ptrace: generic resume

This makes ptrace_request handle all the ptrace requests that wake
up the traced task.  These do low-level ptrace implementation magic
that is not arch-specific and should be kept out of arch code.  The
implementations on each arch usually do the same thing.  The new
generic code makes use of the arch_has_single_step macro and generic
entry points to handle PTRACE_SINGLESTEP.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 61 insertions, 0 deletions

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index c719bb9d79ab..fad5f1e8511f 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -366,6 +366,50 @@ static int ptrace_setsiginfo(struct task_struct *child, siginfo_t __user * data)
         return error;
 }
 
+
+#ifdef PTRACE_SINGLESTEP
+#define is_singlestep(request)          ((request) == PTRACE_SINGLESTEP)
+#else
+#define is_singlestep(request)          0
+#endif
+
+#ifdef PTRACE_SYSEMU
+#define is_sysemu_singlestep(request)   ((request) == PTRACE_SYSEMU_SINGLESTEP)
+#else
+#define is_sysemu_singlestep(request)   0
+#endif
+
+static int ptrace_resume(struct task_struct *child, long request, long data)
+{
+        if (!valid_signal(data))
+                return -EIO;
+
+        if (request == PTRACE_SYSCALL)
+                set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+        else
+                clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+
+#ifdef TIF_SYSCALL_EMU
+        if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
+                set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+        else
+                clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+#endif
+
+        if (is_singlestep(request) || is_sysemu_singlestep(request)) {
+                if (unlikely(!arch_has_single_step()))
+                        return -EIO;
+                user_enable_single_step(child);
+        }
+        else
+                user_disable_single_step(child);
+
+        child->exit_code = data;
+        wake_up_process(child);
+
+        return 0;
+}
+
 int ptrace_request(struct task_struct *child, long request,
                    long addr, long data)
 {
@@ -390,6 +434,23 @@ int ptrace_request(struct task_struct *child, long request,
         case PTRACE_DETACH:      /* detach a process that was attached. */
                 ret = ptrace_detach(child, data);
                 break;
+
+#ifdef PTRACE_SINGLESTEP
+        case PTRACE_SINGLESTEP:
+#endif
+#ifdef PTRACE_SYSEMU
+        case PTRACE_SYSEMU:
+        case PTRACE_SYSEMU_SINGLESTEP:
+#endif
+        case PTRACE_SYSCALL:
+        case PTRACE_CONT:
+                return ptrace_resume(child, request, data);
+
+        case PTRACE_KILL:
+                if (child->exit_state)  /* already dead */
+                        return 0;
+                return ptrace_resume(child, request, SIGKILL);
+
         default:
                 break;
         }