44 lines
1 KiB
C
44 lines
1 KiB
C
/*
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* ftrace graph code
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*
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* Copyright (C) 2009 Analog Devices Inc.
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* Licensed under the GPL-2 or later.
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*/
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#include <linux/ftrace.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <asm/atomic.h>
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/*
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* Hook the return address and push it in the stack of return addrs
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* in current thread info.
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*/
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void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
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unsigned long frame_pointer)
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{
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struct ftrace_graph_ent trace;
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unsigned long return_hooker = (unsigned long)&return_to_handler;
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if (unlikely(atomic_read(¤t->tracing_graph_pause)))
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return;
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if (ftrace_push_return_trace(*parent, self_addr, &trace.depth,
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frame_pointer) == -EBUSY)
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return;
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trace.func = self_addr;
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/* Only trace if the calling function expects to */
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if (!ftrace_graph_entry(&trace)) {
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current->curr_ret_stack--;
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return;
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}
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/* all is well in the world ! hijack RETS ... */
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*parent = return_hooker;
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}
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#endif
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