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authorRoland McGrath <roland@redhat.com>2008-07-25 19:45:43 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-26 12:00:08 -0700
commit88ac2921a71f788ed693bcd44731dd6bc1994640 (patch)
treedb7039299713fec545061f884878563f8ae0caa6 /include/linux/ptrace.h
parent267e2a9c71b8e088ac307f9549f71468e86e26c1 (diff)
downloadop-kernel-dev-88ac2921a71f788ed693bcd44731dd6bc1994640.zip
op-kernel-dev-88ac2921a71f788ed693bcd44731dd6bc1994640.tar.gz
tracehook: add linux/tracehook.h
This patch series introduces the "tracehook" interface layer of inlines in <linux/tracehook.h>. There are more details in the log entry for patch 01/23 and in the header file comments inside that patch. Most of these changes move code around with little or no change, and they should not break anything or change any behavior. This sets a new standard for uniform arch support to enable clean arch-independent implementations of new debugging and tracing stuff, denoted by CONFIG_HAVE_ARCH_TRACEHOOK. Patch 20/23 adds that symbol to arch/Kconfig, with comments listing everything an arch has to do before setting "select HAVE_ARCH_TRACEHOOK". These are elaborted a bit at: http://sourceware.org/systemtap/wiki/utrace/arch/HowTo The new inlines that arch code must define or call have detailed kerneldoc comments in the generic header files that say what is required. No arch is obligated to do any work, and no arch's build should be broken by these changes. There are several steps that each arch should take so it can set HAVE_ARCH_TRACEHOOK. Most of these are simple. Providing this support will let new things people add for doing debugging and tracing of user-level threads "just work" for your arch in the future. For an arch that does not provide HAVE_ARCH_TRACEHOOK, some new options for such features will not be available for config. I have done some arch work and will submit this to the arch maintainers after the generic tracehook series settles in. For now, that work is available in my GIT repositories, and in patch and mbox-of-patches form at http://people.redhat.com/roland/utrace/2.6-current/ This paves the way for my "utrace" work, to be submitted later. But it is not innately tied to that. I hope that the tracehook series can go in soon regardless of what eventually does or doesn't go on top of it. For anyone implementing any kind of new tracing/debugging plan, or just understanding all the context of the existing ptrace implementation, having tracehook.h makes things much easier to find and understand. This patch: This adds the new kernel-internal header file <linux/tracehook.h>. This is not yet used at all. The comments in the header introduce what the following series of patches is about. The aim is to formalize and consolidate all the places that the core kernel code and the arch code now ties into the ptrace implementation. These patches mostly don't cause any functional change. They just move the details of ptrace logic out of core code into tracehook.h inlines, where they are mostly compiled away to the same as before. All that changes is that everything is thoroughly documented and any future reworking of ptrace, or addition of something new, would not have to touch core code all over, just change the tracehook.h inlines. The new linux/ptrace.h inlines are used by the following patches in the new tracehook_*() inlines. Using these helpers for the ptrace event stops makes it simple to change or disable the old ptrace implementation of these stops conditionally later. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Reviewed-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/ptrace.h')
-rw-r--r--include/linux/ptrace.h33
1 files changed, 33 insertions, 0 deletions
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index c6f5f9d..c74abfc 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -121,6 +121,39 @@ static inline void ptrace_unlink(struct task_struct *child)
int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data);
int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data);
+/**
+ * task_ptrace - return %PT_* flags that apply to a task
+ * @task: pointer to &task_struct in question
+ *
+ * Returns the %PT_* flags that apply to @task.
+ */
+static inline int task_ptrace(struct task_struct *task)
+{
+ return task->ptrace;
+}
+
+/**
+ * ptrace_event - possibly stop for a ptrace event notification
+ * @mask: %PT_* bit to check in @current->ptrace
+ * @event: %PTRACE_EVENT_* value to report if @mask is set
+ * @message: value for %PTRACE_GETEVENTMSG to return
+ *
+ * This checks the @mask bit to see if ptrace wants stops for this event.
+ * If so we stop, reporting @event and @message to the ptrace parent.
+ *
+ * Returns nonzero if we did a ptrace notification, zero if not.
+ *
+ * Called without locks.
+ */
+static inline int ptrace_event(int mask, int event, unsigned long message)
+{
+ if (mask && likely(!(current->ptrace & mask)))
+ return 0;
+ current->ptrace_message = message;
+ ptrace_notify((event << 8) | SIGTRAP);
+ return 1;
+}
+
#ifndef force_successful_syscall_return
/*
* System call handlers that, upon successful completion, need to return a
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