X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=kernel%2Fstatic_call.c;h=dc5665b628140ee9b0a841011a4ae495d2c9eee8;hb=f0dfe08ce8fcb9335c7c2dab7e794422c9eedf16;hp=84565c2a41b8f5f6f6961b59c1f5bc42bd1f1b81;hpb=e5acf0ed8a5f0af084b0fdb53b0c7aad47dab29b;p=platform%2Fkernel%2Flinux-rpi.git diff --git a/kernel/static_call.c b/kernel/static_call.c index 84565c2..dc5665b 100644 --- a/kernel/static_call.c +++ b/kernel/static_call.c @@ -12,6 +12,8 @@ extern struct static_call_site __start_static_call_sites[], __stop_static_call_sites[]; +extern struct static_call_tramp_key __start_static_call_tramp_key[], + __stop_static_call_tramp_key[]; static bool static_call_initialized; @@ -33,27 +35,30 @@ static inline void *static_call_addr(struct static_call_site *site) return (void *)((long)site->addr + (long)&site->addr); } +static inline unsigned long __static_call_key(const struct static_call_site *site) +{ + return (long)site->key + (long)&site->key; +} static inline struct static_call_key *static_call_key(const struct static_call_site *site) { - return (struct static_call_key *) - (((long)site->key + (long)&site->key) & ~STATIC_CALL_SITE_FLAGS); + return (void *)(__static_call_key(site) & ~STATIC_CALL_SITE_FLAGS); } /* These assume the key is word-aligned. */ static inline bool static_call_is_init(struct static_call_site *site) { - return ((long)site->key + (long)&site->key) & STATIC_CALL_SITE_INIT; + return __static_call_key(site) & STATIC_CALL_SITE_INIT; } static inline bool static_call_is_tail(struct static_call_site *site) { - return ((long)site->key + (long)&site->key) & STATIC_CALL_SITE_TAIL; + return __static_call_key(site) & STATIC_CALL_SITE_TAIL; } static inline void static_call_set_init(struct static_call_site *site) { - site->key = ((long)static_call_key(site) | STATIC_CALL_SITE_INIT) - + site->key = (__static_call_key(site) | STATIC_CALL_SITE_INIT) - (long)&site->key; } @@ -144,6 +149,7 @@ void __static_call_update(struct static_call_key *key, void *tramp, void *func) }; for (site_mod = &first; site_mod; site_mod = site_mod->next) { + bool init = system_state < SYSTEM_RUNNING; struct module *mod = site_mod->mod; if (!site_mod->sites) { @@ -159,36 +165,38 @@ void __static_call_update(struct static_call_key *key, void *tramp, void *func) stop = __stop_static_call_sites; -#ifdef CONFIG_MODULES if (mod) { +#ifdef CONFIG_MODULES stop = mod->static_call_sites + mod->num_static_call_sites; - } + init = mod->state == MODULE_STATE_COMING; #endif + } for (site = site_mod->sites; site < stop && static_call_key(site) == key; site++) { void *site_addr = static_call_addr(site); - if (static_call_is_init(site)) { - /* - * Don't write to call sites which were in - * initmem and have since been freed. - */ - if (!mod && system_state >= SYSTEM_RUNNING) - continue; - if (mod && !within_module_init((unsigned long)site_addr, mod)) - continue; - } + if (!init && static_call_is_init(site)) + continue; if (!kernel_text_address((unsigned long)site_addr)) { - WARN_ONCE(1, "can't patch static call site at %pS", + /* + * This skips patching built-in __exit, which + * is part of init_section_contains() but is + * not part of kernel_text_address(). + * + * Skipping built-in __exit is fine since it + * will never be executed. + */ + WARN_ONCE(!static_call_is_init(site), + "can't patch static call site at %pS", site_addr); continue; } arch_static_call_transform(site_addr, NULL, func, - static_call_is_tail(site)); + static_call_is_tail(site)); } } @@ -284,13 +292,15 @@ static int addr_conflict(struct static_call_site *site, void *start, void *end) static int __static_call_text_reserved(struct static_call_site *iter_start, struct static_call_site *iter_stop, - void *start, void *end) + void *start, void *end, bool init) { struct static_call_site *iter = iter_start; while (iter < iter_stop) { - if (addr_conflict(iter, start, end)) - return 1; + if (init || !static_call_is_init(iter)) { + if (addr_conflict(iter, start, end)) + return 1; + } iter++; } @@ -316,17 +326,67 @@ static int __static_call_mod_text_reserved(void *start, void *end) ret = __static_call_text_reserved(mod->static_call_sites, mod->static_call_sites + mod->num_static_call_sites, - start, end); + start, end, mod->state == MODULE_STATE_COMING); module_put(mod); return ret; } +static unsigned long tramp_key_lookup(unsigned long addr) +{ + struct static_call_tramp_key *start = __start_static_call_tramp_key; + struct static_call_tramp_key *stop = __stop_static_call_tramp_key; + struct static_call_tramp_key *tramp_key; + + for (tramp_key = start; tramp_key != stop; tramp_key++) { + unsigned long tramp; + + tramp = (long)tramp_key->tramp + (long)&tramp_key->tramp; + if (tramp == addr) + return (long)tramp_key->key + (long)&tramp_key->key; + } + + return 0; +} + static int static_call_add_module(struct module *mod) { - return __static_call_init(mod, mod->static_call_sites, - mod->static_call_sites + mod->num_static_call_sites); + struct static_call_site *start = mod->static_call_sites; + struct static_call_site *stop = start + mod->num_static_call_sites; + struct static_call_site *site; + + for (site = start; site != stop; site++) { + unsigned long s_key = __static_call_key(site); + unsigned long addr = s_key & ~STATIC_CALL_SITE_FLAGS; + unsigned long key; + + /* + * Is the key is exported, 'addr' points to the key, which + * means modules are allowed to call static_call_update() on + * it. + * + * Otherwise, the key isn't exported, and 'addr' points to the + * trampoline so we need to lookup the key. + * + * We go through this dance to prevent crazy modules from + * abusing sensitive static calls. + */ + if (!kernel_text_address(addr)) + continue; + + key = tramp_key_lookup(addr); + if (!key) { + pr_warn("Failed to fixup __raw_static_call() usage at: %ps\n", + static_call_addr(site)); + return -EINVAL; + } + + key |= s_key & STATIC_CALL_SITE_FLAGS; + site->key = key - (long)&site->key; + } + + return __static_call_init(mod, start, stop); } static void static_call_del_module(struct module *mod) @@ -401,8 +461,9 @@ static inline int __static_call_mod_text_reserved(void *start, void *end) int static_call_text_reserved(void *start, void *end) { + bool init = system_state < SYSTEM_RUNNING; int ret = __static_call_text_reserved(__start_static_call_sites, - __stop_static_call_sites, start, end); + __stop_static_call_sites, start, end, init); if (ret) return ret;