3  * thread-stack.c: Synthesize a thread's stack using call / return events
22 #include "thread-stack.h"
40  * struct thread_stack_entry - thread stack entry.
68  * struct thread_stack - thread stack constructed from 'call' and 'return'
70  * @stack: array that holds the stack
71  * @cnt: number of entries in the stack
72  * @sz: current maximum stack size
83  * @br_stack_rb: branch stack (ring buffer)
84  * @br_stack_sz: maximum branch stack size
89 	struct thread_stack_entry *stack;  member
111  * and therefore requires a stack for each cpu.
126 	new_stack = realloc(ts->stack, sz);  in thread_stack__grow()
130 	ts->stack = new_stack;  in thread_stack__grow()
201 	if (!ts->stack &&  in thread_stack__new()
220 	if (!ts->stack)  in thread__cpu_stack()
246 			pr_warning("Out of memory: discarding thread stack\n");  in thread_stack__push()
251 	ts->stack[ts->cnt].trace_end = trace_end;  in thread_stack__push()
252 	ts->stack[ts->cnt++].ret_addr = ret_addr;  in thread_stack__push()
266 	 * further down the stack.  If the return address is not found at all,  in thread_stack__pop()
268 	 * seen for some reason) and leave the stack alone.  in thread_stack__pop()
271 		if (ts->stack[--i].ret_addr == ret_addr) {  in thread_stack__pop()
283 		if (ts->stack[--i].trace_end)  in thread_stack__pop_trace_end()
295 	return ts->stack[ts->cnt - 1].cp->in_kernel;  in thread_stack__in_kernel()
311 	tse = &ts->stack[idx];  in thread_stack__call_return()
355 			pr_err("Error flushing thread stack!\n");  in __thread_stack__flush()
418 			pr_warning("Out of memory: no thread stack\n");  in thread_stack__event()
427 	 * the stack might be completely invalid.  Better to report nothing than  in thread_stack__event()
428 	 * to report something misleading, so flush the stack.  in thread_stack__event()
441 	 * stack.  in thread_stack__event()
459 		 * have flushed the stack) then try to make sense of the stack.  in thread_stack__event()
490 	zfree(&ts->stack);  in __thread_stack__free()
545 		ip = ts->stack[ts->cnt - j].ret_addr;  in thread_stack__sample()
586 		ip = ts->stack[ts->cnt - j].ret_addr;  in thread_stack__sample_late()
596 		ip = ts->stack[ts->cnt - j].ret_addr;  in thread_stack__sample_late()
675  * have subsequent addresses removed from the branch stack.
797 	tse = &ts->stack[ts->cnt++];  in thread_stack__push_cp()
823 		struct thread_stack_entry *tse = &ts->stack[0];  in thread_stack__pop_cp()
830 	if (ts->stack[ts->cnt - 1].ret_addr == ret_addr &&  in thread_stack__pop_cp()
831 	    !ts->stack[ts->cnt - 1].non_call) {  in thread_stack__pop_cp()
838 			if (ts->stack[i].ret_addr != ret_addr ||  in thread_stack__pop_cp()
839 			    ts->stack[i].non_call)  in thread_stack__pop_cp()
925 		/* If the stack is empty, push the userspace address */  in thread_stack__no_call_return()
939 		parent = ts->stack[ts->cnt - 1].cp;  in thread_stack__no_call_return()
945 		 * At the bottom of the stack, assume the missing 'call' was  in thread_stack__no_call_return()
971 			ts->stack[ts->cnt - 1].non_call = true;  in thread_stack__no_call_return()
1007 	tse = &ts->stack[ts->cnt - 1];  in thread_stack__trace_begin()
1025 	/* No point having 'trace end' on the bottom of the stack */  in thread_stack__trace_end()
1026 	if (!ts->cnt || (ts->cnt == 1 && ts->stack[0].ref == ref))  in thread_stack__trace_end()
1029 	cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp, NULL, 0,  in thread_stack__trace_end()
1054 	struct thread_stack_entry *tse = &ts->stack[ts->cnt - 1];  in thread_stack__x86_retpoline()
1064 		 * not itself mean anything. Here the top-of-stack is removed,  in thread_stack__x86_retpoline()
1065 		 * by decrementing the stack count, and then further down, the  in thread_stack__x86_retpoline()
1066 		 * resulting top-of-stack is replaced with the actual target.  in thread_stack__x86_retpoline()
1072 		sym = ts->stack[ts->cnt - 2].cp->sym;  in thread_stack__x86_retpoline()
1091 	cp = call_path__findnew(cpr, ts->stack[ts->cnt - 2].cp, tsym,  in thread_stack__x86_retpoline()
1096 	/* Replace the top-of-stack with the actual target */  in thread_stack__x86_retpoline()
1097 	ts->stack[ts->cnt - 1].cp = cp;  in thread_stack__x86_retpoline()
1129 	/* Flush stack on exec */  in thread_stack__process()
1137 	/* If the stack is empty, put the current symbol on the stack */  in thread_stack__process()
1162 		cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp,  in thread_stack__process()
1185 			/* Pop kernel stack */  in thread_stack__process()
1192 		/* x86 retpoline 'return' doesn't match the stack */  in thread_stack__process()
1194 		    ts->stack[ts->cnt - 1].ret_addr != sample->addr)  in thread_stack__process()
1217 		 * it a jmp. Make that visible by recording on the stack a  in thread_stack__process()
1219 		 * when a ret pops the stack, all jmps must be popped off first.  in thread_stack__process()
1221 		cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp,  in thread_stack__process()
1227 			ts->stack[ts->cnt - 1].non_call = true;  in thread_stack__process()