diff options
Diffstat (limited to 'kernel/kprobes.c')
| -rw-r--r-- | kernel/kprobes.c | 95 |
1 files changed, 39 insertions, 56 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 6e33498d665c..a0d367a49122 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -112,6 +112,7 @@ static struct kprobe_blackpoint kprobe_blacklist[] = { struct kprobe_insn_page { struct list_head list; kprobe_opcode_t *insns; /* Page of instruction slots */ + struct kprobe_insn_cache *cache; int nused; int ngarbage; char slot_used[]; @@ -121,12 +122,6 @@ struct kprobe_insn_page { (offsetof(struct kprobe_insn_page, slot_used) + \ (sizeof(char) * (slots))) -struct kprobe_insn_cache { - struct list_head pages; /* list of kprobe_insn_page */ - size_t insn_size; /* size of instruction slot */ - int nr_garbage; -}; - static int slots_per_page(struct kprobe_insn_cache *c) { return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); @@ -138,8 +133,20 @@ enum kprobe_slot_state { SLOT_USED = 2, }; -static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */ -static struct kprobe_insn_cache kprobe_insn_slots = { +static void *alloc_insn_page(void) +{ + return module_alloc(PAGE_SIZE); +} + +static void free_insn_page(void *page) +{ + module_free(NULL, page); +} + +struct kprobe_insn_cache kprobe_insn_slots = { + .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex), + .alloc = alloc_insn_page, + .free = free_insn_page, .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), .insn_size = MAX_INSN_SIZE, .nr_garbage = 0, @@ -150,10 +157,12 @@ static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c); * __get_insn_slot() - Find a slot on an executable page for an instruction. * We allocate an executable page if there's no room on existing ones. */ -static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c) +kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c) { struct kprobe_insn_page *kip; + kprobe_opcode_t *slot = NULL; + mutex_lock(&c->mutex); retry: list_for_each_entry(kip, &c->pages, list) { if (kip->nused < slots_per_page(c)) { @@ -162,7 +171,8 @@ static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c) if (kip->slot_used[i] == SLOT_CLEAN) { kip->slot_used[i] = SLOT_USED; kip->nused++; - return kip->insns + (i * c->insn_size); + slot = kip->insns + (i * c->insn_size); + goto out; } } /* kip->nused is broken. Fix it. */ @@ -178,37 +188,29 @@ static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c) /* All out of space. Need to allocate a new page. */ kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); if (!kip) - return NULL; + goto out; /* * Use module_alloc so this page is within +/- 2GB of where the * kernel image and loaded module images reside. This is required * so x86_64 can correctly handle the %rip-relative fixups. */ - kip->insns = module_alloc(PAGE_SIZE); + kip->insns = c->alloc(); if (!kip->insns) { kfree(kip); - return NULL; + goto out; } INIT_LIST_HEAD(&kip->list); memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); kip->slot_used[0] = SLOT_USED; kip->nused = 1; kip->ngarbage = 0; + kip->cache = c; list_add(&kip->list, &c->pages); - return kip->insns; -} - - -kprobe_opcode_t __kprobes *get_insn_slot(void) -{ - kprobe_opcode_t *ret = NULL; - - mutex_lock(&kprobe_insn_mutex); - ret = __get_insn_slot(&kprobe_insn_slots); - mutex_unlock(&kprobe_insn_mutex); - - return ret; + slot = kip->insns; +out: + mutex_unlock(&c->mutex); + return slot; } /* Return 1 if all garbages are collected, otherwise 0. */ @@ -225,7 +227,7 @@ static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) */ if (!list_is_singular(&kip->list)) { list_del(&kip->list); - module_free(NULL, kip->insns); + kip->cache->free(kip->insns); kfree(kip); } return 1; @@ -255,11 +257,12 @@ static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c) return 0; } -static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c, - kprobe_opcode_t *slot, int dirty) +void __kprobes __free_insn_slot(struct kprobe_insn_cache *c, + kprobe_opcode_t *slot, int dirty) { struct kprobe_insn_page *kip; + mutex_lock(&c->mutex); list_for_each_entry(kip, &c->pages, list) { long idx = ((long)slot - (long)kip->insns) / (c->insn_size * sizeof(kprobe_opcode_t)); @@ -272,45 +275,25 @@ static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c, collect_garbage_slots(c); } else collect_one_slot(kip, idx); - return; + goto out; } } /* Could not free this slot. */ WARN_ON(1); +out: + mutex_unlock(&c->mutex); } -void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) -{ - mutex_lock(&kprobe_insn_mutex); - __free_insn_slot(&kprobe_insn_slots, slot, dirty); - mutex_unlock(&kprobe_insn_mutex); -} #ifdef CONFIG_OPTPROBES /* For optimized_kprobe buffer */ -static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */ -static struct kprobe_insn_cache kprobe_optinsn_slots = { +struct kprobe_insn_cache kprobe_optinsn_slots = { + .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex), + .alloc = alloc_insn_page, + .free = free_insn_page, .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), /* .insn_size is initialized later */ .nr_garbage = 0, }; -/* Get a slot for optimized_kprobe buffer */ -kprobe_opcode_t __kprobes *get_optinsn_slot(void) -{ - kprobe_opcode_t *ret = NULL; - - mutex_lock(&kprobe_optinsn_mutex); - ret = __get_insn_slot(&kprobe_optinsn_slots); - mutex_unlock(&kprobe_optinsn_mutex); - - return ret; -} - -void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty) -{ - mutex_lock(&kprobe_optinsn_mutex); - __free_insn_slot(&kprobe_optinsn_slots, slot, dirty); - mutex_unlock(&kprobe_optinsn_mutex); -} #endif #endif |