/*      $NetBSD: kgdb_machdep.c,v 1.6 2022/08/22 13:57:24 hannken Exp $ */

/*
 * Copyright (c) 1997, 2017 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Copyright (c) 1996 Matthias Pfaller.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kgdb_machdep.c,v 1.6 2022/08/22 13:57:24 hannken Exp $");

#include "opt_ddb.h"

/*
 * Machine-dependent functions for remote KGDB.  Originally written
 * for NetBSD/pc532 by Matthias Pfaller.  Modified for NetBSD/i386
 * by Jason R. Thorpe. Modified for NetBSD/amd64 by Frank van der Linden.
 */

#include <sys/param.h>
#include <sys/kgdb.h>
#include <sys/systm.h>

#include <machine/pmap_private.h>
#include <machine/pte.h>
#include <machine/trap.h>

/*
 * Determine if the memory at va..(va+len) is valid.
 */
int
kgdb_acc(vaddr_t va, size_t len)
{
        vaddr_t last_va;
        pt_entry_t *pte;

        last_va = va + len;
        va  &= ~PGOFSET;
        last_va &= ~PGOFSET;

        do {
                if (va < VM_MIN_KERNEL_ADDRESS)
                        pte = vtopte(va);
                else
                        pte = kvtopte(va);
                if ((*pte & PTE_P) == 0)
                        return 0;
                if (*pte & PTE_PS)
                        va = (va & PTE_LGFRAME) + NBPD_L2;
                else
                        va += PAGE_SIZE;
        } while (va < last_va);

        return 1;
}

void
kgdb_entry_notice(int type, db_regs_t *regs)
{
        if (type == T_NMI)
                printf("NMI ... going to debugger\n");
}

/*
 * Translate a trap number into a unix compatible signal value.
 * (gdb only understands unix signal numbers).
 */
int
kgdb_signal(int type)
{
        switch (type) {
        case T_NMI:
                return SIGINT;

        case T_ALIGNFLT:
                return SIGILL;

        case T_BPTFLT:
        case T_TRCTRAP:
                return SIGTRAP;

        case T_ASTFLT:
        case T_DOUBLEFLT:
                return SIGEMT;

        case T_ARITHTRAP:
        case T_DIVIDE:
        case T_OFLOW:
        case T_DNA:
        case T_FPOPFLT:
                return SIGFPE;

        case T_PRIVINFLT:
        case T_PROTFLT:
        case T_PAGEFLT:
        case T_TSSFLT:
        case T_SEGNPFLT:
        case T_STKFLT:
                return SIGSEGV;

        case T_BOUND:
                return SIGURG;

        default:
                return SIGEMT;
        }
}

/*
 * Translate the values stored in the kernel regs struct to the format
 * understood by gdb.
 */
void
kgdb_getregs(db_regs_t *regs, kgdb_reg_t *gdb_regs)
{
#ifdef __x86_64__
        gdb_regs[ 0] = regs->tf_rax;
        gdb_regs[ 1] = regs->tf_rbx;
        gdb_regs[ 2] = regs->tf_rcx;
        gdb_regs[ 3] = regs->tf_rdx;
        gdb_regs[ 4] = regs->tf_rsi;
        gdb_regs[ 5] = regs->tf_rdi;
        gdb_regs[ 6] = regs->tf_rbp;
        gdb_regs[ 7] = regs->tf_rsp;
        gdb_regs[ 8] = regs->tf_r8;
        gdb_regs[ 9] = regs->tf_r9;
        gdb_regs[10] = regs->tf_r10;
        gdb_regs[11] = regs->tf_r11;
        gdb_regs[12] = regs->tf_r12;
        gdb_regs[13] = regs->tf_r13;
        gdb_regs[14] = regs->tf_r14;
        gdb_regs[15] = regs->tf_r15;
        gdb_regs[16] = regs->tf_rip;
        gdb_regs[17] = regs->tf_rflags;
        gdb_regs[18] = regs->tf_cs;
        gdb_regs[19] = regs->tf_ss;
#else
        gdb_regs[ 0] = regs->tf_eax;
        gdb_regs[ 1] = regs->tf_ecx;
        gdb_regs[ 2] = regs->tf_edx;
        gdb_regs[ 3] = regs->tf_ebx;
        gdb_regs[ 5] = regs->tf_ebp;
        gdb_regs[ 6] = regs->tf_esi;
        gdb_regs[ 7] = regs->tf_edi;
        gdb_regs[ 8] = regs->tf_eip;
        gdb_regs[ 9] = regs->tf_eflags;
        gdb_regs[10] = regs->tf_cs;
        gdb_regs[12] = regs->tf_ds;
        gdb_regs[13] = regs->tf_es;
        gdb_regs[14] = regs->tf_fs;
        gdb_regs[15] = regs->tf_gs;

        if (KERNELMODE(regs->tf_cs)) {
                /*
                 * Kernel mode - esp and ss not saved.
                 */
                gdb_regs[ 4] = (kgdb_reg_t)&regs->tf_esp; /* kernel stack
                                                             pointer */
                gdb_regs[11] = x86_getss();
        }
#endif
}

/*
 * Reverse the above.
 */
void
kgdb_setregs(db_regs_t *regs, kgdb_reg_t *gdb_regs)
{
#ifdef __x86_64__
        regs->tf_rax = gdb_regs[ 0];
        regs->tf_rbx = gdb_regs[ 1];
        regs->tf_rcx = gdb_regs[ 2];
        regs->tf_rdx = gdb_regs[ 3];
        regs->tf_rsi = gdb_regs[ 4];
        regs->tf_rdi = gdb_regs[ 5];
        regs->tf_rbp = gdb_regs[ 6];
        regs->tf_rsp = gdb_regs[ 7];
        regs->tf_r8  = gdb_regs[ 8];
        regs->tf_r9  = gdb_regs[ 9];
        regs->tf_r10 = gdb_regs[10];
        regs->tf_r11 = gdb_regs[11];
        regs->tf_r12 = gdb_regs[12];
        regs->tf_r13 = gdb_regs[13];
        regs->tf_r14 = gdb_regs[14];
        regs->tf_r15 = gdb_regs[15];
        regs->tf_rip = gdb_regs[16];
        regs->tf_rflags = gdb_regs[17];
        regs->tf_cs  = gdb_regs[18];
        regs->tf_ss  = gdb_regs[19];
#else
        regs->tf_eax    = gdb_regs[ 0];
        regs->tf_ecx    = gdb_regs[ 1];
        regs->tf_edx    = gdb_regs[ 2];
        regs->tf_ebx    = gdb_regs[ 3];
        regs->tf_ebp    = gdb_regs[ 5];
        regs->tf_esi    = gdb_regs[ 6];
        regs->tf_edi    = gdb_regs[ 7];
        regs->tf_eip    = gdb_regs[ 8];
        regs->tf_eflags = gdb_regs[ 9];
        regs->tf_cs     = gdb_regs[10];
        regs->tf_ds     = gdb_regs[12];
        regs->tf_es     = gdb_regs[13];

        if (KERNELMODE(regs->tf_cs) == 0) {
                /*
                 * Trapped in user mode - restore esp and ss.
                 */
                regs->tf_esp = gdb_regs[ 4];
                regs->tf_ss  = gdb_regs[11];
        }
#endif
}

/*
 * Trap into kgdb to wait for debugger to connect,
 * noting on the console why nothing else is going on.
 */
void
kgdb_connect(int verbose)
{
        if (kgdb_dev == NODEV)
                return;

        if (verbose)
                printf("kgdb waiting...");

        breakpoint();

        if (verbose)
                printf("connected.\n");

        kgdb_debug_panic = 1;
}

/*
 * Decide what to do on panic.
 * (This is called by panic, like Debugger())
 */
void
kgdb_panic(void)
{
        if (kgdb_dev != NODEV && kgdb_debug_panic) {
                printf("entering kgdb\n");
                kgdb_connect(kgdb_active == 0);
        }
}