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#include <linux/sched.h>
#include <linux/ftrace.h>
#include <asm/ptrace.h>
#include <asm/bitops.h>
#include <asm/stacktrace.h>
#include <asm/unwind.h>
unsigned long unwind_get_return_address(struct unwind_state *state)
{
unsigned long addr;
if (unwind_done(state))
return 0;
addr = READ_ONCE_NOCHECK(*state->sp);
return ftrace_graph_ret_addr(state->task, &state->graph_idx,
addr, state->sp);
}
EXPORT_SYMBOL_GPL(unwind_get_return_address);
unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
{
return NULL;
}
bool unwind_next_frame(struct unwind_state *state)
{
struct stack_info *info = &state->stack_info;
if (unwind_done(state))
return false;
do {
for (state->sp++; state->sp < info->end; state->sp++) {
unsigned long addr = READ_ONCE_NOCHECK(*state->sp);
if (__kernel_text_address(addr))
return true;
}
state->sp = PTR_ALIGN(info->next_sp, sizeof(long));
} while (!get_stack_info(state->sp, state->task, info,
&state->stack_mask));
return false;
}
EXPORT_SYMBOL_GPL(unwind_next_frame);
void __unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs, unsigned long *first_frame)
{
memset(state, 0, sizeof(*state));
state->task = task;
state->sp = PTR_ALIGN(first_frame, sizeof(long));
get_stack_info(first_frame, state->task, &state->stack_info,
&state->stack_mask);
/*
* The caller can provide the address of the first frame directly
* (first_frame) or indirectly (regs->sp) to indicate which stack frame
* to start unwinding at. Skip ahead until we reach it.
*/
if (!unwind_done(state) &&
(!on_stack(&state->stack_info, first_frame, sizeof(long)) ||
!__kernel_text_address(*first_frame)))
unwind_next_frame(state);
}
EXPORT_SYMBOL_GPL(__unwind_start);
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