* <prasanna@in.ibm.com> added function-return probes.
*/
#include <linux/kprobes.h>
-#include <linux/spinlock.h>
#include <linux/hash.h>
#include <linux/init.h>
+#include <linux/slab.h>
#include <linux/module.h>
#include <linux/moduleloader.h>
+#include <asm-generic/sections.h>
#include <asm/cacheflush.h>
#include <asm/errno.h>
#include <asm/kdebug.h>
static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
-unsigned int kprobe_cpu = NR_CPUS;
-static DEFINE_SPINLOCK(kprobe_lock);
-static struct kprobe *curr_kprobe;
+static DEFINE_SPINLOCK(kprobe_lock); /* Protects kprobe_table */
+DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */
+static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
/*
* kprobe->ainsn.insn points to the copy of the instruction to be
* 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.
*/
-kprobe_opcode_t *get_insn_slot(void)
+kprobe_opcode_t __kprobes *get_insn_slot(void)
{
struct kprobe_insn_page *kip;
struct hlist_node *pos;
return kip->insns;
}
-void free_insn_slot(kprobe_opcode_t *slot)
+void __kprobes free_insn_slot(kprobe_opcode_t *slot)
{
struct kprobe_insn_page *kip;
struct hlist_node *pos;
}
}
-/* Locks kprobe: irqs must be disabled */
-void lock_kprobes(void)
+/* We have preemption disabled.. so it is safe to use __ versions */
+static inline void set_kprobe_instance(struct kprobe *kp)
{
- spin_lock(&kprobe_lock);
- kprobe_cpu = smp_processor_id();
+ __get_cpu_var(kprobe_instance) = kp;
}
-void unlock_kprobes(void)
+static inline void reset_kprobe_instance(void)
{
- kprobe_cpu = NR_CPUS;
- spin_unlock(&kprobe_lock);
+ __get_cpu_var(kprobe_instance) = NULL;
}
-/* You have to be holding the kprobe_lock */
-struct kprobe *get_kprobe(void *addr)
+/*
+ * This routine is called either:
+ * - under the kprobe_lock spinlock - during kprobe_[un]register()
+ * OR
+ * - with preemption disabled - from arch/xxx/kernel/kprobes.c
+ */
+struct kprobe __kprobes *get_kprobe(void *addr)
{
struct hlist_head *head;
struct hlist_node *node;
+ struct kprobe *p;
head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
- hlist_for_each(node, head) {
- struct kprobe *p = hlist_entry(node, struct kprobe, hlist);
+ hlist_for_each_entry_rcu(p, node, head, hlist) {
if (p->addr == addr)
return p;
}
* Aggregate handlers for multiple kprobes support - these handlers
* take care of invoking the individual kprobe handlers on p->list
*/
-static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
+static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kprobe *kp;
- list_for_each_entry(kp, &p->list, list) {
+ list_for_each_entry_rcu(kp, &p->list, list) {
if (kp->pre_handler) {
- curr_kprobe = kp;
+ set_kprobe_instance(kp);
if (kp->pre_handler(kp, regs))
return 1;
}
- curr_kprobe = NULL;
+ reset_kprobe_instance();
}
return 0;
}
-static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
- unsigned long flags)
+static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
+ unsigned long flags)
{
struct kprobe *kp;
- list_for_each_entry(kp, &p->list, list) {
+ list_for_each_entry_rcu(kp, &p->list, list) {
if (kp->post_handler) {
- curr_kprobe = kp;
+ set_kprobe_instance(kp);
kp->post_handler(kp, regs, flags);
- curr_kprobe = NULL;
+ reset_kprobe_instance();
}
}
return;
}
-static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
- int trapnr)
+static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
+ int trapnr)
{
+ struct kprobe *cur = __get_cpu_var(kprobe_instance);
+
/*
* if we faulted "during" the execution of a user specified
* probe handler, invoke just that probe's fault handler
*/
- if (curr_kprobe && curr_kprobe->fault_handler) {
- if (curr_kprobe->fault_handler(curr_kprobe, regs, trapnr))
+ if (cur && cur->fault_handler) {
+ if (cur->fault_handler(cur, regs, trapnr))
return 1;
}
return 0;
}
-static int aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
+static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
{
- struct kprobe *kp = curr_kprobe;
- if (curr_kprobe && kp->break_handler) {
- if (kp->break_handler(kp, regs)) {
- curr_kprobe = NULL;
- return 1;
- }
+ struct kprobe *cur = __get_cpu_var(kprobe_instance);
+ int ret = 0;
+
+ if (cur && cur->break_handler) {
+ if (cur->break_handler(cur, regs))
+ ret = 1;
}
- curr_kprobe = NULL;
- return 0;
+ reset_kprobe_instance();
+ return ret;
}
-struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp)
+/* Called with kretprobe_lock held */
+struct kretprobe_instance __kprobes *get_free_rp_inst(struct kretprobe *rp)
{
struct hlist_node *node;
struct kretprobe_instance *ri;
return NULL;
}
-static struct kretprobe_instance *get_used_rp_inst(struct kretprobe *rp)
+/* Called with kretprobe_lock held */
+static struct kretprobe_instance __kprobes *get_used_rp_inst(struct kretprobe
+ *rp)
{
struct hlist_node *node;
struct kretprobe_instance *ri;
return NULL;
}
-void add_rp_inst(struct kretprobe_instance *ri)
+/* Called with kretprobe_lock held */
+void __kprobes add_rp_inst(struct kretprobe_instance *ri)
{
/*
* Remove rp inst off the free list -
hlist_add_head(&ri->uflist, &ri->rp->used_instances);
}
-void recycle_rp_inst(struct kretprobe_instance *ri)
+/* Called with kretprobe_lock held */
+void __kprobes recycle_rp_inst(struct kretprobe_instance *ri)
{
/* remove rp inst off the rprobe_inst_table */
hlist_del(&ri->hlist);
kfree(ri);
}
-struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk)
+struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk)
{
return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)];
}
* instances associated with this task. These left over instances represent
* probed functions that have been called but will never return.
*/
-void kprobe_flush_task(struct task_struct *tk)
+void __kprobes kprobe_flush_task(struct task_struct *tk)
{
struct kretprobe_instance *ri;
struct hlist_head *head;
struct hlist_node *node, *tmp;
unsigned long flags = 0;
- spin_lock_irqsave(&kprobe_lock, flags);
+ spin_lock_irqsave(&kretprobe_lock, flags);
head = kretprobe_inst_table_head(current);
hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
if (ri->task == tk)
recycle_rp_inst(ri);
}
- spin_unlock_irqrestore(&kprobe_lock, flags);
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
}
/*
* This kprobe pre_handler is registered with every kretprobe. When probe
* hits it will set up the return probe.
*/
-static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
+static int __kprobes pre_handler_kretprobe(struct kprobe *p,
+ struct pt_regs *regs)
{
struct kretprobe *rp = container_of(p, struct kretprobe, kp);
+ unsigned long flags = 0;
/*TODO: consider to only swap the RA after the last pre_handler fired */
+ spin_lock_irqsave(&kretprobe_lock, flags);
arch_prepare_kretprobe(rp, regs);
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
return 0;
}
* Add the new probe to old_p->list. Fail if this is the
* second jprobe at the address - two jprobes can't coexist
*/
-static int add_new_kprobe(struct kprobe *old_p, struct kprobe *p)
+static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p)
{
struct kprobe *kp;
if (p->break_handler) {
- list_for_each_entry(kp, &old_p->list, list) {
+ list_for_each_entry_rcu(kp, &old_p->list, list) {
if (kp->break_handler)
return -EEXIST;
}
- list_add_tail(&p->list, &old_p->list);
+ list_add_tail_rcu(&p->list, &old_p->list);
} else
- list_add(&p->list, &old_p->list);
+ list_add_rcu(&p->list, &old_p->list);
return 0;
}
ap->break_handler = aggr_break_handler;
INIT_LIST_HEAD(&ap->list);
- list_add(&p->list, &ap->list);
+ list_add_rcu(&p->list, &ap->list);
INIT_HLIST_NODE(&ap->hlist);
- hlist_del(&p->hlist);
- hlist_add_head(&ap->hlist,
+ hlist_del_rcu(&p->hlist);
+ hlist_add_head_rcu(&ap->hlist,
&kprobe_table[hash_ptr(ap->addr, KPROBE_HASH_BITS)]);
}
/*
* This is the second or subsequent kprobe at the address - handle
* the intricacies
- * TODO: Move kcalloc outside the spinlock
+ * TODO: Move kcalloc outside the spin_lock
*/
-static int register_aggr_kprobe(struct kprobe *old_p, struct kprobe *p)
+static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
+ struct kprobe *p)
{
int ret = 0;
struct kprobe *ap;
static inline void cleanup_kprobe(struct kprobe *p, unsigned long flags)
{
arch_disarm_kprobe(p);
- hlist_del(&p->hlist);
+ hlist_del_rcu(&p->hlist);
spin_unlock_irqrestore(&kprobe_lock, flags);
arch_remove_kprobe(p);
}
static inline void cleanup_aggr_kprobe(struct kprobe *old_p,
struct kprobe *p, unsigned long flags)
{
- list_del(&p->list);
- if (list_empty(&old_p->list)) {
+ list_del_rcu(&p->list);
+ if (list_empty(&old_p->list))
cleanup_kprobe(old_p, flags);
- kfree(old_p);
- } else
+ else
spin_unlock_irqrestore(&kprobe_lock, flags);
}
-int register_kprobe(struct kprobe *p)
+static int __kprobes in_kprobes_functions(unsigned long addr)
+{
+ if (addr >= (unsigned long)__kprobes_text_start
+ && addr < (unsigned long)__kprobes_text_end)
+ return -EINVAL;
+ return 0;
+}
+
+int __kprobes register_kprobe(struct kprobe *p)
{
int ret = 0;
unsigned long flags = 0;
struct kprobe *old_p;
- if ((ret = arch_prepare_kprobe(p)) != 0) {
+ if ((ret = in_kprobes_functions((unsigned long) p->addr)) != 0)
+ return ret;
+ if ((ret = arch_prepare_kprobe(p)) != 0)
goto rm_kprobe;
- }
+
+ p->nmissed = 0;
spin_lock_irqsave(&kprobe_lock, flags);
old_p = get_kprobe(p->addr);
- p->nmissed = 0;
if (old_p) {
ret = register_aggr_kprobe(old_p, p);
goto out;
arch_copy_kprobe(p);
INIT_HLIST_NODE(&p->hlist);
- hlist_add_head(&p->hlist,
+ hlist_add_head_rcu(&p->hlist,
&kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
arch_arm_kprobe(p);
return ret;
}
-void unregister_kprobe(struct kprobe *p)
+void __kprobes unregister_kprobe(struct kprobe *p)
{
unsigned long flags;
struct kprobe *old_p;
spin_lock_irqsave(&kprobe_lock, flags);
old_p = get_kprobe(p->addr);
if (old_p) {
+ /* cleanup_*_kprobe() does the spin_unlock_irqrestore */
if (old_p->pre_handler == aggr_pre_handler)
cleanup_aggr_kprobe(old_p, p, flags);
else
cleanup_kprobe(p, flags);
+
+ synchronize_sched();
+ if (old_p->pre_handler == aggr_pre_handler &&
+ list_empty(&old_p->list))
+ kfree(old_p);
} else
spin_unlock_irqrestore(&kprobe_lock, flags);
}
.priority = 0x7fffffff /* we need to notified first */
};
-int register_jprobe(struct jprobe *jp)
+int __kprobes register_jprobe(struct jprobe *jp)
{
/* Todo: Verify probepoint is a function entry point */
jp->kp.pre_handler = setjmp_pre_handler;
return register_kprobe(&jp->kp);
}
-void unregister_jprobe(struct jprobe *jp)
+void __kprobes unregister_jprobe(struct jprobe *jp)
{
unregister_kprobe(&jp->kp);
}
#ifdef ARCH_SUPPORTS_KRETPROBES
-int register_kretprobe(struct kretprobe *rp)
+int __kprobes register_kretprobe(struct kretprobe *rp)
{
int ret = 0;
struct kretprobe_instance *inst;
#else /* ARCH_SUPPORTS_KRETPROBES */
-int register_kretprobe(struct kretprobe *rp)
+int __kprobes register_kretprobe(struct kretprobe *rp)
{
return -ENOSYS;
}
#endif /* ARCH_SUPPORTS_KRETPROBES */
-void unregister_kretprobe(struct kretprobe *rp)
+void __kprobes unregister_kretprobe(struct kretprobe *rp)
{
unsigned long flags;
struct kretprobe_instance *ri;
unregister_kprobe(&rp->kp);
/* No race here */
- spin_lock_irqsave(&kprobe_lock, flags);
+ spin_lock_irqsave(&kretprobe_lock, flags);
free_rp_inst(rp);
while ((ri = get_used_rp_inst(rp)) != NULL) {
ri->rp = NULL;
hlist_del(&ri->uflist);
}
- spin_unlock_irqrestore(&kprobe_lock, flags);
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
}
static int __init init_kprobes(void)
git.openpandora.org / pandora-kernel.git / blobdiff