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105 lines
2.8 KiB
105 lines
2.8 KiB
/* |
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* OpenRISC unwinder.c |
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* |
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* Reusable arch specific api for unwinding stacks. |
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* |
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* Copyright (C) 2017 Stafford Horne <[email protected]> |
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* |
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* This file is licensed under the terms of the GNU General Public License |
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* version 2. This program is licensed "as is" without any warranty of any |
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* kind, whether express or implied. |
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*/ |
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#include <linux/sched/task_stack.h> |
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#include <linux/kernel.h> |
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#include <asm/unwinder.h> |
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#ifdef CONFIG_FRAME_POINTER |
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struct or1k_frameinfo { |
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unsigned long *fp; |
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unsigned long ra; |
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unsigned long top; |
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}; |
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/* |
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* Verify a frameinfo structure. The return address should be a valid text |
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* address. The frame pointer may be null if its the last frame, otherwise |
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* the frame pointer should point to a location in the stack after the the |
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* top of the next frame up. |
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*/ |
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static inline int or1k_frameinfo_valid(struct or1k_frameinfo *frameinfo) |
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{ |
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return (frameinfo->fp == NULL || |
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(!kstack_end(frameinfo->fp) && |
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frameinfo->fp > &frameinfo->top)) && |
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__kernel_text_address(frameinfo->ra); |
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} |
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/* |
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* Create a stack trace doing scanning which is frame pointer aware. We can |
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* get reliable stack traces by matching the previously found frame |
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* pointer with the top of the stack address every time we find a valid |
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* or1k_frameinfo. |
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* |
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* Ideally the stack parameter will be passed as FP, but it can not be |
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* guaranteed. Therefore we scan each address looking for the first sign |
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* of a return address. |
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* |
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* The OpenRISC stack frame looks something like the following. The |
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* location SP is held in r1 and location FP is held in r2 when frame pointers |
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* enabled. |
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* |
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* SP -> (top of stack) |
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* - (callee saved registers) |
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* - (local variables) |
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* FP-8 -> previous FP \ |
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* FP-4 -> return address |- or1k_frameinfo |
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* FP -> (previous top of stack) / |
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*/ |
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void unwind_stack(void *data, unsigned long *stack, |
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void (*trace)(void *data, unsigned long addr, int reliable)) |
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{ |
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unsigned long *next_fp = NULL; |
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struct or1k_frameinfo *frameinfo = NULL; |
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int reliable = 0; |
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while (!kstack_end(stack)) { |
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frameinfo = container_of(stack, |
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struct or1k_frameinfo, |
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top); |
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if (__kernel_text_address(frameinfo->ra)) { |
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if (or1k_frameinfo_valid(frameinfo) && |
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(next_fp == NULL || |
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next_fp == &frameinfo->top)) { |
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reliable = 1; |
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next_fp = frameinfo->fp; |
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} else |
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reliable = 0; |
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trace(data, frameinfo->ra, reliable); |
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} |
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stack++; |
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} |
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} |
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#else /* CONFIG_FRAME_POINTER */ |
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/* |
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* Create a stack trace by doing a simple scan treating all text addresses |
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* as return addresses. |
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*/ |
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void unwind_stack(void *data, unsigned long *stack, |
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void (*trace)(void *data, unsigned long addr, int reliable)) |
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{ |
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unsigned long addr; |
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while (!kstack_end(stack)) { |
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addr = *stack++; |
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if (__kernel_text_address(addr)) |
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trace(data, addr, 0); |
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} |
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} |
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#endif /* CONFIG_FRAME_POINTER */ |
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