diff options
| -rw-r--r-- | kernel/trace/Makefile | 1 | ||||
| -rw-r--r-- | kernel/trace/fgraph.c | 232 | ||||
| -rw-r--r-- | kernel/trace/trace_functions_graph.c | 220 |
3 files changed, 233 insertions, 220 deletions
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index f81dadbc7c4a..c7ade7965464 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -57,6 +57,7 @@ obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o obj-$(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 diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c new file mode 100644 index 000000000000..5ad9c0e88b80 --- /dev/null +++ b/kernel/trace/fgraph.c @@ -0,0 +1,232 @@ +// 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; +} diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 0d235e44d08e..b846d82c2f95 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -16,33 +16,6 @@ #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; @@ -117,199 +90,6 @@ static void 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 |