[PATCH 06/13] kallsyms: only build {,module_}kallsyms_on_each_symbol when required

Christoph Hellwig
2021-02-02T12:15:45Z

kallsyms_on_each_symbol and module_kallsyms_on_each_symbol are only used
by the livepatching code, so don't build them if livepatching is not
enabled.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
include/linux/kallsyms.h | 17 ++++-------------
include/linux/module.h | 16 ++++------------
kernel/kallsyms.c | 2 ++
kernel/module.c | 2 ++
4 files changed, 12 insertions(+), 25 deletions(-)

diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index 481273f0c72d42..465060acc9816f 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -71,15 +71,14 @@ static inline void *dereference_symbol_descriptor(void *ptr)
return ptr;
}

-#ifdef CONFIG_KALLSYMS
-/* Lookup the address for a symbol. Returns 0 if not found. */
-unsigned long kallsyms_lookup_name(const char *name);
-
-/* Call a function on each kallsyms symbol in the core kernel */
int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
unsigned long),
void *data);

+#ifdef CONFIG_KALLSYMS
+/* Lookup the address for a symbol. Returns 0 if not found. */
+unsigned long kallsyms_lookup_name(const char *name);
+
extern int kallsyms_lookup_size_offset(unsigned long addr,
unsigned long *symbolsize,
unsigned long *offset);
@@ -108,14 +107,6 @@ static inline unsigned long kallsyms_lookup_name(const char *name)
return 0;
}

-static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *,
- struct module *,
- unsigned long),
- void *data)
-{
- return 0;
-}
-
static inline int kallsyms_lookup_size_offset(unsigned long addr,
unsigned long *symbolsize,
unsigned long *offset)
diff --git a/include/linux/module.h b/include/linux/module.h
index a64aa84d1b182c..3ea4ffae608f97 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -608,10 +608,6 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
/* Look for this name: can be of form module:name. */
unsigned long module_kallsyms_lookup_name(const char *name);

-int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
- struct module *, unsigned long),
- void *data);
-
extern void __noreturn __module_put_and_exit(struct module *mod,
long code);
#define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code)
@@ -795,14 +791,6 @@ static inline unsigned long module_kallsyms_lookup_name(const char *name)
return 0;
}

-static inline int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
- struct module *,
- unsigned long),
- void *data)
-{
- return 0;
-}
-
static inline int register_module_notifier(struct notifier_block *nb)
{
/* no events will happen anyway, so this can always succeed */
@@ -891,4 +879,8 @@ static inline bool module_sig_ok(struct module *module)
}
#endif /* CONFIG_MODULE_SIG */

+int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
+ struct module *, unsigned long),
+ void *data);
+
#endif /* _LINUX_MODULE_H */
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index a0d3f0865916f9..8043a90aa50ed3 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -177,6 +177,7 @@ unsigned long kallsyms_lookup_name(const char *name)
return module_kallsyms_lookup_name(name);
}

+#ifdef CONFIG_LIVEPATCH
/*
* Iterate over all symbols in vmlinux. For symbols from modules use
* module_kallsyms_on_each_symbol instead.
@@ -198,6 +199,7 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
}
return 0;
}
+#endif /* CONFIG_LIVEPATCH */

static unsigned long get_symbol_pos(unsigned long addr,
unsigned long *symbolsize,
diff --git a/kernel/module.c b/kernel/module.c
index 25345792c770d1..470fd9d9d68f97 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4366,6 +4366,7 @@ unsigned long module_kallsyms_lookup_name(const char *name)
return ret;
}

+#ifdef CONFIG_LIVEPATCH
int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
struct module *, unsigned long),
void *data)
@@ -4396,6 +4397,7 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
mutex_unlock(&module_mutex);
return ret;
}
+#endif /* CONFIG_LIVEPATCH */
#endif /* CONFIG_KALLSYMS */

/* Maximum number of characters written by module_flags() */
--
2.29.2