5 files changed, 50 insertions, 42 deletions

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index f53708be95eb..57b1b6811b61 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -166,10 +166,8 @@
         CPU_KEEP(exit.data)                                             \
         MEM_KEEP(init.data)                                             \
         MEM_KEEP(exit.data)                                             \
-        . = ALIGN(32);                                                  \
-        VMLINUX_SYMBOL(__start___tracepoints) = .;                      \
+        STRUCT_ALIGN();                                                 \
         *(__tracepoints)                                                \
-        VMLINUX_SYMBOL(__stop___tracepoints) = .;                       \
         /* implement dynamic printk debug */                            \
         . = ALIGN(8);                                                   \
         VMLINUX_SYMBOL(__start___verbose) = .;                          \
@@ -218,6 +216,10 @@
                 VMLINUX_SYMBOL(__start_rodata) = .;                     \
                 *(.rodata) *(.rodata.*)                                 \
                 *(__vermagic)           /* Kernel version magic */      \
+                . = ALIGN(8);                                           \
+                VMLINUX_SYMBOL(__start___tracepoints_ptrs) = .;         \
+                *(__tracepoints_ptrs)   /* Tracepoints: pointer array */\
+                VMLINUX_SYMBOL(__stop___tracepoints_ptrs) = .;          \
                 *(__markers_strings)    /* Markers: strings */          \
                 *(__tracepoints_strings)/* Tracepoints: strings */      \
         }                                                               \
diff --git a/include/linux/module.h b/include/linux/module.h
index 7695a303bb55..9bdf27c7615b 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -377,7 +377,7 @@ struct module
            keeping pointers to this stuff */
         char *args;
 #ifdef CONFIG_TRACEPOINTS
-        struct tracepoint *tracepoints;
+        struct tracepoint * const *tracepoints_ptrs;
         unsigned int num_tracepoints;
 #endif
 #ifdef HAVE_JUMP_LABEL
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index c6814616653b..97c84a58efb8 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -33,12 +33,7 @@ struct tracepoint {
         void (*regfunc)(void);
         void (*unregfunc)(void);
         struct tracepoint_func __rcu *funcs;
-} __attribute__((aligned(32)));         /*
-                                         * Aligned on 32 bytes because it is
-                                         * globally visible and gcc happily
-                                         * align these on the structure size.
-                                         * Keep in sync with vmlinux.lds.h.
-                                         */
+};
 
 /*
  * Connect a probe to a tracepoint.
@@ -61,15 +56,15 @@ extern void tracepoint_probe_update_all(void);
 
 struct tracepoint_iter {
         struct module *module;
-        struct tracepoint *tracepoint;
+        struct tracepoint * const *tracepoint;
 };
 
 extern void tracepoint_iter_start(struct tracepoint_iter *iter);
 extern void tracepoint_iter_next(struct tracepoint_iter *iter);
 extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
 extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
-extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
-        struct tracepoint *begin, struct tracepoint *end);
+extern int tracepoint_get_iter_range(struct tracepoint * const **tracepoint,
+        struct tracepoint * const *begin, struct tracepoint * const *end);
 
 /*
  * tracepoint_synchronize_unregister must be called between the last tracepoint
@@ -84,11 +79,13 @@ static inline void tracepoint_synchronize_unregister(void)
 #define PARAMS(args...) args
 
 #ifdef CONFIG_TRACEPOINTS
-extern void tracepoint_update_probe_range(struct tracepoint *begin,
-        struct tracepoint *end);
+extern
+void tracepoint_update_probe_range(struct tracepoint * const *begin,
+        struct tracepoint * const *end);
 #else
-static inline void tracepoint_update_probe_range(struct tracepoint *begin,
-        struct tracepoint *end)
+static inline
+void tracepoint_update_probe_range(struct tracepoint * const *begin,
+        struct tracepoint * const *end)
 { }
 #endif /* CONFIG_TRACEPOINTS */
 
@@ -174,12 +171,20 @@ do_trace:								\
         {                                                               \
         }
 
+/*
+ * We have no guarantee that gcc and the linker won't up-align the tracepoint
+ * structures, so we create an array of pointers that will be used for iteration
+ * on the tracepoints.
+ */
 #define DEFINE_TRACE_FN(name, reg, unreg)                               \
         static const char __tpstrtab_##name[]                           \
         __attribute__((section("__tracepoints_strings"))) = #name;      \
         struct tracepoint __tracepoint_##name                           \
-        __attribute__((section("__tracepoints"), aligned(32))) =        \
-                { __tpstrtab_##name, 0, reg, unreg, NULL }
+        __attribute__((section("__tracepoints"))) =                     \
+                { __tpstrtab_##name, 0, reg, unreg, NULL };             \
+        static struct tracepoint * const __tracepoint_ptr_##name __used \
+        __attribute__((section("__tracepoints_ptrs"))) =                \
+                &__tracepoint_##name;
 
 #define DEFINE_TRACE(name)                                              \
         DEFINE_TRACE_FN(name, NULL, NULL);
diff --git a/kernel/module.c b/kernel/module.c
index 34e00b708fad..efa290ea94bf 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2460,9 +2460,9 @@ static void find_module_sections(struct module *mod, struct load_info *info)
 #endif
 
 #ifdef CONFIG_TRACEPOINTS
-        mod->tracepoints = section_objs(info, "__tracepoints",
-                                        sizeof(*mod->tracepoints),
-                                        &mod->num_tracepoints);
+        mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs",
+                                             sizeof(*mod->tracepoints_ptrs),
+                                             &mod->num_tracepoints);
 #endif
 #ifdef HAVE_JUMP_LABEL
         mod->jump_entries = section_objs(info, "__jump_table",
@@ -3393,7 +3393,7 @@ void module_layout(struct module *mod,
                    struct modversion_info *ver,
                    struct kernel_param *kp,
                    struct kernel_symbol *ks,
-                   struct tracepoint *tp)
+                   struct tracepoint * const *tp)
 {
 }
 EXPORT_SYMBOL(module_layout);
@@ -3407,8 +3407,8 @@ void module_update_tracepoints(void)
         mutex_lock(&module_mutex);
         list_for_each_entry(mod, &modules, list)
                 if (!mod->taints)
-                        tracepoint_update_probe_range(mod->tracepoints,
-                                mod->tracepoints + mod->num_tracepoints);
+                        tracepoint_update_probe_range(mod->tracepoints_ptrs,
+                                mod->tracepoints_ptrs + mod->num_tracepoints);
         mutex_unlock(&module_mutex);
 }
 
@@ -3432,8 +3432,8 @@ int module_get_iter_tracepoints(struct tracepoint_iter *iter)
                         else if (iter_mod > iter->module)
                                 iter->tracepoint = NULL;
                         found = tracepoint_get_iter_range(&iter->tracepoint,
-                                iter_mod->tracepoints,
-                                iter_mod->tracepoints
+                                iter_mod->tracepoints_ptrs,
+                                iter_mod->tracepoints_ptrs
                                         + iter_mod->num_tracepoints);
                         if (found) {
                                 iter->module = iter_mod;
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index e95ee7f31d43..68187af4889e 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -27,8 +27,8 @@
 #include <linux/sched.h>
 #include <linux/jump_label.h>
 
-extern struct tracepoint __start___tracepoints[];
-extern struct tracepoint __stop___tracepoints[];
+extern struct tracepoint * const __start___tracepoints_ptrs[];
+extern struct tracepoint * const __stop___tracepoints_ptrs[];
 
 /* Set to 1 to enable tracepoint debug output */
 static const int tracepoint_debug;
@@ -298,10 +298,10 @@ static void disable_tracepoint(struct tracepoint *elem)
  *
  * Updates the probe callback corresponding to a range of tracepoints.
  */
-void
-tracepoint_update_probe_range(struct tracepoint *begin, struct tracepoint *end)
+void tracepoint_update_probe_range(struct tracepoint * const *begin,
+                                   struct tracepoint * const *end)
 {
-        struct tracepoint *iter;
+        struct tracepoint * const *iter;
         struct tracepoint_entry *mark_entry;
 
         if (!begin)
@@ -309,12 +309,12 @@ tracepoint_update_probe_range(struct tracepoint *begin, struct tracepoint *end)
 
         mutex_lock(&tracepoints_mutex);
         for (iter = begin; iter < end; iter++) {
-                mark_entry = get_tracepoint(iter->name);
+                mark_entry = get_tracepoint((*iter)->name);
                 if (mark_entry) {
-                        set_tracepoint(&mark_entry, iter,
+                        set_tracepoint(&mark_entry, *iter,
                                         !!mark_entry->refcount);
                 } else {
-                        disable_tracepoint(iter);
+                        disable_tracepoint(*iter);
                 }
         }
         mutex_unlock(&tracepoints_mutex);
@@ -326,8 +326,8 @@ tracepoint_update_probe_range(struct tracepoint *begin, struct tracepoint *end)
 static void tracepoint_update_probes(void)
 {
         /* Core kernel tracepoints */
-        tracepoint_update_probe_range(__start___tracepoints,
-                __stop___tracepoints);
+        tracepoint_update_probe_range(__start___tracepoints_ptrs,
+                __stop___tracepoints_ptrs);
         /* tracepoints in modules. */
         module_update_tracepoints();
 }
@@ -514,8 +514,8 @@ EXPORT_SYMBOL_GPL(tracepoint_probe_update_all);
  * Will return the first tracepoint in the range if the input tracepoint is
  * NULL.
  */
-int tracepoint_get_iter_range(struct tracepoint **tracepoint,
-        struct tracepoint *begin, struct tracepoint *end)
+int tracepoint_get_iter_range(struct tracepoint * const **tracepoint,
+        struct tracepoint * const *begin, struct tracepoint * const *end)
 {
         if (!*tracepoint && begin != end) {
                 *tracepoint = begin;
@@ -534,7 +534,8 @@ static void tracepoint_get_iter(struct tracepoint_iter *iter)
         /* Core kernel tracepoints */
         if (!iter->module) {
                 found = tracepoint_get_iter_range(&iter->tracepoint,
-                                __start___tracepoints, __stop___tracepoints);
+                                __start___tracepoints_ptrs,
+                                __stop___tracepoints_ptrs);
                 if (found)
                         goto end;
         }
@@ -585,8 +586,8 @@ int tracepoint_module_notify(struct notifier_block *self,
         switch (val) {
         case MODULE_STATE_COMING:
         case MODULE_STATE_GOING:
-                tracepoint_update_probe_range(mod->tracepoints,
-                        mod->tracepoints + mod->num_tracepoints);
+                tracepoint_update_probe_range(mod->tracepoints_ptrs,
+                        mod->tracepoints_ptrs + mod->num_tracepoints);
                 break;
         }
         return 0;