79 lines
2 KiB
C
79 lines
2 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Code for tracing calls in Linux kernel.
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* Copyright (C) 2009-2016 Helge Deller <deller@gmx.de>
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*
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* based on code for x86 which is:
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* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
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*
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* future possible enhancements:
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* - add CONFIG_DYNAMIC_FTRACE
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* - add CONFIG_STACK_TRACER
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*/
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#include <linux/init.h>
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#include <linux/ftrace.h>
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#include <asm/assembly.h>
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#include <asm/sections.h>
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#include <asm/ftrace.h>
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#define __hot __attribute__ ((__section__ (".text.hot")))
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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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static void __hot prepare_ftrace_return(unsigned long *parent,
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unsigned long self_addr)
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{
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unsigned long old;
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extern int parisc_return_to_handler;
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if (unlikely(ftrace_graph_is_dead()))
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return;
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if (unlikely(atomic_read(¤t->tracing_graph_pause)))
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return;
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old = *parent;
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if (!function_graph_enter(old, self_addr, 0, NULL))
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/* activate parisc_return_to_handler() as return point */
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*parent = (unsigned long) &parisc_return_to_handler;
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}
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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void notrace __hot ftrace_function_trampoline(unsigned long parent,
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unsigned long self_addr,
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unsigned long org_sp_gr3)
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{
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extern ftrace_func_t ftrace_trace_function; /* depends on CONFIG_DYNAMIC_FTRACE */
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extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
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if (ftrace_trace_function != ftrace_stub) {
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/* struct ftrace_ops *op, struct pt_regs *regs); */
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ftrace_trace_function(parent, self_addr, NULL, NULL);
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return;
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}
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub ||
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ftrace_graph_entry != ftrace_graph_entry_stub) {
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unsigned long *parent_rp;
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/* calculate pointer to %rp in stack */
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parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET);
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/* sanity check: parent_rp should hold parent */
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if (*parent_rp != parent)
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return;
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prepare_ftrace_return(parent_rp, self_addr);
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return;
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}
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#endif
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}
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