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| 2 | |
| 3 | * arch/sh/kernel/return_address.c
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| 4 | *
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| 5 | * Copyright (C) 2009 Matt Fleming
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| 6 | * Copyright (C) 2009 Paul Mundt
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| 7 |
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| 8 | #include <linux/kernel.h>
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| 9 | #include <linux/module.h>
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| 10 |
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| 11 | #include <asm/dwarf.h>
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| 12 | #include <asm/ftrace.h>
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| 13 |
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| 14 | #ifdef CONFIG_DWARF_UNWINDER
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| 15 |
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| 16 | void *return_address(unsigned int depth)
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| 17 | {
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| 18 | struct dwarf_frame *frame;
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| 19 | unsigned long ra;
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| 20 | int i;
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| 21 |
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| 22 | for (i = 0, frame = NULL, ra = 0; i <= depth; i++) {
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| 23 | struct dwarf_frame *tmp;
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| 24 |
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| 25 | tmp = dwarf_unwind_stack(ra, frame);
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| 26 | if (!tmp)
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| 27 | return NULL;
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| 28 |
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| 29 | if (frame)
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| 30 | dwarf_free_frame(frame);
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| 31 |
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| 32 | frame = tmp;
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| 33 |
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| 34 | if (!frame || !frame->return_addr)
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| 35 | break;
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| 36 |
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| 37 | ra = frame->return_addr;
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| 38 | }
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| 39 |
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| 40 |
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| 41 | WARN_ON(i != depth + 1);
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| 42 |
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| 43 | if (frame)
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| 44 | dwarf_free_frame(frame);
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| 45 |
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| 46 | return (void *)ra;
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| 47 | }
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| 48 |
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| 49 | #else
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| 50 |
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| 51 | void *return_address(unsigned int depth)
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| 52 | {
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| 53 | return NULL;
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| 54 | }
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| 55 |
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| 56 | #endif
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| 57 |
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| 58 | EXPORT_SYMBOL_GPL(return_address);
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