x86 single_step: TIF_FORCED_TF
This changes the single-step support to use a new thread_info flag
TIF_FORCED_TF instead of the PT_DTRACE flag in task_struct.ptrace.
This keeps arch implementation uses out of this non-arch field.
This changes the ptrace access to eflags to mask TF and maintain
the TIF_FORCED_TF flag directly if userland sets TF, instead of
relying on ptrace_signal_deliver. The 64-bit and 32-bit kernels
are harmonized on this same behavior. The ptrace_signal_deliver
approach works now, but this change makes the low-level register
access code reliable when called from different contexts than a
ptrace stop, which will be possible in the future.
The 64-bit do_debug exception handler is also changed not to clear TF
from user-mode registers. This matches the 32-bit kernel's behavior.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/asm-x86/signal.h b/include/asm-x86/signal.h
index 987a422..aee7eca 100644
--- a/include/asm-x86/signal.h
+++ b/include/asm-x86/signal.h
@@ -245,21 +245,14 @@
struct pt_regs;
-#define ptrace_signal_deliver(regs, cookie) \
- do { \
- if (current->ptrace & PT_DTRACE) { \
- current->ptrace &= ~PT_DTRACE; \
- (regs)->eflags &= ~TF_MASK; \
- } \
- } while (0)
-
#else /* __i386__ */
#undef __HAVE_ARCH_SIG_BITOPS
+#endif /* !__i386__ */
+
#define ptrace_signal_deliver(regs, cookie) do { } while (0)
-#endif /* !__i386__ */
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */