From 7523e4dc5057e157212b4741abd6256e03404cf1 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 26 Nov 2015 09:44:08 +1030 Subject: module: use a structure to encapsulate layout. Makes it easier to handle init vs core cleanly, though the change is fairly invasive across random architectures. It simplifies the rbtree code immediately, however, while keeping the core data together in the same cachline (now iff the rbtree code is enabled). Acked-by: Peter Zijlstra Reviewed-by: Josh Poimboeuf Signed-off-by: Rusty Russell Signed-off-by: Jiri Kosina --- include/linux/module.h | 64 +++++++++++++++++++++++--------------------------- 1 file changed, 29 insertions(+), 35 deletions(-) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index 3a19c79918e0..6e68e8cf4d0d 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -302,6 +302,28 @@ struct mod_tree_node { struct latch_tree_node node; }; +struct module_layout { + /* The actual code + data. */ + void *base; + /* Total size. */ + unsigned int size; + /* The size of the executable code. */ + unsigned int text_size; + /* Size of RO section of the module (text+rodata) */ + unsigned int ro_size; + +#ifdef CONFIG_MODULES_TREE_LOOKUP + struct mod_tree_node mtn; +#endif +}; + +#ifdef CONFIG_MODULES_TREE_LOOKUP +/* Only touch one cacheline for common rbtree-for-core-layout case. */ +#define __module_layout_align ____cacheline_aligned +#else +#define __module_layout_align +#endif + struct module { enum module_state state; @@ -366,37 +388,9 @@ struct module { /* Startup function. */ int (*init)(void); - /* - * If this is non-NULL, vfree() after init() returns. - * - * Cacheline align here, such that: - * module_init, module_core, init_size, core_size, - * init_text_size, core_text_size and mtn_core::{mod,node[0]} - * are on the same cacheline. - */ - void *module_init ____cacheline_aligned; - - /* Here is the actual code + data, vfree'd on unload. */ - void *module_core; - - /* Here are the sizes of the init and core sections */ - unsigned int init_size, core_size; - - /* The size of the executable code in each section. */ - unsigned int init_text_size, core_text_size; - -#ifdef CONFIG_MODULES_TREE_LOOKUP - /* - * We want mtn_core::{mod,node[0]} to be in the same cacheline as the - * above entries such that a regular lookup will only touch one - * cacheline. - */ - struct mod_tree_node mtn_core; - struct mod_tree_node mtn_init; -#endif - - /* Size of RO sections of the module (text+rodata) */ - unsigned int init_ro_size, core_ro_size; + /* Core layout: rbtree is accessed frequently, so keep together. */ + struct module_layout core_layout __module_layout_align; + struct module_layout init_layout; /* Arch-specific module values */ struct mod_arch_specific arch; @@ -505,15 +499,15 @@ bool is_module_text_address(unsigned long addr); static inline bool within_module_core(unsigned long addr, const struct module *mod) { - return (unsigned long)mod->module_core <= addr && - addr < (unsigned long)mod->module_core + mod->core_size; + return (unsigned long)mod->core_layout.base <= addr && + addr < (unsigned long)mod->core_layout.base + mod->core_layout.size; } static inline bool within_module_init(unsigned long addr, const struct module *mod) { - return (unsigned long)mod->module_init <= addr && - addr < (unsigned long)mod->module_init + mod->init_size; + return (unsigned long)mod->init_layout.base <= addr && + addr < (unsigned long)mod->init_layout.base + mod->init_layout.size; } static inline bool within_module(unsigned long addr, const struct module *mod) -- cgit v1.2.3 From 85c898db6327353d38f3dd428457384cf81f83f8 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 26 Nov 2015 09:45:08 +1030 Subject: module: clean up RO/NX handling. Modules have three sections: text, rodata and writable data. The code handled the case where these overlapped, however they never can: debug_align() ensures they are always page-aligned. This is why we got away with manually traversing the pages in set_all_modules_text_rw() without rounding. We create three helper functions: frob_text(), frob_rodata() and frob_writable_data(). We then call these explicitly at every point, so it's clear what we're doing. We also expose module_enable_ro() and module_disable_ro() for livepatch to use. Reviewed-by: Josh Poimboeuf Signed-off-by: Rusty Russell Signed-off-by: Jiri Kosina --- include/linux/module.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index 6e68e8cf4d0d..4560d8f1545d 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -762,9 +762,13 @@ extern int module_sysfs_initialized; #ifdef CONFIG_DEBUG_SET_MODULE_RONX extern void set_all_modules_text_rw(void); extern void set_all_modules_text_ro(void); +extern void module_enable_ro(const struct module *mod); +extern void module_disable_ro(const struct module *mod); #else static inline void set_all_modules_text_rw(void) { } static inline void set_all_modules_text_ro(void) { } +static inline void module_enable_ro(const struct module *mod) { } +static inline void module_disable_ro(const struct module *mod) { } #endif #ifdef CONFIG_GENERIC_BUG -- cgit v1.2.3