#include <asm/nmi.h>
-
-#ifdef CONFIG_FUNCTION_RET_TRACER
-
-/*
- * These functions are picked from those used on
- * this page for dynamic ftrace. They have been
- * simplified to ignore all traces in NMI context.
- */
-static atomic_t in_nmi;
-
-void ftrace_nmi_enter(void)
-{
- atomic_inc(&in_nmi);
-}
-
-void ftrace_nmi_exit(void)
-{
- atomic_dec(&in_nmi);
-}
-
-/* Add a function return address to the trace stack on thread info.*/
-static int push_return_trace(unsigned long ret, unsigned long long time,
- unsigned long func)
-{
- int index;
- struct thread_info *ti = current_thread_info();
-
- /* The return trace stack is full */
- if (ti->curr_ret_stack == FTRACE_RET_STACK_SIZE - 1)
- return -EBUSY;
-
- index = ++ti->curr_ret_stack;
- barrier();
- ti->ret_stack[index].ret = ret;
- ti->ret_stack[index].func = func;
- ti->ret_stack[index].calltime = time;
-
- return 0;
-}
-
-/* Retrieve a function return address to the trace stack on thread info.*/
-static void pop_return_trace(unsigned long *ret, unsigned long long *time,
- unsigned long *func)
-{
- int index;
-
- struct thread_info *ti = current_thread_info();
- index = ti->curr_ret_stack;
- *ret = ti->ret_stack[index].ret;
- *func = ti->ret_stack[index].func;
- *time = ti->ret_stack[index].calltime;
- ti->curr_ret_stack--;
-}
-
-/*
- * Send the trace to the ring-buffer.
- * @return the original return address.
- */
-unsigned long ftrace_return_to_handler(void)
-{
- struct ftrace_retfunc trace;
- pop_return_trace(&trace.ret, &trace.calltime, &trace.func);
- trace.rettime = cpu_clock(raw_smp_processor_id());
- ftrace_function_return(&trace);
-
- return trace.ret;
-}
-
-/*
- * Hook the return address and push it in the stack of return addrs
- * in current thread info.
- */
-void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
-{
- unsigned long old;
- unsigned long long calltime;
- int faulted;
- unsigned long return_hooker = (unsigned long)
- &return_to_handler;
-
- /* Nmi's are currently unsupported */
- if (atomic_read(&in_nmi))
- return;
-
- /*
- * Protect against fault, even if it shouldn't
- * happen. This tool is too much intrusive to
- * ignore such a protection.
- */
- asm volatile(
- "1: movl (%[parent_old]), %[old]\n"
- "2: movl %[return_hooker], (%[parent_replaced])\n"
- " movl $0, %[faulted]\n"
-
- ".section .fixup, \"ax\"\n"
- "3: movl $1, %[faulted]\n"
- ".previous\n"
-
- ".section __ex_table, \"a\"\n"
- " .long 1b, 3b\n"
- " .long 2b, 3b\n"
- ".previous\n"
-
- : [parent_replaced] "=r" (parent), [old] "=r" (old),
- [faulted] "=r" (faulted)
- : [parent_old] "0" (parent), [return_hooker] "r" (return_hooker)
- : "memory"
- );
-
- if (WARN_ON(faulted)) {
- unregister_ftrace_return();
- return;
- }
-
- if (WARN_ON(!__kernel_text_address(old))) {
- unregister_ftrace_return();
- *parent = old;
- return;
- }
-
- calltime = cpu_clock(raw_smp_processor_id());
-
- if (push_return_trace(old, calltime, self_addr) == -EBUSY)
- *parent = old;
-}
-
-#endif
-
#ifdef CONFIG_DYNAMIC_FTRACE
union ftrace_code_union {
return 0;
}
#endif
+
+#ifdef CONFIG_FUNCTION_RET_TRACER
+
+#ifndef CONFIG_DYNAMIC_FTRACE
+
+/*
+ * These functions are picked from those used on
+ * this page for dynamic ftrace. They have been
+ * simplified to ignore all traces in NMI context.
+ */
+static atomic_t in_nmi;
+
+void ftrace_nmi_enter(void)
+{
+ atomic_inc(&in_nmi);
+}
+
+void ftrace_nmi_exit(void)
+{
+ atomic_dec(&in_nmi);
+}
+#endif /* !CONFIG_DYNAMIC_FTRACE */
+
+/* Add a function return address to the trace stack on thread info.*/
+static int push_return_trace(unsigned long ret, unsigned long long time,
+ unsigned long func)
+{
+ int index;
+ struct thread_info *ti = current_thread_info();
+
+ /* The return trace stack is full */
+ if (ti->curr_ret_stack == FTRACE_RET_STACK_SIZE - 1)
+ return -EBUSY;
+
+ index = ++ti->curr_ret_stack;
+ barrier();
+ ti->ret_stack[index].ret = ret;
+ ti->ret_stack[index].func = func;
+ ti->ret_stack[index].calltime = time;
+
+ return 0;
+}
+
+/* Retrieve a function return address to the trace stack on thread info.*/
+static void pop_return_trace(unsigned long *ret, unsigned long long *time,
+ unsigned long *func)
+{
+ int index;
+
+ struct thread_info *ti = current_thread_info();
+ index = ti->curr_ret_stack;
+ *ret = ti->ret_stack[index].ret;
+ *func = ti->ret_stack[index].func;
+ *time = ti->ret_stack[index].calltime;
+ ti->curr_ret_stack--;
+}
+
+/*
+ * Send the trace to the ring-buffer.
+ * @return the original return address.
+ */
+unsigned long ftrace_return_to_handler(void)
+{
+ struct ftrace_retfunc trace;
+ pop_return_trace(&trace.ret, &trace.calltime, &trace.func);
+ trace.rettime = cpu_clock(raw_smp_processor_id());
+ ftrace_function_return(&trace);
+
+ return trace.ret;
+}
+
+/*
+ * Hook the return address and push it in the stack of return addrs
+ * in current thread info.
+ */
+void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
+{
+ unsigned long old;
+ unsigned long long calltime;
+ int faulted;
+ unsigned long return_hooker = (unsigned long)
+ &return_to_handler;
+
+ /* Nmi's are currently unsupported */
+ if (atomic_read(&in_nmi))
+ return;
+
+ /*
+ * Protect against fault, even if it shouldn't
+ * happen. This tool is too much intrusive to
+ * ignore such a protection.
+ */
+ asm volatile(
+ "1: movl (%[parent_old]), %[old]\n"
+ "2: movl %[return_hooker], (%[parent_replaced])\n"
+ " movl $0, %[faulted]\n"
+
+ ".section .fixup, \"ax\"\n"
+ "3: movl $1, %[faulted]\n"
+ ".previous\n"
+
+ ".section __ex_table, \"a\"\n"
+ " .long 1b, 3b\n"
+ " .long 2b, 3b\n"
+ ".previous\n"
+
+ : [parent_replaced] "=r" (parent), [old] "=r" (old),
+ [faulted] "=r" (faulted)
+ : [parent_old] "0" (parent), [return_hooker] "r" (return_hooker)
+ : "memory"
+ );
+
+ if (WARN_ON(faulted)) {
+ unregister_ftrace_return();
+ return;
+ }
+
+ if (WARN_ON(!__kernel_text_address(old))) {
+ unregister_ftrace_return();
+ *parent = old;
+ return;
+ }
+
+ calltime = cpu_clock(raw_smp_processor_id());
+
+ if (push_return_trace(old, calltime, self_addr) == -EBUSY)
+ *parent = old;
+}
+
+#endif /* CONFIG_FUNCTION_RET_TRACER */
/* Quick disabling of function tracer. */
int function_trace_stop;
+/* By default, current tracing type is normal tracing. */
+enum ftrace_tracing_type_t ftrace_tracing_type = FTRACE_TYPE_ENTER;
+
/*
* ftrace_disabled is set when an anomaly is discovered.
* ftrace_disabled is much stronger than ftrace_enabled.
}
}
-#define FTRACE_ADDR ((long)(ftrace_caller))
static int
__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
{
unsigned long ip, fl;
+ unsigned long ftrace_addr;
+
+#ifdef CONFIG_FUNCTION_RET_TRACER
+ if (ftrace_tracing_type == FTRACE_TYPE_ENTER)
+ ftrace_addr = (unsigned long)ftrace_caller;
+ else
+ ftrace_addr = (unsigned long)ftrace_return_caller;
+#else
+ ftrace_addr = (unsigned long)ftrace_caller;
+#endif
ip = rec->ip;
}
if (rec->flags & FTRACE_FL_ENABLED)
- return ftrace_make_call(rec, FTRACE_ADDR);
+ return ftrace_make_call(rec, ftrace_addr);
else
- return ftrace_make_nop(NULL, rec, FTRACE_ADDR);
+ return ftrace_make_nop(NULL, rec, ftrace_addr);
}
static void ftrace_replace_code(int enable)
return -1;
mutex_lock(&ftrace_sysctl_lock);
+
+ if (ftrace_tracing_type == FTRACE_TYPE_RETURN) {
+ ret = -EBUSY;
+ goto out;
+ }
+
ret = __register_ftrace_function(ops);
ftrace_startup();
- mutex_unlock(&ftrace_sysctl_lock);
+out:
+ mutex_unlock(&ftrace_sysctl_lock);
return ret;
}
}
#ifdef CONFIG_FUNCTION_RET_TRACER
+
+/* The callback that hooks the return of a function */
trace_function_return_t ftrace_function_return =
(trace_function_return_t)ftrace_stub;
-void register_ftrace_return(trace_function_return_t func)
+
+int register_ftrace_return(trace_function_return_t func)
{
+ int ret = 0;
+
+ mutex_lock(&ftrace_sysctl_lock);
+
+ /*
+ * Don't launch return tracing if normal function
+ * tracing is already running.
+ */
+ if (ftrace_trace_function != ftrace_stub) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ ftrace_tracing_type = FTRACE_TYPE_RETURN;
ftrace_function_return = func;
+ ftrace_startup();
+
+out:
+ mutex_unlock(&ftrace_sysctl_lock);
+ return ret;
}
void unregister_ftrace_return(void)
{
+ mutex_lock(&ftrace_sysctl_lock);
+
ftrace_function_return = (trace_function_return_t)ftrace_stub;
+ ftrace_shutdown();
+ /* Restore normal tracing type */
+ ftrace_tracing_type = FTRACE_TYPE_ENTER;
+
+ mutex_unlock(&ftrace_sysctl_lock);
}
#endif
projects / ~andy / linux / commitdiff