x86 single_step: TIF_FORCED_TF

[pandora-kernel.git] / arch / x86 / ia32 / ptrace32.c

diff --git a/arch/x86/ia32/ptrace32.c b/arch/x86/ia32/ptrace32.c
index 9d754b6..5dee334 100644 (file)
--- a/arch/x86/ia32/ptrace32.c
+++ b/arch/x86/ia32/ptrace32.c
@@ -89,6 +89,15 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 val)
                __u64 *flags = &stack[offsetof(struct pt_regs, eflags)/8];
 
                val &= FLAG_MASK;
+               /*
+                * If the user value contains TF, mark that
+                * it was not "us" (the debugger) that set it.
+                * If not, make sure it stays set if we had.
+                */
+               if (val & X86_EFLAGS_TF)
+                       clear_tsk_thread_flag(child, TIF_FORCED_TF);
+               else if (test_tsk_thread_flag(child, TIF_FORCED_TF))
+                       val |= X86_EFLAGS_TF;
                *flags = val | (*flags & ~FLAG_MASK);
                break;
        }
@@ -179,9 +188,17 @@ static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
        R32(eax, rax);
        R32(orig_eax, orig_rax);
        R32(eip, rip);
-       R32(eflags, eflags);
        R32(esp, rsp);
 
+       case offsetof(struct user32, regs.eflags):
+               /*
+                * If the debugger set TF, hide it from the readout.
+                */
+               *val = stack[offsetof(struct pt_regs, eflags)/8];
+               if (test_tsk_thread_flag(child, TIF_FORCED_TF))
+                       *val &= ~X86_EFLAGS_TF;
+               break;
+
        case offsetof(struct user32, u_debugreg[0]):
                *val = child->thread.debugreg0;
                break;
@@ -425,4 +442,3 @@ asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
        put_task_struct(child);
        return ret;
 }
-