stacktrace.c

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#include <linux/sched.h>
#include <linux/stacktrace.h>
#include <linux/thread_info.h>
#include <linux/ftrace.h>
#include <linux/export.h>
#include <asm/ptrace.h>
#include <asm/stacktrace.h>

#include "kstack.h"

static void __save_stack_trace(struct thread_info *tp,
                   struct stack_trace *trace,
                   bool skip_sched)
{
    unsigned long ksp, fp;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
    struct task_struct *t;
    int graph = 0;
#endif

    if (tp == current_thread_info()) {
        stack_trace_flush();
        __asm__ __volatile__("mov %%fp, %0" : "=r" (ksp));
    } else {
        ksp = tp->ksp;
    }

    fp = ksp + STACK_BIAS;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
    t = tp->task;
#endif
    do {
        struct sparc_stackf *sf;
        struct pt_regs *regs;
        unsigned long pc;

        if (!kstack_valid(tp, fp))
            break;

        sf = (struct sparc_stackf *) fp;
        regs = (struct pt_regs *) (sf + 1);

        if (kstack_is_trap_frame(tp, regs)) {
            if (!(regs->tstate & TSTATE_PRIV))
                break;
            pc = regs->tpc;
            fp = regs->u_regs[UREG_I6] + STACK_BIAS;
        } else {
            pc = sf->callers_pc;
            fp = (unsigned long)sf->fp + STACK_BIAS;
        }

        if (trace->skip > 0)
            trace->skip--;
        else if (!skip_sched || !in_sched_functions(pc)) {
            trace->entries[trace->nr_entries++] = pc;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
            if ((pc + 8UL) == (unsigned long) &return_to_handler) {
                int index = t->curr_ret_stack;
                if (t->ret_stack && index >= graph) {
                    pc = t->ret_stack[index - graph].ret;
                    if (trace->nr_entries <
                        trace->max_entries)
                        trace->entries[trace->nr_entries++] = pc;
                    graph++;
                }
            }
#endif
        }
    } while (trace->nr_entries < trace->max_entries);
}

void save_stack_trace(struct stack_trace *trace)
{
    __save_stack_trace(current_thread_info(), trace, false);
}
EXPORT_SYMBOL_GPL(save_stack_trace);

void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
    struct thread_info *tp = task_thread_info(tsk);

    __save_stack_trace(tp, trace, true);
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);