livepatch: Add arch_klp_init

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5CJ7X

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

For the ARM architecture, need to register the callback function for
processing BRK exception in advance.
Therefore, the architecture-related init interface needs to be provided.
Signed-off-by: NYang Jihong <yangjihong1@huawei.com>
Reviewed-by: NXu Kuohai <xukuohai@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/linux/livepatch.h

@@ -256,6 +256,8 @@ int klp_compare_address(unsigned long pc, unsigned long func_addr,
 	return 0;
 }
 
+void arch_klp_init(void);
+
 #endif
 
 int klp_apply_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,

kernel/livepatch/core.c

@@ -1403,6 +1403,10 @@ long __weak arch_klp_save_old_code(struct arch_klp_data *arch_data, void *old_fu
 	return -ENOSYS;
 }
 
+void __weak arch_klp_init(void)
+{
+}
+
 int __weak arch_klp_check_breakpoint(struct arch_klp_data *arch_data, void *old_func)
 {
 	return 0;
@@ -2293,6 +2297,9 @@ static int __init klp_init(void)
 	if (!klp_root_kobj)
 		goto error_remove;
 
+#ifdef CONFIG_LIVEPATCH_STOP_MACHINE_CONSISTENCY
+	arch_klp_init();
+#endif
 	return 0;
 
 error_remove: