1 /* SPDX-License-Identifier: GPL-2.0 */
17  *   If arch does not support a ftrace feature:
40  * As we need a way to maintain state if we are tracing the function
41  * graph in irq because we want to trace a particular function that
52 	 * at a start of graph tracing, and we want to trace
54 	 * than zero, because of the preempted start of a previous
56 	 * if a softirq interrupted the start of graph tracing,
57 	 * followed by an interrupt preempting a start of graph
60 	 * that preempted a softirq start of a function that
62 	 * greater than 3, so the next two bits are a mask
70 	 * To implement set_graph_notrace, if this bit is set, we ignore
80 #define trace_recursion_set(bit)	do { (current)->trace_recursion |= (1<<(bit)); } while (0)  argument
81 #define trace_recursion_clear(bit)	do { (current)->trace_recursion &= ~(1<<(bit)); } while (0)  argument
82 #define trace_recursion_test(bit)	((current)->trace_recursion & (1<<(bit)))  argument
85 	(((current)->trace_recursion >> TRACE_GRAPH_DEPTH_START_BIT) & 3)
88 		current->trace_recursion &=				\
90 		current->trace_recursion |=				\
100 #define TRACE_CONTEXT_MASK	((1 << (TRACE_LIST_START + TRACE_CONTEXT_BITS)) - 1)
119 	unsigned char bit = interrupt_context_level();  in trace_get_context_bit()  local
121 	return TRACE_CTX_NORMAL - bit;  in trace_get_context_bit()
154  * Preemption is promised to be disabled when return bit >= 0.
159 	unsigned int val = READ_ONCE(current->trace_recursion);  in trace_test_and_set_recursion()
160 	int bit;  in trace_test_and_set_recursion()  local
163 		return -1;  in trace_test_and_set_recursion()
165 	bit = trace_get_context_bit() + start;  in trace_test_and_set_recursion()
166 	if (unlikely(val & (1 << bit))) {  in trace_test_and_set_recursion()
168 		 * If an interrupt occurs during a trace, and another trace  in trace_test_and_set_recursion()
171 		 * will think a recursion occurred, and the event will be dropped.  in trace_test_and_set_recursion()
172 		 * Let a single instance happen via the TRANSITION_BIT to  in trace_test_and_set_recursion()
175 		bit = TRACE_CTX_TRANSITION + start;  in trace_test_and_set_recursion()
176 		if (val & (1 << bit)) {  in trace_test_and_set_recursion()
178 			return -1;  in trace_test_and_set_recursion()
182 	val |= 1 << bit;  in trace_test_and_set_recursion()
183 	current->trace_recursion = val;  in trace_test_and_set_recursion()
188 	return bit;  in trace_test_and_set_recursion()
194 static __always_inline void trace_clear_recursion(int bit)  in trace_clear_recursion()  argument
198 	trace_recursion_clear(bit);  in trace_clear_recursion()
202  * ftrace_test_recursion_trylock - tests for recursion in same context
207  * Returns: -1 if a recursion happened.
217  * ftrace_test_recursion_unlock - called when function callback is complete
218  * @bit: The return of a successful ftrace_test_recursion_trylock()
220  * This is used at the end of a ftrace callback.
222 static __always_inline void ftrace_test_recursion_unlock(int bit)  in ftrace_test_recursion_unlock()  argument
224 	trace_clear_recursion(bit);  in ftrace_test_recursion_unlock()