[REFACTOR] move trampoline_uprobe_handler()

from src/modules/uprobe/arch/asm-arm/swap_uprobes.c
to src/modules/uprobe/swap_uprobes.c

4 files changed, 71 insertions, 67 deletions

diff --git a/uprobe/arch/asm-arm/swap_uprobes.c b/uprobe/arch/asm-arm/swap_uprobes.c
index d4fa8685..954f91e4 100644
--- a/uprobe/arch/asm-arm/swap_uprobes.c
+++ b/uprobe/arch/asm-arm/swap_uprobes.c
@@ -630,76 +630,23 @@ int setjmp_upre_handler(struct kprobe *p, struct pt_regs *regs)
 	return 0;
 }
 
-int trampoline_uprobe_handler(struct kprobe *p, struct pt_regs *regs)
+unsigned long arch_get_trampoline_addr(struct kprobe *p, struct pt_regs *regs)
 {
-	struct uretprobe_instance *ri = NULL;
-	struct hlist_head *head;
-	struct hlist_node *node, *tmp;
-	unsigned long flags, orig_ret_address = 0;
-	unsigned long trampoline_address = 0;
-
-	if (thumb_mode(regs)) {
-		trampoline_address = (unsigned long)(p->ainsn.insn) + 0x1b;
-	} else {
-		trampoline_address = (unsigned long)(p->ainsn.insn + UPROBES_TRAMP_RET_BREAK_IDX);
-	}
-
-	spin_lock_irqsave(&uretprobe_lock, flags);
-
-	head = uretprobe_inst_table_head(current->mm);
-
-	/*
-	 * It is possible to have multiple instances associated with a given
-	 * task either because an multiple functions in the call path
-	 * have a return probe installed on them, and/or more then one
-	 * return probe was registered for a target function.
-	 *
-	 * 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
-	 *       real return address, and all the rest will point to
-	 *       uretprobe_trampoline
-	 */
-	hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
-		if (ri->task != current) {
-			/* another task is sharing our hash bucket */
-			continue;
-		}
-
-		if (ri->rp && ri->rp->handler) {
-			ri->rp->handler(ri, regs, ri->rp->priv_arg);
-		}
-
-		orig_ret_address = (unsigned long)ri->ret_addr;
-		recycle_urp_inst(ri);
+	return thumb_mode(regs) ?
+			(unsigned long)(p->ainsn.insn) + 0x1b :
+			(unsigned long)(p->ainsn.insn + UPROBES_TRAMP_RET_BREAK_IDX);
+}
 
-		if (orig_ret_address != trampoline_address) {
-			/*
-			 * This is the real return address. Any other
-			 * instances associated with this task are for
-			 * other calls deeper on the call stack
-			 */
-			break;
-		}
-	}
+void arch_set_orig_ret_addr(unsigned long orig_ret_addr, struct pt_regs *regs)
+{
+	regs->ARM_lr = orig_ret_addr;
+	regs->ARM_pc = orig_ret_addr;
 
-	regs->ARM_pc = orig_ret_address;
 	if (thumb_mode(regs) && !(regs->ARM_lr & 0x01)) {
 		regs->ARM_cpsr &= 0xFFFFFFDF;
 	} else if (user_mode(regs) && (regs->ARM_lr & 0x01)) {
 		regs->ARM_cpsr |= 0x20;
 	}
-
-	spin_unlock_irqrestore(&uretprobe_lock, flags);
-
-	/*
-	 * 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;
 }
 
 static int check_validity_insn(struct kprobe *p, struct pt_regs *regs, struct task_struct *task)
diff --git a/uprobe/arch/asm-arm/swap_uprobes.h b/uprobe/arch/asm-arm/swap_uprobes.h
index e76cb9c7..5ce45cc4 100644
--- a/uprobe/arch/asm-arm/swap_uprobes.h
+++ b/uprobe/arch/asm-arm/swap_uprobes.h
@@ -20,6 +20,9 @@ static inline int longjmp_break_uhandler(struct kprobe *p, struct pt_regs *regs)
 
 void arch_prepare_uretprobe_hl(struct uretprobe_instance *ri, struct pt_regs *regs);
 
+unsigned long arch_get_trampoline_addr(struct kprobe *p, struct pt_regs *regs);
+void arch_set_orig_ret_addr(unsigned long orig_ret_addr, struct pt_regs *regs);
+
 int swap_arch_init_uprobes(void);
 void swap_arch_exit_uprobes(void);
 
diff --git a/uprobe/swap_uprobes.c b/uprobe/swap_uprobes.c
index f289b8eb..55a82313 100644
--- a/uprobe/swap_uprobes.c
+++ b/uprobe/swap_uprobes.c
@@ -389,7 +389,7 @@ static void remove_uprobe(struct kprobe *p, struct task_struct *task)
 #endif /* CONFIG_ARM */
 }
 
-struct hlist_head *uretprobe_inst_table_head(void *hash_key)
+static struct hlist_head *uretprobe_inst_table_head(void *hash_key)
 {
 	return &uretprobe_inst_table[hash_ptr (hash_key, UPROBE_HASH_BITS)];
 }
@@ -413,7 +413,7 @@ static void add_urp_inst(struct uretprobe_instance *ri)
 }
 
 /* Called with uretprobe_lock held */
-void recycle_urp_inst(struct uretprobe_instance *ri)
+static void recycle_urp_inst(struct uretprobe_instance *ri)
 {
 	if (ri->rp) {
 		hlist_del(&ri->hlist);
@@ -673,6 +673,60 @@ void dbi_unregister_ujprobe(struct task_struct *task, struct jprobe *jp, int ato
 #endif /* CONFIG_ARM */
 }
 
+int trampoline_uprobe_handler(struct kprobe *p, struct pt_regs *regs)
+{
+	struct uretprobe_instance *ri = NULL;
+	struct hlist_head *head;
+	struct hlist_node *node, *tmp;
+	unsigned long flags, tramp_addr, orig_ret_addr = 0;
+
+	tramp_addr = arch_get_trampoline_addr(p, regs);
+	spin_lock_irqsave(&uretprobe_lock, flags);
+
+	head = uretprobe_inst_table_head(current->mm);
+
+	/*
+	 * It is possible to have multiple instances associated with a given
+	 * task either because an multiple functions in the call path
+	 * have a return probe installed on them, and/or more then one
+	 * return probe was registered for a target function.
+	 *
+	 * 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
+	 *       real return address, and all the rest will point to
+	 *       uretprobe_trampoline
+	 */
+	hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
+		if (ri->task != current) {
+			/* another task is sharing our hash bucket */
+			continue;
+		}
+
+		if (ri->rp && ri->rp->handler) {
+			ri->rp->handler(ri, regs, ri->rp->priv_arg);
+		}
+
+		orig_ret_addr = (unsigned long)ri->ret_addr;
+		recycle_urp_inst(ri);
+
+		if (orig_ret_addr != tramp_addr) {
+			/*
+			 * This is the real return address. Any other
+			 * instances associated with this task are for
+			 * other calls deeper on the call stack
+			 */
+			break;
+		}
+	}
+
+	spin_unlock_irqrestore(&uretprobe_lock, flags);
+	arch_set_orig_ret_addr(orig_ret_addr, regs);
+
+	return 1;
+}
+
 static int pre_handler_uretprobe(struct kprobe *p, struct pt_regs *regs)
 {
 	struct uretprobe *rp = container_of(p, struct uretprobe, kp);
diff --git a/uprobe/swap_uprobes.h b/uprobe/swap_uprobes.h
index a5c7113f..f8b2aa67 100644
--- a/uprobe/swap_uprobes.h
+++ b/uprobe/swap_uprobes.h
@@ -29,6 +29,8 @@
 
 #include "dbi_kprobes.h"
 
+struct uretprobe_instance;
+
 typedef int (*uretprobe_handler_t)(struct uretprobe_instance *, struct pt_regs *, void *);
 
 /*
@@ -78,8 +80,6 @@ struct kprobe *get_uprobe(kprobe_opcode_t *addr, pid_t tgid);
 
 void disarm_uprobe(struct kprobe *p, struct task_struct *task);
 
-extern spinlock_t uretprobe_lock;
-struct hlist_head *uretprobe_inst_table_head(void *hash_key);
-void recycle_urp_inst(struct uretprobe_instance *ri);
+int trampoline_uprobe_handler(struct kprobe *p, struct pt_regs *regs);
 
 #endif /*  _DBI_UPROBES_H */