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 #include -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;