/* Keep image as writeable. The alternative is to keep flipping ro/rw
	* everytime new program is attached or detached.
	*/
	set_memory_x((long)image, 1);
	tr->image = image;		tr->image = image;
	out:		out:
	mutex_unlock(&trampoline_mutex);		mutex_unlock(&trampoline_mutex);

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