[PATCH] x86_64: Some fixes for single step handling

Ported from i386/Linus

Be more careful with TF handling to fix some copy protection codes in Wine

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 12 insertions, 16 deletions

diff --git a/arch/x86_64/kernel/signal.c b/arch/x86_64/kernel/signal.c
index 5ace32c6ac5c..4ff0f0117a09 100644
--- a/arch/x86_64/kernel/signal.c
+++ b/arch/x86_64/kernel/signal.c
@@ -185,7 +185,6 @@ static inline int
 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me)
 {
         int err = 0;
-        unsigned long eflags;
 
         err |= __put_user(0, &sc->gs);
         err |= __put_user(0, &sc->fs);
@@ -209,11 +208,7 @@ setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned lo
         err |= __put_user(me->thread.trap_no, &sc->trapno);
         err |= __put_user(me->thread.error_code, &sc->err);
         err |= __put_user(regs->rip, &sc->rip);
-        eflags = regs->eflags;
-        if (current->ptrace & PT_PTRACED) {
-                eflags &= ~TF_MASK;
-        }
-        err |= __put_user(eflags, &sc->eflags);
+        err |= __put_user(regs->eflags, &sc->eflags);
         err |= __put_user(mask, &sc->oldmask);
         err |= __put_user(me->thread.cr2, &sc->cr2);
 
@@ -323,14 +318,9 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
         regs->rsp = (unsigned long)frame;
 
         set_fs(USER_DS);
-        if (regs->eflags & TF_MASK) {
-                if ((current->ptrace & (PT_PTRACED | PT_DTRACE)) == (PT_PTRACED | PT_DTRACE)) {
-                        ptrace_notify(SIGTRAP);
-                } else {
-                        regs->eflags &= ~TF_MASK;
-                }
-        }
-
+        regs->eflags &= ~TF_MASK;
+        if (test_thread_flag(TIF_SINGLESTEP))
+                ptrace_notify(SIGTRAP);
 #ifdef DEBUG_SIG
         printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
                 current->comm, current->pid, frame, regs->rip, frame->pretcode);
diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index 2707a27b81cd..09e4a6460e74 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -688,8 +688,14 @@ asmlinkage void *do_debug(struct pt_regs * regs, unsigned long error_code)
                  */
                 if ((regs->cs & 3) == 0)
                        goto clear_TF_reenable;
-                if ((tsk->ptrace & (PT_DTRACE|PT_PTRACED)) == PT_DTRACE)
-                        goto clear_TF;
+                /*
+                 * Was the TF flag set by a debugger? If so, clear it now,
+                 * so that register information is correct.
+                 */
+                if (tsk->ptrace & PT_DTRACE) {
+                        regs->eflags &= ~TF_MASK;
+                        tsk->ptrace &= ~PT_DTRACE;
+                }
         }
 
         /* Ok, finally something we can handle */