94 lines
2.5 KiB
C
94 lines
2.5 KiB
C
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#include <linux/sched.h>
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#include <asm/ptrace.h>
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#include <asm/bitops.h>
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#include <asm/stacktrace.h>
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#include <asm/unwind.h>
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#define FRAME_HEADER_SIZE (sizeof(long) * 2)
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unsigned long unwind_get_return_address(struct unwind_state *state)
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{
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unsigned long addr;
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unsigned long *addr_p = unwind_get_return_address_ptr(state);
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if (unwind_done(state))
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return 0;
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addr = ftrace_graph_ret_addr(state->task, &state->graph_idx, *addr_p,
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addr_p);
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return __kernel_text_address(addr) ? addr : 0;
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}
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EXPORT_SYMBOL_GPL(unwind_get_return_address);
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static bool update_stack_state(struct unwind_state *state, void *addr,
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size_t len)
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{
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struct stack_info *info = &state->stack_info;
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/*
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* If addr isn't on the current stack, switch to the next one.
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*
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* We may have to traverse multiple stacks to deal with the possibility
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* that 'info->next_sp' could point to an empty stack and 'addr' could
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* be on a subsequent stack.
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*/
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while (!on_stack(info, addr, len))
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if (get_stack_info(info->next_sp, state->task, info,
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&state->stack_mask))
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return false;
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return true;
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}
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bool unwind_next_frame(struct unwind_state *state)
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{
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unsigned long *next_bp;
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if (unwind_done(state))
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return false;
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next_bp = (unsigned long *)*state->bp;
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/* make sure the next frame's data is accessible */
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if (!update_stack_state(state, next_bp, FRAME_HEADER_SIZE))
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return false;
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/* move to the next frame */
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state->bp = next_bp;
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return true;
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}
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EXPORT_SYMBOL_GPL(unwind_next_frame);
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void __unwind_start(struct unwind_state *state, struct task_struct *task,
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struct pt_regs *regs, unsigned long *first_frame)
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{
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memset(state, 0, sizeof(*state));
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state->task = task;
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/* don't even attempt to start from user mode regs */
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if (regs && user_mode(regs)) {
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state->stack_info.type = STACK_TYPE_UNKNOWN;
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return;
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}
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/* set up the starting stack frame */
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state->bp = get_frame_pointer(task, regs);
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/* initialize stack info and make sure the frame data is accessible */
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get_stack_info(state->bp, state->task, &state->stack_info,
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&state->stack_mask);
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update_stack_state(state, state->bp, FRAME_HEADER_SIZE);
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/*
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* The caller can provide the address of the first frame directly
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* (first_frame) or indirectly (regs->sp) to indicate which stack frame
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* to start unwinding at. Skip ahead until we reach it.
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*/
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while (!unwind_done(state) &&
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(!on_stack(&state->stack_info, first_frame, sizeof(long)) ||
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state->bp < first_frame))
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unwind_next_frame(state);
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}
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EXPORT_SYMBOL_GPL(__unwind_start);
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