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authorRoland McGrath <roland@redhat.com>2008-01-30 13:30:47 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-30 13:30:47 +0100
commitfb7fa8f1741c91f6c6e958762155abe9339476ca (patch)
treece916e9e735cdd0202015cd52f5e93b7a2df7011 /include
parent022eb43419f896a3647f769cdc3b5e13a8fb8ee7 (diff)
ptrace: arch_has_single_step
This defines the new macro arch_has_single_step() in linux/ptrace.h, a default for when asm/ptrace.h does not define it. It declares the new user_enable_single_step and user_disable_single_step functions. This is not used yet, but paves the way to harmonize on this interface for the arch-specific calls on all machines. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include')
-rw-r--r--include/linux/ptrace.h46
1 files changed, 46 insertions, 0 deletions
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 3ea5750a0f7e..8f06c6fb22a5 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -129,6 +129,52 @@ int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data);
#define force_successful_syscall_return() do { } while (0)
#endif
+/*
+ * <asm/ptrace.h> should define the following things inside #ifdef __KERNEL__.
+ *
+ * These do-nothing inlines are used when the arch does not
+ * implement single-step. The kerneldoc comments are here
+ * to document the interface for all arch definitions.
+ */
+
+#ifndef arch_has_single_step
+/**
+ * arch_has_single_step - does this CPU support user-mode single-step?
+ *
+ * If this is defined, then there must be function declarations or
+ * inlines for user_enable_single_step() and user_disable_single_step().
+ * arch_has_single_step() should evaluate to nonzero iff the machine
+ * supports instruction single-step for user mode.
+ * It can be a constant or it can test a CPU feature bit.
+ */
+#define arch_has_single_step() (0)
+
+/**
+ * user_enable_single_step - single-step in user-mode task
+ * @task: either current or a task stopped in %TASK_TRACED
+ *
+ * This can only be called when arch_has_single_step() has returned nonzero.
+ * Set @task so that when it returns to user mode, it will trap after the
+ * next single instruction executes.
+ */
+static inline void user_enable_single_step(struct task_struct *task)
+{
+ BUG(); /* This can never be called. */
+}
+
+/**
+ * user_disable_single_step - cancel user-mode single-step
+ * @task: either current or a task stopped in %TASK_TRACED
+ *
+ * Clear @task of the effects of user_enable_single_step(). This can
+ * be called whether or not user_enable_single_step() was ever called
+ * on @task, and even if arch_has_single_step() returned zero.
+ */
+static inline void user_disable_single_step(struct task_struct *task)
+{
+}
+#endif /* arch_has_single_step */
+
#endif
#endif