Commit ca261d60 authored by Zheng Yejian's avatar Zheng Yejian
Browse files

livepatch: Use func->func_node directly 

hulk inclusion
category: cleanup
bugzilla: https://gitee.com/openeuler/kernel/issues/I9R2TB



--------------------------------

When run into arch_klp_check_activeness_func(), func_node corresponding
to func->old_func has been stored in func->func_node and it must be valid,
So no need to find func_node again or validate it again.
  __klp_enable_patch()
    klp_mem_prepare()
      func_node_alloc
        // 1. Alloc func->func_node for func->old_func
    klp_try_enable_patch()
      klp_check_calltrace()
        arch_klp_check_activeness_func()
            // 2. Access func_node found by func->old_func
    klp_breakpoint_optimize()
      klp_breakpoint_enable_patch()
        ...
          arch_klp_check_activeness_func()
              // 3. Access func_node found by func->old_func

Signed-off-by: default avatarZheng Yejian <zhengyejian1@huawei.com>
parent 6b65db0b

arch/powerpc/kernel/livepatch_64.c

+3 −4
Original line number Diff line number Diff line
@@ -85,7 +85,7 @@ int arch_klp_check_activeness_func(struct klp_func *func, int enable, 
	unsigned long func_addr, func_size;

	struct klp_func_node *func_node = NULL;



	func_node = klp_find_func_node(func->old_func);

	func_node = func->func_node;

	/* Check func address in stack */

	if (enable) {

		if (func->patched || func->force == KLP_ENFORCEMENT)
@@ -94,7 +94,7 @@ int arch_klp_check_activeness_func(struct klp_func *func, int enable, 
		 * When enable, checking the currently

		 * active functions.

		 */

		if (!func_node || list_empty(&func_node->func_stack)) {

		if (list_empty(&func_node->func_stack)) {

			/*

			 * No patched on this function

			 * [ the origin one ]
@@ -169,8 +169,7 @@ int arch_klp_check_activeness_func(struct klp_func *func, int enable, 
			return ret;

#endif



		if (func_node == NULL ||

		    func_node->arch_data.trampoline.magic != BRANCH_TRAMPOLINE_MAGIC)

		if (func_node->arch_data.trampoline.magic != BRANCH_TRAMPOLINE_MAGIC)

			return 0;



		func_addr = (unsigned long)&func_node->arch_data.trampoline;

include/linux/livepatch.h

+0 −1
Original line number Diff line number Diff line
@@ -239,7 +239,6 @@ struct klp_func_node { 
	void *brk_func;

};



struct klp_func_node *klp_find_func_node(const void *old_func);

void klp_add_func_node(struct klp_func_node *func_node);

void klp_del_func_node(struct klp_func_node *func_node);

void *klp_get_brk_func(void *addr);

kernel/livepatch/core.c

+2 −2
Original line number Diff line number Diff line
@@ -1359,7 +1359,7 @@ int __weak arch_klp_check_activeness_func(struct klp_func *func, int enable, 
	struct klp_func_node *func_node = NULL;

	unsigned long old_func = (unsigned long)func->old_func;



	func_node = klp_find_func_node(func->old_func);

	func_node = func->func_node;

	/* Check func address in stack */

	if (enable) {

		if (func->patched || func->force == KLP_ENFORCEMENT)
@@ -1551,7 +1551,7 @@ static LIST_HEAD(klp_func_list); 
 * The caller must ensure that the klp_mutex lock is held or is in the rcu read

 * critical area.

 */

struct klp_func_node *klp_find_func_node(const void *old_func)

static struct klp_func_node *klp_find_func_node(const void *old_func)

{

	struct klp_func_node *func_node;