* interface to access function arguments.
* 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
* exceptions notifier to be first on the priority list.
+ * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
+ * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
+ * <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/module.h>
+#include <linux/moduleloader.h>
+#include <asm-generic/sections.h>
#include <asm/cacheflush.h>
#include <asm/errno.h>
#include <asm/kdebug.h>
#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
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;
+/*
+ * kprobe->ainsn.insn points to the copy of the instruction to be
+ * single-stepped. x86_64, POWER4 and above have no-exec support and
+ * stepping on the instruction on a vmalloced/kmalloced/data page
+ * is a recipe for disaster
+ */
+#define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
+
+struct kprobe_insn_page {
+ struct hlist_node hlist;
+ kprobe_opcode_t *insns; /* Page of instruction slots */
+ char slot_used[INSNS_PER_PAGE];
+ int nused;
+};
+
+static struct hlist_head kprobe_insn_pages;
+
+/**
+ * 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 __kprobes *get_insn_slot(void)
+{
+ struct kprobe_insn_page *kip;
+ struct hlist_node *pos;
+
+ hlist_for_each(pos, &kprobe_insn_pages) {
+ kip = hlist_entry(pos, struct kprobe_insn_page, hlist);
+ if (kip->nused < INSNS_PER_PAGE) {
+ int i;
+ for (i = 0; i < INSNS_PER_PAGE; i++) {
+ if (!kip->slot_used[i]) {
+ kip->slot_used[i] = 1;
+ kip->nused++;
+ return kip->insns + (i * MAX_INSN_SIZE);
+ }
+ }
+ /* Surprise! No unused slots. Fix kip->nused. */
+ kip->nused = INSNS_PER_PAGE;
+ }
+ }
+
+ /* All out of space. Need to allocate a new page. Use slot 0.*/
+ kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL);
+ if (!kip) {
+ return NULL;
+ }
+
+ /*
+ * 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);
+ if (!kip->insns) {
+ kfree(kip);
+ return NULL;
+ }
+ INIT_HLIST_NODE(&kip->hlist);
+ hlist_add_head(&kip->hlist, &kprobe_insn_pages);
+ memset(kip->slot_used, 0, INSNS_PER_PAGE);
+ kip->slot_used[0] = 1;
+ kip->nused = 1;
+ return kip->insns;
+}
+
+void __kprobes free_insn_slot(kprobe_opcode_t *slot)
+{
+ struct kprobe_insn_page *kip;
+ struct hlist_node *pos;
+
+ hlist_for_each(pos, &kprobe_insn_pages) {
+ kip = hlist_entry(pos, struct kprobe_insn_page, hlist);
+ if (kip->insns <= slot &&
+ slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
+ int i = (slot - kip->insns) / MAX_INSN_SIZE;
+ kip->slot_used[i] = 0;
+ kip->nused--;
+ if (kip->nused == 0) {
+ /*
+ * Page is no longer in use. Free it unless
+ * it's the last one. We keep the last one
+ * so as not to have to set it up again the
+ * next time somebody inserts a probe.
+ */
+ hlist_del(&kip->hlist);
+ if (hlist_empty(&kprobe_insn_pages)) {
+ INIT_HLIST_NODE(&kip->hlist);
+ hlist_add_head(&kip->hlist,
+ &kprobe_insn_pages);
+ } else {
+ module_free(NULL, kip->insns);
+ kfree(kip);
+ }
+ }
+ return;
+ }
+ }
+}
+
/* Locks kprobe: irqs must be disabled */
-void lock_kprobes(void)
+void __kprobes lock_kprobes(void)
{
+ unsigned long flags = 0;
+
+ /* Avoiding local interrupts to happen right after we take the kprobe_lock
+ * and before we get a chance to update kprobe_cpu, this to prevent
+ * deadlock when we have a kprobe on ISR routine and a kprobe on task
+ * routine
+ */
+ local_irq_save(flags);
+
spin_lock(&kprobe_lock);
kprobe_cpu = smp_processor_id();
+
+ local_irq_restore(flags);
}
-void unlock_kprobes(void)
+void __kprobes unlock_kprobes(void)
{
+ unsigned long flags = 0;
+
+ /* Avoiding local interrupts to happen right after we update
+ * kprobe_cpu and before we get a a chance to release kprobe_lock,
+ * this to prevent deadlock when we have a kprobe on ISR routine and
+ * a kprobe on task routine
+ */
+ local_irq_save(flags);
+
kprobe_cpu = NR_CPUS;
spin_unlock(&kprobe_lock);
+
+ local_irq_restore(flags);
}
/* You have to be holding the kprobe_lock */
-struct kprobe *get_kprobe(void *addr)
+struct kprobe __kprobes *get_kprobe(void *addr)
{
struct hlist_head *head;
struct hlist_node *node;
* Aggregate handlers for multiple kprobes support - these handlers
* take care of invoking the individual kprobe handlers on p->list
*/
-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) {
if (kp->pre_handler) {
curr_kprobe = kp;
- kp->pre_handler(kp, regs);
- curr_kprobe = NULL;
+ if (kp->pre_handler(kp, regs))
+ return 1;
}
+ curr_kprobe = NULL;
}
return 0;
}
-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;
return;
}
-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)
{
/*
* if we faulted "during" the execution of a user specified
return 0;
}
+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;
+ }
+ }
+ curr_kprobe = NULL;
+ return 0;
+}
+
+struct kretprobe_instance __kprobes *get_free_rp_inst(struct kretprobe *rp)
+{
+ struct hlist_node *node;
+ struct kretprobe_instance *ri;
+ hlist_for_each_entry(ri, node, &rp->free_instances, uflist)
+ return ri;
+ return NULL;
+}
+
+static struct kretprobe_instance __kprobes *get_used_rp_inst(struct kretprobe
+ *rp)
+{
+ struct hlist_node *node;
+ struct kretprobe_instance *ri;
+ hlist_for_each_entry(ri, node, &rp->used_instances, uflist)
+ return ri;
+ return NULL;
+}
+
+void __kprobes add_rp_inst(struct kretprobe_instance *ri)
+{
+ /*
+ * Remove rp inst off the free list -
+ * Add it back when probed function returns
+ */
+ hlist_del(&ri->uflist);
+
+ /* Add rp inst onto table */
+ INIT_HLIST_NODE(&ri->hlist);
+ hlist_add_head(&ri->hlist,
+ &kretprobe_inst_table[hash_ptr(ri->task, KPROBE_HASH_BITS)]);
+
+ /* Also add this rp inst to the used list. */
+ INIT_HLIST_NODE(&ri->uflist);
+ hlist_add_head(&ri->uflist, &ri->rp->used_instances);
+}
+
+void __kprobes recycle_rp_inst(struct kretprobe_instance *ri)
+{
+ /* remove rp inst off the rprobe_inst_table */
+ hlist_del(&ri->hlist);
+ if (ri->rp) {
+ /* remove rp inst off the used list */
+ hlist_del(&ri->uflist);
+ /* put rp inst back onto the free list */
+ INIT_HLIST_NODE(&ri->uflist);
+ hlist_add_head(&ri->uflist, &ri->rp->free_instances);
+ } else
+ /* Unregistering */
+ kfree(ri);
+}
+
+struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk)
+{
+ return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)];
+}
+
+/*
+ * This function is called from exit_thread or flush_thread when task tk's
+ * stack is being recycled so that we can recycle any function-return probe
+ * instances associated with this task. These left over instances represent
+ * probed functions that have been called but will never return.
+ */
+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);
+ 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);
+}
+
+/*
+ * This kprobe pre_handler is registered with every kretprobe. When probe
+ * hits it will set up the return probe.
+ */
+static int __kprobes pre_handler_kretprobe(struct kprobe *p,
+ struct pt_regs *regs)
+{
+ struct kretprobe *rp = container_of(p, struct kretprobe, kp);
+
+ /*TODO: consider to only swap the RA after the last pre_handler fired */
+ arch_prepare_kretprobe(rp, regs);
+ return 0;
+}
+
+static inline void free_rp_inst(struct kretprobe *rp)
+{
+ struct kretprobe_instance *ri;
+ while ((ri = get_free_rp_inst(rp)) != NULL) {
+ hlist_del(&ri->uflist);
+ kfree(ri);
+ }
+}
+
+/*
+ * Keep all fields in the kprobe consistent
+ */
+static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
+{
+ memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
+ memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
+}
+
+/*
+* 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 __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) {
+ if (kp->break_handler)
+ return -EEXIST;
+ }
+ list_add_tail(&p->list, &old_p->list);
+ } else
+ list_add(&p->list, &old_p->list);
+ return 0;
+}
+
/*
* Fill in the required fields of the "manager kprobe". Replace the
* earlier kprobe in the hlist with the manager kprobe
*/
static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
{
+ copy_kprobe(p, ap);
ap->addr = p->addr;
- ap->opcode = p->opcode;
- memcpy(&ap->ainsn, &p->ainsn, sizeof(struct arch_specific_insn));
-
ap->pre_handler = aggr_pre_handler;
ap->post_handler = aggr_post_handler;
ap->fault_handler = aggr_fault_handler;
+ ap->break_handler = aggr_break_handler;
INIT_LIST_HEAD(&ap->list);
list_add(&p->list, &ap->list);
* the intricacies
* TODO: Move kcalloc outside the spinlock
*/
-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;
- if (old_p->break_handler || p->break_handler) {
- ret = -EEXIST; /* kprobe and jprobe can't (yet) coexist */
- } else if (old_p->pre_handler == aggr_pre_handler) {
- list_add(&p->list, &old_p->list);
+ if (old_p->pre_handler == aggr_pre_handler) {
+ copy_kprobe(old_p, p);
+ ret = add_new_kprobe(old_p, p);
} else {
ap = kcalloc(1, sizeof(struct kprobe), GFP_ATOMIC);
if (!ap)
return -ENOMEM;
add_aggr_kprobe(ap, old_p);
- list_add(&p->list, &ap->list);
+ copy_kprobe(ap, p);
+ ret = add_new_kprobe(ap, p);
}
return ret;
}
/* kprobe removal house-keeping routines */
static inline void cleanup_kprobe(struct kprobe *p, unsigned long flags)
{
- *p->addr = p->opcode;
+ arch_disarm_kprobe(p);
hlist_del(&p->hlist);
- flush_icache_range((unsigned long) p->addr,
- (unsigned long) p->addr + sizeof(kprobe_opcode_t));
spin_unlock_irqrestore(&kprobe_lock, flags);
arch_remove_kprobe(p);
}
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;
- }
+
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;
hlist_add_head(&p->hlist,
&kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
- p->opcode = *p->addr;
- *p->addr = BREAKPOINT_INSTRUCTION;
- flush_icache_range((unsigned long) p->addr,
- (unsigned long) p->addr + sizeof(kprobe_opcode_t));
+ arch_arm_kprobe(p);
+
out:
spin_unlock_irqrestore(&kprobe_lock, flags);
rm_kprobe:
return ret;
}
-void unregister_kprobe(struct kprobe *p)
+void __kprobes unregister_kprobe(struct kprobe *p)
{
unsigned long flags;
struct kprobe *old_p;
.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 __kprobes register_kretprobe(struct kretprobe *rp)
+{
+ int ret = 0;
+ struct kretprobe_instance *inst;
+ int i;
+
+ rp->kp.pre_handler = pre_handler_kretprobe;
+
+ /* Pre-allocate memory for max kretprobe instances */
+ if (rp->maxactive <= 0) {
+#ifdef CONFIG_PREEMPT
+ rp->maxactive = max(10, 2 * NR_CPUS);
+#else
+ rp->maxactive = NR_CPUS;
+#endif
+ }
+ INIT_HLIST_HEAD(&rp->used_instances);
+ INIT_HLIST_HEAD(&rp->free_instances);
+ for (i = 0; i < rp->maxactive; i++) {
+ inst = kmalloc(sizeof(struct kretprobe_instance), GFP_KERNEL);
+ if (inst == NULL) {
+ free_rp_inst(rp);
+ return -ENOMEM;
+ }
+ INIT_HLIST_NODE(&inst->uflist);
+ hlist_add_head(&inst->uflist, &rp->free_instances);
+ }
+
+ rp->nmissed = 0;
+ /* Establish function entry probe point */
+ if ((ret = register_kprobe(&rp->kp)) != 0)
+ free_rp_inst(rp);
+ return ret;
+}
+
+#else /* ARCH_SUPPORTS_KRETPROBES */
+
+int __kprobes register_kretprobe(struct kretprobe *rp)
+{
+ return -ENOSYS;
+}
+
+#endif /* ARCH_SUPPORTS_KRETPROBES */
+
+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);
+ 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);
+}
+
static int __init init_kprobes(void)
{
int i, err = 0;
/* FIXME allocate the probe table, currently defined statically */
/* initialize all list heads */
- for (i = 0; i < KPROBE_TABLE_SIZE; i++)
+ for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
INIT_HLIST_HEAD(&kprobe_table[i]);
+ INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
+ }
+
+ err = arch_init_kprobes();
+ if (!err)
+ err = register_die_notifier(&kprobe_exceptions_nb);
- err = register_die_notifier(&kprobe_exceptions_nb);
return err;
}
EXPORT_SYMBOL_GPL(register_jprobe);
EXPORT_SYMBOL_GPL(unregister_jprobe);
EXPORT_SYMBOL_GPL(jprobe_return);
+EXPORT_SYMBOL_GPL(register_kretprobe);
+EXPORT_SYMBOL_GPL(unregister_kretprobe);
+
git.openpandora.org / pandora-kernel.git / blobdiff