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Subject[RFC PATCH 5/6] jump label v3 - add module support
Add support for 'jump label' for modules.

Signed-off-by: Jason Baron <jbaron@redhat.com>
---
arch/x86/kernel/jump_label.c | 5 ++++-
include/linux/jump_label.h | 2 ++
include/linux/module.h | 12 +++++++++++-
kernel/module.c | 25 +++++++++++++++++++++++++
4 files changed, 42 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index 4131bbd..080062d 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -1,6 +1,7 @@
#include <linux/jump_label.h>
#include <linux/memory.h>
#include <linux/uaccess.h>
+#include <linux/module.h>
#include <asm/alternative.h>

#ifdef __HAVE_ARCH_JUMP_LABEL
@@ -47,8 +48,10 @@ int jump_label_update(const char *name, enum jump_label_type type, void *mod)
{
struct jump_entry *iter;

- if (mod)
+ if (mod) {
+ jump_label_update_module(name, type, mod);
return 0;
+ }

for (iter = __start___jump_table; iter < __stop___jump_table; iter++) {
if (!strcmp(name, iter->name)) {
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 2719506..7935ff6 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -17,6 +17,8 @@ enum jump_label_type {
#ifdef __HAVE_ARCH_JUMP_LABEL

extern int jump_label_update(const char *name, enum jump_label_type type, void *mod);
+extern void jump_label_transform(struct jump_entry *entry,
+ enum jump_label_type type);

#define enable_jump_label(name, mod) \
jump_label_update(name, JUMP_LABEL_ENABLE, mod);
diff --git a/include/linux/module.h b/include/linux/module.h
index 819354a..307b64a 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -16,6 +16,7 @@
#include <linux/kobject.h>
#include <linux/moduleparam.h>
#include <linux/tracepoint.h>
+#include <linux/jump_label.h>

#include <asm/local.h>
#include <asm/module.h>
@@ -355,7 +356,10 @@ struct module
struct tracepoint *tracepoints;
unsigned int num_tracepoints;
#endif
-
+#ifdef __HAVE_ARCH_JUMP_LABEL
+ struct jump_entry *jump_entries;
+ unsigned int num_jump_entries;
+#endif
#ifdef CONFIG_TRACING
const char **trace_bprintk_fmt_start;
unsigned int num_trace_bprintk_fmt;
@@ -557,6 +561,7 @@ extern void print_modules(void);

extern void module_update_tracepoints(void);
extern int module_get_iter_tracepoints(struct tracepoint_iter *iter);
+extern void jump_label_update_module(const char *name, enum jump_label_type type, void *mod);

#else /* !CONFIG_MODULES... */
#define EXPORT_SYMBOL(sym)
@@ -678,6 +683,11 @@ static inline int module_get_iter_tracepoints(struct tracepoint_iter *iter)
return 0;
}

+static inline void jump_label_update_module(const char *name, enum jump_label_type type, void *mod)
+{
+ return;
+}
+
#endif /* CONFIG_MODULES */

struct device_driver;
diff --git a/kernel/module.c b/kernel/module.c
index 8b7d880..6b8a754 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -55,6 +55,7 @@
#include <linux/async.h>
#include <linux/percpu.h>
#include <linux/kmemleak.h>
+#include <linux/jump_label.h>

#define CREATE_TRACE_POINTS
#include <trace/events/module.h>
@@ -2378,6 +2379,12 @@ static noinline struct module *load_module(void __user *umod,
sizeof(*mod->tracepoints),
&mod->num_tracepoints);
#endif
+#ifdef __HAVE_ARCH_JUMP_LABEL
+ mod->jump_entries = section_objs(hdr, sechdrs, secstrings,
+ "__jump_table",
+ sizeof(*mod->jump_entries),
+ &mod->num_jump_entries);
+#endif
#ifdef CONFIG_EVENT_TRACING
mod->trace_events = section_objs(hdr, sechdrs, secstrings,
"_ftrace_events",
@@ -3143,4 +3150,22 @@ int module_get_iter_tracepoints(struct tracepoint_iter *iter)
mutex_unlock(&module_mutex);
return found;
}
+
+#endif
+
+#ifdef __HAVE_ARCH_JUMP_LABEL
+
+void jump_label_update_module(const char *name, enum jump_label_type type, void *data)
+{
+ struct jump_entry *entry;
+ struct module *mod = data;
+
+ for (entry = mod->jump_entries;
+ entry < mod->jump_entries + mod->num_jump_entries;
+ entry++) {
+ if (!strcmp(name, entry->name))
+ jump_label_transform(entry, type);
+ }
+}
+
#endif
--
1.6.5.1


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