From: Dmitry Kovalenko <d.kovalenko@samsung.com>
Date: Mon, 10 Jun 2013 09:29:46 +0000 (+0400)
Subject: [IMPROVE] Kernel retprobes without exceptions
X-Git-Tag: Tizen_SDK_2.3~309^2~4
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9f9fc82513d5ed46d099615b1c1ce37bc5b437c5;p=kernel%2Fswap-modules.git

[IMPROVE] Kernel retprobes without exceptions
---

diff --git a/kprobe/arch/asm-arm/dbi_kprobes.c b/kprobe/arch/asm-arm/dbi_kprobes.c
index 68f17fb..219e0d3 100644
--- a/kprobe/arch/asm-arm/dbi_kprobes.c
+++ b/kprobe/arch/asm-arm/dbi_kprobes.c
@@ -1438,6 +1438,7 @@ int trampoline_probe_handler (struct kprobe *p, struct pt_regs *regs)
 	struct hlist_node *node, *tmp;
 	unsigned long flags, orig_ret_address = 0;
 	unsigned long trampoline_address = (unsigned long) &kretprobe_trampoline;
+	unsigned long ret = 1;
 
 	struct kretprobe *crp = NULL;
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk ();
@@ -1509,7 +1510,9 @@ int trampoline_probe_handler (struct kprobe *p, struct pt_regs *regs)
 	if ((ri->rp && ri->rp->kp.tgid) || (ri->rp2 && ri->rp2->kp.tgid))
 		BUG_ON (trampoline_address == (unsigned long) &kretprobe_trampoline);
 
-	regs->uregs[14] = orig_ret_address;
+	if (p && p->tgid)
+		regs->uregs[14] = orig_ret_address;
+
 	DBPRINTF ("regs->uregs[14] = 0x%lx\n", regs->uregs[14]);
 	DBPRINTF ("regs->uregs[15] = 0x%lx\n", regs->uregs[15]);
 
@@ -1517,8 +1520,7 @@ int trampoline_probe_handler (struct kprobe *p, struct pt_regs *regs)
 	{
 		regs->uregs[15] = orig_ret_address;
 	}else{
-		if (!thumb_mode( regs )) regs->uregs[15] += 4;
-		else regs->uregs[15] += 2;
+		ret = (void *)orig_ret_address;
 	}
 
 	DBPRINTF ("regs->uregs[15] = 0x%lx\n", regs->uregs[15]);
@@ -1596,7 +1598,20 @@ int trampoline_probe_handler (struct kprobe *p, struct pt_regs *regs)
 	 * to run (and have re-enabled preemption)
 	 */
 
-	return 1;
+	return ret;
+}
+
+void __naked kretprobe_trampoline(void)
+{
+	__asm__ __volatile__ (
+		"stmdb	sp!, {r0 - r11}		\n\t"
+		"mov	r1, sp			\n\t"
+		"mov	r0, #0			\n\t"
+		"bl	trampoline_probe_handler\n\t"
+		"mov	lr, r0			\n\t"
+		"ldmia	sp!, {r0 - r11}		\n\t"
+		"bx	lr			\n\t"
+		: : : "memory");
 }
 
 void  __arch_prepare_kretprobe (struct kretprobe *rp, struct pt_regs *regs)
@@ -1706,10 +1721,6 @@ int __init arch_init_kprobes (void)
 	do_kpro(&undef_ho_k);
 	do_kpro(&undef_ho_u);
 	do_kpro(&undef_ho_u_t);
-	if ((ret = dbi_register_kprobe (&trampoline_p)) != 0) {
-		//dbi_unregister_jprobe(&do_exit_p, 0);
-		return ret;
-	}
 	return ret;
 }
 
diff --git a/kprobe/arch/asm-arm/dbi_kprobes_arm.S b/kprobe/arch/asm-arm/dbi_kprobes_arm.S
index 73199c9..5b4c7bc 100644
--- a/kprobe/arch/asm-arm/dbi_kprobes_arm.S
+++ b/kprobe/arch/asm-arm/dbi_kprobes_arm.S
@@ -4,14 +4,6 @@
  * 	- When the probed function returns, this probe
  * 		causes the handlers to fire
  */
-		.global kretprobe_trampoline
-
-kretprobe_trampoline:
-		nop
-		nop
-		mov pc, r14
-
-
 
 		.global gen_insn_execbuf
 gen_insn_execbuf:
diff --git a/kprobe/arch/asm-arm/dbi_kprobes_arm.h b/kprobe/arch/asm-arm/dbi_kprobes_arm.h
index d9d1890..914303a 100644
--- a/kprobe/arch/asm-arm/dbi_kprobes_arm.h
+++ b/kprobe/arch/asm-arm/dbi_kprobes_arm.h
@@ -1,3 +1,2 @@
-void kretprobe_trampoline(void);
 void gen_insn_execbuf(void);
 void pc_dep_insn_execbuf(void);
diff --git a/kprobe/arch/dbi_kprobes.h b/kprobe/arch/dbi_kprobes.h
index b1237e1..737d4db 100644
--- a/kprobe/arch/dbi_kprobes.h
+++ b/kprobe/arch/dbi_kprobes.h
@@ -48,7 +48,7 @@
  * 2010         Ekaterina Gorelkina <e.gorelkina@samsung.com>: redesign module for separating core and arch parts
  *
  */
-
+#include <linux/compiler.h>
 
 #define REENTER
 
@@ -64,7 +64,7 @@ struct prev_kprobe {
 	unsigned long status;
 };
 
-void kretprobe_trampoline (void);
+void __naked kretprobe_trampoline (void);
 
 extern void __arch_prepare_kretprobe (struct kretprobe *rp, struct pt_regs *regs);
 extern int arch_prepare_kprobe (struct kprobe *p);
diff --git a/kprobe/dbi_kprobes.c b/kprobe/dbi_kprobes.c
index c0519f2..9d66ac1 100644
--- a/kprobe/dbi_kprobes.c
+++ b/kprobe/dbi_kprobes.c
@@ -767,12 +767,12 @@ void dbi_unregister_kretprobe (struct kretprobe *rp)
 		sched_rp = NULL;
 
 	while ((ri = get_used_rp_inst (rp)) != NULL) {
-		if (dbi_disarm_krp_inst(ri) == 0)
-			recycle_rp_inst(ri);
-		else
-			panic("%s (%d/%d): cannot disarm krp instance (%08lx)",
+		if (!dbi_disarm_krp_inst(ri)) {
+			printk("%s (%d/%d): cannot disarm krp instance (%08lx)\n",
 					ri->task->comm, ri->task->tgid, ri->task->pid,
 					(unsigned long)rp->kp.addr);
+		}
+		recycle_rp_inst(ri);
 	}
 
 	spin_unlock_irqrestore (&kretprobe_lock, flags);