[PATCH] kprobes: arch_remove_kprobe

Currently arch_remove_kprobes() is only implemented/required for x86_64 and
powerpc.  All other architecture like IA64, i386 and sparc64 implementes a
dummy function which is being called from arch independent kprobes.c file.

This patch removes the dummy functions and replaces it with
#define arch_remove_kprobe(p, s)	do { } while(0)

Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/i386/kernel/kprobes.c

@@ -77,10 +77,6 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
 			   (unsigned long) p->addr + sizeof(kprobe_opcode_t));
 }
 
-void __kprobes arch_remove_kprobe(struct kprobe *p)
-{
-}
-
 static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb)
 {
 	kcb->prev_kprobe.kp = kprobe_running();

arch/ia64/kernel/kprobes.c

@@ -467,10 +467,6 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
 	flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
 }
 
-void __kprobes arch_remove_kprobe(struct kprobe *p)
-{
-}
-
 /*
  * We are resuming execution after a single step fault, so the pt_regs
  * structure reflects the register state after we executed the instruction

arch/powerpc/kernel/kprobes.c

@@ -80,9 +80,11 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
 			   (unsigned long) p->addr + sizeof(kprobe_opcode_t));
 }
 
-void __kprobes arch_remove_kprobe(struct kprobe *p)
+void __kprobes arch_remove_kprobe(struct kprobe *p, struct semaphore *s)
 {
+	down(s);
 	free_insn_slot(p->ainsn.insn);
+	up(s);
 }
 
 static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)

arch/sparc64/kernel/kprobes.c

@@ -61,10 +61,6 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
 	flushi(p->addr);
 }
 
-void __kprobes arch_remove_kprobe(struct kprobe *p)
-{
-}
-
 static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb)
 {
 	kcb->prev_kprobe.kp = kprobe_running();

arch/x86_64/kernel/kprobes.c

@@ -220,9 +220,11 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
 			   (unsigned long) p->addr + sizeof(kprobe_opcode_t));
 }
 
-void __kprobes arch_remove_kprobe(struct kprobe *p)
+void __kprobes arch_remove_kprobe(struct kprobe *p, struct semaphore *s)
 {
+	down(s);
 	free_insn_slot(p->ainsn.insn);
+	up(s);
 }
 
 static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb)

include/asm-i386/kprobes.h

@@ -40,6 +40,7 @@ typedef u8 kprobe_opcode_t;
 
 #define JPROBE_ENTRY(pentry)	(kprobe_opcode_t *)pentry
 #define ARCH_SUPPORTS_KRETPROBES
+#define arch_remove_kprobe(p, s)	do { } while(0)
 
 void kretprobe_trampoline(void);
 

include/asm-ia64/kprobes.h

@@ -89,6 +89,7 @@ struct kprobe_ctlblk {
 #define IP_RELATIVE_PREDICT_OPCODE	(7)
 #define LONG_BRANCH_OPCODE		(0xC)
 #define LONG_CALL_OPCODE		(0xD)
+#define arch_remove_kprobe(p, s)	do { } while(0)
 
 typedef struct kprobe_opcode {
 	bundle_t bundle;

include/asm-powerpc/kprobes.h

@@ -50,6 +50,7 @@ typedef unsigned int kprobe_opcode_t;
 
 #define ARCH_SUPPORTS_KRETPROBES
 void kretprobe_trampoline(void);
+extern void arch_remove_kprobe(struct kprobe *p, struct semaphore *s);
 
 /* Architecture specific copy of original instruction */
 struct arch_specific_insn {

include/asm-sparc64/kprobes.h

@@ -12,6 +12,7 @@ typedef u32 kprobe_opcode_t;
 #define MAX_INSN_SIZE 2
 
 #define JPROBE_ENTRY(pentry)	(kprobe_opcode_t *)pentry
+#define arch_remove_kprobe(p, s)	do { } while(0)
 
 /* Architecture specific copy of original instruction*/
 struct arch_specific_insn {

include/asm-x86_64/kprobes.h

@@ -78,6 +78,7 @@ static inline void restore_interrupts(struct pt_regs *regs)
 		local_irq_enable();
 }
 
+extern void arch_remove_kprobe(struct kprobe *p, struct semaphore *s);
 extern int post_kprobe_handler(struct pt_regs *regs);
 extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
 extern int kprobe_handler(struct pt_regs *regs);

include/linux/kprobes.h

@@ -152,7 +152,6 @@ extern spinlock_t kretprobe_lock;
 extern int arch_prepare_kprobe(struct kprobe *p);
 extern void arch_arm_kprobe(struct kprobe *p);
 extern void arch_disarm_kprobe(struct kprobe *p);
-extern void arch_remove_kprobe(struct kprobe *p);
 extern int arch_init_kprobes(void);
 extern void show_registers(struct pt_regs *regs);
 extern kprobe_opcode_t *get_insn_slot(void);

kernel/kprobes.c

@@ -532,9 +532,7 @@ void __kprobes unregister_kprobe(struct kprobe *p)
 			list_del_rcu(&p->list);
 			kfree(old_p);
 		}
-		down(&kprobe_mutex);
+		arch_remove_kprobe(p, &kprobe_mutex);
-		arch_remove_kprobe(p);
-		up(&kprobe_mutex);
 	}
 }