backtrace.c

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/*
 * S390 Version
 *   Copyright IBM Corp. 2005
 *   Author(s): Andreas Krebbel <[email protected]>
 */

#include <linux/oprofile.h>

#include <asm/processor.h> /* for struct stack_frame */

static unsigned long
__show_trace(unsigned int *depth, unsigned long sp,
         unsigned long low, unsigned long high)
{
    struct stack_frame *sf;
    struct pt_regs *regs;

    while (*depth) {
        sp = sp & PSW_ADDR_INSN;
        if (sp < low || sp > high - sizeof(*sf))
            return sp;
        sf = (struct stack_frame *) sp;
        (*depth)--;
        oprofile_add_trace(sf->gprs[8] & PSW_ADDR_INSN);

        /* Follow the backchain.  */
        while (*depth) {
            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;
            (*depth)--;
            oprofile_add_trace(sf->gprs[8] & PSW_ADDR_INSN);

        }

        if (*depth == 0)
            break;

        /* 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;
        (*depth)--;
        oprofile_add_trace(sf->gprs[8] & PSW_ADDR_INSN);
        low = sp;
        sp = regs->gprs[15];
    }
    return sp;
}

void s390_backtrace(struct pt_regs * const regs, unsigned int depth)
{
    unsigned long head;
    struct stack_frame* head_sf;

    if (user_mode(regs))
        return;

    head = regs->gprs[15];
    head_sf = (struct stack_frame*)head;

    if (!head_sf->back_chain)
        return;

    head = head_sf->back_chain;

    head = __show_trace(&depth, head, S390_lowcore.async_stack - ASYNC_SIZE,
                S390_lowcore.async_stack);

    __show_trace(&depth, head, S390_lowcore.thread_info,
             S390_lowcore.thread_info + THREAD_SIZE);
}