jump label: Add jump_label_text_reserved() to reserve jump points (4c3ef6d7) · Commits · 戴 / test

arch/x86/kernel/kprobes.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1218,7 +1218,8 @@ static int __kprobes copy_optimized_instructions(u8 dest, u8 src)
		}
		/* Check whether the address range is reserved */
		if (ftrace_text_reserved(src, src + len - 1) \|\|
		alternatives_text_reserved(src, src + len - 1))
		alternatives_text_reserved(src, src + len - 1) \|\|
		jump_label_text_reserved(src, src + len - 1))
		return -EBUSY;

		return len;

include/linux/jump_label.h

+7 −1

Original line number	Diff line number	Diff line
		@@ -20,9 +20,10 @@ extern struct jump_entry __stop___jump_table[];

		extern void arch_jump_label_transform(struct jump_entry *entry,
		enum jump_label_type type);
		extern void arch_jump_label_text_poke_early(jump_label_t addr);
		extern void jump_label_update(unsigned long key, enum jump_label_type type);
		extern void jump_label_apply_nops(struct module *mod);
		extern void arch_jump_label_text_poke_early(jump_label_t addr);
		extern int jump_label_text_reserved(void start, void end);

		#define enable_jump_label(key) \
		jump_label_update((unsigned long)key, JUMP_LABEL_ENABLE);
		@@ -53,6 +54,11 @@ static inline int jump_label_apply_nops(struct module *mod)
		return 0;
		}

		static inline int jump_label_text_reserved(void start, void end)
		{
		return 0;
		}

		#endif

		#endif

kernel/jump_label.c

+83 −0

Original line number	Diff line number	Diff line
		@@ -177,6 +177,89 @@ void jump_label_update(unsigned long key, enum jump_label_type type)
		mutex_unlock(&jump_label_mutex);
		}

		static int addr_conflict(struct jump_entry entry, void start, void *end)
		{
		if (entry->code <= (unsigned long)end &&
		entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start)
		return 1;

		return 0;
		}

		#ifdef CONFIG_MODULES

		static int module_conflict(void start, void end)
		{
		struct hlist_head *head;
		struct hlist_node node, node_next, module_node, module_node_next;
		struct jump_label_entry *e;
		struct jump_label_module_entry *e_module;
		struct jump_entry *iter;
		int i, count;
		int conflict = 0;

		for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) {
		head = &jump_label_table[i];
		hlist_for_each_entry_safe(e, node, node_next, head, hlist) {
		hlist_for_each_entry_safe(e_module, module_node,
		module_node_next,
		&(e->modules), hlist) {
		count = e_module->nr_entries;
		iter = e_module->table;
		while (count--) {
		if (addr_conflict(iter, start, end)) {
		conflict = 1;
		goto out;
		}
		iter++;
		}
		}
		}
		}
		out:
		return conflict;
		}

		#endif

		/***
		* jump_label_text_reserved - check if addr range is reserved
		* @start: start text addr
		* @end: end text addr
		*
		* checks if the text addr located between @start and @end
		* overlaps with any of the jump label patch addresses. Code
		* that wants to modify kernel text should first verify that
		* it does not overlap with any of the jump label addresses.
		*
		* returns 1 if there is an overlap, 0 otherwise
		*/
		int jump_label_text_reserved(void start, void end)
		{
		struct jump_entry *iter;
		struct jump_entry *iter_start = __start___jump_table;
		struct jump_entry *iter_stop = __start___jump_table;
		int conflict = 0;

		mutex_lock(&jump_label_mutex);
		iter = iter_start;
		while (iter < iter_stop) {
		if (addr_conflict(iter, start, end)) {
		conflict = 1;
		goto out;
		}
		iter++;
		}

		/* now check modules */
		#ifdef CONFIG_MODULES
		conflict = module_conflict(start, end);
		#endif
		out:
		mutex_unlock(&jump_label_mutex);
		return conflict;
		}

		static __init int init_jump_label(void)
		{
		int ret;

kernel/kprobes.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1147,7 +1147,8 @@ int __kprobes register_kprobe(struct kprobe *p)
		preempt_disable();
		if (!kernel_text_address((unsigned long) p->addr) \|\|
		in_kprobes_functions((unsigned long) p->addr) \|\|
		ftrace_text_reserved(p->addr, p->addr)) {
		ftrace_text_reserved(p->addr, p->addr) \|\|
		jump_label_text_reserved(p->addr, p->addr)) {
		preempt_enable();
		return -EINVAL;
		}

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