3 files changed, 18 insertions, 3 deletions

diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 8826d9803aeb..2b92ce85f97f 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -214,11 +214,13 @@ ENTRY(vector_swi)
          * context switches, and waiting for our parent to respond.
          */
 __sys_trace:
+        mov     r2, scno
         add     r1, sp, #S_OFF
         mov     r0, #0                          @ trace entry [IP = 0]
         bl      syscall_trace
 
         adr     lr, __sys_trace_return          @ return address
+        mov     scno, r0                        @ syscall number (possibly new)
         add     r1, sp, #S_R0 + S_OFF           @ pointer to regs
         cmp     scno, #NR_syscalls              @ check upper syscall limit
         ldmccia r1, {r0 - r3}                   @ have to reload r0 - r3
@@ -227,6 +229,7 @@ __sys_trace:
 
 __sys_trace_return:
         str     r0, [sp, #S_R0 + S_OFF]!        @ save returned r0
+        mov     r2, scno
         mov     r1, sp
         mov     r0, #1                          @ trace exit [IP = 1]
         bl      syscall_trace
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index e591f72bcdeb..7b6256bb590e 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -766,6 +766,11 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                                        (unsigned long __user *) data);
                         break;
 
+                case PTRACE_SET_SYSCALL:
+                        ret = 0;
+                        child->ptrace_message = data;
+                        break;
+
                 default:
                         ret = ptrace_request(child, request, addr, data);
                         break;
@@ -774,14 +779,14 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
         return ret;
 }
 
-asmlinkage void syscall_trace(int why, struct pt_regs *regs)
+asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
 {
         unsigned long ip;
 
         if (!test_thread_flag(TIF_SYSCALL_TRACE))
-                return;
+                return scno;
         if (!(current->ptrace & PT_PTRACED))
-                return;
+                return scno;
 
         /*
          * Save IP.  IP is used to denote syscall entry/exit:
@@ -790,6 +795,8 @@ asmlinkage void syscall_trace(int why, struct pt_regs *regs)
         ip = regs->ARM_ip;
         regs->ARM_ip = why;
 
+        current->ptrace_message = scno;
+
         /* the 0x80 provides a way for the tracing parent to distinguish
            between a syscall stop and SIGTRAP delivery */
         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
@@ -804,4 +811,6 @@ asmlinkage void syscall_trace(int why, struct pt_regs *regs)
                 current->exit_code = 0;
         }
         regs->ARM_ip = ip;
+
+        return current->ptrace_message;
 }
diff --git a/include/asm-arm/ptrace.h b/include/asm-arm/ptrace.h
index f40948d54448..77adb7fa169b 100644
--- a/include/asm-arm/ptrace.h
+++ b/include/asm-arm/ptrace.h
@@ -23,6 +23,9 @@
 #define PTRACE_OLDSETOPTIONS    21
 
 #define PTRACE_GET_THREAD_AREA  22
+
+#define PTRACE_SET_SYSCALL      23
+
 /*
  * PSR bits
  */