obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += trace_functions_graph.o
obj-$(CONFIG_TRACE_BRANCH_PROFILING) += trace_branch.o
obj-$(CONFIG_BLK_DEV_IO_TRACE) += blktrace.o
+obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += fgraph.o
ifeq ($(CONFIG_BLOCK),y)
obj-$(CONFIG_EVENT_TRACING) += blktrace.o
endif
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Infrastructure to took into function calls and returns.
+ * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
+ * Mostly borrowed from function tracer which
+ * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
+ *
+ * Highly modified by Steven Rostedt (VMware).
+ */
+#include <linux/ftrace.h>
+
+#include "trace.h"
+
+static bool kill_ftrace_graph;
+
+/**
+ * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
+ *
+ * ftrace_graph_stop() is called when a severe error is detected in
+ * the function graph tracing. This function is called by the critical
+ * paths of function graph to keep those paths from doing any more harm.
+ */
+bool ftrace_graph_is_dead(void)
+{
+ return kill_ftrace_graph;
+}
+
+/**
+ * ftrace_graph_stop - set to permanently disable function graph tracincg
+ *
+ * In case of an error int function graph tracing, this is called
+ * to try to keep function graph tracing from causing any more harm.
+ * Usually this is pretty severe and this is called to try to at least
+ * get a warning out to the user.
+ */
+void ftrace_graph_stop(void)
+{
+ kill_ftrace_graph = true;
+}
+
+/* Add a function return address to the trace stack on thread info.*/
+static int
+ftrace_push_return_trace(unsigned long ret, unsigned long func,
+ unsigned long frame_pointer, unsigned long *retp)
+{
+ unsigned long long calltime;
+ int index;
+
+ if (unlikely(ftrace_graph_is_dead()))
+ return -EBUSY;
+
+ if (!current->ret_stack)
+ return -EBUSY;
+
+ /*
+ * We must make sure the ret_stack is tested before we read
+ * anything else.
+ */
+ smp_rmb();
+
+ /* The return trace stack is full */
+ if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
+ atomic_inc(¤t->trace_overrun);
+ return -EBUSY;
+ }
+
+ /*
+ * The curr_ret_stack is an index to ftrace return stack of
+ * current task. Its value should be in [0, FTRACE_RETFUNC_
+ * DEPTH) when the function graph tracer is used. To support
+ * filtering out specific functions, it makes the index
+ * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
+ * so when it sees a negative index the ftrace will ignore
+ * the record. And the index gets recovered when returning
+ * from the filtered function by adding the FTRACE_NOTRACE_
+ * DEPTH and then it'll continue to record functions normally.
+ *
+ * The curr_ret_stack is initialized to -1 and get increased
+ * in this function. So it can be less than -1 only if it was
+ * filtered out via ftrace_graph_notrace_addr() which can be
+ * set from set_graph_notrace file in tracefs by user.
+ */
+ if (current->curr_ret_stack < -1)
+ return -EBUSY;
+
+ calltime = trace_clock_local();
+
+ index = ++current->curr_ret_stack;
+ if (ftrace_graph_notrace_addr(func))
+ current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
+ barrier();
+ current->ret_stack[index].ret = ret;
+ current->ret_stack[index].func = func;
+ current->ret_stack[index].calltime = calltime;
+#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
+ current->ret_stack[index].fp = frame_pointer;
+#endif
+#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
+ current->ret_stack[index].retp = retp;
+#endif
+ return 0;
+}
+
+int function_graph_enter(unsigned long ret, unsigned long func,
+ unsigned long frame_pointer, unsigned long *retp)
+{
+ struct ftrace_graph_ent trace;
+
+ trace.func = func;
+ trace.depth = ++current->curr_ret_depth;
+
+ if (ftrace_push_return_trace(ret, func, frame_pointer, retp))
+ goto out;
+
+ /* Only trace if the calling function expects to */
+ if (!ftrace_graph_entry(&trace))
+ goto out_ret;
+
+ return 0;
+ out_ret:
+ current->curr_ret_stack--;
+ out:
+ current->curr_ret_depth--;
+ return -EBUSY;
+}
+
+/* Retrieve a function return address to the trace stack on thread info.*/
+static void
+ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
+ unsigned long frame_pointer)
+{
+ int index;
+
+ index = current->curr_ret_stack;
+
+ /*
+ * A negative index here means that it's just returned from a
+ * notrace'd function. Recover index to get an original
+ * return address. See ftrace_push_return_trace().
+ *
+ * TODO: Need to check whether the stack gets corrupted.
+ */
+ if (index < 0)
+ index += FTRACE_NOTRACE_DEPTH;
+
+ if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
+ ftrace_graph_stop();
+ WARN_ON(1);
+ /* Might as well panic, otherwise we have no where to go */
+ *ret = (unsigned long)panic;
+ return;
+ }
+
+#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
+ /*
+ * The arch may choose to record the frame pointer used
+ * and check it here to make sure that it is what we expect it
+ * to be. If gcc does not set the place holder of the return
+ * address in the frame pointer, and does a copy instead, then
+ * the function graph trace will fail. This test detects this
+ * case.
+ *
+ * Currently, x86_32 with optimize for size (-Os) makes the latest
+ * gcc do the above.
+ *
+ * Note, -mfentry does not use frame pointers, and this test
+ * is not needed if CC_USING_FENTRY is set.
+ */
+ if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
+ ftrace_graph_stop();
+ WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
+ " from func %ps return to %lx\n",
+ current->ret_stack[index].fp,
+ frame_pointer,
+ (void *)current->ret_stack[index].func,
+ current->ret_stack[index].ret);
+ *ret = (unsigned long)panic;
+ return;
+ }
+#endif
+
+ *ret = current->ret_stack[index].ret;
+ trace->func = current->ret_stack[index].func;
+ trace->calltime = current->ret_stack[index].calltime;
+ trace->overrun = atomic_read(¤t->trace_overrun);
+ trace->depth = current->curr_ret_depth--;
+ /*
+ * We still want to trace interrupts coming in if
+ * max_depth is set to 1. Make sure the decrement is
+ * seen before ftrace_graph_return.
+ */
+ barrier();
+}
+
+/*
+ * Send the trace to the ring-buffer.
+ * @return the original return address.
+ */
+unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
+{
+ struct ftrace_graph_ret trace;
+ unsigned long ret;
+
+ ftrace_pop_return_trace(&trace, &ret, frame_pointer);
+ trace.rettime = trace_clock_local();
+ ftrace_graph_return(&trace);
+ /*
+ * The ftrace_graph_return() may still access the current
+ * ret_stack structure, we need to make sure the update of
+ * curr_ret_stack is after that.
+ */
+ barrier();
+ current->curr_ret_stack--;
+ /*
+ * The curr_ret_stack can be less than -1 only if it was
+ * filtered out and it's about to return from the function.
+ * Recover the index and continue to trace normal functions.
+ */
+ if (current->curr_ret_stack < -1) {
+ current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
+ return ret;
+ }
+
+ if (unlikely(!ret)) {
+ ftrace_graph_stop();
+ WARN_ON(1);
+ /* Might as well panic. What else to do? */
+ ret = (unsigned long)panic;
+ }
+
+ return ret;
+}
#include "trace.h"
#include "trace_output.h"
-static bool kill_ftrace_graph;
-
-/**
- * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
- *
- * ftrace_graph_stop() is called when a severe error is detected in
- * the function graph tracing. This function is called by the critical
- * paths of function graph to keep those paths from doing any more harm.
- */
-bool ftrace_graph_is_dead(void)
-{
- return kill_ftrace_graph;
-}
-
-/**
- * ftrace_graph_stop - set to permanently disable function graph tracincg
- *
- * In case of an error int function graph tracing, this is called
- * to try to keep function graph tracing from causing any more harm.
- * Usually this is pretty severe and this is called to try to at least
- * get a warning out to the user.
- */
-void ftrace_graph_stop(void)
-{
- kill_ftrace_graph = true;
-}
-
/* When set, irq functions will be ignored */
static int ftrace_graph_skip_irqs;
print_graph_duration(struct trace_array *tr, unsigned long long duration,
struct trace_seq *s, u32 flags);
-/* Add a function return address to the trace stack on thread info.*/
-static int
-ftrace_push_return_trace(unsigned long ret, unsigned long func,
- unsigned long frame_pointer, unsigned long *retp)
-{
- unsigned long long calltime;
- int index;
-
- if (unlikely(ftrace_graph_is_dead()))
- return -EBUSY;
-
- if (!current->ret_stack)
- return -EBUSY;
-
- /*
- * We must make sure the ret_stack is tested before we read
- * anything else.
- */
- smp_rmb();
-
- /* The return trace stack is full */
- if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
- atomic_inc(¤t->trace_overrun);
- return -EBUSY;
- }
-
- /*
- * The curr_ret_stack is an index to ftrace return stack of
- * current task. Its value should be in [0, FTRACE_RETFUNC_
- * DEPTH) when the function graph tracer is used. To support
- * filtering out specific functions, it makes the index
- * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
- * so when it sees a negative index the ftrace will ignore
- * the record. And the index gets recovered when returning
- * from the filtered function by adding the FTRACE_NOTRACE_
- * DEPTH and then it'll continue to record functions normally.
- *
- * The curr_ret_stack is initialized to -1 and get increased
- * in this function. So it can be less than -1 only if it was
- * filtered out via ftrace_graph_notrace_addr() which can be
- * set from set_graph_notrace file in tracefs by user.
- */
- if (current->curr_ret_stack < -1)
- return -EBUSY;
-
- calltime = trace_clock_local();
-
- index = ++current->curr_ret_stack;
- if (ftrace_graph_notrace_addr(func))
- current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
- barrier();
- current->ret_stack[index].ret = ret;
- current->ret_stack[index].func = func;
- current->ret_stack[index].calltime = calltime;
-#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
- current->ret_stack[index].fp = frame_pointer;
-#endif
-#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
- current->ret_stack[index].retp = retp;
-#endif
- return 0;
-}
-
-int function_graph_enter(unsigned long ret, unsigned long func,
- unsigned long frame_pointer, unsigned long *retp)
-{
- struct ftrace_graph_ent trace;
-
- trace.func = func;
- trace.depth = ++current->curr_ret_depth;
-
- if (ftrace_push_return_trace(ret, func, frame_pointer, retp))
- goto out;
-
- /* Only trace if the calling function expects to */
- if (!ftrace_graph_entry(&trace))
- goto out_ret;
-
- return 0;
- out_ret:
- current->curr_ret_stack--;
- out:
- current->curr_ret_depth--;
- return -EBUSY;
-}
-
-/* Retrieve a function return address to the trace stack on thread info.*/
-static void
-ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
- unsigned long frame_pointer)
-{
- int index;
-
- index = current->curr_ret_stack;
-
- /*
- * A negative index here means that it's just returned from a
- * notrace'd function. Recover index to get an original
- * return address. See ftrace_push_return_trace().
- *
- * TODO: Need to check whether the stack gets corrupted.
- */
- if (index < 0)
- index += FTRACE_NOTRACE_DEPTH;
-
- if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
- ftrace_graph_stop();
- WARN_ON(1);
- /* Might as well panic, otherwise we have no where to go */
- *ret = (unsigned long)panic;
- return;
- }
-
-#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
- /*
- * The arch may choose to record the frame pointer used
- * and check it here to make sure that it is what we expect it
- * to be. If gcc does not set the place holder of the return
- * address in the frame pointer, and does a copy instead, then
- * the function graph trace will fail. This test detects this
- * case.
- *
- * Currently, x86_32 with optimize for size (-Os) makes the latest
- * gcc do the above.
- *
- * Note, -mfentry does not use frame pointers, and this test
- * is not needed if CC_USING_FENTRY is set.
- */
- if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
- ftrace_graph_stop();
- WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
- " from func %ps return to %lx\n",
- current->ret_stack[index].fp,
- frame_pointer,
- (void *)current->ret_stack[index].func,
- current->ret_stack[index].ret);
- *ret = (unsigned long)panic;
- return;
- }
-#endif
-
- *ret = current->ret_stack[index].ret;
- trace->func = current->ret_stack[index].func;
- trace->calltime = current->ret_stack[index].calltime;
- trace->overrun = atomic_read(¤t->trace_overrun);
- trace->depth = current->curr_ret_depth--;
- /*
- * We still want to trace interrupts coming in if
- * max_depth is set to 1. Make sure the decrement is
- * seen before ftrace_graph_return.
- */
- barrier();
-}
-
-/*
- * Send the trace to the ring-buffer.
- * @return the original return address.
- */
-unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
-{
- struct ftrace_graph_ret trace;
- unsigned long ret;
-
- ftrace_pop_return_trace(&trace, &ret, frame_pointer);
- trace.rettime = trace_clock_local();
- ftrace_graph_return(&trace);
- /*
- * The ftrace_graph_return() may still access the current
- * ret_stack structure, we need to make sure the update of
- * curr_ret_stack is after that.
- */
- barrier();
- current->curr_ret_stack--;
- /*
- * The curr_ret_stack can be less than -1 only if it was
- * filtered out and it's about to return from the function.
- * Recover the index and continue to trace normal functions.
- */
- if (current->curr_ret_stack < -1) {
- current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
- return ret;
- }
-
- if (unlikely(!ret)) {
- ftrace_graph_stop();
- WARN_ON(1);
- /* Might as well panic. What else to do? */
- ret = (unsigned long)panic;
- }
-
- return ret;
-}
-
/**
* ftrace_graph_ret_addr - convert a potentially modified stack return address
* to its original value
projects / linux.git / commitdiff