diff mbox series

[v5,04/13] module: Move livepatch support to a separate file

Message ID 20220209170358.3266629-5-atomlin@redhat.com (mailing list archive)
State Superseded
Headers show
Series module: core code clean up | expand

Commit Message

Aaron Tomlin Feb. 9, 2022, 5:03 p.m. UTC 
No functional change.

This patch migrates livepatch support (i.e. used during module
add/or load and remove/or deletion) from core module code into
kernel/module/livepatch.c. At the moment it contains code to
persist Elf information about a given livepatch module, only.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
---
 include/linux/module.h    |   5 +-
 kernel/module/Makefile    |   3 ++
 kernel/module/internal.h  |  18 +++++++
 kernel/module/livepatch.c |  80 ++++++++++++++++++++++++++++++
 kernel/module/main.c      | 102 ++++----------------------------------
 5 files changed, 112 insertions(+), 96 deletions(-)
 create mode 100644 kernel/module/livepatch.c

Comments

Christophe Leroy Feb. 9, 2022, 6:51 p.m. UTC | #1 
Le 09/02/2022 à 18:03, Aaron Tomlin a écrit :
> No functional change.
> 
> This patch migrates livepatch support (i.e. used during module
> add/or load and remove/or deletion) from core module code into
> kernel/module/livepatch.c. At the moment it contains code to
> persist Elf information about a given livepatch module, only.

   LD      .tmp_vmlinux.kallsyms1
powerpc64-linux-ld: kernel/livepatch/core.o: in function `klp_enable_patch':
(.text+0x1a0c): undefined reference to `is_livepatch_module'
powerpc64-linux-ld: kernel/module/main.o: in function `free_module':
main.c:(.text+0x50f4): undefined reference to `is_livepatch_module'
powerpc64-linux-ld: kernel/module/main.o: in function `load_module':
main.c:(.text+0x6f20): undefined reference to `is_livepatch_module'
powerpc64-linux-ld: main.c:(.text+0x8390): undefined reference to 
`is_livepatch_module'
powerpc64-linux-ld: main.c:(.text+0x8d6c): undefined reference to 
`is_livepatch_module'
make: *** [Makefile:1155 : vmlinux] Erreur 1


I don't understand why you are uninlining that so simple function.
Such a function is likely a single instruction in assembly, it is 
definitely not worth inlining.

Christophe

> 
> Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
> ---
>   include/linux/module.h    |   5 +-
>   kernel/module/Makefile    |   3 ++
>   kernel/module/internal.h  |  18 +++++++
>   kernel/module/livepatch.c |  80 ++++++++++++++++++++++++++++++
>   kernel/module/main.c      | 102 ++++----------------------------------
>   5 files changed, 112 insertions(+), 96 deletions(-)
>   create mode 100644 kernel/module/livepatch.c
> 
> diff --git a/include/linux/module.h b/include/linux/module.h
> index 1e135fd5c076..680b31ff57fa 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -664,10 +664,7 @@ static inline bool module_requested_async_probing(struct module *module)
>   }
>   
>   #ifdef CONFIG_LIVEPATCH
> -static inline bool is_livepatch_module(struct module *mod)
> -{
> -	return mod->klp;
> -}
> +bool is_livepatch_module(struct module *mod);
>   #else /* !CONFIG_LIVEPATCH */
>   static inline bool is_livepatch_module(struct module *mod)
>   {
> diff --git a/kernel/module/Makefile b/kernel/module/Makefile
> index 2902fc7d0ef1..ee20d864ad19 100644
> --- a/kernel/module/Makefile
> +++ b/kernel/module/Makefile
> @@ -7,3 +7,6 @@ obj-$(CONFIG_MODULES) += main.o
>   obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o
>   obj-$(CONFIG_MODULE_SIG) += signing.o
>   obj-$(CONFIG_MODULE_SIG_FORMAT) += signature.o
> +ifdef CONFIG_MODULES
> +obj-$(CONFIG_LIVEPATCH) += livepatch.o
> +endif
> diff --git a/kernel/module/internal.h b/kernel/module/internal.h
> index 1cf5d6dabc97..d252e0af1c54 100644
> --- a/kernel/module/internal.h
> +++ b/kernel/module/internal.h
> @@ -58,6 +58,24 @@ struct load_info {
>   
>   int mod_verify_sig(const void *mod, struct load_info *info);
>   
> +#ifdef CONFIG_LIVEPATCH
> +int copy_module_elf(struct module *mod, struct load_info *info);
> +void free_module_elf(struct module *mod);
> +bool set_livepatch_module(struct module *mod);
> +#else /* !CONFIG_LIVEPATCH */
> +static inline int copy_module_elf(struct module *mod, struct load_info *info)
> +{
> +	return 0;
> +}
> +
> +static inline bool set_livepatch_module(struct module *mod)
> +{
> +	return false;
> +}
> +
> +static inline void free_module_elf(struct module *mod) { }
> +#endif /* CONFIG_LIVEPATCH */
> +
>   #ifdef CONFIG_MODULE_DECOMPRESS
>   int module_decompress(struct load_info *info, const void *buf, size_t size);
>   void module_decompress_cleanup(struct load_info *info);
> diff --git a/kernel/module/livepatch.c b/kernel/module/livepatch.c
> new file mode 100644
> index 000000000000..7e9cf530c3f0
> --- /dev/null
> +++ b/kernel/module/livepatch.c
> @@ -0,0 +1,80 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Module livepatch support
> + *
> + * Copyright (C) 2016 Jessica Yu <jeyu@redhat.com>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/string.h>
> +#include <linux/slab.h>
> +#include "internal.h"
> +
> +/*
> + * Persist Elf information about a module. Copy the Elf header,
> + * section header table, section string table, and symtab section
> + * index from info to mod->klp_info.
> + */
> +int copy_module_elf(struct module *mod, struct load_info *info)
> +{
> +	unsigned int size, symndx;
> +	int ret;
> +
> +	size = sizeof(*mod->klp_info);
> +	mod->klp_info = kmalloc(size, GFP_KERNEL);
> +	if (mod->klp_info == NULL)
> +		return -ENOMEM;
> +
> +	/* Elf header */
> +	size = sizeof(mod->klp_info->hdr);
> +	memcpy(&mod->klp_info->hdr, info->hdr, size);
> +
> +	/* Elf section header table */
> +	size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
> +	mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);
> +	if (mod->klp_info->sechdrs == NULL) {
> +		ret = -ENOMEM;
> +		goto free_info;
> +	}
> +
> +	/* Elf section name string table */
> +	size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
> +	mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);
> +	if (mod->klp_info->secstrings == NULL) {
> +		ret = -ENOMEM;
> +		goto free_sechdrs;
> +	}
> +
> +	/* Elf symbol section index */
> +	symndx = info->index.sym;
> +	mod->klp_info->symndx = symndx;
> +
> +	/*
> +	 * For livepatch modules, core_kallsyms.symtab is a complete
> +	 * copy of the original symbol table. Adjust sh_addr to point
> +	 * to core_kallsyms.symtab since the copy of the symtab in module
> +	 * init memory is freed at the end of do_init_module().
> +	 */
> +	mod->klp_info->sechdrs[symndx].sh_addr = (unsigned long) mod->core_kallsyms.symtab;
> +
> +	return 0;
> +
> +free_sechdrs:
> +	kfree(mod->klp_info->sechdrs);
> +free_info:
> +	kfree(mod->klp_info);
> +	return ret;
> +}
> +
> +void free_module_elf(struct module *mod)
> +{
> +	kfree(mod->klp_info->sechdrs);
> +	kfree(mod->klp_info->secstrings);
> +	kfree(mod->klp_info);
> +}
> +
> +inline bool set_livepatch_module(struct module *mod)
> +{
> +	mod->klp = true;
> +	return true;
> +}
> diff --git a/kernel/module/main.c b/kernel/module/main.c
> index 750e3ad28679..5f5bd7152b55 100644
> --- a/kernel/module/main.c
> +++ b/kernel/module/main.c
> @@ -2042,81 +2042,6 @@ static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
>   }
>   #endif /*  CONFIG_STRICT_MODULE_RWX */
>   
> -#ifdef CONFIG_LIVEPATCH
> -/*
> - * Persist Elf information about a module. Copy the Elf header,
> - * section header table, section string table, and symtab section
> - * index from info to mod->klp_info.
> - */
> -static int copy_module_elf(struct module *mod, struct load_info *info)
> -{
> -	unsigned int size, symndx;
> -	int ret;
> -
> -	size = sizeof(*mod->klp_info);
> -	mod->klp_info = kmalloc(size, GFP_KERNEL);
> -	if (mod->klp_info == NULL)
> -		return -ENOMEM;
> -
> -	/* Elf header */
> -	size = sizeof(mod->klp_info->hdr);
> -	memcpy(&mod->klp_info->hdr, info->hdr, size);
> -
> -	/* Elf section header table */
> -	size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
> -	mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);
> -	if (mod->klp_info->sechdrs == NULL) {
> -		ret = -ENOMEM;
> -		goto free_info;
> -	}
> -
> -	/* Elf section name string table */
> -	size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
> -	mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);
> -	if (mod->klp_info->secstrings == NULL) {
> -		ret = -ENOMEM;
> -		goto free_sechdrs;
> -	}
> -
> -	/* Elf symbol section index */
> -	symndx = info->index.sym;
> -	mod->klp_info->symndx = symndx;
> -
> -	/*
> -	 * For livepatch modules, core_kallsyms.symtab is a complete
> -	 * copy of the original symbol table. Adjust sh_addr to point
> -	 * to core_kallsyms.symtab since the copy of the symtab in module
> -	 * init memory is freed at the end of do_init_module().
> -	 */
> -	mod->klp_info->sechdrs[symndx].sh_addr = \
> -		(unsigned long) mod->core_kallsyms.symtab;
> -
> -	return 0;
> -
> -free_sechdrs:
> -	kfree(mod->klp_info->sechdrs);
> -free_info:
> -	kfree(mod->klp_info);
> -	return ret;
> -}
> -
> -static void free_module_elf(struct module *mod)
> -{
> -	kfree(mod->klp_info->sechdrs);
> -	kfree(mod->klp_info->secstrings);
> -	kfree(mod->klp_info);
> -}
> -#else /* !CONFIG_LIVEPATCH */
> -static int copy_module_elf(struct module *mod, struct load_info *info)
> -{
> -	return 0;
> -}
> -
> -static void free_module_elf(struct module *mod)
> -{
> -}
> -#endif /* CONFIG_LIVEPATCH */
> -
>   void __weak module_memfree(void *module_region)
>   {
>   	/*
> @@ -3091,30 +3016,23 @@ static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned l
>   	return 0;
>   }
>   
> -#ifdef CONFIG_LIVEPATCH
>   static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
>   {
> -	if (get_modinfo(info, "livepatch")) {
> -		mod->klp = true;
> +	if (!get_modinfo(info, "livepatch"))
> +		/* Nothing more to do */
> +		return 0;
> +
> +	if (set_livepatch_module(mod)) {
>   		add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
>   		pr_notice_once("%s: tainting kernel with TAINT_LIVEPATCH\n",
> -			       mod->name);
> -	}
> -
> -	return 0;
> -}
> -#else /* !CONFIG_LIVEPATCH */
> -static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
> -{
> -	if (get_modinfo(info, "livepatch")) {
> -		pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
> -		       mod->name);
> -		return -ENOEXEC;
> +				mod->name);
> +		return 0;
>   	}
>   
> -	return 0;
> +	pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
> +		mod->name);
> +	return -ENOEXEC;
>   }
> -#endif /* CONFIG_LIVEPATCH */
>   
>   static void check_modinfo_retpoline(struct module *mod, struct load_info *info)
>   {
Christophe Leroy Feb. 10, 2022, 11:44 a.m. UTC | #2 
Le 09/02/2022 à 18:03, Aaron Tomlin a écrit :
> No functional change.
> 
> This patch migrates livepatch support (i.e. used during module
> add/or load and remove/or deletion) from core module code into
> kernel/module/livepatch.c. At the moment it contains code to
> persist Elf information about a given livepatch module, only.
> 
> Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
> ---
>   include/linux/module.h    |   5 +-
>   kernel/module/Makefile    |   3 ++
>   kernel/module/internal.h  |  18 +++++++
>   kernel/module/livepatch.c |  80 ++++++++++++++++++++++++++++++
>   kernel/module/main.c      | 102 ++++----------------------------------
>   5 files changed, 112 insertions(+), 96 deletions(-)
>   create mode 100644 kernel/module/livepatch.c
> 
> diff --git a/include/linux/module.h b/include/linux/module.h
> index 1e135fd5c076..680b31ff57fa 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -664,10 +664,7 @@ static inline bool module_requested_async_probing(struct module *module)
>   }
>   
>   #ifdef CONFIG_LIVEPATCH
> -static inline bool is_livepatch_module(struct module *mod)
> -{
> -	return mod->klp;
> -}
> +bool is_livepatch_module(struct module *mod);

This change is wrong, build fails with it because is_livepatch_module() 
is nowhere defined.

You could move is_livepatch_module() to include/linux/livepatch.h but as 
a separate patch.

>   #else /* !CONFIG_LIVEPATCH */
>   static inline bool is_livepatch_module(struct module *mod)
>   {
> diff --git a/kernel/module/Makefile b/kernel/module/Makefile
> index 2902fc7d0ef1..ee20d864ad19 100644
> --- a/kernel/module/Makefile
> +++ b/kernel/module/Makefile
> @@ -7,3 +7,6 @@ obj-$(CONFIG_MODULES) += main.o
>   obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o
>   obj-$(CONFIG_MODULE_SIG) += signing.o
>   obj-$(CONFIG_MODULE_SIG_FORMAT) += signature.o
> +ifdef CONFIG_MODULES

CONFIG_LIVEPATCH depends on CONFIG_MODULES so this ifdef is not needed 
(See kernel/livepatch/Kconfig)

> +obj-$(CONFIG_LIVEPATCH) += livepatch.o
> +endif
> diff --git a/kernel/module/internal.h b/kernel/module/internal.h
> index 1cf5d6dabc97..d252e0af1c54 100644
> --- a/kernel/module/internal.h
> +++ b/kernel/module/internal.h
> @@ -58,6 +58,24 @@ struct load_info {
>   
>   int mod_verify_sig(const void *mod, struct load_info *info);
>   
> +#ifdef CONFIG_LIVEPATCH
> +int copy_module_elf(struct module *mod, struct load_info *info);
> +void free_module_elf(struct module *mod);
> +bool set_livepatch_module(struct module *mod);
> +#else /* !CONFIG_LIVEPATCH */
> +static inline int copy_module_elf(struct module *mod, struct load_info *info)
> +{
> +	return 0;
> +}
> +
> +static inline bool set_livepatch_module(struct module *mod)
> +{
> +	return false;
> +}
> +
> +static inline void free_module_elf(struct module *mod) { }
> +#endif /* CONFIG_LIVEPATCH */
> +
>   #ifdef CONFIG_MODULE_DECOMPRESS
>   int module_decompress(struct load_info *info, const void *buf, size_t size);
>   void module_decompress_cleanup(struct load_info *info);
> diff --git a/kernel/module/livepatch.c b/kernel/module/livepatch.c
> new file mode 100644
> index 000000000000..7e9cf530c3f0
> --- /dev/null
> +++ b/kernel/module/livepatch.c

Checkpatch reports the following:

WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
#80:
new file mode 100644

CHECK: Comparison to NULL could be written "!mod->klp_info"
#109: FILE: kernel/module/livepatch.c:25:
+	if (mod->klp_info == NULL)

CHECK: Comparison to NULL could be written "!mod->klp_info->sechdrs"
#119: FILE: kernel/module/livepatch.c:35:
+	if (mod->klp_info->sechdrs == NULL) {

CHECK: Comparison to NULL could be written "!mod->klp_info->secstrings"
#127: FILE: kernel/module/livepatch.c:43:
+	if (mod->klp_info->secstrings == NULL) {

CHECK: No space is necessary after a cast
#142: FILE: kernel/module/livepatch.c:58:
+	mod->klp_info->sechdrs[symndx].sh_addr = (unsigned long) 
mod->core_kallsyms.symtab;


> +inline bool set_livepatch_module(struct module *mod)

'inline' keyword is pointless here, as far as this function is in a .c 
and is not static, it won't be inlined.

Given how simple this function is, it should be a 'static inline' in 
internal.c

> +{
> +	mod->klp = true;
> +	return true;
> +}



> diff --git a/kernel/module/main.c b/kernel/module/main.c
> index 750e3ad28679..5f5bd7152b55 100644
> --- a/kernel/module/main.c
> +++ b/kernel/module/main.c

> @@ -3091,30 +3016,23 @@ static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned l
>   	return 0;
>   }
>   
> -#ifdef CONFIG_LIVEPATCH
>   static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
>   {
> -	if (get_modinfo(info, "livepatch")) {
> -		mod->klp = true;
> +	if (!get_modinfo(info, "livepatch"))
> +		/* Nothing more to do */
> +		return 0;
> +
> +	if (set_livepatch_module(mod)) {
>   		add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
>   		pr_notice_once("%s: tainting kernel with TAINT_LIVEPATCH\n",
> -			       mod->name);
> -	}
> -
> -	return 0;
> -}
> -#else /* !CONFIG_LIVEPATCH */
> -static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
> -{
> -	if (get_modinfo(info, "livepatch")) {
> -		pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
> -		       mod->name);
> -		return -ENOEXEC;
> +				mod->name);

This change seems wrong, mod->name must remain aligned to open parenthesis.


> +		return 0;
>   	}
>   
> -	return 0;
> +	pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
> +		mod->name);

CHECK: Alignment should match open parenthesis
#285: FILE: kernel/module/main.c:3033:
+	pr_err("%s: module is marked as livepatch module, but livepatch 
support is disabled",
+		mod->name);

> +	return -ENOEXEC;
>   }
> -#endif /* CONFIG_LIVEPATCH */
>   
>   static void check_modinfo_retpoline(struct module *mod, struct load_info *info)
>   {
Aaron Tomlin Feb. 10, 2022, 5:20 p.m. UTC | #3 
On Thu 2022-02-10 11:44 +0000, Christophe Leroy wrote:
> This change is wrong, build fails with it because is_livepatch_module()
> is nowhere defined.

Yes, sorry about that. This was an omission/or oversight during the rebase
attempt.

> You could move is_livepatch_module() to include/linux/livepatch.h but as
> a separate patch.

Fair enough. Albeit, I'd prefer to revert and keep is_livepatch_module()
in include/linux/module.h - this is likely the best solution.
Note: set_livepatch_module() will remain for internal use only.

> >   #else /* !CONFIG_LIVEPATCH */
> >   static inline bool is_livepatch_module(struct module *mod)
> >   {
> > diff --git a/kernel/module/Makefile b/kernel/module/Makefile
> > index 2902fc7d0ef1..ee20d864ad19 100644
> > --- a/kernel/module/Makefile
> > +++ b/kernel/module/Makefile
> > @@ -7,3 +7,6 @@ obj-$(CONFIG_MODULES) += main.o
> >   obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o
> >   obj-$(CONFIG_MODULE_SIG) += signing.o
> >   obj-$(CONFIG_MODULE_SIG_FORMAT) += signature.o
> > +ifdef CONFIG_MODULES
>
> CONFIG_LIVEPATCH depends on CONFIG_MODULES so this ifdef is not needed

Agreed.

> Checkpatch reports the following:
>
> WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
> #80:
> new file mode 100644
>
> CHECK: Comparison to NULL could be written "!mod->klp_info"
> #109: FILE: kernel/module/livepatch.c:25:
> +    if (mod->klp_info == NULL)
>
> CHECK: Comparison to NULL could be written "!mod->klp_info->sechdrs"
> #119: FILE: kernel/module/livepatch.c:35:
> +    if (mod->klp_info->sechdrs == NULL) {
>
> CHECK: Comparison to NULL could be written "!mod->klp_info->secstrings"
> #127: FILE: kernel/module/livepatch.c:43:
> +    if (mod->klp_info->secstrings == NULL) {
>
> CHECK: No space is necessary after a cast
> #142: FILE: kernel/module/livepatch.c:58:
> +    mod->klp_info->sechdrs[symndx].sh_addr = (unsigned long)
> mod->core_kallsyms.symtab;

Ok.

> Given how simple this function is, it should be a 'static inline' in
> internal.c

Agreed.

> CHECK: Alignment should match open parenthesis
> #285: FILE: kernel/module/main.c:3033:
> +    pr_err("%s: module is marked as livepatch module, but livepatch
> support is disabled",
> +        mod->name);

Fair enough.


Kind regards,
diff mbox series

Patch

diff --git a/include/linux/module.h b/include/linux/module.h
index 1e135fd5c076..680b31ff57fa 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -664,10 +664,7 @@  static inline bool module_requested_async_probing(struct module *module)
 }
 
 #ifdef CONFIG_LIVEPATCH
-static inline bool is_livepatch_module(struct module *mod)
-{
-	return mod->klp;
-}
+bool is_livepatch_module(struct module *mod);
 #else /* !CONFIG_LIVEPATCH */
 static inline bool is_livepatch_module(struct module *mod)
 {
diff --git a/kernel/module/Makefile b/kernel/module/Makefile
index 2902fc7d0ef1..ee20d864ad19 100644
--- a/kernel/module/Makefile
+++ b/kernel/module/Makefile
@@ -7,3 +7,6 @@  obj-$(CONFIG_MODULES) += main.o
 obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o
 obj-$(CONFIG_MODULE_SIG) += signing.o
 obj-$(CONFIG_MODULE_SIG_FORMAT) += signature.o
+ifdef CONFIG_MODULES
+obj-$(CONFIG_LIVEPATCH) += livepatch.o
+endif
diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index 1cf5d6dabc97..d252e0af1c54 100644
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -58,6 +58,24 @@  struct load_info {
 
 int mod_verify_sig(const void *mod, struct load_info *info);
 
+#ifdef CONFIG_LIVEPATCH
+int copy_module_elf(struct module *mod, struct load_info *info);
+void free_module_elf(struct module *mod);
+bool set_livepatch_module(struct module *mod);
+#else /* !CONFIG_LIVEPATCH */
+static inline int copy_module_elf(struct module *mod, struct load_info *info)
+{
+	return 0;
+}
+
+static inline bool set_livepatch_module(struct module *mod)
+{
+	return false;
+}
+
+static inline void free_module_elf(struct module *mod) { }
+#endif /* CONFIG_LIVEPATCH */
+
 #ifdef CONFIG_MODULE_DECOMPRESS
 int module_decompress(struct load_info *info, const void *buf, size_t size);
 void module_decompress_cleanup(struct load_info *info);
diff --git a/kernel/module/livepatch.c b/kernel/module/livepatch.c
new file mode 100644
index 000000000000..7e9cf530c3f0
--- /dev/null
+++ b/kernel/module/livepatch.c
@@ -0,0 +1,80 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Module livepatch support
+ *
+ * Copyright (C) 2016 Jessica Yu <jeyu@redhat.com>
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+/*
+ * Persist Elf information about a module. Copy the Elf header,
+ * section header table, section string table, and symtab section
+ * index from info to mod->klp_info.
+ */
+int copy_module_elf(struct module *mod, struct load_info *info)
+{
+	unsigned int size, symndx;
+	int ret;
+
+	size = sizeof(*mod->klp_info);
+	mod->klp_info = kmalloc(size, GFP_KERNEL);
+	if (mod->klp_info == NULL)
+		return -ENOMEM;
+
+	/* Elf header */
+	size = sizeof(mod->klp_info->hdr);
+	memcpy(&mod->klp_info->hdr, info->hdr, size);
+
+	/* Elf section header table */
+	size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
+	mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);
+	if (mod->klp_info->sechdrs == NULL) {
+		ret = -ENOMEM;
+		goto free_info;
+	}
+
+	/* Elf section name string table */
+	size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
+	mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);
+	if (mod->klp_info->secstrings == NULL) {
+		ret = -ENOMEM;
+		goto free_sechdrs;
+	}
+
+	/* Elf symbol section index */
+	symndx = info->index.sym;
+	mod->klp_info->symndx = symndx;
+
+	/*
+	 * For livepatch modules, core_kallsyms.symtab is a complete
+	 * copy of the original symbol table. Adjust sh_addr to point
+	 * to core_kallsyms.symtab since the copy of the symtab in module
+	 * init memory is freed at the end of do_init_module().
+	 */
+	mod->klp_info->sechdrs[symndx].sh_addr = (unsigned long) mod->core_kallsyms.symtab;
+
+	return 0;
+
+free_sechdrs:
+	kfree(mod->klp_info->sechdrs);
+free_info:
+	kfree(mod->klp_info);
+	return ret;
+}
+
+void free_module_elf(struct module *mod)
+{
+	kfree(mod->klp_info->sechdrs);
+	kfree(mod->klp_info->secstrings);
+	kfree(mod->klp_info);
+}
+
+inline bool set_livepatch_module(struct module *mod)
+{
+	mod->klp = true;
+	return true;
+}
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 750e3ad28679..5f5bd7152b55 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2042,81 +2042,6 @@  static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 }
 #endif /*  CONFIG_STRICT_MODULE_RWX */
 
-#ifdef CONFIG_LIVEPATCH
-/*
- * Persist Elf information about a module. Copy the Elf header,
- * section header table, section string table, and symtab section
- * index from info to mod->klp_info.
- */
-static int copy_module_elf(struct module *mod, struct load_info *info)
-{
-	unsigned int size, symndx;
-	int ret;
-
-	size = sizeof(*mod->klp_info);
-	mod->klp_info = kmalloc(size, GFP_KERNEL);
-	if (mod->klp_info == NULL)
-		return -ENOMEM;
-
-	/* Elf header */
-	size = sizeof(mod->klp_info->hdr);
-	memcpy(&mod->klp_info->hdr, info->hdr, size);
-
-	/* Elf section header table */
-	size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
-	mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);
-	if (mod->klp_info->sechdrs == NULL) {
-		ret = -ENOMEM;
-		goto free_info;
-	}
-
-	/* Elf section name string table */
-	size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
-	mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);
-	if (mod->klp_info->secstrings == NULL) {
-		ret = -ENOMEM;
-		goto free_sechdrs;
-	}
-
-	/* Elf symbol section index */
-	symndx = info->index.sym;
-	mod->klp_info->symndx = symndx;
-
-	/*
-	 * For livepatch modules, core_kallsyms.symtab is a complete
-	 * copy of the original symbol table. Adjust sh_addr to point
-	 * to core_kallsyms.symtab since the copy of the symtab in module
-	 * init memory is freed at the end of do_init_module().
-	 */
-	mod->klp_info->sechdrs[symndx].sh_addr = \
-		(unsigned long) mod->core_kallsyms.symtab;
-
-	return 0;
-
-free_sechdrs:
-	kfree(mod->klp_info->sechdrs);
-free_info:
-	kfree(mod->klp_info);
-	return ret;
-}
-
-static void free_module_elf(struct module *mod)
-{
-	kfree(mod->klp_info->sechdrs);
-	kfree(mod->klp_info->secstrings);
-	kfree(mod->klp_info);
-}
-#else /* !CONFIG_LIVEPATCH */
-static int copy_module_elf(struct module *mod, struct load_info *info)
-{
-	return 0;
-}
-
-static void free_module_elf(struct module *mod)
-{
-}
-#endif /* CONFIG_LIVEPATCH */
-
 void __weak module_memfree(void *module_region)
 {
 	/*
@@ -3091,30 +3016,23 @@  static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned l
 	return 0;
 }
 
-#ifdef CONFIG_LIVEPATCH
 static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
 {
-	if (get_modinfo(info, "livepatch")) {
-		mod->klp = true;
+	if (!get_modinfo(info, "livepatch"))
+		/* Nothing more to do */
+		return 0;
+
+	if (set_livepatch_module(mod)) {
 		add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
 		pr_notice_once("%s: tainting kernel with TAINT_LIVEPATCH\n",
-			       mod->name);
-	}
-
-	return 0;
-}
-#else /* !CONFIG_LIVEPATCH */
-static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
-{
-	if (get_modinfo(info, "livepatch")) {
-		pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
-		       mod->name);
-		return -ENOEXEC;
+				mod->name);
+		return 0;
 	}
 
-	return 0;
+	pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
+		mod->name);
+	return -ENOEXEC;
 }
-#endif /* CONFIG_LIVEPATCH */
 
 static void check_modinfo_retpoline(struct module *mod, struct load_info *info)
 {