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/*

 * arch/s390/kernel/stacktrace.c

 *

 * Stack trace management functions

 *

 *  Copyright (C) IBM Corp. 2006

 *  Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>

 */

#include <linux/sched.h>

#include <linux/stacktrace.h>

#include <linux/kallsyms.h>

static unsigned long save_context_stack(struct stack_trace *trace,

                                        unsigned long sp,

                                        unsigned long low,

                                        unsigned long high)

{

        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 (!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);

        if (new_sp != orig_sp)

                return;

        new_sp = save_context_stack(trace, new_sp,

                                    S390_lowcore.async_stack - ASYNC_SIZE,

                                    S390_lowcore.async_stack);

        if (new_sp != orig_sp)

                return;

        save_context_stack(trace, new_sp,

                           S390_lowcore.thread_info,

                           S390_lowcore.thread_info + THREAD_SIZE);

}