* Added function return probes functionality
*/
-#include <linux/config.h>
#include <linux/kprobes.h>
#include <linux/ptrace.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/preempt.h>
+#include <linux/module.h>
#include <asm/cacheflush.h>
#include <asm/pgtable.h>
#include <asm/kdebug.h>
+#include <asm/uaccess.h>
void jprobe_return_end(void);
static void __kprobes arch_copy_kprobe(struct kprobe *p);
/*
* returns non-zero if opcode modifies the interrupt flag.
*/
-static inline int is_IF_modifier(kprobe_opcode_t *insn)
+static __always_inline int is_IF_modifier(kprobe_opcode_t *insn)
{
switch (*insn) {
case 0xfa: /* cli */
* If it does, return the address of the 32-bit displacement word.
* If not, return null.
*/
-static inline s32 *is_riprel(u8 *insn)
+static s32 __kprobes *is_riprel(u8 *insn)
{
#define W(row,b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,ba,bb,bc,bd,be,bf) \
(((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
- down(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn);
- up(&kprobe_mutex);
+ mutex_lock(&kprobe_mutex);
+ free_insn_slot(p->ainsn.insn, 0);
+ mutex_unlock(&kprobe_mutex);
}
-static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb)
+static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
{
kcb->prev_kprobe.kp = kprobe_running();
kcb->prev_kprobe.status = kcb->kprobe_status;
kcb->prev_kprobe.saved_rflags = kcb->kprobe_saved_rflags;
}
-static inline void restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
{
__get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
kcb->kprobe_status = kcb->prev_kprobe.status;
kcb->kprobe_saved_rflags = kcb->prev_kprobe.saved_rflags;
}
-static inline void set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
+static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb)
{
__get_cpu_var(current_kprobe) = p;
struct pt_regs *regs)
{
unsigned long *sara = (unsigned long *)regs->rsp;
- struct kretprobe_instance *ri;
+ struct kretprobe_instance *ri;
- if ((ri = get_free_rp_inst(rp)) != NULL) {
- ri->rp = rp;
- ri->task = current;
+ if ((ri = get_free_rp_inst(rp)) != NULL) {
+ ri->rp = rp;
+ ri->task = current;
ri->ret_addr = (kprobe_opcode_t *) *sara;
/* Replace the return addr with trampoline addr */
*sara = (unsigned long) &kretprobe_trampoline;
-
- add_rp_inst(ri);
- } else {
- rp->nmissed++;
- }
+ add_rp_inst(ri);
+ } else {
+ rp->nmissed++;
+ }
}
int __kprobes kprobe_handler(struct pt_regs *regs)
*/
int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
{
- struct kretprobe_instance *ri = NULL;
- struct hlist_head *head;
- struct hlist_node *node, *tmp;
+ struct kretprobe_instance *ri = NULL;
+ struct hlist_head *head, empty_rp;
+ struct hlist_node *node, *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
+ INIT_HLIST_HEAD(&empty_rp);
spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
+ head = kretprobe_inst_table_head(current);
/*
* It is possible to have multiple instances associated with a given
* We can handle this because:
* - instances are always inserted at the head of the list
* - when multiple return probes are registered for the same
- * function, the first instance's ret_addr will point to the
+ * function, the first instance's ret_addr will point to the
* real return address, and all the rest will point to
* kretprobe_trampoline
*/
hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
- if (ri->task != current)
+ if (ri->task != current)
/* another task is sharing our hash bucket */
- continue;
+ continue;
if (ri->rp && ri->rp->handler)
ri->rp->handler(ri, regs);
orig_ret_address = (unsigned long)ri->ret_addr;
- recycle_rp_inst(ri);
+ recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address)
/*
spin_unlock_irqrestore(&kretprobe_lock, flags);
preempt_enable_no_resched();
- /*
- * By returning a non-zero value, we are telling
- * kprobe_handler() that we don't want the post_handler
+ hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
+ hlist_del(&ri->hlist);
+ kfree(ri);
+ }
+ /*
+ * By returning a non-zero value, we are telling
+ * kprobe_handler() that we don't want the post_handler
* to run (and have re-enabled preemption)
- */
- return 1;
+ */
+ return 1;
}
/*
*tos = orig_rip + (*tos - copy_rip);
break;
case 0xff:
- if ((*insn & 0x30) == 0x10) {
+ if ((insn[1] & 0x30) == 0x10) {
/* call absolute, indirect */
/* Fix return addr; rip is correct. */
next_rip = regs->rip;
*tos = orig_rip + (*tos - copy_rip);
- } else if (((*insn & 0x31) == 0x20) || /* jmp near, absolute indirect */
- ((*insn & 0x31) == 0x21)) { /* jmp far, absolute indirect */
+ } else if (((insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */
+ ((insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */
/* rip is correct. */
next_rip = regs->rip;
}
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ const struct exception_table_entry *fixup;
- if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
- return 1;
-
- if (kcb->kprobe_status & KPROBE_HIT_SS) {
- resume_execution(cur, regs, kcb);
+ switch(kcb->kprobe_status) {
+ case KPROBE_HIT_SS:
+ case KPROBE_REENTER:
+ /*
+ * We are here because the instruction being single
+ * stepped caused a page fault. We reset the current
+ * kprobe and the rip points back to the probe address
+ * and allow the page fault handler to continue as a
+ * normal page fault.
+ */
+ regs->rip = (unsigned long)cur->addr;
regs->eflags |= kcb->kprobe_old_rflags;
-
- reset_current_kprobe();
+ if (kcb->kprobe_status == KPROBE_REENTER)
+ restore_previous_kprobe(kcb);
+ else
+ reset_current_kprobe();
preempt_enable_no_resched();
+ break;
+ case KPROBE_HIT_ACTIVE:
+ case KPROBE_HIT_SSDONE:
+ /*
+ * We increment the nmissed count for accounting,
+ * we can also use npre/npostfault count for accouting
+ * these specific fault cases.
+ */
+ kprobes_inc_nmissed_count(cur);
+
+ /*
+ * We come here because instructions in the pre/post
+ * handler caused the page_fault, this could happen
+ * if handler tries to access user space by
+ * copy_from_user(), get_user() etc. Let the
+ * user-specified handler try to fix it first.
+ */
+ if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
+ return 1;
+
+ /*
+ * In case the user-specified fault handler returned
+ * zero, try to fix up.
+ */
+ fixup = search_exception_tables(regs->rip);
+ if (fixup) {
+ regs->rip = fixup->fixup;
+ return 1;
+ }
+
+ /*
+ * fixup() could not handle it,
+ * Let do_page_fault() fix it.
+ */
+ break;
+ default:
+ break;
}
return 0;
}
struct die_args *args = (struct die_args *)data;
int ret = NOTIFY_DONE;
+ if (args->regs && user_mode(args->regs))
+ return ret;
+
switch (val) {
case DIE_INT3:
if (kprobe_handler(args->regs))
git://git.onelab.eu / linux-2.6.git / blobdiff