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// SPDX-License-Identifier: GPL-2.0
#include <linux/ftrace.h>
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
extern void (*ftrace_trace_function)(unsigned long, unsigned long,
struct ftrace_ops*, struct pt_regs*);
extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
extern void ftrace_graph_caller(void);
noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
{
__asm__ (""); /* avoid to optimize as pure function */
}
noinline void _mcount(unsigned long parent_ip)
{
/* save all state by the compiler prologue */
unsigned long ip = (unsigned long)__builtin_return_address(0);
if (ftrace_trace_function != ftrace_stub)
ftrace_trace_function(ip - MCOUNT_INSN_SIZE, parent_ip,
NULL, NULL);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if (ftrace_graph_return != (trace_func_graph_ret_t)ftrace_stub
|| ftrace_graph_entry != ftrace_graph_entry_stub)
ftrace_graph_caller();
#endif
/* restore all state by the compiler epilogue */
}
EXPORT_SYMBOL(_mcount);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
unsigned long frame_pointer)
{
unsigned long return_hooker = (unsigned long)&return_to_handler;
struct ftrace_graph_ent trace;
unsigned long old;
int err;
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
return;
old = *parent;
trace.func = self_addr;
trace.depth = current->curr_ret_stack + 1;
/* Only trace if the calling function expects to */
if (!ftrace_graph_entry(&trace))
return;
err = ftrace_push_return_trace(old, self_addr, &trace.depth,
frame_pointer, NULL);
if (err == -EBUSY)
return;
*parent = return_hooker;
}
noinline void ftrace_graph_caller(void)
{
unsigned long *parent_ip =
(unsigned long *)(__builtin_frame_address(2) - 4);
unsigned long selfpc =
(unsigned long)(__builtin_return_address(1) - MCOUNT_INSN_SIZE);
unsigned long frame_pointer =
(unsigned long)__builtin_frame_address(3);
prepare_ftrace_return(parent_ip, selfpc, frame_pointer);
}
extern unsigned long ftrace_return_to_handler(unsigned long frame_pointer);
void __naked return_to_handler(void)
{
__asm__ __volatile__ (
/* save state needed by the ABI */
"smw.adm $r0,[$sp],$r1,#0x0 \n\t"
/* get original return address */
"move $r0, $fp \n\t"
"bal ftrace_return_to_handler\n\t"
"move $lp, $r0 \n\t"
/* restore state nedded by the ABI */
"lmw.bim $r0,[$sp],$r1,#0x0 \n\t");
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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