stacktrace.c

Go to the documentation of this file.

/*
 * Stack trace management functions
 *
 *  Copyright IBM Corp. 2006
 *  Author(s): Heiko Carstens <[email protected]>
 */

#include <linux/sched.h>
#include <linux/stacktrace.h>
#include <linux/kallsyms.h>
#include <linux/module.h>

static unsigned long save_context_stack(struct stack_trace *trace,
                    unsigned long sp,
                    unsigned long low,
                    unsigned long high,
                    int savesched)
{
    struct stack_frame *sf;
    struct pt_regs *regs;
    unsigned long addr;

    while(1) {
        sp &= PSW_ADDR_INSN;
        if (sp < low || sp > high)
            return sp;
        sf = (struct stack_frame *)sp;
        while(1) {
            addr = sf->gprs[8] & PSW_ADDR_INSN;
            if (!trace->skip)
                trace->entries[trace->nr_entries++] = addr;
            else
                trace->skip--;
            if (trace->nr_entries >= trace->max_entries)
                return sp;
            low = sp;
            sp = sf->back_chain & PSW_ADDR_INSN;
            if (!sp)
                break;
            if (sp <= low || sp > high - sizeof(*sf))
                return sp;
            sf = (struct stack_frame *)sp;
        }
        /* Zero backchain detected, check for interrupt frame. */
        sp = (unsigned long)(sf + 1);
        if (sp <= low || sp > high - sizeof(*regs))
            return sp;
        regs = (struct pt_regs *)sp;
        addr = regs->psw.addr & PSW_ADDR_INSN;
        if (savesched || !in_sched_functions(addr)) {
            if (!trace->skip)
                trace->entries[trace->nr_entries++] = addr;
            else
                trace->skip--;
        }
        if (trace->nr_entries >= trace->max_entries)
            return sp;
        low = sp;
        sp = regs->gprs[15];
    }
}

void save_stack_trace(struct stack_trace *trace)
{
    register unsigned long sp asm ("15");
    unsigned long orig_sp, new_sp;

    orig_sp = sp & PSW_ADDR_INSN;
    new_sp = save_context_stack(trace, orig_sp,
                    S390_lowcore.panic_stack - PAGE_SIZE,
                    S390_lowcore.panic_stack, 1);
    if (new_sp != orig_sp)
        return;
    new_sp = save_context_stack(trace, new_sp,
                    S390_lowcore.async_stack - ASYNC_SIZE,
                    S390_lowcore.async_stack, 1);
    if (new_sp != orig_sp)
        return;
    save_context_stack(trace, new_sp,
               S390_lowcore.thread_info,
               S390_lowcore.thread_info + THREAD_SIZE, 1);
}
EXPORT_SYMBOL_GPL(save_stack_trace);

void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
    unsigned long sp, low, high;

    sp = tsk->thread.ksp & PSW_ADDR_INSN;
    low = (unsigned long) task_stack_page(tsk);
    high = (unsigned long) task_pt_regs(tsk);
    save_context_stack(trace, sp, low, high, 0);
    if (trace->nr_entries < trace->max_entries)
        trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);