forked from luck/tmp_suning_uos_patched
f8a9a269c2
Terminating the last trace entry with ULONG_MAX is a completely pointless exercise and none of the consumers can rely on it because it's inconsistently implemented across architectures. In fact quite some of the callers remove the entry and adjust stack_trace.nr_entries afterwards. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Potapenko <glider@google.com> Cc: Guan Xuetao <gxt@pku.edu.cn> Link: https://lkml.kernel.org/r/20190410103644.036077691@linutronix.de
131 lines
3.2 KiB
C
131 lines
3.2 KiB
C
/*
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* linux/arch/unicore32/kernel/stacktrace.c
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*
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* Code specific to PKUnity SoC and UniCore ISA
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*
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* Copyright (C) 2001-2010 GUAN Xue-tao
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/sched/debug.h>
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#include <linux/stacktrace.h>
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#include <asm/stacktrace.h>
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#if defined(CONFIG_FRAME_POINTER)
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/*
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* Unwind the current stack frame and store the new register values in the
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* structure passed as argument. Unwinding is equivalent to a function return,
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* hence the new PC value rather than LR should be used for backtrace.
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*
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* With framepointer enabled, a simple function prologue looks like this:
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* mov ip, sp
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* stmdb sp!, {fp, ip, lr, pc}
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* sub fp, ip, #4
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*
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* A simple function epilogue looks like this:
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* ldm sp, {fp, sp, pc}
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*
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* Note that with framepointer enabled, even the leaf functions have the same
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* prologue and epilogue, therefore we can ignore the LR value in this case.
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*/
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int notrace unwind_frame(struct stackframe *frame)
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{
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unsigned long high, low;
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unsigned long fp = frame->fp;
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/* only go to a higher address on the stack */
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low = frame->sp;
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high = ALIGN(low, THREAD_SIZE);
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/* check current frame pointer is within bounds */
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if (fp < (low + 12) || fp + 4 >= high)
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return -EINVAL;
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/* restore the registers from the stack frame */
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frame->fp = *(unsigned long *)(fp - 12);
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frame->sp = *(unsigned long *)(fp - 8);
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frame->pc = *(unsigned long *)(fp - 4);
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return 0;
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}
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#endif
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void notrace walk_stackframe(struct stackframe *frame,
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int (*fn)(struct stackframe *, void *), void *data)
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{
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while (1) {
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int ret;
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if (fn(frame, data))
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break;
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ret = unwind_frame(frame);
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if (ret < 0)
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break;
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}
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}
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EXPORT_SYMBOL(walk_stackframe);
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#ifdef CONFIG_STACKTRACE
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struct stack_trace_data {
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struct stack_trace *trace;
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unsigned int no_sched_functions;
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unsigned int skip;
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};
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static int save_trace(struct stackframe *frame, void *d)
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{
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struct stack_trace_data *data = d;
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struct stack_trace *trace = data->trace;
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unsigned long addr = frame->pc;
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if (data->no_sched_functions && in_sched_functions(addr))
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return 0;
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if (data->skip) {
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data->skip--;
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return 0;
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}
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trace->entries[trace->nr_entries++] = addr;
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return trace->nr_entries >= trace->max_entries;
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}
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void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
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{
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struct stack_trace_data data;
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struct stackframe frame;
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data.trace = trace;
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data.skip = trace->skip;
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if (tsk != current) {
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data.no_sched_functions = 1;
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frame.fp = thread_saved_fp(tsk);
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frame.sp = thread_saved_sp(tsk);
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frame.lr = 0; /* recovered from the stack */
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frame.pc = thread_saved_pc(tsk);
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} else {
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register unsigned long current_sp asm("sp");
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data.no_sched_functions = 0;
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frame.fp = (unsigned long)__builtin_frame_address(0);
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frame.sp = current_sp;
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frame.lr = (unsigned long)__builtin_return_address(0);
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frame.pc = (unsigned long)save_stack_trace_tsk;
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}
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walk_stackframe(&frame, save_trace, &data);
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}
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void save_stack_trace(struct stack_trace *trace)
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{
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save_stack_trace_tsk(current, trace);
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}
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EXPORT_SYMBOL_GPL(save_stack_trace);
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#endif
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