107 lines
2.5 KiB
C
107 lines
2.5 KiB
C
/*
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* Copyright (c) 2023 KNS Group LLC (YADRO)
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <zephyr/kernel.h>
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static bool valid_stack(uintptr_t addr, k_tid_t current)
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{
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return current->stack_info.start <= addr &&
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addr < current->stack_info.start + current->stack_info.size;
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}
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static inline bool in_text_region(uintptr_t addr)
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{
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extern uintptr_t __text_region_start, __text_region_end;
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return (addr >= (uintptr_t)&__text_region_start) && (addr < (uintptr_t)&__text_region_end);
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}
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/*
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* This function use frame pointers to unwind stack and get trace of return addresses.
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* Return addresses are translated in corresponding function's names using .elf file.
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* So we get function call trace
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*/
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size_t arch_perf_current_stack_trace(uintptr_t *buf, size_t size)
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{
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if (size < 2U) {
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return 0;
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}
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size_t idx = 0;
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/*
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* In riscv (arch/riscv/core/isr.S) ra, ip($mepc) and fp($s0) are saved
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* at the beginning of _isr_wrapper in order, specified by z_arch_esf_t.
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* Then, before calling interruption handler, core switch $sp to
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* _current_cpu->irq_stack and save $sp with offset -16 on irq stack
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*
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* The following lines lines do the reverse things to get ra, ip anf fp
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* from thread stack
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*/
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const struct arch_esf * const esf =
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*((struct arch_esf **)(((uintptr_t)_current_cpu->irq_stack) - 16));
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/*
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* $s0 is used as frame pointer.
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*
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* stack frame in memory (commonly):
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* (addresses growth up)
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* ....
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* [-] <- $fp($s0) (curr)
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* $ra
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* $fp($s0) (next)
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* ....
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*
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* If function do not call any other function, compiller may not save $ra,
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* then stack frame will be:
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* ....
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* [-] <- $fp($s0) (curr)
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* $fp($s0) (next)
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* ....
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*
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*/
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void **fp = (void **)esf->s0;
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void **new_fp = (void **)fp[-1];
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buf[idx++] = (uintptr_t)esf->mepc;
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/*
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* During function prologue and epilogue fp is equal to fp of
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* previous function stack frame, it looks like second function
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* from top is missed.
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* So saving $ra will help in case when irq occurred in
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* function prologue or epilogue.
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*/
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buf[idx++] = (uintptr_t)esf->ra;
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if (valid_stack((uintptr_t)new_fp, _current)) {
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fp = new_fp;
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}
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while (valid_stack((uintptr_t)fp, _current)) {
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if (idx >= size) {
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return 0;
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}
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if (!in_text_region((uintptr_t)fp[-1])) {
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break;
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}
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buf[idx++] = (uintptr_t)fp[-1];
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new_fp = (void **)fp[-2];
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/*
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* anti-infinity-loop if
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* new_fp can't be smaller than fp, cause the stack is growing down
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* and trace moves deeper into the stack
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*/
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if (new_fp <= fp) {
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break;
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}
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fp = new_fp;
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}
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return idx;
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}
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